The CS 505-3 is a semi-automatic turntable with full-size suspended sub-chassis that effectively protects the unit's drive mechanism from external vibrations. The 505 features a straight, tubular, high torsion aluminium tonearm measuring just over 22cm in length, and a low-resonance, non-magnetic platter that is driven by a 16-pole-synchronous Dual motor and belt-drive mechanism. The turntable's basic design and layout have been tried and tested and it can, at the time of writing this, still be purchased new, in the form of the revised Dual CS 505-4 that is built by Alfred Fehrenbacher’s Dual Phono GmbH, in the company’s original home town of St. Georgen. The factory is located deep in the Black Forrest, a region famous for its customs, folklore, and precision clockwork mechanisms.

The CS 505-3’s semi-automatic drive unit is easy to operate. Moving the tonearm in position over the record will automatically set the platter in motion at the pre-selected speed. The tonearm initially remains in raised position, until a lever is flipped to gently put it down. The platter stops spinning automatically when the stylus reaches the end of a record, and the tonearm is automatically raised once again. On our unit, there was a mild plopping sound as the turntable shut off. It was probably caused by the tonearm lifting rather abruptly. However, this is just meant as an observation and not as complaint. I was at first a little surprised by the phenomenon, but it never really bothered me. The tonearm remains raised and then needs to be returned to the start position by hand.

In 1987, the first CS 505-3 sold for just under 500.00 DM, (96.00 GBP) and modern customers of its successor, the CS 505-4, are once again asked to pay the same in euros. This might seem a bit pricey in both cases. However, having listened to the CS 505-3 perform in our living room for some days, I feel it is still quite a good deal. More so than our Sansui 525, the Dual with its original ULM 65 E cartridge and elliptical diamond stylus had me listening to one record after another, enjoying its charming sincerity and musical drive. But what was it exactly that enthralled me?

I have always been fond of the Thorens 318 turntable design for getting the balance between technical sophistication and elegant understatement right. As if its engineers had taken their pointers from Japanese furniture design, more so than the tech-savvy Japanese electronics industry ever had by itself. And I found very similar design choices to be present in the Dual CS 505-3, especially in combination with its black, wooden plinth. Sadly, most turntables of those days still featured permanent interconnects which made it difficult to make adjustments to the sonic balance by means of connection alone. I would have loved to attach my favourite silver solid-core cables, of course.

The ULM 65 E was the original Dual cartridge for the 505-3 to which an Ortofon-made, bonded, elliptical, diamond stylus was attached. The ULM was not a High End cartridge and only offered a limited frequency bandwidth of 10-25,000 Hertz. Channel separation was also not impressive at 20dB. And still, it offered considerable output rated at 4 mV. This suggested that it could play loud. The combination of cartridge, stylus, and drive unit worked quite well, but also showed some obvious weaknesses that one could find either off-putting or endearing, case by case.

I first whipped out a bad pressing of Norah Jones’ album “Come Away With Me”, and was disappointed that the Dual’s elliptical stylus brought out lots of sibilance that our Sansui 505 with AT VM 95 ML cartridge had so well hidden. This was not surprising perhaps, considering how deeply the micro-linear stylus of the AT could reach into the groove. The record sounded worse the closer the stylus moved to the centre. I next put on Stacey Kent’s album “I Know I Dream” and was surprised by a pleasant forward drive and rhythm that instantly made me tap my foot. I loved how Stacey’s voice seemed stronger, more direct, and also more engaging than I was used to. The music sounded slightly less delicate and did not reveal transients so well, but I did not miss this somehow.

The Dual’s ferocious and rhythmically engaging character had me smiling several times though the album. “I Know I Dream” being a good pressing, I had no issues with sibilance whatsoever. I noticed that voices were perhaps not revealed in the most authentic fashion and could sound a little “vintage” at times. They did not manage to free themselves from the instruments as much as I was used to, but, in the overall scheme of things, were endearing and lots of fun to listen to. If I had first thought about replacing the permanent interconnects with RCA jacks and upgrading the cartridge to a modern one with a more sophisticated stylus and better specs, every time that I came back listened I decided that any updates or upgrades could wait for another day.

Dual Company History

Christian and Joseph Steidinger started out as a manufacturer of clockwork and gramophone in the German Back Forest town of St. Georgen in 1907. The original company simply bore the family name, until they rebranded as Dual in 1927. The new company name was chosen in reference to their signature “dual-mode” power supplies in which they were true pioneers. Gramophones featuring these supplies, could either be powered by electricity or wound up for playback. Given their early success as a parts supplier, the Steidinger brothers began designing their own turntables.

During the German economic recovery that followed World War II, Dual became the largest producer of turntables in Europe. The German economy still enjoyed a price advantage over the rest of Europe and became known for high-quality once again. The Steidinger brothers had to hire up to 3,000 factory staff in order to keep up with the growing demand in entertainment devices in the world. Although Dual stretched the brand into other consumer electronics items, their turntables have remained iconic to this day.

The original Dual company went bankrupt in the early 1980s, following a decade of fierce competition from cheap and sophisticated imports from Japan. It was sold to the French electronics group Thomson SA. In 1988, the German company Schneider Rundfunkwerke AG bought Dual and then spun off the ‘Dual Phono GmbH’ to Alfred Fehrenbacher in 1993. Fehrenbacher produces Dual turntables 'Made in Germany', in the Black Forest town of St. Georgen, based on Dual’s original product lines until this very day.

Specifications

• Concept: suspended chassis, belt-drive
• Drive unit: 16-pole-synchronous motor
• Motor type: Dual SM 100-1
• Power consumption: 8 Watts
• Platter: non-magnetic, 1.2 kg
• Platter speeds: 33 1/2 and 45 RPM
• Pitch control: +/- 6%
• Wow and Flutter: 0.06% (WRMS 0.035%)
• Rumble: 52 dB (75% weighted)
• Channel separation: > 25 dB
• Channel balance: < 2 dB
• Arm length: 221 mm
• Offset angle: 24” 30’
• Tracking error: 0,15 “/cm
• Cartridge type: Dual ULM 65 E
• Cartridge system: moving magnet (MM)
• Stylus model: Ortofon DN 165 E
• Stylus type: elliptical diamond, bonded
• Tracking force: 15 mN (10-20 mN)
• Frequency range: 10-25,000 Hz
• Output: 4 mV / 5cms (1,000 Hz)
• Compliance: (h) 25 um/mN; (v) 30 um/mN
• Cartridge weight: 2.5 g
• Total capacitance: 160 pF
• Dimensions: (W) 437mm; (D) 369mm; (H) 138mm
• Weight: 6kg
• Country of manufacture: Germany
• Year(s): 1987-1990

I confess that, when the Dual CS 630Q was brand new on the shelves during the early 1980s, I would have walked straight past it, only to marvel at the cleaner-looking and trendier Technics decks from Japan. And the sad demise of the Dual company alongside many other German manufacturers of quality audio gear during that same period suggests that I was not alone in this assessment. 40 years later, I am sitting in our studio listening to one Dual turntable after another only to find that we had been utterly wrong in ignoring them. But, as so many times in the history of mankind, we are only smarter after the fact. 

During the 1980s, I was a teenager who had to stretch his allowance. More often than not, the money for HiFi gear came from my father. I mostly liked what my friends at school liked and what I was able afford. And this is also my excuse for purchasing a JVC AL-F3 as my first turntable, a mass-produced fully automatic direct-drive deck in plain black that can be found in mint condition for EUR 20.00 on ebay these days. Sellers of the Dual, on the other hand, usually for at least five times as much for their machine regardless of its condition. The trouble for Dual was that both turntables played music, and, as most people did not have the time, expertise, or equipment to compare the sound of turntables, the difference between the devices was a matter of marketing.

Japanese turntables often boasted the latest in technology, even before it was proven that this actually served the purpose better than established means. The S-shaped tonearm, turntable automation, and direct drive technology were cases in which German manufacturers were slow to follow the hype. The ULM tonearm, for example, did have excellent tonal and rhythmical characteristics on the Dual turntables. It was lightweight and torsion-free by which it could offer a forward drive that feels natural in music. Earlier idler wheel turntables and some well-engineered belt drives could very well compete with newer direct drive models and have remained favourite classics in many audiophile communities. And turntable automation has long since outlived itself, with modern decks often only having a single switch that is required to set the motor speed.

While Dual and other German manufacturers were seemingly out-classed in the 1980s, listening to the old decks perform suggested that they were still excellent choices when it came to their musicality, especially when played within a well-set-up system. The Dual CS 630Q that is presented here was handed down to my daughter from her recently deceased great aunt along with some other mid-Fi gear. Among the items were a Dual CV 1260 receiver (manufactured by Denon), a Dual CT 1260 tuner that was connected via 5-DIN plug, a Denon DCD 660 CD player, and two Canton GLX 100 bookshelf speakers that served to wrap up the ensemble. And, as the equipment had been sitting on a shelf for some years, I wanted to take the opportunity to run some routine checks and to present it in this forum.

Among these new devices, the CS 630Q interested me the most. I was already a great fan of the earlier and more elaborate Dual CS 721, for which I had built a walnut plinth for improved drive isolation. The CS 630Q was claimed to offer an improved signal-to-noise ratio paired with a more modern look. Where the famous Technics decks had a visible strobe light that reflected on iconic dots along the platter rim, Dual featured an accurate LCD display that interpreted the speed reading electronically. Dual’s legendary 4-point gimbal rested on adjustable tip bearings and served to stabilise the straight ultra-low-mass (ULM) tonearm well. The Start, Stop, and Lift buttons felt firm and gave great sensory feedback, and I also enjoyed the fact that the rotation speed adjustment was executed in the same manner. The record size was set separately via a selector switch located to the right of the tonearm. All in all, this seems like a well thought out design.

Modern users might object that the layer’s surface was not flat but instead showed all kinds of elevations and crevices. On the other hand, these oddities gave the CS 630Q its low silhouette and recognisable appearance. While I would not perhaps have thought of purchasing this Dual for myself, I did enjoy the look of it while it was perched on our makeshift audio sideboard with our experimental system in the studio. The system consisted of the Dual CV 1260 integrated amplifier and our Epicure 3.0 loudspeakers that had already shown that it worked very well together when playing from a CD source. I did have some difficulties adjusting the tracking force, because the automatic features got in the way of performing the action: Moving the arm towards the platter started the motor, and taking the Dual off the power grid automatically elevated the arm. There seemed to be no way out of this predicament, and I ended up adjusting the raised arm by also raising the tracking scales, which was probably not the most accurate method.

My reason for wanting to confirm and set the tracking force was due to an error that I could hear as sibilance on the inner LP tracks. The original ULM 66E cartridge had been replaced with an Ortofon DN 166 E which still seemed to work alright. I started my explorations with Fleetwood Mac’s 1977 album Rumours, of which I had the 2009 pressing. For a 70s album, Rumours offered a decent recording quality, as well as a wide range of songs that varied both tonally and rhythmically. Listening to the album with the CS 630Q for the first time, I also notice a humming that sounded like a grounding issue. I inspected the original cinch plugs and found that the metal grounding had corroded. The original plugs were already quite cleverly designed featuring a broken outer ring and a split centre prong. I decided to replace them with some decent modern standard Neutrik Rean, which were much less sophisticated in terms of sonic virtues, except for their debatable gold-plating, perhaps.

Looking at stylus options for the ULM/Ortofon cartridge, I came across the elliptical stylus that was now in place for about 75.00 EUR and then found the complete headshell with cartridge and Shibata stylus for just 14.00 EUR more. For my daughter learning to play records for the first time, the present stylus would do, but if this turntable had been mine for the keeping, I would have gone for the ‘Ortofon OM PRO S SH4 bl hs’ full package as advertised on the Thomann website, among others. For the time being, I set the tracking force with the scales on a CD case next to the rotating platter to 1.05g and the anti-skating to approximately half this value. I noticed that the Ortofon cartridge started to muffle the treble when the tracking force exceeded 1.25g. The original sibilance might have been caused by the anti-skating force exceeding the tracking force when, really, the opposite should be the case.

Fleetwood Mac’s album Rumours had started to sound just right, with a good amount of drive and swing. I enjoyed the amount of detail presented by the elliptical stylus, but I could also hear its limitations in terms of treble nuances. The higher the tone, the more it seemed to blend in with other high tones playing in the recording. This gave the music a robust and danceable presence rather than an audiophile experience. Bass on the other hand was tight and layered. I was able to get a good feel for the different materials of the drum set that stayed quite separate of the other instruments in “Don’t Stop Thinking About Tomorrow”. At the same time, I was missing some of the genuinely low bass frequencies that would have served the overall music impression well.

Considering the fact that the Dual CS 630Q already had a universal headshell mount, there was a wide range of cartridges available for the arm that were easy to swap and experiment with. While setting the tracking and anti-skating correctly improved the sibilance on the inner tracks, I was not able to eliminate it completely using the old stylus. The straight arm’s tracking error of 0.15° was, at least in my opinion, not large enough to explain the extent of the phenomenon. And it was sad as well, because “Songbird” was among my favourite tunes on the album. If I could only trust our kids and their friends (and the friends of their friends) to keep the stylus free from harm, I would be tempted to take that Ortofon SH4 offer.

Specifications

• Type: direct drive turntable
• Features: Fully automatic, with PLL quartz lock
• Microprocessor type: EDS 910
• Platter type: non-magnetic, removable
• Platter dimensions: (D) 304mm x (H) 10mm
• Platter weight: 1,170gr (700gr, without matt)
• Speeds: 33.33 and 45rpm
• Pitch-control: 30-36 RPM / 42-48 RPM
• Wow and flutter: +/- 0.035%
• Signal to noise ratio: 80dB, weighted
• Tonearm: distortion free ultra-low-mass tubular aluminium
• Gimbal: 4-point tip bearing
• Effective tonearm length: 211 mm
• Offset angle: 26°
• Tangential tracking error: 0,15°
• Headshell overhang: 19.5 mm
• Original cartridge: Dual ULM 66E
• Stylus-replacement: DN 166E
• Stylus-type: biradial diamond
• Tracking force: from 1 to 1.5g
• Frequency response: 10Hz to 28kHz
• Power consumption: 12,5 watts
• Compliance: (h) 35 / (v) 30
• Original cartridge weight: 2.0 g
• Dimensions: (W) 440mm x (H) 111mm x (D) 364mm
• Total weight: 5.5 kg
• Country of manufacture: Germany
• Year(s): 1983 - 1986

The CS 721 was Dual’s flagship turntable towards the end of the 1970s and is, by many, considered to rank among the best Dual turntables ever made. When there is disagreement between the experts, this is usually about the merits of the drive system. Proponents of idler wheel turntables, the ‘Treibrad Classics’, would cite Dual models CS 1219 and CS 1229 as their favourites, whereas belt-drive fans would give preference to the CS 5000 or CS 7000 Golden. The CS 721 was a direct drive design (DD) and, in all fairness to the other two camps, had the most audiophile specifications in terms of rumble, wow, and flutter of them all. However, we do not listen to specifications but to music, of course. And I must confess that I do love the straightforward sound of our smaller CS 505-3 as well. 

In its most affordable form, the CS 721 was not the most beautiful deck on the market. Its plinth was a base of cheap plastic that was skirted with a frame of laminated wood. Dual had to rely on its good name in audiophile circles in order to be able to sell its products next to the sleek and slim looking Asian designs from Technics, Pioneer, Sony, etc. In fact, the new lack of genuine wood on the products of the German manufacturer from the Black Forest was already a tribute to the increasingly price-driven market. However, the pressure to surpass its competition by means of sophistication assured the CS 721 some highly sophisticated features that are rarely found on turntables of any age.

One obvious highlight of the CS 721 was its tonally rich made-for-Dual Shure V15-III cartridge with its Super-Track-Plus stylus. The Shure V15-III was an excellent tracker with a low stylus force of merely 0.75g to 1.25g. The cartridge exhibited the usual Shure bass qualities while performing smoothly across an extensive frequency range from 10 Hz to 25,000 Hz. Sadly, the original Shure stylus was too worn out on our model, so that I had to look for a suitable replacement. My first impulse was to take the plunge on a Jico SAS stylus with boron cantilever; however, an indefinite delivery impasse from Jico forced me to settle for a Tonar Shibata stylus instead. Shibata needles were originally developed for use with quadrophonic recordings, reached deeply into the record groove, and, similar to Jico’s SAS styli, were capable of great nuance. However, listening to the two styli in direct comparison, it was hard not to favour the worn-out Super-Track-Plus for its amount of delicacy.

I also decided that I was going to improve the plinth of the turntable to isolate any physical vibrations from the floating chassis, as the thin plastic vat did not seem sufficient for the job. You will find a full article on the project in the 'Explorations' section of this blog. The result was a solid wood plinth that held the original structure suspended whilst silencing any vibrations to the plastic through the use of rubber foam. I used tri-ball absorbers to further isolate the plinth from potential vibrations caused by steps, slamming doors, or the other Hi-Fi units in the rack. The result was a tonally rich, precise, and undisturbed sound, just as one would expect from one of Dual’s top players.

Next to its precise and quiet motor, rigid tonearm, and legendary Shure cartridge, the CS 721 offered a host of adjustable settings that were class-leading at its time. Like all Duals of this period, it offered three transport screws to clamp down the chassis during transport. I always loved this feature on the Dual decks, as I had to spend lots of time transporting them in the car. Even the dust cover lift could be adjusted on the CS 721 just in case the spring should soften with age. The tonearm had a 2-fold dampened, adjustable counterweight and could additionally be altered in lateral length to perfectly accommodate most cartridge weights.

The vertical tracking of the CS 721 tonearm could be calibrated via a lever. Most other turntables only offered socket screws for the purpose. In a similar way, one could adjust the lift angle and the precise touchdown position of the stylus on the record groove. The touchdown speed could be adjusted to suit the weight of the cartridge. It was interesting to note that the manual lift function was not affected by adjustments to the lift height, as this, too, was set via a separate control. When playing back records, the CS 721 could be set from single to infinity mode, by which it would repeat playing a record until it was manually interrupted. When taking a closer look at the headshell, I was surprised to find that the cartridge was clamped into position and additionally secured by two screws. I learned that there had been two headshells sold of which only one could be adjusted. So I ended up purchasing an additional TK-24 headshell to have more freedom in my settings.

While the tonearm was adjusted by changing the lateral length of the arm and then via the knurled ring of the counterweight, a further adjustment ring was available to set the stylus down force. In combination, this was one of the most sophisticated settings I had ever seen. Anti-skating could be adjusted to suit conical and bi-radial styli. It was conceivable that the CS 721’s vast combination of settings would have been more confusing than helpful to some owners. On the other hand, listening to records had always been similar to fly fishing, with lots of time, skills, and effort needed to achieve a somewhat short-lived result. In other words, the Dual was anything but plug-and-play. All the more, it was gratifying to own and listen to, once the perfect setting was achieved, especially with its new walnut plinth.

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< Constructing the Plinth | Dust Cover Restoration >

Dual Company History

Christian and Joseph Steidinger started out as a manufacturer of clockwork and gramophone in the German Back Forest town of St. Georgen in 1907. The original company simply bore the family name, until they rebranded as Dual in 1927. The new company name was chosen in reference to their signature “dual-mode” power supplies in which they were true pioneers. Gramophones featuring these supplies, could either be powered by electricity or wound up for playback. Given their early success as a parts supplier, the Steidinger brothers began designing their own turntables.

During the German economic recovery that followed World War II, Dual became the largest producer of turntables in Europe. The German economy still enjoyed a price advantage over the rest of Europe and became known for high-quality once again. The Steidinger brothers had to hire up to 3,000 factory staff in order to keep up with the growing demand in entertainment devices in the world. Although Dual stretched the brand into other consumer electronics items, their turntables have remained iconic to this day.

The original Dual company went bankrupt in the early 1980s, following a decade of fierce competition from cheap and sophisticated imports from Japan. It was sold to the French electronics group Thomson SA. In 1988, the German company Schneider Rundfunkwerke AG bought Dual and then spun off the ‘Dual Phono GmbH’ to Alfred Fehrenbacher in 1993. Fehrenbacher produces Dual turntables 'Made in Germany', in the Black Forest town of St. Georgen, based on Dual’s original product lines until this very day.

Specifications

• Turntable type: Fully automatic
• Motor: direct drive, electronically controlled
• Motor type: Dual EDS 1000-2
• Speeds: 33.33 and 45rpm
• Platter weight: 1.5 kg, aluminum die cast
• Platter weight with rotor: 3.0 kg
• Platter size: 305mm, dynamically balanced
• Pitch control: +/- 10%
• Wow and flutter: < 0.03%
• Rumble: > 70dB
• Tonearm: extended tubular, 2x damping
• Tonearm effective length: 222mm, height adjustable
• Cartridge: Shure V15 III (1973 - 1987)
• Stylus pressure: 0.75 to 1.25g (1.0g)
• Stylus type: Microline, elliptical diamond
• Channel separation: 28dB @1kHz
• Frequency range: 10 - 25,000 Hz
• Cartridge inductance: 500 mH
• DC resistance: 1,350 Ohms
• Resistance: 47 kOhms
• Output: 3,5 mV @1kHz
• Cartridge weight: 6.0 g
• Turntable Weight: 7.8 kg
• Dimensions: (W) 424 mm x (H) 150 x (D) 368 mm
• Country of manufacture: Germany
• Year(s): 1976 - 1979

Fritz and Marie Laeng founded the Lenco turntable company in Burgdorf, Switzerland in 1946. The name Lenco was derived from the Laeng’s family name, largely due to Marie’s initiative. In the time before turntable production in Burgdorf, the Laeng couple had already been fascinated with audio technology and had been running an electrical business since 1925. The Laeng’s genuine enthusiasm for sound reproduction resulted in reliable quality products and excellent service for the few units that were returned to the factory for reworking. Lots of passion, high quality, and excellent service proved to be a solid foundation for success, and the company soon opened a second factory in Italy to satisfy the growing demand.

Lenco partnered with specialist companies in the production of accessories that they could not easily produce themselves. Komet was a specialist for tube amplifiers and supported Lenco in producing turntable & amplifier combinations. Another, perhaps more famous, partner was Goldring, a specialist manufacturer of phono cartridges. Some Lenco turntables were marketed bearing the Goldring logo. In doing so, the lesser known Lenco of Switzerland was able to benefit from Goldring’s established sales network, a circumstance that made it easier for Lenco to reach out to customers around the globe. Within just a couple of years, Lenco was able to generate sales in more than 80 countries.

Sadly, Marie Laeng died at a particularly vulnerable time for the company, during the oil crisis of 1974. She had been the heart and soul of the operations, and the business was now simultaneously hit from at least two directions: a declining global economy and the loss of their chief motivator. A third hit was then caused by the influx of cheaper priced electronics from newly rising Asian countries that turned out to be the winner of Europe’s new price driven economy. Lenco AG Burgdorf declared bankruptcy in 1977, with the newly formed Lenco Audio AG taking over existing service agreements and completing what was to be the final generation of Lenco products.

The Lenco L75 was built from the early 1970s and designed to meet the challenges of a price driven market. Just affordable enough to be purchased by university students, it was designed with the intention of bringing audiophile sound quality made in Switzerland to a young consumer group. Despite the ever so slight rumble coming from the sturdy idler wheel drive construction, the woodcased Lenco included some welcome features, such as a floating cabinet, a newly designed tone arm with visible anti skating weight, and four playing speeds ranging from 78 RPM all the way down to 16 RPM. Available accessories included a strobe speed control disk for fine adjustment, a record sweeper with fixture on the deck, and record clamps to reduce vibrations. Today, the L75 ranks among the best idler turntables ever made. Especially audiophile listeners hold the L75 in high esteem, knowing well that even the considerable success of the L75 in the end was not enough to save the failing company from extinction.

< Tri-Ball Absorbers | Vinyl-Singles Puck >

Specifications

• Drive: Idler drive
• Motor: 4-pole synchronous with conical axis
• Speeds: 78, 45, 33-⅓, 16-2/3
• Wow and Flutter: ±0,08% / ±0,4%
• Rumble: 36 dB (unweighted); 60 dB (weighted)
• Plater: 306 mm, 3,7 kg, Zinc-alloy
• Tone-arm length: 227 mm
• Overhang: 17 mm (adjustable)
• Offset Angle: 23°12' (±0,8° max.)
• Material: Tubular Aluminium
• Stylus pressure: 0,5 g
• Dimensions: 445 x 335 x 150 mm
• Weight: 10,5 kg

Built from 1971 to 1976, the Philips 22 GA 212 Electronic turntable is still considered to be among the best Philips turntables ever made. Better known as Philips 212, the unit has achieved somewhat of a cult status among vinyl fans and vintage collectors. Key features include a floating suspension of the platter and sub chassis that provides excellent shock protection and capacitive touch keys featuring green backlights. The unit shown here was built in 1972 and, with some maintenance, is still running smoothly without any audible noise coming from the bearings or motor.

The floating sub chassis results in a very low rumble value, and the light weight aluminum platter works quite well and does provide an interesting alternative to the more common approach of providing more mass to the platter and chassis. Playing speeds are set at 30 and 45 RPM and pitch can be independently (!) adjusted for both speeds. The Philips 212 came fitted with Philips’ own GP400 cartridge which was durable but little adapted to audiophile needs. The company’s own upgrade was the GP401 which offered greater sonic accuracy and detail.

On the unit shown here, the GP400 was replaced by an Audio-Technica at-VM 95 E pickup. The Philips 22 GA 212 headshell can easily be removed by pulling it out forwardly from underneath the tonearm bracket along with the wiring. A welcome feature, for owners who wish to have multiple cartridges at hand. The modern Audio-Technica easily outperforms both the GP400 and GP401. It provides an honest well-detailed and lavish sound, perhaps with a slight tendency to sounding unrefined. There are better cartridges in the Audio-Technica range, all of them being quite affordable, but considering the lightweight tonearm’s limitations of adjustment and control the VM 95 E is certainly a risk free choice. The original 5-pin DIN plug on this unit was replaced with Neutrik cinch/RCA connectors.

Specifications

• Speeds: 33 and 45 RPM
• Dimensions: 39x14x34 cm
• Weight: 7 kg
• Voltage rating: 240 V AC switchable, 5 W, 50 Hz
• Rumble: < -62 dB (DIN B)

Following the sale of our Tannoy DC6t speakers to a fellow audiophile in northern Germany, I again had some money to spend on explorations. Looking for improvements to make on our HiFi setup, I decided that much could be gained from upgrading the record player on our main system. While our Philips GA 212 still put out a solid performance, its tonearm and chassis did have some limitations in terms of cartridge upgrades, etc. For vinyl to sound even better, it was high time to change to a more sophisticated concept altogether.

I scanned the web for vintage offers and asked friends for suggestions. Among our choices were the typical Dual, Thorens, Denon, Technics and Micro Seiki brands, all offering well-known classics in their own right, but none of the more affordable ones looked attractive to me, until I came across an unlikely contender in the upper mid-market segment, the Sansui SR-525 DD. Based on a similar chassis and tonearm design as Sansui’s SR-323 belt-driven turntable, the SR-525 offers some significant upgrades, such as the quietest direct drive motor of its time and a quartz speed control with built-in strobe light. The technology is state of the art, especially for a 1976 machine, and I have read nothing but praise about this player.

This is no surprise, really. The Sansui Electric Company was founded by Kosaku Kikuchi in Tokyo, Japan in 1947. Similar to many of his contemporaries, Kosaku cut his teeth in the industry by manufacturing transformers and simple radio parts, until he realised that fluctuation in the quality of components was making it difficult for manufacturers to consistently assemble high quality devices. Kosaku therefore determined that Sansui should prioritise product quality over manufacturing cost. Later, as Sansui diversified into more complex products, this focus on quality proved to be beneficial to the reputation of the brand.

By 1954, Sansui was manufacturing preamplifiers and amplifiers that were sold both as kit for home assembly and as finished product. Although the first units were based on mono tube designs, stereo tube systems were introduced in 1958. By the mid-60s, Sansui’s internal and external design choices had earned the company a solid reputation for high quality audio products. It was at this time that the company started producing its iconic black-faced AU-series amplifiers. Among these were to be found many units that can well be classified as ‘High End’ and remain much sought after by audio enthusiasts until this day. The company produced its first turntable in 1967, a full nine years before the SR-525 came to life.

I found our SR-525 at a vintage HiFi dealer in Mannheim called ‘Goldladen’, combining the family name of its owner with the German word for shop. And although I had to pay a little extra for buying from a proper retailer, I liked the idea that I could drive there and inspect it, before making a purchase. Upon arriving at the shop, I found the Sansui to be in absolutely mint condition. With the platter raised, it was impossible to tell, if the motor had ever run, and there were hardly any scratches on the cover either. Standing in front of the SR-525, there is very little in its design, touch, and feel that makes it out to be a vintage player. In its simplicity and dark grey paint coat, it rather resembles the players around the turn of the century. The only item that gives it away are the clunky rubber feet, perhaps. But they do a fabulous job in keeping the record from skipping.

The tonearm is of sophisticated design with a suspended anti-skating weight and an additional lateral weight to keep resonances at bay. Its S-shape assures that the stylus angle is nearly perfect over most of the record’s surface. The Sansui’s total weight of nearly 10kg provides a solid base to absorb vibrations of any kind. At its original German sales price of 865,00 DM, it was nearly 200 DM more expensive than the belt-driven Philips, and this really shows. Other models in the SR series were the belt driven 323, the similar but wood finished 626, and the higher specced 929.

Do you have some personal experience with Sansui turntables? Please feel free to share your thoughts in the comments section below. Your perspective will be highly appreciated.

Specifications

• Type: manual direct drive turntable
• Platter: 310mm, die-cast aluminium alloy, 1,4kg
• Motor: 20-pole, 30-slot DC brushless
• Speeds: 33 and 45 RPM, servo-controlled
• Wow and flutter: < 0.03% WRMS
• Signal to noise ratio: > 64dB
• Rumble: > 72dB
• Tonearm: statically balanced, s-shaped, resonance-free, adjustable height
• Effective length: 220mm
• Overhang: 17,5mm
• Cartridge weight: 4 to 11g
• Dimensions: 46,9 x 15,0 x 37,5cm
• Weight: 9.5kg
• Year(s): 1976 - 1978

Purchased at:

www.goldladen-mannheim.de
Laurentiusstraße 26
68167 Mannheim
Tel.: 0151 241 643 55

Following the stellar performance of our 1977 Sansui SR-525 direct drive turntable, I began scanning the web for other direct drive contenders from the 70s. And, since Technics had been the company to invent the direct drive concept, I was curious to learn how their turntables compared against the formidable standard set by our Sansui. By the 1970s and 80s, Technics decks had earned a reputation for being at the cutting edge of turntable technology. In addition to introducing and refining the direct drive, a design by which the motor shaft itself serves as the axis of the turntable platter, Technics was also credited with being among the first manufacturers to bring the sophisticated S-shaped tonearm to the mass market. I therefore decided that a Technics deck would be a worthy contender for exploration.

The brand’s most iconic turntable is arguably the SL-1200. To my knowledge, it is also the longest turntable in production. It first came out in October 1972, just one month after I was born, and continued to be in production until 2010. After a six-year break during the vinyl crisis, production resumed in 2016. Although primarily intended as a high fidelity consumer record player, the SL-1200’s superb build quality and high torque motor made it an instant success with radio stations and club disk jockeys. To date, more than 3 million units of this player have been sold. And, considering that it is back in production, we are still counting. Perhaps it is no surprise then, that an SL-1210 turntable is on display at the London Science Museum, as one of the icons that have shaped our modern world.

Since so much had been said and written about the SL-1200, prices for them used were quite high at my time of searching. This was even true for specimens that were in relatively poor shape and had been dragged around clubs, etc. Regardless of the condition, the name alone seemed to validate a higher price. I therefore decided to look for Technics turntables that offered a similarly sophisticated design but were missed by mainstream attention. I soon learned that the Technics 1310 offered much of the same technology that is found on its famous sibling, but this at a far lower price tag. And, due to its mostly domestic use, chances of this player having been dragged from club to club were rather slim. It appeared to me that the major differences between the two decks rested on their ability to absorb chassis resonances, to maintain exact speed in the event of physical force against the platter, and in the stress resistance of their lower chassis. In all these disciplines, the SL-1200 clearly had the upper hand.

And still, the SL-1310 can rightfully be considered an audiophile record player, even if it was not built to be carried around as a professional DJ or radio player. For my intended usage in our domestic environment, the SL-1310 had all the relevant features without the high price tag of its sturdier sibling. I began to narrow my search to the SL-1310 and noticed that cracked lower chassis were the norm rather than the exception. It seemed to me that the combined weight of the aluminium top casing and platter were simply too much weight for the lower plastic chassis to carry, especially when the Technics was moved carelessly. Other specimens had ugly scratches along the front or showed some discolouration of the body paint where they were mostly touched. Some had missing or broken dust covers, faulty mechanisms, or were simply missing the cartridge or stylus. On the positive side, most of these symptoms were relatively easy to spot. I therefore decided that I would focus on SL-1310s that were visually intact and would then see to it that functionality was properly restored.

The specimen that I ended up buying seemed to offer both. Its body and cover were in excellent condition with just a tiny hairline scratch at the front. It was still fitted with the original Shure M75 cartridge and ED stylus, a clear indication that this player had not been used much. There was no damage to the lower plastic body. The price still was relatively high, considering that the player was nearly half a century old, however, I decided to be open-minded during my visit to the owner. If the condition was as described, perhaps the higher price was justified.

Upon arrival, I found the player set up in the basement. It was connected to power but without an audio signal connection. I was informed that the owner had sold all his original HiFi components and moved on to more convenient Bluetooth devices. The SL-1310 was the last remaining item from the glory days of high fidelity. And although he remembered his turntable to have been in working condition when he had stowed it away some seven years earlier, we found that many of the original functions were no longer intact. The automatic cueing did not meet the start of the record. Instead, the stylus landed somewhere between songs, regardless of the disc diameter setting. We managed to set the speed for 33 rpm correctly, but all attempts failed when trying to stabilise the record speed for 45 rpm. A little confused by the number of issues, we estimated the price of repair, and he offered to deduct these costs from the offer price. Under these circumstances, I was happy to agree to the deal.

Upon connecting the Technics at home, I discovered that the player’s left audio channel failed after a few minutes of playing. I managed turn it back on by re-connecting the cinch cable, but shortly after, the left channel failed again. Unlike our Sansui SR-525, all Technics decks of the period came equipped with non-detachable cinch/RCA interconnects, a factor that made it difficult to locate the left channel’s contact issue and also seemed a hindrance to upgrading the sonic ability of the player. I therefore made a list of all defects and added to this the need for proper cinch/RCA sockets to be installed. Luckily, our trusted mechanic for such audio matters had some time available, and I drove by for a visit the next day.

In terms of product innovation, the SL-1310 carried the direct drive concept one step further than the original designs. While most record players of the time, including the Sansui, had their large motors sitting centrally under the platter, a concept that required a certain minimum height, the revised Technics design used the platter itself as rotor and the player’s chassis as the stator. The turntable could therefore have a lower silhouette, used fewer parts, dissipated less heat, lowered electricity consumption to less than 0,1 watts, and decreased resonances. Speed-accuracy was class-leading at the time, at just 0.1% error over 30 min playing time. It is often said that disc-cutting lathes of the time were less accurate than this. Due to the slow-revolving motor, rumble was found mostly outside the relevant frequency band, namely from 20 - 35 Hz. The two peaks measured are at around 22 and 34 Hz. And of course, the iconic Technics platter showed a wide tapered rim with strobe markings for 33-1/3 and 45 rpm synchronisation at 50 or 60 Hz, i.e. four dotted lines in total.

As it turned out, our SL-1310 was mostly suffering from corrosion to the switches that had accumulated over the years. This was most likely facilitated by moisture while being stored in the basement. We discovered that most switches could be taken apart to be serviced. Only one of them, the one to set the record size, was beyond repair and needed replacement. Two holes were bored into the back of the turntable to hold the new cinch/RCA sockets. This step enabled me to use my own interconnects with this player, a seemingly small improvement but with a major impact on sound. The faulty left channel turned out to be caused by a loose connection inside the Shure cartridge itself. It was decided that we would heat the relevant pin with a soldering iron, until we could push the pin a few millimetres into the cartridge housing. The trick worked, and both channels played music again.

Back at home, I connected the Technics SL-1310 to our office system and was very pleased with the way it performed and handled. I set the 'Memo-Repeat' dial to 'three (3)' and the platter started spinning silently. I then pulled the lever downwards to the 'Start' position. The player reacted by gently lifting the tonearm and setting it down at the start of the first title. I noticed that the placing of the needle could have been a bit gentler, perhaps. However, the small thump it produced was still within reasonable limits. The Shure M75 with elliptical stylus used to be a mid-market cartridge back in the day and could not rival the Shure V15 that was found as standard on German-made High End Dual turntables. However, in typical Shure fashion, the M75 ED put forth a warm and delicate sound with long-trailing decay. It may not have exhibited the bass-slam of the Shure 6S, but it did play accurately and endearingly. It seemed to me that upgrading to the V15 cartridge, perhaps with a Jico replacement stylus would be a welcome but costly alternative for a later day.

The Technics SL-1310 itself could certainly do with some additional decoupling of the chassis. Right from the start, I noticed that any touching of the rack had a similar popping effect as the touching of a microphone. This effect vanished completely, after I placed the Technics on four Oehlbach isolation pads. Since the player is rather heavy with its aluminium platter and aluminium top-chassis, it remains wonderfully stable, despite the inherent softness of the pads. Among the features that I enjoy most about this player are its automatic functions that keep me from having to crawl into the small space under the slope of the roof where our system stands, and its life-like three-dimensional presentation of the music. Paired with our Hafler XL-280 power amp and Tannoy speakers, a deep holographic image of the stage is projected into the room right in front of me. Not bad at all, especially for a deck that is nearly half a century old.

Specifications

• Type: fully automatic direct drive turntable

• Platter: 312 mm aluminium diecast

• Speeds: 33 and 45 rpm

• Motor: ultra-low speed, brushless DC

• Motor Power Consumption: < 0,1 Watts

• Wow and flutter: < 0.03% WRMS

• Rumble: - 70 dB

• Tonearm: S-shaped, tubular, 4-pin connector

• Effective length: 230 mm

• Effective mass: 23g (incl. 6g cartridge)

• Effective length: 230 mm

• Tracking force adjustment: 0,25 to 3g by 0.1g

• Cartridge weight range: 4,5 - 9g

• Dimensions: (W) 430 x (H) 130 x (D) 375 mm

• Power consumption: 8,0 Watts

• Power Supply: AC 110 - 240V, 50/60 Hz

• Weight: 9,4 kg

• Year(s): 1975 - 1977

  

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For many years, the Thorens DT 320 headed my list of most desirable affordable turntables, as it already boasted some audiophile features that would only find their way into modern 'High-End' designs much later. When it was first released to the public in 1984, the TD 320 was the top of the Thorens 300-series and was also more generally considered to be top-of-its-class. Early models came equipped with the TP16 MK-III tonearm. Later, this was succeeded by the MK-IV tonearm which was also featured on the model shown here. This places our specimen in the model years from 1986 to 1988. The 300-series was among Thorens’s most successful model ranges and was later extended with some new and revised versions: the TD 325, TD 2001, and the TD 3001.

The TD 320 featured a suspended sub-chassis hinged on 3-point leaf springs that held the tonearm and platter separated from the vibrations of the motor. The use of leaf springs proved to be beneficial when compared to earlier coil spring designs, as they limited wobble on the horizontal axis. To eliminate the effect of transformer vibrations, the TD 320 came with a separate power supply. And although the original Thorens supply was simply built into the AC plug, power supply upgrades were among the first and most viable tuning choices for the TD 320. The power supply that is shown here was sold by the French audio distributer 'Audiophonics'. It is of linear low-noise design and has dedicated EMI and RFI filters. Its output is rated at 1.25 A and 16 V. Placing the power supply on a separate shelf-board will effectively eliminate power supply vibrations from the music signal.

The Thorens TP16 MK-IV tonearm featured adjustable horizontal and vertical bearings to keep the amount of arm play to a minimum. The black dust cap on top of the pivot could be removed to allow easy access to the top bearing. Unlike many of its foreign contemporaries, the MK-IV tonearm came with a fixed headshell that could not easily be swapped around. Its sleve wrapped around the arm’s aluminum tube and was fixed with a single screw. The vertical tracking angle (VTA) of the cartridge and stylus combination could be adjusted by loosening the screw and twisting the headshell into position. There were, however, some flaws with this crude system. For one thing, twisting the headshell on the arm could have a negative or even damaging effect on the fragile tonearm bearings. Second, removing the arm from the overly tight tonearm clamp on a regular basis could negatively affect the VTA setting. And, third, tightening the headshell screw almost inevitably altered the vertical tracking angle again in an unpredictable manner. On the other hand, the arm’s no-frills, anti-skating mechanism could also be conveniently set via a single screw. This affected the position of permanent magnets and actually worked quite well.

When I picked up our TD 320 from a private seller in the Taunus region near Frankfurt, it was in arguably poor condition. Its wood veneer had lost most of its lustre, its dust cover had been deeply scratched. The 3-point suspension had come loose on the inside, and the platter was lopsided and scraping over the plinth with each turn. The drive belt was loose and needed replacement, and the original yellow Linn-branded pickup (made by Audio Technica) had a badly-worn stylus. I placed the Thorens on the back seat of our car and wondered how much time and effort it would take to restore this once great turntable to its original splendour.

I bought a new drive belt from Thakker.eu, fixed and adjusted the 3-point suspension until it held the arm-board at the correct height and level again. I used furniture polish to restore the original wooden shine of the plinth. Following a short interlude with a Sumiko Olympia cartridge (which I ended up sending back to Thakker), I installed our Audio Technica VM95 ML cartridge with a very positive result. Since both the Sumiko and the Audio Technica had a lower body than the original cartridge, I also needed to adjust the tonearm-height for the arm to be level with the record during playback. I replaced the original power supply with the one from Audiophonics and removed the original felt pads under the plinth to replace them with height-adjustable copper spikes. Determined to restore the dust cover, I showed it to my friend Thomas who is an expert on car body work and paint jobs. He offered to sand it down and polish it for me. When he returned it to me one week later, the scratched, old cover looked as though it had come fresh from the shop.

Listening to music on the TD 320 with an Audio Technica VM95 ML cartridge produced a warm, balanced and natural sound. Background noise was low, and channel separation was great. There was a sense of elegant delicacy that was embedded in believable tonality and excellent musical flow. The VM95 ML was a superb tracker and worked well with the TP16 MK-IV tonearm. The Sumiko, on the other hand, had seemed more bottom heavy and much less refined with continuous distortion and sibilance, especially towards the inner groove of records, which was also the reason for me sending it back to the shop. I found that the TD 320 in combination with the Audio Technica VM95 ML lent itself to classical music and Jazz and to those seeking a laid back and insightful sound rather than in-your-face attack. It was perhaps not the most enthralling combination, and I sometimes wondered how a louder and more boisterous Ortofon 2M Bronze cartridge might perform in the balance of things.

There are still some design flaws to the TD 320 which I might address at a later stage. For example, a look under the hood revealed that the audio signals were in fact running in parallel with some of the power and switching electronics, a circumstance I intend to change for greater dynamics and transparency. There was also the questionable quality of the interconnects themselves that had come pre-installed on the turntable. One could possibly get a better result by changing to a silver solid-core interconnect from our trusted HBS series. Both the platter and the plinth floor might benefit from additional damping matts being applied. The sub-chassis might be re-adjusted to allow for the use of an additional record weight, etc. However, for the time being, I was indeed very happy to have given new life to one of the all-time legends in the world of turntable designs. I understood that there was a lot more fun to be had with the TD 320 than with any of the sleek and modern direct-drive decks from Japan. Although, the Thorens was more complicated to deal with on a daily basis and screamed: Caution, handle with care!

Thorens Company History

Thorens was originally founded in the town of Sainte-Croix, Switzerland, in 1883. Similar to the German Dual, Thorens started out as a specialist for clock movements before producing phonographs from 1903. The company’s first turntables date back as early as 1928. This makes Thorens one of the oldest existing producers of turntables in the world.

During the 1950s and 1960s, Thorens produced a range of sophisticated turntables for private and professional use that continue to be regarded as audiophile High-End equipment. The TD150 MK II was produced for the private market from 1965-1972, and the heavy-built TD 124 was found among audiophiles and studios alike. It was produced from 1957 to 1965.

Following its insolvency of 1999, the newly formed 'Suisse Thorens Export Company' took over the Thorens assets and continued to produce and sell Thorens turntables under the leadership of Heinz Roher. In May 2018, Gunter Kürten took over the company and moved its headquarters to Bergisch Gladbach in Germany. Current models include the TD 124 DD, the TD 1500 with TP 150 tonearm and SME headshell, and the similarly equipped TD 403 DD.

Specifications

• Drive method: one step belt drive
• Motor: 16-pole synchronous motor, 16V
• Platter speed: 33 and 45rpm
• Speed control: 2-phase generator
• Platter: 3.1kg, 300mm, zinc alloy, dynamically balanced
• Wow and flutter: 0.035%
• Rumble: > -72B
• Tonearm: TP16 MK IV
• Tonearm length: 232mm
• Pivot to spindle: 215.6mm
• Effective mass: 12.5g
• Overhang: 16.4mm
• Offset angle: 23 degrees
• Dimensions: 440 x 350 x 170mm
• Weight: 11kg (plus power supply)
• Power supply: Audiophonics LPSU25 (China)
• Supply type: 25VA, linear regulated, EMI RFI filters
• Country of manufacture: Germany
• Year(s): 1986-1988

Nikko Audio was a division of the Japanese electronics company Nikko Electric Industry Co, which was formed in 1933 in Kanagawa. The company's audio components earned a good reputation, however the brand only reached a limited distribution and during a general decline in the market in the 90's, the division was forced to close.

The history of the Nikko Audio company reads like a rollercoaster ride between a genuine interest in high quality products and inexplicable failure in managing to sell these to the world. The original ‚Nikko Electric Works‘ was re-founded shortly after WW2 as a designer, manufacturer and installer of communication technology and electrical equipment in Japan. In those early years, Nikko mostly manufactured fuses for the Japanese National Railroad - until the daughter of the boss married a young audiophile lad who allegedly had "golden ears" and persuaded his father-in-law to put on a range of HiFi products, a process that began in the late 1960s. The son-in-law understood about good sound, but he was only marginally interested in the marketing of his products, so that he initially developed devices that were very good, but also very expensive and therefore difficult to sell.

With the Audio Division hardly generating enough income for itself in the 1970s, Nikko was forced to revise its strategy and spin off into various foreign subsidiaries. The product range was streamlined and most of the early High End gear was removed in favour of less expensive and therefore more marketable equipment. Although the product quality was easily able to keep up with the competition, they did not perform in terms of sales, which was mainly due to their overly conservative appearance. In contrast to Sony or other big names with their brushed aluminium fronts, Nikko designers could not (or did not want to) follow this trend and therefore had a hard time holding their own in the market.

A later reorganisation of the product range saw the launch of compact equipment in the lower and medium price range. Nikko also entered the German market with these products, among others; they were introduced via various importers and then sold preferably via department store chains or mail order (i.e. the low-cost segment). Soon, a name and products that were still relatively unknown but that had been poised for greatness sold out to the market and the company finally closed business following the general market slump after the Asian flu at the end of the 90s.

The FAM 600 tuner shown here is of elegant design, not only from the outside, but also in terms of the simplicity found within. It came pre-equipped with outputs for quatrophonic users (the big idea at the time) and feels great in the choice of materials. The company’s High End origins still shine through on this device. Although there are better tuners e.g. in the higher Sansui price ranges, this unit offers a great way to experience analog radio at its best. As analog listeners will know, there is radio weather - and then there are those other times, when something is just not right in the universe. On good listening nights, the analog experience, if done right, has all the magic it takes for us to lose ourselves over and over again. connectors.

Specifications

• Manufacturer: Nikko Electric Manufacturing Co., Ltd.; Tokyo
• Product launch: 1975
• Category: stereo broadcast receiver, past WW2 Tuner
• Main principle: Superheterodyne
• Body: Copper chassis, brushed aluminum front, wood case
• Dimensions: 380 x 130 x 300 mm
• Weight: 5kg

Picture description:

Moving clockwise from top center we can identify the back of the operating panel, the transformer and, below this, the circuit board of the customer made power supply. The 5-pin DIN is located in the bottom right corner, inconveniently just above the power cord. Antenna inputs are in the lower left corner and above these is the tuner's main board. The large tuning rotary capacitor is in the top left of the board. A copper sandwich floor protects the underside of the board from electrical interference with all the internal wiring remaining hidden from view.

Having owned the smaller brother, a Denon DCD-1420, for some time now, a look under the hood revealed larger placement markings around the smallish capacitors that showed the dimensions of the parts used on ‘the real thing’, namely, the larger DCD-1500 unit. And, although the DCD-1420 is a reliable middle-class player, even after four decades, I have often asked myself, what I would be hearing, had I bought the fully equipped unit instead.

Therefore, when Luigi showed me two CD-players and asked me which of the two to get, I had a strong leaning towards the Denon DCD-1500 II. The photos we saw showed it in good used condition, but they were far from impressive. Both the Denon’s size and design did not give away its exceptional build quality and internal merits. To me, it looked like just another CD player. This impression changed, when I visited Luigi and saw the player, with its display turned on, perched on a proper HiFi rack. Although its size had not changed and its design was still an understatement, there now was a cleaned-up seriousness about it that made me curious at an instant. This was certainly a whole other beast from my 1420.

Luigi played me a few songs on the Denon DCD-1500 II before he switched to vinyl. While I usually cherish the transition from digital to analog, I noticed that I was a little sad to stop listening to the 1500 so soon. Perhaps this was because the player’s cleaned-up looks had been wonderfully present in the music as well. While the player had not sounded spectacular by any means, the music simply had this air of dependability to it that made it endearing to my ears. I had instantly trusted this player to sound pleasant. The lack of this quality is  often an issue with CD players; actually, when audiophiles describe devices as sounding analog or warm, it is sonic dependability rather than spectacle that they are referring to.

Luigi suggested I should take the Denon home with me, explore it further and, perhaps, write a review on it, to which I gladly consented. When I was ready to leave and picked the Denon up from the rack, I was surprised by its weight. For a moment, it felt as if it had been glued to the boards. This aspect of the player is so well hidden, it struck me by surprise, despite having read in the advertisement that it was close to 10kg. Coming from a larger and higher built amplifier, the weight would not have surprised me, but from a standard-looking Japanese consumer device, I was positively surprised.

When I came home, I placed the Denon on our conference table and opened the chassis to look under the hood. While the top cover was made of the same bent metal as is custom on today’s units, I did find a 4mm sheet of lead glued to the inside of the cover. This certainly helps to keep the typical drive and chassis resonances at bay and also increases the player’s resilience in case of resonances coming from the outside. I guess anyone could glue a sheet of lead under the cover of their CD players to the same effect, but thinking of my DCD-1420, I could see how pointless that would be, considering that it was not even made of Denon’s full-size parts.

While performing the first operations on the DCD-1500 II placed in our rack, I noticed that some of the buttons on the front were actually made of metal. This has some advantages when it comes to durability. On our silver 1420 for instance, some of the more frequently used buttons have already lost their silver shine. This was not the case on the 1500. Like many of Denon’s players, the 1500 features both a fixed and a variable output which can be convenient in some cases. For any listening test, I used the fixed output to leave out any unnecessary augmentation to the sound. The CD transport is of excellent quality, and the drawer opens promptly and quickly.

In our living room setup, the 1500 had to compete with the 16-years younger 3.7kg lightweight Rega Planet 2000 CD-player, which was our standard choice for CDs. The interconnect used on both devices was a new type of silver solid core with KLE Innovations silver plugs that had been custom made for eiaudio.de and had not been completely run in. This is to say that bass extension had not completely evolved after two weeks of playing. Since this was our best interconnect at the time, I decided that I would stick with this cable despite this small flaw in the setup. The song played was “No Moon at All” on Diana Krall’s ‘Turn up the Quiet’ album. 

The Rega came first and played this song with realistic dimension and tonality. I found that timing could at times have been better, with the player showing a slight tendency of dragging its feet, but overall it was an accurate representation with lots of warmth, musical detail, size, and natural space around the instruments. The DCD-1500 II came next and, in comparison, played slightly darker and fuller with a striking three-dimensional richness in Diana Krall’s voice. It did not present the same amount of detail; however, its timing was more accurate with slightly more drive and consistency to it. The Denon came across as slightly more controlled and dryer with individual notes being stopped earlier. The Rega in comparison appeared to be less predictable, was able to present more of the disc’s nuances, gave a fruitier performance and allowed the music more space to perform. 

Both players sounded very pleasing, are excellent companions for extended late night listening sessions and renowned for their warm and analog sound. The Denon is surely the mechanically more sophisticated player, whereas the Rega wins its points on the basis of modern DAC circuitry, a more detailed presentation, and lots of musical charm. Considering that the Rega has a 16-year edge over the Denon, the DCD-1500 II a still very good and worthwhile CD-player, indeed. Its build quality, touch and feel, general usability, and its excellent remote control position it well ahead of today’s mid-market competition.

Testing environment: Denon DCD-1500 II (via HBPS pure silver solid core interconnects to) DB Systems DB1 preamplifier; (via Audiocrast OCC and Silver interconnect to) B&K ST140 power amplifier; (via Belden 9497 speaker cables in bi-wiring to) Martin Logan SL3 electrostatic speakers

Specifications

• Digital Converter:  2 x PCM54HP-K
• CD mechanism:  KSS-121A / KSS-123A
• Frequency response:  5 Hz to 20 kHz
• Dynamic range:  96 dB
• Signal-to-noise ratio:  103 dB
• Channel separation:  100 dB
• Total harmonic distortion:  0.0025%
• Power Consumption:  17 W
• Line output:  2 V
• Extras: remote control, variable line output
• Dimensions:  434 x 89 x 350 mm
• Weight:  9 kg
• Year: 1986

Frederick Whitney Horn, an American entrepreneur, started the Nippon Denki Onkyo Kabushikigaisha in 1910 as a subsidiary of the Japanese Recorders Corp. Even before record players, cylinder recorders were common, and Denki Onkyo produced both the media and the players for them. Following mergers with other companies, the name was shortened to DEN-ON which later became Denon. The company was, next to Philips and Sony, a front runner in the development of digital technology and has made a name for itself as manufacturer of professional studio machines as well as HiFi products for the private user market.

The Denon track record of providing new ideas in music reproduction to the world is quite immense. In 1939, Denon manufactured the first (analog) disc recorder for use in the broadcast industry. In 1951, the company played a major role in selling the first long play records to the Japanese population. Two years later, Denon launched a well received line of reel to reel recorders for the broadcast industry. The first Denon HiFi components were launched in 1971. Among them were turntables, amplifiers, tuners, and speakers. In 1999, Denon produced the world's first THX-EX home theater system, in collaboration with Dolby Laboratories. Over the years, Denon has won many prizes for its outstanding contribution to the industry. Recent trends are up to 13-channel multi-channel and wireless multi room systems. Although the company has also produced some outstanding High End components, the bread and butter business has always been divided between their professional line and HiFi products for the broader consumer market.

Some of Denon’s outstanding consumer to High End products were, among many others: the TU 400 Stereo Tuner (1977): the rather peculiar two-coloured PMA 850 amplifier (1977); the DCD-1800 CD player (1985); the by any standard enormous POA-S1 mono power amplifiers (1996), and the Denon DL-103R Shibata cartridge for vinyl fans. The DCD-1420 that is shown here is not listed in the Denon Hall of Fame, as even at that time, there was the more sophisticated (10 Kg) DCD-1520 with better specifications. Despite its non-cult status, I decided to include it here, as it is a great player to begin your explorations in audio. It is well constructed, relatively easy to repair, nearly all parts for the laser drive can still be bought, and the usability is simply excellent. I love the fact that I automatically starts playing when I turn it on and that I can use the numeric keys on the unit to jump straight to the title, even if I do not have the remote at hand. The large display is dimmable and adaptable in content, which is useful for nightly sessions.

Going through the player’s internal DAC, the sound is detailed and leaning towards refined, but it feels a bit light and is lacking the stamina and tonal balance of higher priced units. Since the DCD-1420 has a digital coax connector, one can connect an external DAC, and this is where the fun begins. Putting the player on a base with absorbers and placing a ferrite clamp on the power cord inside the unit as well as outside, have greatly contributed to the musicality of the player + DAC combo. I might be a little biased, however, having owned three of these players over the years. All of them should still be playing just fine, I would assume.

Specifications

• Digital converter: 2 x PCM54HP
• CD Mechanism: KSS-150A / KSS-210A
• Frequency response: 2Hz to 20kHz
• Dynamic range: 97dB
• Signal to Noise Ratio: 108dB
• Channel separation: 102dB
• Total harmonic distortion: 0.003%
• Line output: 2V
• Digital outputs: coaxial, optical
• Dimensions: 434 x 135 x 310mm
• Weight: 6.3kg

Let’s face it: There have been some outstanding CD player designs since the dawn of the medium through a joint venture of Sony and Philips in 1982. The Meridian MCD of 1985, for example, that took the housing for a Philips CD 100 and gave it a complete hauling over in terms of the output stage and error correction, similar to the German Roman Gross modifications that came much later. Cambridge followed in the subsequent year with their CD1 that already boasted a separate stack-on-top DAC unit. Arcam, Naim, and Quad all came out with excellent machines that got the HiFi press interested. So did Cyrus and Chord in more recent times, and this list only includes some of the British makers of CD players. However, these renditions all cost a fortune and remained out of reach for all but the most hardcore enthusiasts. 

The real bread-and-butter business of the industry were low-priced machines such as the Denon DCD-660 that is the subject of this report. While the Cambridge CD 1 may have changed what was possible with the medium, the Denon DCD-660 affected what was accessible to the households of the average consumers. The Denon answered the question of how many (and what quality of) parts it took to satisfy the prevailing needs of shoppers at this price level. And, as this particular DCD-660 had been handed down to my daughter from her recently deceased great aunt, I wanted to take the opportunity for a quick exploration of its capabilities before installing it in her room. One of the other devices that my daughter had received was a Dual CV 1260 Class-A amplifier, which I enjoyed listening to quite a lot and dreaded having to surrender.

The CV 1260 was connected to our Epicure 3.0 loudspeakers via a pair of unterminated Belden 9497 speaker cables in single wiring. I used our larger and more elaborate Denon DCD 1420 as benchmark and took Diana Krall’s Album All for You as music material for my listening explorations. This album sounded really satisfying on the DCD 1420, and I could not have said that I was missing anything in the music. This in itself was a surprising realisation given the relatively small Dual amplifier driving the large Epicure tower speakers. On the other hand, 44 watts idle power on the side of the Dual suggested that it possessed a sufficient amount of Class-A amplification, as its name suggested.

Opening the DCD-660’s sliding tray for the first time, I noticed that it had some difficulties overcoming the first 1-2 centimetres of its journey. I helped the process by tugging it out gently with my fingers. I repeated the procedure a few times and noticed that it worked better with each application. When CD players remained unused for a long time, the rubber belts that were driving loading mechanism could at times permanently assume the oval shape they were last left in. If the tray had not recovered from my moving it by hand, I would have probably had to change the belt, which could turn out to be a little tricky, depending on the model. On the positive side, I found that the DCD-1420's remote control also worked on the DCD-660.

Right after start-up, the small Denon still sounded a bit harsh and grainy; however, this effect subsided as the machine reached operating temperature. Perhaps this was another indication of the unit having been sitting around unused over a long period of time. I noticed that the tonality was the same between the two Denon players. I would have liked to turn the LCD display off via the remote control to achieve that extra-clean sound, but I found that this function was missing on the DCD-660. The resulting soundstage, therefore, was not quite as clean cut and three dimensional, although I did have the feeling that the larger player sounded even hazier with the display turned on and consequently also benefitted from the display-off feature more. In direct comparison, ultra-low bass seemed a bit more profound on the DCD 1420, but not to the point where I would have minded much.

System integration was not great on the DCD-660, though. It was missing the separate variable Cinch/RCA output sockets of its larger sibling, did not have a digital S/PDIF output to connect an external DAC, and was also missing an optical output for integration in systems with grounding issues. As these criteria had become more and more important to me over the years, I would not have chosen the DCD-660 for myself. However, listeners who exclusively used the direct analog cinch/RCA output anyways, did get a capable CD player with natural tonality and a decent soundstage for a budget price. And, since switching the LCD display off in order to achieve an enhanced soundstage experience is only common in audiophile circles anyway, most owners of the Denon DCD-660 would have had every reason to be happy with and proud of their new device.

Specifications

• Digital converter: PCM61P
• CD Mechanism: KSS-210A (linear tracking)
• Frequency response: 2 Hz - 20,000 Hz
• Dynamic range: 95 dB
• Signal to noise ratio: 103 dB
• Channel separation: 99 dB
• Total harmonic distortion: 0.004%
• Filters: 20 bit / 8-times oversampling
• Line output: 2V (cinch/RCA)
• Variable line output: none
• Digital S/PDIF output: none
• Optical output: none
• Features: 1/3-headphones jack, volume poti
• Accessories: RC-226 remote control
• Dimensions: 434 x 105 x 280mm
• Weight: 3.8 kg
• Country of manufacture: Japan
• Year: 1991

Saul Marantz built his first audio product, the ‘Consolette’ preamp in Kew Gardens, New York. Although the Marantz Corporation today have their headquarters in Kanagawa, Japan, the Marantz success story began in America and reached its biggest relative success in the 1970s. Throughout its lifetime, the company formed joint ventures and changed owners many times. With the emergence of CD technology in the 80s, for example, Marantz partnered with Philips to manufacture CD players under the Marantz brand that were generally well received. Ownership was only transferred to Japan in 2001, when Marantz Japan bought the brand from Philips and, in the following year, merged with Denon to form the D&M Holdings Inc. After 28 years of partnership, Philips sold the remaining stakes it held in Marantz in 2008, and the Holding is today owned by Sound United LLC.

Among the company’s most noteworthy products are the Marantz 2325 and 2600 receivers, the CD63 and, more generally, the Ken Ishiwata signature product series, such as the Marantz PM-KI Ruby and the Marantz CD17-KI which is shown here. When it was released to the public at the end of the 1990s, the DC17 was already well-received by the audio world. With plenty of detail in treble, a clear and full mid range and Marantz-typical bass extension, the sound was described as ‘analog’ and attracted vinyl fans all over the world. However, there was also another aspect to the CD17 that was troubling audiophiles, as it also marked the departure from the fabled Philips swing-arm laser as well as other former brand features, such as diecast chassis and metal loaders. At the turn of the century, sales of high priced audio products were on the decline and cost driven choices became the new norm all around.

The CD17 Ken Ishiwata signature, 1997, is Marantz’s attempt to re-imagine a world in which cost cutting had not taken place. The ‘money-no-object’ approach did not mean a return to the swing-arm laser or diecast chassis, but it did introduce some interesting features, such as an upgrade to the drive unit, a full copper shielding of the interior, a toroidal transformer, upgrades to the analog stage, improvements on current noise cancellation, etc. The result is a super silent player with a sophisticated sound stage. Similar to the outer design of the unit, there is not much splendour or extravagance to the music, but if you prefer to be caressed rather than impressed, the Marantz CD17-KI is not a bad choice at all.

Specifications

• Frequency range: 5Hz-20kHz
• Dynamic range: > 98 dB
• S/N ratio (WTD): > 103 dB
• Channel separation (1 kHz): >100 dB
• THD (1 kHz): 0.0015 % Analog output
• Output level (cinch JACKS): 2.2 V RMS
• Output impedance: 250 ohms
• Dimensions: 458 mm x 83 mm x 313 mm
• Weight: 7.8 kg

I first came across the Philips CD 104 in the early 1990s, when a school buddy of mine was looking to buy a used CD player and asked me for support. Since he was a ‘Philips man’, we checked the journals for budget offers from this company and ended up visiting a CD 104 owner to audition his player. At the time, I was used to the soothing amber glow and sleek modern design of JVC players, and the Philips struck me as being smallish in size and particularly ugly. The buttons seemed oddly out of place. And yet—against my advice—my friend ended up buying the unit and seemed rather happy with his purchase. The player was 8 years old at the time, and I must have been around twenty.

Back then, I was still unaware that Philips had been the company to introduce the CD player to the world, alongside Sony, in 1982, or that the CD 104 had only been the company’s second model. And since my friend had carried the player out of the house by himself, I was also left unaware of the seven kilograms in weight that the compact design so cleverly concealed. As far as I could see, my friend had simply paid too much for outdated junk. All the more, I was surprised to see a rather beaten up looking CD 104 perched on a CREACTIV HiFi-rack at a fellow audiophile’s house—in fact, as the only CD player among some famous turntables and amps. “If done well, the 104 has the potential for greatness.” my friend insisted. I was highly sceptical. This was in 2015, the player was 31 years old, and I was around forty-three.

A few weeks after my visit to the audiophile friend, our 5-year-old Marantz SA 7003 CD player quit working for the second time. The first time had been due to belt failure, and this time the laser had settled and could no longer read any medium. I was furious, and we decided that we would sell it broken, fully prepared to take a hefty 500 EUR loss. To us, the Marantz was not worth repairing, as its transport had been rather loud from the very beginning, with the servo correction being constantly in action. Experiencing such poor quality from a well-known brand destroyed my trust in the achievements of modern HiFi. How was it possible, that a more than 30-year old player could read CDs completely without servo noise and access individual titles faster than a 2010 state-of-the-art Super Audio player? How could the old player run for a great number of years without service, while the new unit seemed to break down every two and a half years?

I did some research on CD players and found that modern machines, even High End ones, are of modular construction with standardised and highly integrated circuits. Manufacturers essentially purchase and combine finished modules, box them in some uniform housing and stamp their name on the units. Sadly, this is done without the manufacturer having much influence on the quality of the parts, nor on the unit’s abilities in terms of sound reproduction. For example, I found that the laser on the broken Marantz player had been built by Pioneer and that many products using this type of SACD laser ended up having the same issues. What is the point of buying a Marantz, one might wonder, if the essential parts in the machine come from other manufacturers and are destined to fail? To make matters worse, modular construction often means that items such as transport and control, D/A converter, S/PDIF decoder, clock and perhaps even the output stage are combined into a single module. This scenario does not leave much room for the manufacturer to intervene, augment and improve the sound.

In the late 70s, when Philips set out to build the CD 104, things were quite different. Because the technology was new, Philips had to take full control and responsibility over the whole process. The new technology still had to prove itself to audiophiles with the money to spend. For the offer price of over 2,000 DM, and with few discs available on the market, the vinyl record player was still hard to beat in terms of sound. Philips had to give their new creation all the love and attention they possibly could. The CD 104 has a full metal chassis and includes the CDM-1 transport that Philips developed by themselves. The basis of this is a cast-iron form which holds a sophisticated swing-arm laser paired with six Rodenstock glass-lenses. In terms of musicality, the CDM-1 is considered to be the best transport ever made. Following the audiophile rule of “garbage in = garbage out”, a flawless reading of the source material is the basis for musicality.

While Philips engineers included everything they understood about transport construction to get their first players right, the focus of later players was to make the technology more accessible to the average consumer, and this meant bringing costs down. Iron, metal and glass gave way to plastic. And, since software and electronics are cheaper in production than precision optics, modern CD players will correct the tolerance of mediocre transport optics by using their servo motors and error correction at full capacity. Since these features are on board anyway, they might as well have a job to do, right? Before customers notice the handicap, and before their players fail, the warranty period will have expired. This explains why we could hear the servo motors on our Marantz SA 7003 CD player from the very beginning, and perhaps also why the player failed after a short five years.

When the Philips CD 104 tray opens, the sound, speed, and grace is similar to that of a bank volt opening. I catch myself holding my breath each time, hoping that it will once again make the full journey, just as it has so dutifully done for four decades. The player that Luigi brought by our house for testing has been skilfully reworked and upgraded to combine the physical assets of the eighties with the electronic insights of today. And although we are not quite certain to which extent the upgrade was made, typical improvements include making full use of the CDM-1 transport and the player’s two legendary TDA1540 mono multi-bit DACs by eliminating the digital oversampling and the analog filter in the output stage. Eliminating S/PDIF and jitter, and correcting channel delay. Further upgrades may include replacing the analog output amp from the original 35 transistors version to just two high quality FETs per channel, improving internal shielding, wiring, etc. German mods are currently available from Roman Groß ‘New Perspectives on Sound’ and from ‘KR High End Laboratory’.

From the outside, our unit shows gold-plated RCA/cinch sockets in place of the formerly fixed cable and plugs, as well as a three-prong power socket to allow the connection of a higher quality cord. The finished player not only surpasses its original setup in terms of sound performance, it also beats most of today’s players in terms of tonality, nuance, soundstage, and musicality. If the 14-bit DAC was ever considered to be a handicap by hasty customers, I can assure you that no handicap is audible at all. In fact, the later Philips 16-bit TDA1541 DACs (corrected 31.05.2021: see below) were used in Sony’s High End players well into the 1990s, which says a lot about what Sony thought of the Philips DACs.

Although I was quite sceptical at first, just a few seconds of listening made it clear to me that this vintage player performs well above the level that I was used to from our Marantz CD-17, an audiophile legend in its own right. CD never sounded this good in our house. If Marantz’s CD-17 is best described as sounding ‘analog’ and ‘warm’, I would not even know how to attribute special character to the Philips CD 104 NOS modification, except to say that it sounds —real.

At the time of writing this, the player is 37 years old. And just last night, I showed it to my seven-year-old daughter, and she ended up dancing to an Alin Coen CD.

Specifications

• Digital converter: 2 x TDA1540P
• CD transport: CDM-1
• Frequency response: 20Hz to 20kHz
• Signal to Noise Ratio: 90dB
• Channel separation: 86dB
• Total harmonic distortion: 0.005%
• Line output: 2V
• Dimensions: 320 x 86 x 300mm
• Weight: 7kg
• Year: 1984

NOS Modification

• No oversampling
• No analog filter
• No S/PDIF format
• No Jitter
• Channel Sync
• FET output amp

I came across our specimen of Pioneer’s 1995 budget CD player PD-S604 while looking for an affordable replacement for our trusted Sony CDP-502ES on which the original laser unit had begun to fail. Replacement lasers for the 30-year-old Sony had been out of production for some time, and the sources I was aware of had either sold their last stock or had since become ridiculously expensive. The Pioneer was by no means on the same technical level as the Sony, however, it did have a 10-year advantage as far as our understanding of laser technology is concerned, and, like the Sony, it was built at a time when decent HiFi still mattered. The PD-S604 ranked between the lower PD-S504 and the higher-specced PD-S904 in Pioneer’s price-conscious consumer range. As such, it was no match for the fully-specced PD-S06 that came out in 1997 and weighed around 10kg, however, at just over three kilograms, the PD-S604 already offered much of the same technology.

What attracted me to the Pioneer players of this time was their patented Stable Platter mechanism which firmly holds the CD in upside-down position on a revolving platter. In this constellation, the laser reads the disc from above, finding a nearly perfect focus plane each time. On most rival mechanisms, the CD will unavoidably wobble slightly, thereby requiring constant focus and error corrections from the mechanism itself and from the software. A further benefit of the laser positioned above the disc was the superior dust protection of the optical lens. Dust particles in the room are less likely to ‘settle’ under a suspended laser than they are on a laser that sits beneath the disk. Following the old HiFi principle of “garbage in, garbage out”, the output quality greatly depends on the integrity of the early signals in the chain. Having spent years of critical listening, I have become more aware of the audible effects on music shortly before a laser starts to skip. Thinning bass output and increased sharpness of the treble are the most obvious side effects.

There is a fine line between consciously detectable noise and the kind of subconscious noise that simply makes us think less favourably of a product without the reasons being quite clear to us. The PD-S604 promised to eliminate such noise on at least two levels: Via the Stable Platter drive mechanism described above and via an upsampling feature called Legato Link. The CD’s Red Book standard supports 2-channel stereo at 16 Bit & 44.1 kHz allowing for frequencies up to 20,000 Hz. While this is also considered to be the upper end of human hearing, the sound spectrum of natural music does not end there. Vinyl LPs allow turntables to naturally attenuate higher frequencies through the limiting physical properties of the needle, thus creating a smoother fade-out. CD players, however, cut off the upper spectrum by means of filters. This way of handling the high frequencies is said to give CDs a sharper and less tonally pleasant top-end. This circumstance is often quoted among the reasons for some audiophiles to prefer turntables.

Legato Link promised to process high frequency information in a more delicate manner by using spline interpolation to recalculate the missing original waveform. Pioneer’s Legato Link was among the first digital filters using spline interpolation to pass through superior transient information, however, this did not come without side-effects and could at times leave behind some unpleasant modulation at higher frequencies. It has sometimes been said that on well recorded CDs Legato Link did work its magic, but on some recordings, the algorithm seemed to be at a loss and added information that more resembled distortion than music material. I had to find out for myself how these claims would play out in real life and decided that the PD-S604 offered the best value for money of the range. Both the PD-S904 and the PD-S06 offered a digital cinch/RCA output which the PD-S604 did not have. However, since I wanted to listen to the player by itself without the use of an external DAC, I could live with its existing features.

The original owner of the PD-S604 reported that he had been more than happy with the player’s features and sound as well. He said that it sounded superior to all the players he had owned since and that his reason for selling had more to do with the family’s sleek new audio rack that offered room for a single combined CD/DVD unit only. Upon my arrival, I found the Pioneer perched on the dining room table with some old headphones attached for demonstration. The resulting sound was mediocre at best, and so I could only test if the player was basically functional and decided I would give it a more thorough inspection at home. When I left the house of the seller, I promised that I would make his player famous by presenting it on the eiaudio blog and invited him for a visit if he should ever be in Marne. When I arrived home that night, I gave our Sony CDP-502ES one final listen and then set up the Pioneer in its place. I would test my luck with having the Sony repaired once again, but I understood that this would take some months.

With its functional but not exactly audiophile power cord connected, the PD-S604 instantly went into standby. This was a welcome feature for me, because it meant that I could rouse it from its sleep via remote control. In fact, CD players were often the only audio devices in my setups to offer the luxury of remote operation at all. OK, to offer true luxury, the layout of the remote control (CU-PD045) might have been better arranged. The Power button, the Numeric Keys for the title selection, and the Play, Pause, and Stop buttons were all of equal size and integrated within a uniform grid of buttons. This made nighttime operation a real nightmare. And the controls on the front of the player were not without quirks, either. While Numeric Keys on the front of the player made it easy to begin playback from a given title, the placement of controls here was also quite counterintuitive. The Stop button, for instance, was placed in a different row than Play & Pause, which were positioned next to the button to Open/Close the tray. I wonder how many times this player has been opened by mistake in an effort to stop the CD from playing.

On some CD players using a single power supply for the digital and analog section (e.g. Denon DCD-1420) turning off the display will lead to a cleaner sound by removing some of the digital haze. However, turning off the LCD display on the PD-S604 simply turns on a red LCD display message saying that the CD display is currently turned off. Therefore, perhaps unsurprisingly, I was unable to detect an acoustic benefit in turning the display off. Perhaps another such quirk is that the motor-driven headphones volume attenuator also affects the variable line-out volume. In audiophile listening, we attempt to reduce the number of controls and attenuators in the signal path and mostly give preference to the fixed line output. However, users who prefer the variable option may well find it a nuisance to have the two features connected. The headphone amplifier itself is a bit weak and will only sound decent with low impedance headphones made for laptops or other portable devices. Audiophile 300 Ohms would quickly drive this headphone amplifier to its limits.

I connected the Pioneer to our upgraded Rotel preamplifier with Becker ST-200 MOSFET amplifier using HBS2 silver solid core wires. The Rotel-Becker combination is generally more musical than analytical, it sounds rather enjoyable and is tonally rich rather than bland sounding. When paired with our Epicure EPI 500 loudspeakers, the combo is ideal for relaxed nighttime cruises and a great companion for hours of effortless listening. I found the PD-S604 to blend in well here. The Becker amplifier provides a good sense of order with most music choices, and the Pioneer enhanced this impression adding even more depth to the soundstage. On many occasions, I felt that the music was positioned in a perfect round circle spanning from my ears to the speakers and beyond. I appreciated the fact that with the PD-S604 the music did not lose any of the intimacy that I was used to from this amplifier to speaker combo. 

Reading the disc with great accuracy and refining the top-end with Legato Link proved to be beneficial to most recordings of natural instruments as they are found in Jazz, Blues, Singer-Songwriter, Classical Music, and other handmade materials. One some recordings, however, it seemed that the high-frequency algorithm had some difficulty discerning music content from distortion and served to amplify this noise in a manner that I had not heard from other players. These artefacts could span from pure pink noise distortion to genuine background occurrences that remained hidden on other players. On one instance, the music material repeatedly changed from muffled to transparent as if the player could not make up its mind how to best handle the high frequency roll off. On the other hand, I must confess that I have not yet heard a CD player on which all recordings sound equally well. Suffice it to say that on some recordings the treble could be more accurate and better integrated.

There is one small upgrade I could not stop myself from adding: While taking the photos for the website, I noticed how unusually light the player felt. With its disk platter ejected, one might worry that it might fall over. I therefore added a sheet of anti-resonant coating to the inside of the cabinet (see last photo). Doing so added some 500 grams to the unit and served to reduce drive vibrations on the chassis which in turn led to an even more ordered sound. I once saw this method applied from factory on the Denon DCD 1500 II and rather liked the idea as a quick fix to mechanic issues. CD-players greatly benefit from a firm stand and lots of body weight to quiet their moving parts. A small tweak with audible effect.

Adding the anti-resonant coating, I noticed another small issue with the player. On some recordings there seemed to be a slight lack of forward drive. The player could sound a bit slow on occasion, especially when the music got faster. It is well possible that this effect was further highlighted in combination with the Becker amp that would at times display a similar tendency. The impression never stayed for long, but it was noteworthy enough for me to mention it here. Fans of faster music might want to take this into consideration or at least test the player with their material to first see if it works for them. On the music that I listen to, the occasional loss of momentum never troubled me a bit.

In its current state, I am indeed very satisfied with my purchase and enjoy the warm and pleasant sound of the PD-S604. There is sufficient bass presence to make instruments sound real and well-rounded. The Pioneer’s superior sense of order and its generous spacing of instruments are attractive features for the recreation of natural instrument recordings. In my experience, the musical benefits of Legato Link far outweigh the few instances in which it does not work so well. All in all, the PD-S604 has grown on me more than our Sony ever had. The better the music material is recorded, the better this player can show what it can do.

What experiences have you encountered with this player? At the time of writing this, there was not much information on this Pioneer player to be found on the web. Click on the header picture to activate commenting and be sure to share your personal experience with us.

Specifications:

• Type:  Stable Patter mechanism CD player
• Power requirements:  AC 220 - 240 V, 50/60 Hz
• Digital converter:  PD2029A
• CD Mechanism:  PEA1179
• Frequency response:  2 Hz - 20,000 Hz
• Signal to noise ratio:  > 108 dB
• Dynamic range:  > 96 dB
• Total harmonic distortion:  < 0.0028%
• Line output voltage (max.):  2 V
• Wow and flutter:  < 0.001% (below measurable)
• Number of channels:  2-channel (stereo)
• Variable line output (stereo):  1x cinch/RCA
• Fixed line output (stereo):  1x cinch/RCA
• Digital output (stereo): 1x optical 
• Accessory jack: CD-Deck synchro to tape
• Headphone jack: motor drive volume control
• Accessories: remote control unit
• Remote batteries: 2x AAA
• Power consumption: 15 Watts
• Operating temperature:  +5 to + 35 C
• Dimensions: (W) 420mm, (D) 286mm, (H) 110mm
• Product weight:  3.9 kg
• Country of Manufacture: Japan
• Year(s): 1995 - 1996

It is sometimes suggested that the CD today is an outdated medium, and that its prescribed 16-bit, 44.1 kHz Red Book standard places it well below the musical abilities of other analog and digital devices. This is no wonder, of course, as today’s audiophile competition comes in form of high-resolution formats from digital streaming services and from the analog revival that, after decades of stagnation, has once again led to rising vinyl sales. In addition to this, the CD is sidelined by audio formats of lesser significance, such as Super-Audio CDs, DVD-Audio, reel-to-reel, etc.

And yet, the medium has a lot going for itself. For one thing, it is tangible. Touch is something that a subscription to Tidal or Amazon HD is sorely lacking. While it is true that many CDs are sitting on our shelves never to be heard again, there are currently around ten CDs in our home collection—mostly Jazz and vocal Jazz albums—that are getting all the attention they could ever ask for. And then there is the pride of ownership, of course, as the hunter-gatherer in me is enjoying the fruits of said labor. And—since the laser does not physically touch the track while reading—there is no immediate worry about deterioration either. In obvious contrast to vinyl, CDs do not suffer as much from the effects of repeat play.

Similar to records, audiophile CD players read the information straight from the disk and shy away from unnecessary storage or modulation of sound. They will expose the shortcomings of both the medium and the recording, important factors in providing a reassuring sense of realism and dimension. In contrast to vinyl, however, the CD itself does not contribute its own material resonances that would make it sound organic and therefore familiar to the human ear. Instead, CD data is likely to be affected by resonances emanating from the drive motor, the laser’s queuing mechanism, vibrations from the built-in transformer, and from other units in the rack. It can be said that all electronics and mechanics around the music information on a CD are larger, louder, and prepared to spoil the listening fun. And since the resulting effects are unfamiliar to the human ear, they can be deemed unpleasant. Still, the CDs biggest sonic advantages over modern streaming services are that it is both tangible and local. Its data stream does not depend on the integrity of various relay servers along the way to reaching our ears.

The first Rega Plant CD player came out in 1997, a time when the CD was at the height of its popularity, and four long years before the first mp3 players came to the market. Rega was already a familiar brand in the audiophile community. Founded in 1973, the British ‘Rega Research Ltd.’ had been known as a notable manufacturer of audiophile amplifiers, loudspeakers, and—most significantly—turntables long before they ever considered making a CD player. The famously affordable Planar 3 turntable had won Rega international recognition among vinyl enthusiasts and become a bedrock for analog playback. In addition to selling under their own brand name, Rega had also been asked to supply turntables, tonearms, and related parts to other brands, such as NAD and Rotel.

For a vinyl specialist to enter the CD player market, the company needed to come up with a convincing argument for its followers. The original Planet was marketed as offering true ‘vinyl-like’ sound made by a company that normally hated the sound of CD players. This created some curiosity, and the original Planet sold well, despite its quirky industrial look. It favoured musical flow over detail and achieved a soft top-end despite sounding a bit bland and crude, as some reviewers of the player have observed. Especially the lack of detail on the Rega's customised Burr Brown 16-bit DAC has sometimes been criticised as being outdated in more recent reviews.

The Planet 2000 brought about a major facelift to the original Planet. Instead of plastic, it is housed in a custom-built extruded aluminium case with a central top-loading lid. The 2000 uses similar circuit topology as the original Planet but features an improved DAC (Wolfson 24-bit, Sigma Delta IC40), power supply and coupling capacitors. Instead of a conventional iron core transformer, the 2000 version has a toroidal transformer with separate windings for the display and audio stages. Display and controls were also given a makeover, giving the Planet 2000 a better performance, look, and feel in comparison with its predecessor. However, while many things have been improved, the player does have some surprising quirks that make it difficult to compare the Rega design with more conventional front-loading players.

For one thing, the top-loading mechanism means that the Rega 2000 requires at least 20cm of rack space height for the lid to fully open. Due to some necessary adjustments made for the Rega, my rack only offers 17cm which makes changing CDs less than convenient. The drive itself sits in a plastic tray at the centre of the player’s aluminium case. Where it has not been painted, the plastic has become tobacco-coloured from UV radiation on one side. Both the front and rear panel are made of plastic. While the front panel has been painted in cabinet colour, the rear has been left unpainted and also shows discolouration. Although we hardly come in contact with the front or the back of the player during operation, the use of plastic on the front has proven to be somewhat disappointing.

The Planet’s CD drive holds the CD in a peculiar way. Similar to a turntable, there is a central prong surrounded by a cone-shaped centre that is sitting on a spring. The CD is placed on the cone and continues to wobble. Pushing the lid down then lowers a magnet onto the centre of the CD and pushes down the cone with the CD exactly centred, or at least this is the theory. In reality, CDs are sometimes slightly off axis, resulting in a wobble of the disk and the magnet on top. And since the top of the magnet is visible though the lid from the outside, one cannot help but wonder how long this will continue to go on well. While the Rega’s custom made Sony transport is surprisingly resilient in reading despite disk wobble, it is at times possible to hear the wobble in the music though strangely elongated, followed by compressed, passages. When the disk does skip, the jump is quite brutal and can misplace the laser by as much as half a song. To be fair, most CDs play with only a tiny amount of wobble, and of those that exhibit wobble, side effects will be minimal. But the player is far less forgiving than any CD player I have ever had. Playing a CD becomes as delicate a ritual as playing a vinyl record.

Due to the excessive weight of the magnet, the Planet 2000 is quite demanding in terms of proper placement in the rack. The drive is in the centre of the extruded aluminium case that channels vibrations along its curved sides down to the four rubber feet. In contrast to our other CD players, the Rega requires just the right amount of support to keep it still. My first attempt was to place it in our rack without the support a base, but this made the player sound harsh and agitated. I then brought in a base placed on Oehlbach spiked absorbers. The player sounded soft but exhibited serious timing issues that made me look for the quirks rather than listen to the music. I swapped the absorbers for Harder Oehlbach pucks which helped to improve timing but somehow resulted in a lack of bass. I finally placed the base directly on the rack and was surprised that this by far sounded the best.

I love the fact that the Planet 2000 allows us to connect a dedicated power cord. Sadly though, the central position of the socket makes it more challenging to avoid the touching of cables behind the rack, especially, since dedicated cords, such as Lapp Ölflex are quite stiff. Turning the player on and off is possible while preamp and power amplifier are turned on without any trace of popping. This excellent muting of the player during operational changes is definitely noteworthy and very practical. SPDIF, Toslink, and RCA/cinch sockets are available to allow for all kind of applications, however, the plugs are slightly recessed into the rear panel, which might render them inconvenient in combination with some types of plugs. They could also feel a little sturdier, perhaps. Although the display has its own source of energy from the toroidal transformer, the sonic effects of having the display switched on are still audible in a slightly compressed and hazy soundstage. The display-off function allows the display to be turned off during playback with a positive effect on the sound. And since one can hear the difference, with a system and ears so inclined, it makes sense to use the display-off feature. When this function is engaged, however, the display will only light up briefly to acknowledge remote commands. While this is quite convenient, the on-time is a little too short for me to read the title. The display itself is red and relatively dark when turned on. This makes it difficult to read over long distances.

For optimum performance, the Planet 2000 needs to be paired with an excellent interconnect. In my experience, simple copper cables will not be able to show its full potential and could be a reason for some private reviewers reporting a lack of detail. I have tested the player with different types of RCE/cinch-type interconnects, from solid core copper, via silver coated multi-stand copper, to solid core silver, and I can report that the ladder surpassed all other choices by far. Using the silver solid core HBS2, the 2000 is sufficiently forward sounding and creates a wide open sound stage with an broad and accurate phantom centre image. I have no complaints about the amount of detail. If a disc should wobble, this can be heard mostly through timing issues and alternating channel imbalances.

If the recording permits, the Planet 2000 offers a smooth flow of music with a refined top-end. It is not quite as lush as the Philips CD 104 (NOS mod.) player, nor does it bring the music forward with such ferocity. It does, however, offer sufficient bass if properly placed on the rack. The music it produces is tonality accurate on piano, voice, percussion. The overall impression is laid-back with a sufficient amount of entertainment to keep me interested during longer listening sessions.

The biggest downside to the Rega Planet 2000 appears to be the magnet that holds down the disc. Rega have physically decoupled the toroidal transformer from the main board and the CD transport. They have asked Sony to aid them in the development of a unique transport mechanism, and yet, a wobbly magnet brings a new uncertainty into the equation. Since the whole CD transport can be replaced in the form of a low-cost kit that is screwed under the loading mechanism, I will attempt to fix the issue with a new drive. But if the magnet itself is to blame for the wobble, this matter will need further attention. All said, attempting to fully restore the Planet 2000 is a worthwhile activity, as the player itself performs far better than the typical mid-priced CD player found on the market today. In keeping with the tradition of other British audio brands, this player offers a gutsy and unique design approach that merits further exploration and therefore fits well with our website motto.

Specifications

• Laser type: semiconductor
• Wavelength: 780nm
• Transport: Sony, top-loading
• DAC: Wolfson, 24-bit Sigma Delta IC40
• Filtering: 3-stage linear FIR, 16x oversampling
• Connections: line (unbalanced), S/PDIF (coaxial), Toslink
• Line output (max.): 2V
• Output impedance: 930 ohms
• Digital output: 0.5V
• Load impedance (min.): 75 Ohms
• Power consumption (max.): 10 Watts
• Formats: CD, CD-R, MP3, WMA, WAV, AIFF
• Extras: 'Solar Wind' remote control, CD text display
• Dimensions: 43.5cm (w) x 10.0cm (h) x 27.0cm (d)
• Required Space: 43.5cm (w) x 18.0cm (h) x 31.5cm (d)
• Weight: 3.65kg
• Year: 2000

The CDP 502 ES was one of the early Sony CD players. It stemmed from a time in which engineers were given enormous budgets to derive what was humanly possible from their new digital audio medium. And, although Sony’s CDP 101 had been the first CD player to enter the world market, in early 1982, the company knew that they were not alone in the race. To share R&D costs and spread the risk, Sony had developed the technology in a joint venture with Philips, who were the first to launch their CD-100 in Europe in that same year. Marantz, Denon, and other manufacturers were soon to follow, and Sony had to innovate quickly in order to stay abreast of the competition. Launched in 1984, just two years after the CDP 101, the CDP 502 ES already showed many improvements over the company's first designs.

I received my test specimen from Luigi, who had purchased it from a collector along with some other audio devices. At first glance, there were no clues to betray the CDP 502 ES’s exceptionally high quality. To me, it looked like yet another CD player of the early 1980s. Black-box design with front-loading tray, lots of square buttons, an inconspicuous display, new infrared remote sensor, and headphone/output volume control. There really was nothing special in the design, until I tried lifting the Sony off the table where Luigi had placed it. Not only was it much heavier than the standard gear sold, it also seemed more rigid in its construction. I wondered if Sony had also glued lead sheets under the unit’s top plate, as I had previously seen on the Denon DCD 1500 II; however, a swift look under the hood revealed more substantial reasons for CDP 502 ES’s weight.

The front-loading drive mechanism was constructed out of machined metal blocks, instead of the already more common plastic. There was a large transformer with separate outputs for the digital and analog audio sections, as well as for the front display, and the drive and loading section. The stabilising power supply capacitors looked large enough even to serve a small amplifier. There was a copper-plated metal sheet to separate the drive unit and power supply from the audio signal section, and another sheet to separate the digital processing unit from the analog output stage. Although this was not instantly visible from the outside, the Sony engineers had taken many precautions to take audio performance to the next level. Due to its massive components and quality loading mechanism, the CDP 502 ES had the touch-and-feel of professional studio gear.

Although it was difficult for any CD player to compete with the cast-iron transport of the Philips CD 104 with sophisticated swing-arm laser paired with Rodenstock glass lenses, I must say that I preferred the smoother and more elegant feel of this Sony tray. The simple act of placing the disc on the tray felt very reassuring. I could also see how the understated design might have even highlighted this effect. There was no detectable time lag in closing the tray, and the unit offered ultra-fast pre-scan and disc access. Button commands were prompted by instant relay-switching feedback that was still audible from as far as 4 meters (!) distance. When the CDP 502 ES was in operation, one of three back-lit buttons served to indicate the play mode (Program, Shuffle, and Continuous).

The Sony offered two chinch/RCA outputs, of which one was variable via the Line Out/Headphone volume control. This feature allowed for the CD player to be integrated in a system with components of various audio output levels. I would have liked to see a digital S/PDIF output socket for added versatility and also welcomed a display-off function for additional noise reduction. However, as I had not been given the remote control along with the player, I remained unsure, if the display-off function had at all been available there. The headphone jack was of the larger 3/4-inch type, which was also my personal preference. Playback accuracy was said to be excellent due to the use of a new unilinear converter system that performed all digital signal processing in synchronisation with a single clock.

Sony proclaimed the CDP 502 ES to stand for a new generation of reference machines, and audiophiles have commented on the player’s ability to reproduce lots of musical detail while preserving the tonal warmth that was often associated with analogue equipment. Sony were also pioneers in the development of phase-correct analog and digital filters, as well as in advanced error correction that were all incorporated in the 502 design. The analog stage and output amplifiers were of a double-mono design and used Sony’s newly developed OP-amps. In many ways, the CDP 502 ES incorporated the best of CD player technology that was available at the time, and I was eager to find out how the 40-year-old unit would perform.

I hooked the CDP 502 ES up to our main system consisting of a Dynaco PAS-4 tube preamplifier and Hafler 280 XL Linear MOSFET power amplifier. The speakers were a pair of Martin Logan SL-3. The Martin Logans’s electrostatic panels were capable of reproducing even the most subtle nuances, and the Dynaco preamplifier served to assure that the overall impression was tonally rich and not overly analytical. The Hafler amp offered approximately 250 watts per channel into a 4 Ohms load and showed great low-resistance capabilities down to 1-Ohm loads. It was also known for its ultra-flat amplification well beyond the audible spectrum. Our usual CD player in this position was a Rega Planet 2000, of which it was also said that it offered an analogue-like sound.

For my listening tests, I used an assortment of Jazz and Vocal Jazz CDs, Rock, and even some Hip Hop. I wanted to find out how the CDP 502 ES would perform over a wide range of styles. From what I had seen on its circuit boards, I could imagine that the Sony would pack a punch, and I was not disappointed: The music was fast and loud with slight upper-bass emphasis. Using the fixed output cinch/RCA sockets, there was massive gain right from the very first second, and the music seemed so punchy that it bordered on overly potent. And yet, there was also an element of tight-fisted control that somehow reminded me of Denon’s DCD 1500 II, a CD player that had come out two years later. 

Both the Denon and the Sony were High End players in their time, and both weighed around 9kg. A lot had been done to reign in high-frequency distortion on both of them. As a result, both machines seemed to march through the songs rather than swing though them. The resulting sound felt a little lifeless at times, and I would have wished for more freedom for the music to unfold and for individual notes to be allowed to simmer longer. The strong upper-bass presence could serve to give vocals a little more substance, which was a welcome effect. On the other hand, faster passages could at times sound a bit cluttered or congested because of it. 

Piano keys did not simmer as long or resonate as low as they did on our 30-years younger Rega CD player. Low-bass extension was generally good on the Sony but not great. Despite Sony’s lead in error correction, the CDP 502 ES did not perform too well on dirty or scratched CDs. For the music to sound at its best, the discs needed to be in excellent condition. I could confirm that the 1984 Sony provided an analog and non-analytical sound experience on our system. The CDP 502 ES sounded fuller, richer, and darker than many of its competitors. Due to excessive filtering, however, some of the intrinsic flow and musicality of the performance was lost, which also took away from the believability of the music event. 

Finally, I could not help but wonder, if there were available modifications for this player that would remove some of the analog and digital filter stages to uncover the beauty and power of the diamond underneath. Considering what Roman Groß ‘New Perspectives on Sound’ and ‘KR High End Laboratory’ had accomplished with the Philips CD 104, it was only fair to assume that the CDP 502 ES also had the potential of blowing most modern CD players out of the water, simply because of the impressive components that were used inside.

Specifications

• Type: Compact Disk player
• Laser principle: GaAlAs double hetero diode
• Disk revolutions per minute: 500 ~ 200 (CLV)
• Paying speed: 1.2 - 1.4 m/s
• Error correction: Sony Super Strategy
• DAC compound: 16-bit, straight line
• Frequency range: 2 - 20,000 Hz (+/- 0.3 dB)
• Harmonic distortion: < 0.0025% (1 kHz)
• Dynamic range: < 96 dB
• Wow and flutter: below measurable limits
• Line output: 2 Volts
• Headphone output: 28 mw (32 Ohms) 
• Power consumption: 16 watts
• Dimensions: (W) 430mm x (H) 80mm x (D) 335mm
• Weight: 8.5 kg
• Accessories: Wireless Remote, RM-D502
• Country of manufacture: Japan
• Year(s): 1984-1987

Cambridge Audio have long since made a name for themselves, offering very decent sounding gear at entry level prices. Perfectly fine for beginner audiophiles, as long as we do not insist on impressive build quality. Having said this, the tiny ‘DacMagic 100’ is certainly in keeping with this tradition. Similarly equipped as its larger brother, the ‘DacMagic Plus’, the unit offers a single 8742 Wolfson chip that can easily be found in higher priced digital to analog converters made by Rega and similar brands. Its USB 1.0 port might sound a little outdated, but it will handle data at rates of up to 192 kHz. In addition to the USB port, it features two S/PDIF inputs and one Toslink optical input. Outputs are RCA/cinch only, an inadequacy for some users that it does not share with its larger and better equipped stablemate.

Ken Rockwell has written an extensive review of both Cambridge DACs and in his measurements concludes that especially the USB signal processing is of unquestionable quality. In my own listening tests I have found that the DacMagic 100 performs very well over the whole bandwidth without any instantly recognisable imbalances. The stage impression is both wide and deep with plenty of space between the instruments. Voices come across in a life-like fashion with perhaps a slight tendency of too much transparency. Although bass performance was lean and fast from the start, it did not have the fullness of some pricier components. Understandably in this price range, the product’s weakness lies in its power supply. Adding a more potent power supply than the cheap plastic switching device, however, really made the bass open up and has left nothing to wish for ever since.

The DacMagic 100 is a great entry level DAC for audiophiles on a budget who shy away from the initial purchase price. Adding in a power supply at a later stage is nearly a must, although this will at least double the price of the unit. For buyers who can live with this two step process, the DAC really offers quality. On the other hand, if you are willing to invest the whole sum right from the start, you might as well get a DAC that has a decent power supply to begin with.

Specifications

• Digital to analog converter: Wolfson WM8742 24-bit DAC
• frequency response: 20Hz to 20kHz (±0.1dB)
• THD @ 1kHz 0dBFS <0.0025% 24-bit
• THD @ 1kHz -10dBFS <0.0025% 24-bit
• THD @ 20KHZ 0DBFS <0.0025%
• Signal to noise ratio: -113dBr
• Jitter <130pS
• Crosstalk: @ 1KHZ < -130dB
• Crosstalk: @ 20KHZ < -112dB
• Output impedance: <50 ohms
• Output level unbalanced: 2.3V rms
• Digital input width: 16-24bit
• Digital input frequencies: 32kHz, 44.1kHz, 48kHz, 88.2kHz, 96kHz, 192kHz
• Power consumption: 5W
• Dimensions: 106 x 46 x 130 mm

Picture description

Picture Description Seen from above, we can identify three separate sections, the internal power supply section (bottom third), the unit's operating and switching section located around the main processor (center), as well as the digital to analog processing section (top third). The top third can be divided into the digital section featuring three clocks and the Wolfson 8742 DAC chip (right) and the analog output section with one operating amp chip per channel and a set of capacitors (left).

As some of you might remember from my review of our Technics SL1310 turntable, this had moved in with us equipped with its original Shure M75 cartridge and ED stylus (elliptical diamond) from the late 1970s. In order to assure that the worn cartridge would not destroy our records, I had first checked the stylus under a microscope and found it fit to perform. There were some initial electric issues on the left channel, which our trusted technician solved by pushing a faulty pin into the cartridge with his soldering iron. He had thereby re-established the connection, and the turntable did perform well, until recently, when the left channel failed once again. It was high time to make a change.

Upon inspecting the tonearm of the Technics, I was reminded that this table already featured the practical half-inch headshell mount. Therefore, if I was going to invest in a new cartridge, I could also easily exchange the headshell and wiring along with it. And, since the headshell held both the cartridge and connectors, its resonances and the quality of its wiring would have some influence on sound quality. I checked the web for possible cartridge and stylus combinations and shortlisted three rather affordable MM (moving magnet) models among the more audiophile specimen that were all designed for medium-compliance tonearms: the Ortofon 2M Silver, the Nagaoka MP-150 - which is actually an MI (moving iron) cartridge and thereby similar to an MM - and the Audio Technica VM 540 ML.

Among the tree cartridges, the Audio Technica had the most sophisticated stylus, and, since we were still very happy with our previous purchase of the Audio Technica VM 95 ML for our Sansui SR-525, I was curious to explore the differences between the two cartridges of the same manufacturer, that were both equipped with micro-linear styli, with the specifications of the 500 series being slightly superior to those of the 95. To confirm the result of my musings, I discussed my considerations with a gentleman at thakker.eu, who confirmed that the sophistication of its stylus placed the ML version ahead of the competition at the given price point. For the 500 series, the total choices of styli were as follows:

Stylus Choices

• AT-VM510 CB = Conical - Bonded Round Shank
• AT-VM520 EB = Elliptical - Bonded Round Shank
• AT-VM530 EN = Elliptical - Nude Round Shank
• AT-VM540 ML = Microlinear - Nude Square Shank
• AT-VM550 SH = Shibata - Nude Square Shank
• AT-VM560 SLC = 0.28 x 1.5 Mil Special Line Contact

Except for the VM560 SLC, which was more than double the price of the VM540 ML (and at that time Audio Technica’s most expensive MM cartridge ever), the micro-linear version was considered to be the most versatile performer among the choices. Although the 500 series would still be deemed an entry-level cartridge by some, the stylus's micro-linear cut in combination with the nude mounting on a square shank made the ML very capable of extracting the tiniest nuances from the record groove. Similar to the 95, the 500 series cartridge used dual magnets that were arranged in the shape of a ‘V’ to resemble the shape of the cutter-head. The design was to assure maximum amplitude and improved channel separation. The cartridge had been laid out to work equally well on most low and medium mass tonearms. In its VM540 ML/H version, it came pre-mounted on Audio Technica’s HS-10 headshell, and I decided that this was the most practical solution for our SL1310.

When the cartridge arrived, I was pleasantly surprised by the easy way in which I could twist the headshell out of its socket in the packaging and decided that I would use this same box to securely store our old headshell. As I had already been warned by the vendor, the cartridge first needed to be aligned to fit the specific layout of the SL1310. I used my old alignment protractor, on which the inner groove position can be aligned with the device staying in place, and was pleasantly surprised that the VM540 ML’s fold-down stylus cover also served in setting the correct angle and overhang. It produced a straight line on the protractor which made it easier to perform the setting. I also noticed that the new VM540 ML/H was lighter than our original setup, which meant that I had to dial back the tonearm weight quite substantially. I set the overhang and adjusted the tracking force to the recommended 2.0 grams using our digital tracking force scale.

One thing that took me a little by surprise, was the fact that I had to disconnect the SL1310 from the wall socket in order to perform these settings, as I could not shift the tonearm sideways without activating the built-in autostart. The platter jumped into action each time the tonearm was brought near to it, and, although this was quite clearly a feature of the automatic drive, it took me a moment to appreciate that there was no way around physically pulling the plug. Perhaps this is just me, but for some reason pulling the plug seemed rather crude to me, and I could not shake the feeling that I had overlooked some detail, like an on/off-switch perhaps.

When I finally did sit down to listen, I could hardly believe the improvement I was hearing over the previously mounted Shure M75 ED. There was simply more of everything. Listening to Carmen Lundy’s album “Soul to Soul”, I first noticed the superior exactness of the micro-linear stylus. And even though I had already experienced this effect in transitioning to the ML cartridge on our Sansui SR-525 turntable, I was deeply impressed once again. I had become so familiar with the little inaccuracies of our vintage Shure cartridge that hearing the album without them brought a whole new sensation to the medium. The VM540 ML produced a very low noise floor, showed no sibilance at all, and was capable of providing a highly accurate impression of the original musical event. And while it presented lots of musical detail, it did so in great harmonic coherence with no aspect being accentuated. I found this to be enjoyable, engaging, and superbly balanced at the same time.

The Audio Technica made our Tannoy XT8F loudspeakers sound larger and more intense than I was previously used to. The soundstage was excellent, with Lundy’s voice positioned smack center stage and all instruments arranged spaciously around her. This effect was aided by the long-trailing decay of individual tones. Transients had always been a special strength of the ML styli. In Lundy’s “Sardegna”, the xylophone appeared to be almost three-dimensional with individual notes appearing as vividly as bubbles in a glass of champagne. Trumpets and higher piano notes reached deeply into the room, whereas percussions remained slightly recessed. Bass notes were present but not as pronounced as they had been on the Shure. This impression stayed the same, even after I changed to Ted Poor’s album “You Already Know” that has much stronger bass lines. Instead of being boomy or overly extended, bass remained nuanced and controlled at all times. Bass enthusiasts would probably do well to increase tracking force to 2.2 or 2.5 grams, but I usually prefer stellar transients over mighty bass roar.

The Helge Lien Trio’s “Guzu Guzu” was more densely arranged than the previous two albums and gave the VM540 ML cartridge opportunity to show that it could also stay accurate in more volatile and cluttered situations, in which a multitude of natural sounds from acoustic instruments overlap. To my great satisfaction it also played this album effortlessly and smoothely to the last groove, accurately tracing each nuance without loosing itself in the detail. When compared to the VM 95 ML of the same company, I found that the two are very similar, but that the VM540 ML plays vocals with a softer and more balanced top end. This could be due to its extended frequency range or superior channel separation, but it could just as well be attributed to the periphery used. Technics decs are said to be very well engineered turntables. At this point, I can only say for certain that the VM540 ML was much easier to align with the built-in stylus protector folded down. If you are thinking about upgrading a vintage turntable with low or medium mass tonearm, Audio Technica’s 500 series is certainly worth considering.

Specifications

• Sound: Silent on the record, balanced and highly nuanced, warm with silky vocals, controlled and well-contoured bass
• Type: dual moving magnet
• Frequency Response: 20-27.000 kHz
• Channel Separation at 1KHz: 28 dB
• Input Load: 47,000 Ohm
• Output at 1KHz 5cm/sec.: 4mV
• Recommended Tracking Force: 2.0 g
• Stylus Type: Nude Micro Linear Square Shank
• Inductance: 550 mH
• Resistance: 485 Ω
• Weight: 6.4 g
• Height: 17,3 mm
• Year: 2020 -
• OSP: EUR 246,00 (Germany)
• Stylus Replacement: VMN40ML

Sound impressions based on the following system: Technics SL1310 record player, Dynaco PAS4 preamplifier, Hafler XL 280 power amplifier, Tannoy XT8F loudspeakers.

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Audio Technica’s VM95 E is an entry-level moving magnet cartridge that succeeded the widely known AT95 E in 2019. The new design includes improvements to the elliptical stylus, which is now thinner, as well as a higher output voltage. The new VM95 engine supports a whole range of compatible styluses, which should make upgrades a little cheaper and more convenient, compared with having to replace the whole cartridge. The available styluses range in 6 steps from simple conical design to complex 'shibata' (patented cut). While the lower-range styluses are bonded to the shaft using a type of solder, the higher-range ones are joined directly, i.e. ’nude’.

Stylus Choices

• AT-VM95 C = Conical - Bonded Round Shank
• AT-VM95 E = Elliptical - Bonded Round Shank
• AT-VM95 SP = Conical SP - Bonded Round Shank (shellack)
• AT-VM95 EN = Elliptical - Nude Round Shank
• AT-VM95 ML = Microlinear - Nude Square Shank
• AT-VM95 SH = Shibata - Nude Square Shank

The VM95 E is equiped with the second possible entry-level stylus and already shows some marked improvements to the discontinued AT95 E, although it maintains some of the typical traits that are to be expected from an elliptical bonded design. Especially when coming from the more sophisticated styluses such as the micro-linear or the shibata, the AT95 E lacks some of the clarity and nuance that the higher up versions are capable of. On Katie Melua’s 2020 “Album No. 8”, for instance, the music appears to be more compressed. A general lack of sonic detail makes her voice seem less revealing and therefore not as intimate as we are used to from the micro-linear stylus.

While there is still sufficient space between the instruments, poorer recordings will more easily sound muffled and restrained. Voices are portrayed in a tonally balanced and full-bodied fashion, however, which is certainly a strength. I feel the VM95 E plays voices tonally more accurate than some of the higher versions, as there is no trace of nasal effects. On the down-side, the elliptical stylus can produce sibilant vocals, as is the case on my not-so-great pressing of Norah Jones’s “Come Away with Me” album, which is still fun on the ML stylus and only just bearable on the E version.

While bass performance is accurate and certainly fuller and more present than on the former AT95 E, bass nuance, extension, and detail is sometimes missing, especially in direct comparison with the higher-priced versions. And this is arguably the aspect that makes it the most difficult for the entry-level AT95 E: the stylus competition that is based on the same engine. When we started our explorations with the AT95 E two years earlier, I did not think I would mind the lack of detail for as long as the music was tonally balanced. Coming from the more recent and more capable ML version on our other system, however, now makes it less enjoyable to listen to AT95 E. Not because it puts up a poor performance, but simply because I have meanwhile come to enjoy the more sophisticated sound, which, sadly, is a well-known audiophile's dilemma: "Once you have heard it, there is no going back."

Specifications

Character: a solid tracker with occasional sibilance, semi-revealing of musical detail, full-bodied, warm and leaning towards neutral, musically balanced

• Frequency Response: 20-22.000 kHz
• Channel Separation at 1KHz: 20 dB
• Input Load: 47 kOhms
• Output at 1KHz 5CM/sec.: 4.0 mV
• Recommended Tracking Force: 2.0 g
• Stylus Type: elliptical stylus, bonded fixture
• Inductance: 550 mH
• Resistance: 485 Ω
• Weight: 6.1 g
• Year: 2019 -
• OSP: EUR 46,00 (Germany)
• Stylus Replacement: Original, EUR 28,00
  

Audio Technica
Technica House
Unit 5, Millennium Way
Leeds
United Kingdom
LS11 5AL

The Audio-Technica Corporation is a Japanese manufacturer of phono cartridges, turntables, headphones and professional microphones. The company has its headquarters in Tokyo and launched its first products, the AT-1 and AT-3 MM phono cartridges, in 1962. Its most notable devices include a long list of headphones, a portable record player, and also some phone cartridges. Among the latter was to be found the entry level AT-95 E which became renowned for its outstanding quality-to-price ratio and was therefore predestined as an entry-drug to audiophile listening.

The now discontinued AT-95 E set itself apart from the competition by featuring a more sophisticated elliptical stylus while its price competitors were still equipped with simpler conical or spherical styluses. The elliptical shape of the stylus allowed for more detail to be picked up from the record and made for excellent treble performance. The midrange was sometimes perceived to run a little thin and nasal. Bass performance on the other hand was tight, full-bodied, but not overly heavy or particularly noteworthy. The AT-95 E’s in-house competition came from the more expensive AT100E, which outperformed the entry level cartridge in most aspects.

With their new AT VM95 cartridge, Audio Technica have given the AT95 a long needed overhaul. The full cartridge name is comprised of the company acronym ‘AT’, the body or engine type ‘VM95’ and the type of stylus attached. On the AT VM95 ML, the final two letters stand for ‘Micro-Linear’, which is one of five possible stylus choices for the new VM95 engine. The ‘ML’ version is a dual moving magnet stylus construction with nude needle attachment and a micro-linear cut. ‘Nude’ means that the needle is attached directly, instead of being soldered onto the shaft.

Stylus Choices

• AT-VM95 C = Conical - Bonded Round Shank
• AT-VM95 E = Elliptical - Bonded Round Shank
• AT-VM95 SP = Conical SP - Bonded Round Shank (shellack)
• AT-VM95 EN = Elliptical - Nude Round Shank
• AT-VM95 ML = Microlinear - Nude Square Shank
• AT-VM95 SH = Shibata - Nude Square Shank

From our own listening experience it can be said that the VM95 is a no-frills entry to mid-level engine with sufficient dynamic potential and average channel separation. It appears that the sound has been optimised for modern listening preferences in that it is balanced, detailed and forward sounding with all stylus combinations.

Paired with the ML stylus, the VM95 manages to present lots of detail from the record that simply remains hidden from the simpler stylus versions. The sonic impression is that the frequency band is extended, revealing even the tiniest nuances in the music. With the ML stylus, cymbals sound more delicate and ring much longer than on the lower cartridge versions, and no two drum beats sound the same. There is more insight into the various playing styles of other instruments as well: piano keys sound a little softer, and there now is a marked difference of duration and force on each one.

Voices sound full and warm with no traceable bias to my ears. Female solo artists appear to have more air in their lungs and to carry notes longer and with greater accuracy than I have ever heard on any other medium, such as CD or streaming. Despite this amount of delicacy and detail in the presentation, we could detect hardly any mechanical noise coming from the record itself. Instead, the record remained ultra silent with only the music in the listener’s focus.

With the ML stylus it is easy to hear right through poor recordings. Although I have found both new and old recordings to play well, the ML stylus sounds best with more recent productions that also take into consideration the more revealing nature of today’s equipment. Listening to Bob Seger’s “Greatest Hits” album for instance, the ML stylus made the limitations of the original recording far more obvious than the elliptical ‘E’ stylus would have done. On Katie Melua’s newly released “Album No. 8” the voice comes across in a strange combination of purity and a silvery overtone that seems to stem from the studio microphone design. One needs to at least be aware that opting for the micro-linear or Shibata stylus versions for the VM95 engine will bring a great deal of detail to the music that may become a blessing or a nuisance depending on the quality of your gear and the quality of the recording.

The AT VM95 ML is also capable in terms of bass notes. While bass can certainly swell and become both loud and full, this is never coincidental and always with good measure. Instead of sloppy bass, the cartridge sheds as much light on bass notes as it does on the highs and the midrange. There is lots of bass contour and very little else to be desired for. The music easily manages to free itself from the loudspeakers and becomes a true performance. There is always sufficient flow with plenty of dynamics, although the AT VM95 ML to my ears could be slightly less academic and more engaging perhaps. However, due to its ability to present lots of musical detail, the ML version will bring even rather boring performances back to life.

Specifications

Sound: Silent on the record, revealing and highly nuanced, warm and leaning towards neutral, controlled and well-contoured bass

• Frequency Response: 20-25.000 kHz
• Channel Separation at 1KHz: 23 dB
• Input Load: 47K
• Output at 1KHz 5CM/sec.: 3.5mV
• Recommended Tracking Force: 2.0 g
• Stylus Type: Nude Micro Linear Square Shank
• Inductance: 550 mH
• Resistance: 485 Ω
• Weight: 6.1 g
• Year: 2019 -
• OSP: EUR 146,00 (Germany)
• Stylus Replacement: Original, EUR 129,00
  

Audio Technica
Technica House
Unit 5, Millennium Way
Leeds
United Kingdom
LS11 5AL

Sound impressions based on the following system: Lenco L75 record player, Restek V1 preamplifier, Hafler XL 280 power amplifier, Tannoy XZ8F loudspeakers.

I stumbled upon the Sumiko range of phono cartridges while I was looking for a suitable pickup to complement our Thorens TD320 semi-automatic turntable. The TD320 came equipped with a TP16 MK IV tonearm, at a mass of 12.5 grams, which theoretically made it compatible with a wide selection of medium-compliance cartridges. Among the possible choices were MM (moving magnet) cartridges from Audio Technica, Grado, Ortofon, Nagaoka, and Sumiko. However, since I had already presented two Audio Technica cartridges in this blog and found the Grado Gold rather pricy, I narrowed it down to the Ortofon M2 Blue and the Sumiko Olympia, which ranked similarly in specs and performance.

In the end, my vote fell on the Olympia, as its dimensions and colour scheme worked well with the black and silver Thorens design. I had read that it sounded less analytical than the Ortofon, which I thought might compliment our fairly open sounding electrostatic speakers. My first impression when the cartridge arrived seemed to suggest that I had made a good decision. Taking it out of its wooden box was a lovely ritual that highlighted the company’s high-quality “handcrafted in Japan” mission statement. When mounted on the TP16, the sleek black body with clean white lettering looked absolutely stunning. I took special care to properly adjust all parameters, and the pictures below show part of this process before completion.

The first record I put on was Stacey Kent’s album “I Know I Dream” which happened to be of an acceptable pressing and worked quite well, until inner-groove sibilance increased on the final two tracks to such an extent that I was happy for the record to be over. Since I was still unfamiliar with the Thorens, I re-checked the VTA on the seamlessly adjustable shell and also tightened the vertical and horizontal tonearm bearings, thinking that this might be the cause of the problem. When this did not eliminate the sibilance, I played with the tracking and re-adjusted the platter level. However, no matter how hard I tried, the TP16 MK IV was unable to hold the Sumiko in place sufficiently to play without sibilance and inner-groove distortion. I called support at Thakker.eu to ask for advice, and they suggested that the Thorens’ arm might not be rigid enough for the Sumiko to perform well.

I ran some more tests with other settings and recordings and found that Katie Melua’s “Album No 8” was distorted from start to finish with the Sumiko, while it tracked well with both our Audio Technica cartridges equipped with micro-linear styli. I was feeling quite shattered at first, but then I decided to test the Sumiko on our Technics SL-1310 turntable in the other listening room. While inner-groove distortion remained an issue here, the Sumiko did produce a pleasant, super-wide, and solid soundstage that was so impressive, I could see myself having trouble returning the cartridge to the vendor without feeling regret.

I decided to check the stylus under a microscope and saw that the diamond was hidden under a thin cloak of residue that made the surface look grainy. I was familiar with this look from NOS styli made during the 70s. How could this be the case on the factory-fitted stylus of a brand new 2021 model cartridge, I wondered. Perhaps it was just a matter of wearing down the residue until the stylus’ diamond could once again shine through? I was starting to feel some regret that my records would have to go through this unhealthy treatment. Perhaps ambient moisture or seawater had played a role in corroding the stylus? After all, I had read somewhere that Sumiko cartridges were made in a town located close to the sea. This was confirmed on the company website.

Sumiko Company History

Sumiko was co-founded by former U.C. Berkeley experimental physicist David Fletcher in 1972. Fletcher made a name for himself in analogue music design and later went on to become the co-founder of SOTA turntables, another well-known brand that is still in business today. During the 1970s and 80s, Sumiko grew to be a leading importer of cartridges and tonearms of various brands to the USA. Some of Sumiko’s milestones were: the MDC-800 tonearm (1980); the Talisman high output MC cartridges (1982); and a series of “Premier” tonearms (1983-1988).

According to the company website, Sumiko’s Oyster series cartridges were hand-crafted in Yokohama. The factory was in fact located “near the waters where our namesake Oysters dwell”. The website goes on to describe how each cartridge was rigorously assembled and checked by expert cartridge makers before it was packaged and despatched. This, however, made it difficult for me to understand how my residue-covered and sibilant stylus could have escaped Sumiko’s rigourous inspections. Unless, of course, the fitting of the styli was not part of this process.

Determined to wear down the residue, I played Bob Seger’s “Greatest Hits” album on repeat for the next few hours. The Sumiko Olympia, however, continued to produce more noise and sibilance than I was used to, and it dawned on me that I was probably spoiled by the excellent tracking and low noise of our micro-linear styli from Audio Technica. For final proof of my suspicion, I decided to send the Olympia back to Thakker.eu who ran some tests on their own Technics deck and could not find anything wrong with either the cartridge or stylus. Sensing my disappointment, they offered to refund my investment that I could try my luck with a different cartridge.

In the end, I may have been unlucky with my combinations of arm and stylus or with the manufacturing tolerance of the cartridge itself. I greatly enjoyed the sound but could not relax while listening, because I always feared the next noise or sibilance to pierce through. For those of us used to listening to higher grade styli, the Sumiko Moonstone should be the minimum consideration. I am, however, hesitant to try the next level Sumiko stylus because of my utter disappointment with the Olympia.

Specifications

• Cartridge: high output, moving magnet
• Stylus type: 0.3 x 0.7mil Elliptical
• Cantilever type: Aluminum Pipe
• Induction coils: High-Purity Copper
• Internal impedance: 1,130Ω
• Load impedance: 47kΩ
• Frequency response: 12Hz – 30,000Hz
• Output level: 4.0mV
• Channel separation: >30dB @ 1kHz
• Channel balance: >1.5dB @ 1kHz
• Compliance: 12×10-6cm/dyn @ 100Hz
• Capacitance: 100pF – 200pF
• Vertical tracking angle: 25°
• Tracking force range: 1.8g – 2.2g
• Recommended tracking force: 2.0g
• Effective mass: 6.5g
• Dimensions: (W) 17.2 x (H) 18.8 x (D) 29mm
• Stylus compatibility: RS Rainier (lower), RS Moonstone (higher), Wellfleet (highest)

High Definition Stereo Preamplifier

As the vacuum tube was phased out in home audio appliances during the late 1960s, for the sake of cheaper production and more versatile equipment, some music lovers believed that the industry was heading in the wrong direction. While transistors outperformed tubes in terms of size and heat dissipation, their musical performance was not yet great.

Among the transistor sceptics was a man called William Zane Johnson. Bill had been running his own specialty audio store in south Minneapolis, out of which had he designed sophisticated amplifiers for those who cared deeply about accuracy and musicality in sound reproduction since 1951.

In 1970, following a failed attempt of developing his existing store model, he decided to start a company that would do justice to his designs, patents, as well as to himself. He named it ‘Audio Research’, and from the beginning it was clear that this company would put its focus on vacuum tubes for music reproduction.

While Bill held fast in the belief that vacuum tubes could convey a more realistic, and therefore convincing, sonic picture, there was still some work to be done for tubes to match transistors in terms of agility and control. The challenge was to marry the accuracy in sound reproduction that is typical of the tube with the ability to present detail in music that is common with the transistor.

The successful marriage of these properties Bill Johnson named ‘High Definition’ audio, now a well-known trademark and mission statement that has been stamped on Audio Research products ever since. While his tube designs were at times perceived to be a disruption to the progress of the industry, Audio Research proved to be well ahead of the competition during the tube revival that followed in the 1980s.

The success of the Audio Research Corporation was also helped by the fact that it was declared the official benchmark of sound by some of the most influential audio magazines of the time, such as ‘The Absolute Sound’ and ‘Stereophile’. Audio Research is today the oldest existing manufacturer of high-end audio products and is considered to have given rise to the very notion of high-end audio. Their SP-3 High Definition preamplifier was said to be the best preamplifier on the market over a period of many years.

The unit discussed here, the Audio Research SP-6 High Definition preamplifier, was built from 1978 to 1982 in only slightly deviating versions (models A-E), with the exception of the SP-6F version which has been stated to be the SP-8 MK II with a different face plate. The unit shown here is the SP-6B of 1980 fitted with Russian 12AX7 Tung-Sol tubes. For a preamplifier, the cabinet is quite tall at 13.4cm, and at 10kg also quite heavy. Although general power consumption is at a relatively low 50 watts, the internal tubes do get quite hot, so that there should be 5 cm of ventilation space kept free above the unit.

The turning knobs are of excellent touch and feel with a stepped volume attenuator. The row of switches could perhaps be a bit more refined. The muting switch can especially give an occasional plop when turned on or off. All great preamplifiers play loud, and so does the SP-6. This can make it a little difficult to set subtle volume differences for night-time listening, especially when playing from a loud CD player, DAC, or streamer as source, and when powering high decibel speakers. Due to this, we have often ended up playing our music a little louder than we would otherwise have done.

Bringing the SP-6 to operating temperature after turning it on takes about four minutes. The unit is fully warmed up when the power LED stops flashing. However, its full sonic capacity is reached only after about thirty minutes. This is when the preamplifier begins to sound the most musical. And, no surprise, what we get when the SP-6 is fully warmed up is very pleasing, indeed. Compared to our DB Systems DB1, the Audio Research preamplifier sounds wonderfully voluptuous, but it does not do so at the expense of focus. Voices simply take up more space in the virtual center. Singers are accurately allowed their own realistic dimension. Where the DB 1 can make voices sound frail at times, the SP-6 makes them sound lush and solid. Accurate tonal color and realistic musical detail are present at all times.

Similar to our DB1, the SP-6 builds a realistic and three-dimensional sound stage. Both preamplifiers play accurately and provide a warm and pleasing signature to the system; however, the SP-6 provides more bass slam and dynamic drive than the DB1. On our main system consisting of a B&K ST140 amp and Martin Logan SL3 speakers, the SP-6 offers the most balanced, musical, and entertaining performance of any preamplifier we have had the pleasure of exploring here to date.

Note: In the end I was relieved to find that returning to our DB Systems preamplifier with satisfaction was still possible after this tour of exploration. While the two preamps accentuate different aspects of the music, they both provide an endearing and convincing performance at a very high level.

Specifications:

• Frequency response: 10 Hz to 30 kHz
• Total harmonic distortion: 0.01%
• Gain: 50dB 60dB (MM), 26dB (line)
• Signal to noise ratio: 66dB (MM), 90dB (line)
• Output: 5V (Pre out), 60V (Pre out Max)
• Valve complement: 6 x ECC83 (6 x 12AX7 Tung-Sol)
• Dimensions: 480 x 134 x 260mm
• Weight: 10kg
• Year: 1980

David Hadaway established DB Systems in Ridge, New Hampshire in 1975 and has been quietly manufacturing world class home audio equipment ever since. Similar to many manufacturers of audiophile gems, DB Systems has been flying under the radar of mainstream HiFi discourse and has gradually and meticulously developed its line of exceptional designs for a small group of followers. The DB-1 preamplifier was among DB Systems’s first products and was well ahead of the competition at the time of its debut. To this day, the company offers revisions and updates to all their products, and the DB-1 can well hold its own in the audiophile market.

DB’s line of audio products includes preamplifiers, power amplifiers, electronic crossovers, tone controls, phase inverters, and accessories. All products are designed and hand made in the U.S.A. using selected parts. The DB-1 comes with the DB-2 linear power supply and includes the DB-designed MM phono stage, the DB-5 precision tone control and the DB-4 MC head amp. When new, the complete preamplifier setup sells for 2,200 dollars. Used versions of the preamp can be found at very competitive prices.

The DB-1 shown here arrived in very a poor state despite being advertised as ‘in mint condition’. The phono stage was dead on both channels and suffering from multiple contact-related issues. The power supply was also dysfunctional due to a faulty DIY job and fitted additional capacitors that had come loose during transport. After a few weeks of care and attention, we were able to restore the unit’s original design and functionality. The time and effort was well worth it, as there are not many preamplifiers around that can measure up to the DB-1’s performance.

For a transistor preamplifier device, the DB-1 offers a surprisingly homogeneous and ‘analog’ sound. Its sound stage is both wide and deep, and separation of instruments is commendable. The phono stage is among the best in the market with an extremely low noise floor and superb RIA compensation. Paired with the right cartridge, it is detailed, dynamic, and extended.

Specifications

• Total harmonic distortion: < 0.0008%
• Intermodulation distortion: < 0.001%
• Noise separation (Phono): > 89 dB
• Freq. resp. (Phono, -1 dB): 2 Hz to 50 kHz
• Freq. resp. (Phono, -0.25 dB), 10 Hz to 20 kHz
• Inputs: Phono, Tuner, Aux 1, Aux 2, Tape
• Outputs: 2x Tape, 2x Amplifier
• Dimensions, preamp: 22 cm x 8.4 cm x 23 cm
• Dimensions, power supply: 16.61 cm x 11 cm

In audiophile circles, the name Dynaco is reminiscent of the famous budget assembly kits that would hold up against some of the most exquisit audio products on the HiFi market during the 1960s and 70s. Originally founded by David Hafler and Ed Laurent in Philadelphia in 1955, the company’s first products were the 50 and 60 watts mono amplifiers Dynaco Mark II and III and the preamplifier PAM-1. But it was not until the launch of the Dynaco ST-70, a 2x35 watts tube amplifier design in 1959 that the company made its entry to the audiophile mass market.

Dynaco went on to manufacture other tube and solid state amplifiers, preamplifiers, radio tuners, and bookshelf speakers. Their most powerful amplifier was the solid state Dynaco ST-400 which was launched in 1972 and offered 2x200 watts of continuous output power with sophisticated speaker protection. By this time, the formerly independent Dynaco had already become a subsidiary of Tyco, Inc. with David Hafler still active until 1974, when he finally left the company to join Ortofon in 1974 and then went on to start his own Hafler Company in 1977. 

The original Dynaco was liquidated in 1980 and lay dormant until the Pan Orient Corporation acquired the trademark in 1993 and began marketing audio components under the Dynaco brand. Pan Orient soon shortened its name to ‘Panor’ and began launching updated versions of Dynaco classics as well as some new designs. Among these were the ST-70 successor ‘Stereo 70 II’ and the more powerful ‘Stereo 160’, a 2x70 watts all-tube power amplifier that was packed with audiophile features, such as switchable pentode/triode modes and adjustable tube bias.

When it comes to the Dynaco PAS-4, vintage audio fans will be quick to point out that this preamplifier design is a Dynaco in name only, because it was produced and sold by Panor during the early 90s. However, the Dynaco brand name was not chosen without reason, as Panor was serious about improving the original Dynaco/Hafler designs and was set on once again producing affordable audiophile gear for the average consumer with a medium-sized budget. Visible proof of this mission are the PAS-4’s no-frills industrial cabinet and design choices, as well as its selection of audiophile components.

The PAS-4 was developed under the direction of John Nunez, a former developer with the high-priced tube equipment specialist Moore Franklin Associates (MFA). John knew that, if he wanted to convince audiophile consumers of the PAS-4’s merits, he needed to get vinyl reproduction right. He therefore took good care to make the phono stage of the PAS-4 outstanding. Manufacturing quality was also intended to be excellent, with all units sold being designed and manufactured in the USA. Sadly, however, Panor had to make some concessions to meet the relatively low price point which hindered some of the PAS-4’s audiophile potential and frustrated some of the early customers.

Despite its outstanding design, the PAS-4 was sold fitted with the cheapest tubes available and came equipped with switches that were given to fail. It also offered additional circuits for improved usability that were not in keeping with the audiophile tradition of reducing the circuitry to the bare essentials. The first customer reviews of the new preamplifier reflected these shortcomings, and resulted in only a few thousand units of the PAS-4 being sold, thus making it a rare find on today’s vintage market.

The unit shown here is a completely different beast from the version sold by Panor. It is closer to the original audiophile design and includes most of the recommended updates and modifications that have been found beneficial over the nearly three decades of its existence. Of course, it helped that the original basis was excellent: 1/8” thick circuit boards, high quality tube sockets, excellent trace layout with star grounding, and each tube with its own voltage regulator. Changes and updates to our PAS-4 include changing to an improved hum-free 230V transformer, adding a high-quality rotary Elma switch for source selection, bypassing the tape monitor and tape dubbing circuitry, eliminating the channel balance attenuator, and bringing in an audiophile grade Noble volume attenuator.

The original tubes were replaced with Russian Tung-Sol 12AX7 SC803S and SOVTEK type 6922 for the 2-stage phono section, as well as a pair of Genalex 20 03 for the hybrid line stage. The capacitors were updated to Mundorf Supreme EVO Silver Gold Oil. The aim of the updates was to minimise internal and external noise and distortion and to increase transparency, responsiveness, and dynamics. Configured in this way, the PAS-4 becomes a worthy audiophile contender in true Dynaco tradition. And, while the original preamp cost around 1,000 dollars new, following these updates, it can easily compete with preamplifiers costing 2-3 times this amount. Hafler trusted in the craftsmanship of the DIY home builder, and, apparently, so did Panor. While it took some expertise to unravel the PAS-4’s genuine character and potential, the good news is that it was possible by simply building on the superb infrastructure that was already present.

Setting up the PAS-4 in our household for the first time, I noticed that tube gear is a little more difficult to set up than solitary state equipment. My preference was to fit the PAS-4 in our main system where it was to replace our DB1 preamplifier and to play with our B&K ST-140 amplifier into Martin Logan electrostatic speakers. In this position, however, the PAS-4 was lacking the upper frequency band in a way that most of the transients were lost and that the music sounded stale. It sounded as if the tubes had reached the end of their life expectancy, or as if there was some other major problem with this preamplifier. After 2 days of trying different cable combinations I gave up and took the PAS-4 to our other system. 

In its new position, the PAS-4 was to replace our Restek V1 preamp and to play with our Hafler XL-280 amp into Tannoy XT8F speakers. Here it immediately showed that the Panor/Dynaco is a Hafler derivative. The PAS-4 pre and Hafler XL-280 amp turned out to be a match made in heaven. In retrospect, this is perhaps not surprising, given the PAS-4’s pedigree, but to me it came as a revelation at the time. I simply could not understand how the same preamplifier could perform so differently in combination with two amps that it sounded broken in the one position and absolutely brilliant in the other. For the first time, the Tannoys’s sonic character also matched their physical appearance. The XT8F are not exactly small speakers, but somehow the Restek V1 in combination with the Hafler had made them sound overly precise and academic, instead of musical and dynamic.

The PAS-4 is able to build a huge stage from left to right that extends far beyond the speakers. Instruments position themselves freely with plenty of dark spaces around them. I have found that treble highlights are fewer than in combination with the Restek V1 but more pronounced when they occur. Transients are fully present and sounds linger in realistic fashion. Similar to most tube equipment, the PAS-4 can introduce interference, which will result in humming or hissing when something is not right in the setup. In my first attempt to pair it with our Hafler amp, I had not noticed that its power cord was touching that of the Hafler amp. This resulted in audible hissing on both amp channels. In fact, noise was a complaint that I had also read in some owner reviews. When everything is set up properly, however, the PAS-4 is nearly as silent as the Restek V1. One would have to hold the ear directly to the tweeter section of the speakers to hear the remaining noise.

As is the case with most serious HiFi gear, the PAS-4 will reveal the difference between a standard power cord and one that has been designed specifically for use in audio applications. On our own system, we have paired the PAS-4 with a Lapp Ölflex 2,5mm fitted with ferrite clamp to good result, but I suspect that one could get even better performance from this preamp with a more sophisticated cord. The difference between the standard cord and the Lapp cable was so striking that I suspect that further improvements in this position will again have a major impact.

After switching on, the PAS-4 needs about 15 minutes for the tubes to warm up. Actually, it will already play music after 45 seconds, but sound stage and dynamics do need some time to develop. Transients only sound right after some 30-40 minutes of playing. At this time, the six tubes will have reached their full operating temperature—which is actually quite hot. The slim cabinet design means that the tubes are literally touching the top of the enclosure, and I have meanwhile read that many users are leaving the lid off completely to improve ventilation. My reasons for leaving the cover on despite this are the presence of children in the household and the belief that the enclosure functions as a Pharadeic cage to protect the inner circuits from outside interference.

The PAS-4 puts out lots of power, with normal listening volumes being present at around 9 o’clock on the volume dial. Since the same is true for our DB1 and V1 preamplifiers, I suspect that this is a general tendency with audiophile grade preamplifiers. In contrast to our solid state gear, the PAS-4 strikes a more soothing balance between treble and bass notes without sacrificing transparency. Voices sound fuller and richer, double bass and lower piano notes have a greater sense of dimension and authority to them. To my ears, the PAS-4 puts out a more satisfying and realistic bass performance without the aid of a subwoofer in our system. Our Tannoys surely benefit from this and are sounding even more engaging. It is therefore not surprising to me that the PAS-4 is awarded 4.8 out of 5 stars in audioreview. For us as well, this unpretentious looking preamp is a definite keeper. If you can get your hands on a specimen in good condition and find yourself in a position to have the basic modifications done: do it. Where it fits in, the PAS-4 is going to be very hard to beat at this price point.

Specifications

Phono

• Gain:  40 dB
• RIAA accuracy:  +/-0.5 dB (20 Hz-20,000 Hz)
• THD:  <0,025% (@2V RMS output)
• Input impedance:  47k (shunted by 10 pF)
• Signal to noise ratio:  -86dB (<10mV RMS input)
• Absolute phase:  non-inverting
• Tube complement:  2ae 6DJ8/6922; 2ae 12AX7/ECC83

Line

• Gain:  18,5 dB
• Frequency response:  2 Hz-150,000 Hz (-3 dB)
• THD:  <0,025% (@2V RMS output)
• Input impedance:  25k (nominal, all inputs)
• Output impedance:  40 Ohms
• Signal to noise ratio:  -90dB (<10mV RMS output)
• Absolute phase:  inverting
• Slew rate:  40 volts per uS
• Tube complement:  2ae 6DJ8/6922

Physical

• Power consumption:  45 Watts
• Dimensions:  (W) 43.18cm x (H) 9.52cm x (D) 30.48cm
• Weight:  5,44 kg
• Year:  1993

David Hafler was an American Audio engineer who was best known for his work on improving the Williamson amplifier design through the use of ultra-linear circuitry. His background as a producer of linear power supplies for use in audio applications lead to the founding of Dynaco, and later, in 1972, to the founding of the David Hafler Company, a manufacturer of high quality audio products at affordable prices. Under the supervision of its founder, the company produced many famous preamps, among them the DH-101 and DH-110, as well as a line of MOSFET power amps, including the DH-120, DH-200, DH-220, DH-500, and XL-280.

The Hafler DH-110 was the company’s second preamplifier design. It replaced the DH-101 and was built from the early 1980s to the early 1990s. In typical Halfer fashion, the unit came in form of a DIY kit as well as in fully pre-assembled condition. The DH-110 has a sleek and unobtrusive design and is very well equipped. The features include a headphone amplifier, a muting circuit to prevent downstream thumps, a mono and tone control defeat switch, a rumble filter, as well as an external processing loop. The body is well constructed and protected from outer interference through full copper coating, similar to the Harman / Kardon designs of that time period. With two tape loops and two phono stages, the amplifier offers great connectivity.

While this is a great preamplifier for the price and can well keep up with mid-priced modern designs in terms of tonality, there is also some criticism. For example, the headphone stage is not very loud. Therefore, if your headphones need lots of clean power, this preamp might not be the right on for you. The volume attenuator steps are quite enormous, this especially becomes and issue when listening at night when the house is asleep and the steps at low volume leave you stranded between to quiet and too loud. Another issue is that only one of the two outputs is actually run though the volume attenuator, which does not make it a great companion when bi-amping your speakers or wanting to add a subwoofer – whoever would want to do such a thing. In combination with the Hafler DH-120 amplifier, the unit produces a decent and musical sound with lots of drive forward. It is not as delicate and refined as the Restek V1 or the DB Systems DB1 preamplifiers, but then these cost 3-5 times the amount of the Hafler, and many will wonder whether it is actually worth paying the extra.

Specifications

PHONO PREAMP SECTION

• Rated Output: 3 Wms, 8 Hz-105 kHz
• Maximum Output (3.5): 12 Vrms, 20 Hz-20 kHz
• Total Harmonic Distortion: Less than 0.0006% @ 1 kHz
• RIAA Equalization Accuracy: +0, -0.1 dB, 30 Hz-15 kHz
• Full Power Bandwidth: -6 dB, 4 Hz-210 kHz
• Sensitivity (3.7): 12.5 millivolts
• Signal to Noise: 87 dB
• Slew Rate: 12 volts per microsecond

LINE AMPLIFIER SECTION

• Rated Output: 3 Vrms, 4 Hz-210 kHz
• Maximum Output (3.5): 14 Vrms, 20 Hz-20 kHz
• Total Harmonic Distortion: <0.001%, 20 Hz-20 kHz
• Signal to Noise: 90 dB
• Slew Rate: 12 volts per microsecond
• Rise Time: 2.5 microseconds maximum
• Channel Separation: > 82 dB @ 1 kHz

GENERAL SPECIFICATIONS

• Inputs: 2 Phono, Tuner, Compact Disc or Video, 2 Tape recorders, EPL Outputs: 2 Tape (buffered), 2 Line, EPL, Headphone Jack
• Controls: Volume, Balance, Bass, Treble, Input Selector, Phono l/2 Selector,
• Monitor Selector, Mono-Stereo, Filter, External Processor Loop,
• Power Consumption: 3.5 watts
• Dimensions: 17” wide x 3” high x 81⁄2” deep
• Net Weight: 5 Kg.

The Model 4 was the successor of the Model 3 preamplifier and was built by the American audio engineer and former Audio Research (ARC) developer Robert Grodinsky in his newly founded company. The Robert Grodinsky Research (RGR) was based in Lincolnwood, Illinois, and built a select range of High-End audio equipment that included its own brand pre and power amplifiers, as well as processors for other companies, e.g., Audio Research, Koss, and Pioneer). Robert Grodinsky himself also offered tuning and upgrade solutions to owners of Audio Research equipment.

The Model 4 came in various sub-versions that mostly differed in the design and functions of the phono stage. The basic model came with two phono inputs on which the capacitance could be independently adjusted in three steps: 30, 130, 360 pF. It was designed in the early 1980s, when phono was still the most likely source for High-End audio listening. Having two adjustable inputs would have made the Model 4 a welcome feature for vinyl heads of the time. Early versions offered moving magnet (MM) inputs, whereas the revised Model 4-1HG featured inputs for MM and moving coil (MC) cartridges.

The renowned HiFi magazine The Absolute Sound made Robert Grodinsky Research famous by discussing the merits and shortcomings of the Model 4 at length. While the soundstage was deep and wide with an open and holographic representation of music, the Model 4 was also a departure from the slightly darker and fuller American sound. As such, the Model 4 was more similar to the High End sound familiar from Germany and Japan. The phono stage was described as outstanding in the given price range. As Robert Grodinsky continued to make adjustments to the Model 4 design throughout its 2-year history, it will be difficult to find two preamps that sound identical.

At 6.5 kg, the Model 4 was of surprisingly heavy build for a preamplifier. All controls were made of metal with the knobs being L-shaped. Volume was set via stepped attenuator. The active signal source was indicated via warm-glowing LED light. There were two buttons to set the tape dubbing direction and two buttons to activate the tape monitors which could also be used as pass-through to other components. A versatile Mode-selector allowed the user to play the left or right channel signal independently, to reverse channels, or to down-mix the output signal to mono. For those working with HiFi or PA equipment professionally, features like these could come in very handy, e.g., when trying to identify and correct an electronic or acoustic issue.

The RGR Model 4 also included knobs to adjust bass, treble, and balance to the room, as well as a subsonic filter for eliminating rumble and feedback that would typically come from playing records. It was surely a concession to the High-End purist and not the PA user that the tone controls could be fully discharged from the signal path at the touch of a button. All buttons and switches gave great haptic feedback, except for the small switches at the back of the unit that were used to adjust phono capacitance and that were sometimes described as imprecise and below expectations. Another such quirk from today’s perspective was the unusually narrow gab between the cinch/RCA sockets that allowed for standard diameter cinch/RCA plugs only. However, with the cinch terminal being bolted in with studs and the internal free wiring, it would be an easy task to upgrade the terminal to the modern standard. 

The Model 4 also featured an external processor loop, a field that Robert Grodinsky was an expert in. A look inside of the unit revealed a large motherboard on which smaller modules were vertically stacked. These modules functioned as discrete operating amps and were used to produce signal gain. Perhaps it is this particular design that led to the Model 4’s non-fatiguing and airy sound that provides good sound-staging, imaging and bass. There was also a Model 5 power amplifier to accompany the preamplifier which has meanwhile become quite rare on the market. While the early Model 4 was sometimes criticised for its build quality, particularly the quality of its soldering, the Model 5 amplifier was seemed to have been under better supervision right from the start. 

Robert Grodinsky Research closed its doors in the early eighties only to resurface under the name RG Dynamics shortly after. It is said that Robert Grodinsky was also the driving force behind a later company by the name of State Technology Research.

Specifications

• Type: Solid state stereo preamplifier
• Version: Mark I (without MC connectivity)
• Phono inputs: 2x moving magnet (MM)
• Phono adjustments: 30, 130, 360 pF capacitance
• Phono equalisation: RIAA +/= 0.1 dB
• Line inputs: 2x Auxiliary, 2x Monitor
• Tape record outputs: 2x cinch/RCA
• Rated output voltage: > 2.0 V
• Harmonic distortion (1 kHz): < 0.005%
• Intermodulation noise: 0.006%
• Power bandwidth: 0.5 Hz to 300 kHz
• Frequency response: 20 Hz to 20 kHz (+/- 0.05 dB)
• Signal-to-noise ratio: Phono MM/MC: > 80 dB
• Signal outputs to amplifier: 4x line/RCA
• Tone controls: Bass (20 Hz) +/-12 dB, Treble (15 kHz) +/-12 dB
• Dimensions: (W) 484mm x (H) 95mm x (D) 300mm
• Weight: 6.5 kilograms
• Country of manufacture: USA
• Year(s): 1980-1982

Rotel today has a good name in providing no-frills HiFi components, featuring what has come to be termed ‘British sound’. In this context, I was surprised to learn that Rotel is a family-owned Japanese manufacturer of audio and video equipment established in 1961. Perhaps the image of Rotel as a British manufacturer has rubbed off from the company’s 40-year strategic alliance with Bowers & Wilkins, based in Worthing, UK. But perhaps it is also due to the rather English or at least germanophone sounding company name. In the company fact files, we can read that Rotel was formed by Tomoki Tachikawa, is currently run by the nephew, Peter Kao and has had a major influence on the direction of Bowers & Wilkins, by setting up the global sales network for the loudspeaker manufacturer.

Although Rotel is primarily known for its range of High End HiFi components, including amplifiers and preamplifiers, they have always maintained a line of affordable, entry-level gear that boasted the Rotel design features and carried some of the myth of the ‘British sound’ to a new generation of audio enthusiasts. The Rotel RC-960BX is such a case in point. Paired with one or two of the RB-960BX dual-mono amplifiers, the combination of pre and amp could easily beat many of the contemporary receivers at the same price point in terms of tonal balance and punch. The wise lack of controls and the ability to bypass those that remained, paired with the separation of channels and tasks, brought something solid to the table that many other devices were lacking. Coming from a mid-priced Denon Amplifier, the Rotel combo sure was a revelation.

Although the Rotel sound can be described as sophisticated, the entry level gear shown here maintains tonal balance at the cost of providing that highly engaging musicality we have come to love from Hafler, Restek, and DB-Systems preamplifiers. The build quality shows some obvious sacrifices to careful budgeting: a plastic floor plate that broke during transportation and has since been replaced by a more solid version, plastic absorber feet that were an integral part of the broken floor plate and have also been replaced, a cheap but quite common folded sheet metal casing without copper plating, a single circuit board construction with the humming transformer placed directly on it, a balance control that is part of the volume knob and generally feels a bit iffy when trying to get the balance right. While the performance is commendable at the given price range, piano sounds do not extend into the room as well as on the other devices, separation of instruments is present but not great. The stage feels more confined than on the other devices, although there is a great center image and the mids are nice and full, features that are at once endearing.

I found the Rotel to work well with soft dome tweeters and generally speakers that would blend over occasional blunders. The RC-960BX is not a bad choice, if you are getting started in High End and need to purchase lots of gear at the same time. It usually holds its price when purchased used. Just make sure the floor plate does not get broken during transportation, because that really is a hassle to fix.

Specifications

• Frequency response (line): 4 - 100.000 Hz, -3 dB
• Frequency response (phono): 40 - 100.000 Hz, +/- 0.2 dB
• Total harmonic distortion: < 0.004%
• Signal to noise ratio (line): 95 dB
• Signal to noise ratio (phono MM): 78 dB
• Signal to noise ratio (phono MC): 64 dB
• Dimensions: 440mm x 72mm x 286mm
• Weight: 3.0 Kg (now 5.5 Kg, with new floor plate and feet)

The Restek Elektronik Hugo + Elschot oHG was founded in September 1975 by two electronics engineers. In its early years, the company manufactured not only HiFi equipment, but also electric vehicles and components for industrial applications. The first HiFi components were produced at the company’s headquarters in Fuldabrück from 1977. Although each unit sold was designed and hand assembled locally, Restek partnered with the HiFi equipment manufacturer Thorens in the distribution of their products. Although Restek is best known for their exceptional FM-3003 tuner, the V1 class A preamplifier was among the company’s very first products ever produced. The label ‘High End Audio made in Germany’ has kept the company in business until this day, and one of the company two founders, Mr. Adrianus Elschot, is still heading the company today.

Restek manufactured two preamplifiers by the name of V, namely the V1 that is shown here and the V2a which offered extended functions, such as remote switching, separate headphones level adjustment and connections for two tape loops instead of just one. The V1 is perhaps the purist’s choice and does offer some very promising features. A stepped volume attenuator assures maximum contact and channel balance at each volume level, separate output level attenuators at the back of the unit allow for optimum balance setting and adjustment to the amp. For the sake of signal integrity, all unnecessary switches and attenuators have been left out, such as tone level adjustments or loudness circuitry. The Restek V1 can handle both MM and MC phono cartridges and, next to phono, has cinch/RCA connections for a tuner, a non-specified device such as a DAC, and for a reel to reel deck.

The unit is able to play back frequencies from 2 to 200.000 Hz. Linearity measured between 20 and 20.000 Hz is at a stunning +/- 0 dB (THD 0,001%) and even for phono at a mere +/- 0.2 dB (THD 0,004%). In the days when it was first released to the public, the then young German ‘Audio’ magazine even compared this unit of a relative newcomer to the established products of Burmester and other High End manufacturers of the time. Often, the extent to which a company stands behind their products can be seen by the amount of support that one can expect to receive, say, 40 years after the initial date of purchase. In the case of Restek, service can very well be regarded as excellent. Here is why:

When in 2017 the unit shown here came to show first signs of ageing, we were pleased to learn that there was not only service available, but also a complete upgrade. This included: Replacement of the relays and all electrolytic capacitors, adjustment and replacement of components that were outside the specifications, circuitry modifications according to the latest standard, and the installation of new operational amplifiers. In other words, a complete reworking of the more than 40 years old unit, to prepare it for the new millenium.

Specifications

• Type: Class A transistor preamplifier
• Frequency range: 2-200.000 Hz
• Frequency response (2-200.000 Hz): -3dB
• Frequency response (20-20.000 Hz): +/- 0 dB, phono +/- 0.2 dB
• Total harmonic distortion: 0,001%, phono 0,004%
• Ext. potential difference: 128 dB (phono)
• Channel separation: 110 dB
• Intermodulation: 0,001%
• Slew rate: 15 V/uS
• Dimensions: 360 mm x 50 mm x 190 mm
• Weight: 3,6 Kg

Ever since the revelatory experience of playing music on his Dynaco ST-70, my friend Luigi had been scanning the market for an all-tube pre and amp combination capable of delivering abundant power into even the most demanding speakers. This proved to be a difficult task, because large tube amplifiers had been well out of fashion for at least 30 years. Then, one night, he called me to say that he had made a purchase. The units he had found were an Audio Research SP6 preamplifier and a D-115 tube amplifier, both in need of a massive technical overhaul. He consequently dropped the units off at his trusted technician, and for the next few months that was the last we heard of them.

After what seemed like an eternity, I was invited to Luigi’s house for a listening session and immediately noticed the large silver face plates that are so typical for the Audio Research products of the 80s. I could not help but grin with apprehension. So, they had finally come back from the shop, fitted with new quality capacitors, boasting re-soldered connections and a brand new set of the finest matched tubes. All the dust of 40 years had been cleaned out, and lots of love and energy had been invested to make this set of tube separates one of the best of its kind on the audio market today.

As I would find out, this type of gear certainly merits the effort. Audio Research has an excellent name amongst tube enthusiasts. In fact, the company can look back on a long history of audio excellence and is today the oldest remaining manufacturer of high-end audio products. Audio Research is considered to have given rise to the very notion of High End audio, and their SP-3 High Definition preamplifier was said to be the best preamplifier on the market over a period of many years. A whole range of products manufactured by the Audio Research Corporation (ARC) were declared the official benchmark of music by some of the most influential audio magazines of the 1980s, among them ‘The Absolute Sound’ and ‘Stereophile’. Read the full history of the Audio Research Corporation in my review of the SP-6.

Instead of listening to the preamplifier and amplifier combination as a set, Luigi and I agreed that we should take a step-by-step approach in writing reviews. It would be far more interesting to learn how each component performed when playing against and among the units that we were familiar with. I therefore first took the ARC SP-6 preamplifier for testing in December 2020. Despite its advanced age, the large and heavy preamplifier gave a stellar performance, making our otherwise excellent DB Systems DB1 preamp sound a little thin and analytical in direct comparison. And—while I had no difficulty readjusting my ear to the familiar sound of our DB1 following the test—I still hold the SP-6 in very high esteem. It actually inspired me to purchase our first tube preamp a few month later.

Having returned the SP-6 preamp to Luigi, I was hesitant to take the complimentary ARC D-115 out for testing. I suspected that dealing with the amp would not be quite as easy. One reason for this suspicion was the amp’s weight. With its 3+1 large transformers and thick sandwich base plate, it weighs just above 30kg. And with the speaker terminals protruding out the back, I could not simply pick it up by the handles, either. The D-115 rather needed to be carried horizontally, like a serving tray, which all the more accentuated the fact that this was, indeed, a very heavy piece of equipment. When I finally did bring it home, I arrived at our house in the middle of the night and telephoned my wife to give me a hand in carrying the D-115 up our long flight of stairs. I remember feeling quite embarrassed about it, like someone who had bitten off more than he could chew.

But weight was not the only consideration. The second factor was its operating temperature. When switched on, the D-115 draws close to 400 watts of idle power from the grid. That’s a lot of juice for a machine that is not yet playing music, and most of this energy is simply transformed into heat. When placing the amp in our rack, I first had to make some adjustments to provide it with the ventilation it needs. This included taking out one shelf board and dismantling the front door. Just out of curiosity, I then placed one of our children’s bathing thermometers on the grill above the tubes. It soon reached 50 centigrade, which was also the end of this particular thermometer’s scale. A reminder that an all-tube power amplifier is a serious piece of gear that requires some thought and attention before first operation.

The D-115 likes to be positioned close to the floor where it is relatively cool and vibrations coming from the transformers can be channelled directly to the ground. The amp’s three rubber feet assure that it will not wobble when placed on a stable surface. Thorough mechanical decoupling from source devices is advisable for an amp of this caliber. I have sometimes read that tube amplifiers prefer to play into close to linear 8 Ohm loads or higher. On the other hand, there are some reports of the D-115 being paired with Magnepan and Martin Logan speakers with some success. For this reason, I thought it safe to begin my exploration on our SL3 electrostatic speakers via the amp’s 4 Ohm output terminals, before attempting to pair it with our 8 Ohms Tannoy system. The amp actually has separate binding posts for 16, 8, and 4 Ohm speaker loads—another indication that 4 Ohm connections are possible. Connecting to the correct terminal is important in order to protect the D-115 from undesirable levels back current.

Martin Logan SL3 (DB Systems DB1)

After about 30 minutes of the tubes heating up without music playing, I started my session with “Turn up the quiet” by Diana Krall. The album has been my personal benchmark for studio recordings for some time now. Playing the album’s familiar songs, I first noticed the D-115’s thick and fruity midrange that manifested itself around Diana Krall’s vocals. The singer’s voice carried more weight than I was used to from our B&K ST-140 class-A MOSFET amp. There was greater focus on the voice itself, with the instruments being slightly set back. The sound was darker and tonally rich, as one would expect from a live performance. Where the ST-140 had dug out even the tiniest nuances of the studio recording, the Audio Research D-115 painted a slightly more homogenous and live-sounding image.

After listening to Diana Krall for some time, I changed to “All the Little Lights” by Passenger. This used to be my favourite non-audiophile recording. As far as singer-songwriter albums go, “All the Little Lights” is a decent recording, and yet with each advancement of technology on my side, I was also beginning to hear the limitations of the studio. To my delight, the D-115’s more forgiving approach to music worked rather well with this album. The amp was revealing enough for the music to be entertaining, but it did not reach as deeply into the spaces as some of its solid state competitors will. I found listening to Passenger tonally charming and occasionally magical. The D-115 was neither technical nor overly analytical sounding. There was no trace of harshness, and the whole experience proved to be non-fatiguing.

Although the D-115 perhaps did not offer as much presence at the frequency extremes as some of its more recent cousins, it did present its music with lots of slam and rhythm. This impression was supported by the fact that it created a huge and spacious soundstage with full-bodied yet soothingly intimate vocals. And—although bass contour was slightly limited, perhaps due to its relatively low damping factor—its overall bass performance did feel natural. Tube amps are special in their ability to interact with the listening room in a way that solid state amplifiers simply cannot. The effect on voices is magical and thought to be unique to tubes. With its strong centre focus, the D-115 without fail found and caressed the singers voice at an instance. And the same magic happened when strings were playing.

The final album I listened to was “Foot Tappin’ Boogie” by Jörg Hegemann. This is still a relatively new addition to my benchmark series, and yet, I enjoy every minute of it. Since Jörg’s album is mostly instrumental, I was able to focus on the D-115’s depiction of instruments. In this context, I felt that the Audio Research slightly favoured the double-bass performance over that of the piano, specifically in combination with the SL3 loudspeakers. While the double-bass was presented fully and elaborately, especially the higher piano keys did not have the same piercing authority that I had come to enjoy from our B&K ST-140. As it turns out, the D-115 is quite sensitive to power cord issues. I was able to improve piano playback by moving the amp’s power cord away from all other cords in a way that they would neither touch nor cross. A re-play of the same song showed some improvement to piano notes, although an audible difference to the solid state amp remained.

Tannoy XT8F (Dynaco PAS-4)

Listening to the D-115 on our Tannoy system with Dynaco tube preamplifier produced a more insightful and perhaps more widely applicable result. Similar to the first scenario, the all-tube setup created a huge and mesmerising soundstage with the music being lush, agile and forward sounding. As I was sitting only two meters from the speakers, I could literally feel the D-115 throwing music at me with a vengeance. Walking around the ample space and listening in different positions, it became clear to me that this amp could fill large venues with ease, exhibiting its full dynamics in every corner, even at low volumes. While imaging may have been crisper with our solid state amps, the Audio Research excelled in giving each sound full body and life-like dimension, with excellent piano and double-bass on Diana Krall’s “No Moon at All”.

The D-115 sounded non-aggressive, exhibiting a slightly mitigated top-end. In marked difference to our solid state amps, piano notes remained non-piercing throughout. I noticed a slight sibilance on Diana Krall’s voice that might have stemmed from the simpler power cord I used and that I had not noticed on our other system with the higher quality cord. In comparison with our solid state amplifiers, the tube amp’s bass notes did not extend quite as low. Diana Krall, for example, often finishes her songs with a bass thump, and so does Jörg Hegemann in “Foot Tappin’ Boogie”. The effect is especially highlighted when playing music via our silver cables. Listening with the D-115, this final thump was audible but it was not quite as pronounced. From my early experience with Hafler, I remembered that the real merits of an amp can often be judged when listening to it play from another room with the doors left open and asking myself the question “What is playing: an amplifier or a band?” For the D-115, the answer to this question clearly leans towards the latter.

In summary, it can be said that the Audio Research D-115 is a highly musical tube amplifier for experienced audio enthusiasts who prefer to be tonally caressed rather than impressed with extended range. It prefers to drive conventional speakers with higher and more linear Ohm loads. As far as tube amps are concerned, the D-115 offers a balanced and smooth sound with a slight emphasis on vocals which it plays in a lush and full manner. Rather than impressive bass contour or treble extension, the D-115 offers a huge and spacious sound that is highly engaging and non-fatiguing to listen to. Later models of the same manufacturer are said to perform in a more extended, analytical, and less charming manner. For audiophiles who have the necessary skills and resources to set up and maintain an all-tube power amp of this caliber, the D-115 is certainly an excellent pic.

I thank Luigi for this new opportunity of exploration. It is through his passion and good ear that I have learned more about HiFi in just a few years than I otherwise could have done in a lifetime. The above is a factual account of the subjective listening events with the D-115 in our two systems around the time from 5. - 9. July 2021. As always in HiFi, alternative listening setups may lead to different results. Readers familiar with the D-115 or related all-tube designs, please feel free to leave a comment below.

Specifications:

• Power output: 100 WPC (16 Ohms, 20Hz to 20kHz < 1% THD)
• Total harmonic distortion: <005%, 1 watt
• Power bandwidth: 10 Hz to 60 kHz, -3 dB
• Input sensitivity: 1.2V RMS
• Input impedance: 75K ohms
• Output regulation: 0.4dB, 16 ohm
• Negative feedback: 20dB
• Damping factor: 20
• Slew rate: 15 V/µs
• Rise time: 5 µs
• Hum: 90dB below output
• Power supply: 1000 watts, 280 joules; 400 watts idle
• Tube complements: 4 x matched pairs KT77; 1 x 6550, 1 x 12AT7; 7 x 6DJ8/ECC88
• Dimensions: 48 cm (W) x 18 cm (H) x 42 cm (D)
• Weight: 31 kg
• Year: 1983-1989

B&K Components Ltd. was founded by John Beyer and Steve Keiser in Buffalo, NY, in 1981. The company evolved out of a single amplifier design that Steve Keiser had created attending electrical engineering school during his final year of college. Upon showing his amplifier to John Beyer, who was thinking about putting together a stereo system for his own use, John was so overwhelmed by the performance of the unit that he convinced Steve they should found a company together to market it. Initially, all units were built by hand and by the new owners themselves. From the time of the Chicago CES show, where the products were first shown to the greater public, John Beyer acted as sales and business director, and Steven Keiser performed all technical functions.

The first amplifier was to be called the ST-140 and was poised to become an instant success with audiophiles, due to its musicality and its relatively affordable purchasing price. The first version of the ST-140 was a 70 watts per channel into 8 ohms design using a standard iron core transformer. The model shown here is the updated version featuring a toroidal transformer and 105 watts per channel into eight ohms. Right from the beginning, the ST-140 followed a ‘less-is-more’ approach that makes it the ideal playing ground for music enthusiasts. While many things can go musically wrong with such a design, the right setup and combination of accessories will easily lead to a highly engaging because unfiltered musical experience.

Over the years, B&K have derived most of their income from Original Equipment Manufacturing (OEM) designing, engineering, and manufacturing products for other electronics companies and to be sold under their various brand names. The company has manufactured many amplifiers and other components that were sold under brand names such as Crestron, Harman / Kardon, Lexicon, and Onkyo Integra Research.

The ST-140 is a simple Dynaco inspired design that is able to perform into low ohm loads, an important criteria when driving ‘difficult’ speakers, such as electrostatic or magnetostatic designs. This is especially true for the revised 1989 version of the amp. It offers great musical balance and dynamics and in this sense can really ‘sing and breathe’ though a musical performance. When comparing a design like the ST-140 with more sophisticated amps, such as the higher powered Harman / Kardon Citation 22 (200 watts per channel into 8 ohms), the transparency and musicality of the smaller ST-140 is truly astounding.

Specifications

• Type: Solid-state stereo power amplifier
• Manufacturer: B&K Components Ltd., Buffalo, NY
• Output power (RMS, 8 ohms): 105 watts per channel
• Total harmonic distortion (5 Hz - 45 kHz): 0.09%
• Frequency response: 3 Hz - 70.000 Hz.
• Year: 1989, revised 105 watts version

Do you have a bucket list? I have sometimes heard and read of people who write up a personal list of experiences that they hope to have during their lifetime. I suppose, bucket lists include places to travel to and experiences to have, and—until a few days ago—I was not aware that I even had items to put on such a list. But, when I dropped by Luigi’s new apartment to listen to his current HiFi setup and he suggested that I give his B&K Sonata mono block amplifiers a try, I suddenly had a great sensation that an important item was being crossed off my list.

Ever since I first listened to an ST-140 stereo amplifier, I have been a fan of the B&K sound. Simple in their design, these relatively inexpensive amplifiers offer great musicality while being very articulate in their presentation. There is nothing careless or sloppy about their approach to music. And, if the 105 watts RMS per channel amplifier can drive even difficult speakers with ease, just imagine what the 200 watts RMS per channel M-200 mono block amplifiers can do. After all, there is something humbling in a dedicated 19.5 kg amplifier designed to power a single speaker.

Luckily, my car was not parked too far away that evening, so that carrying the equipment to it proved to be an easy enough task. Getting them up the stairs on my own later that night was another story, of course. While the amps have handles up front, the sharp cooling fins extend out the back, causing ugly marks on tables and racks. It is therefore much wiser to ignore the handles and grab the amps by the body to raise them straight up. To be honest, I actually prefer this amp design, as it supports passive cooling when the units are mounted in a rack. Since both HiFi and professional racks are usually open towards the back, having the fins in this position facilitates convection cooling.

In our living room setup, the two B&K M-200 mono blocks were to replace the ST-140 stereo amplifier by the same manufacturer and to drive our Martin Logan SL3 electrostatic speakers. This is not an easy mission at all, because of the Martin Logan’s hybrid design, featuring a conventional woofer that is matched with a Mylar foil electrostatic panel. The difficulty is the low impedance of the panel—of below 2 ohms at 20,000 Hz—but also handling woofer reactance with the panel in the signal path. The SL3s therefore need a powerful amp that will perform into low ohms and offers enough damping to steady the woofer. 105 watts are barely enough for this task, although the ST-140 does have massive reserves and with its huge caps and power supply is relatively unimpressed with the Martin Logan’s impedance curve.

As usual, I gave the ST-140 a good listen first, playing Jazz, Folk, and Gospel that I know well. The Martin Logans sounded large, relatively slow, and relaxed. As a two way system, with a low crossover frequency towards the bass, the sound is generally homogenous and smooth. The ST-140 in combination with the SL3’s closed cabinet woofer produces a full bottom end but does lack some punch in the representation of kick drums. The highs are pleasant but not too crisp. This may have to do with the felt pads that we use as spike coasters to reign in the sound for a more musical and less technical performance.

Changing over to the M-200, I first noticed improved stereo imaging. The sound was still large, but now it was more articulate and slightly more spacious. Not in the sense of wider, but here was simply more room around the instruments. The SL3s now appeared more naturally agile and more forward directed. When listening to Springsteen’s ‘London Calling’ concert, for instance, ‘Youngstown’ had that same immediacy to it that I remember so well from the live concert. Since I already know this DVD well, the ability to evoke such memories at the blink of an eye really says a lot about the quality of the amplifiers. With the M-200 mono blocks, the music found it easier to loosen itself from the speakers.

Bass performance was less boomy and more refined with slightly more punch on the kick drums. While this was still not the SL3’s strong point, I now understand that larger amps will help in blending the bass in with the panel frequencies. And there is another difference that I noticed while watching TV later that night. Namely, that cinematic effects sometimes seemed to be unnecessarily emphatic, as if the engineers had mastered the sound track for equipment that was less revealing.

I hope I will be afforded the luxury of being able to listen to these amps for a few days, before returning them to their rightful owner. Well done, B&K. The Sonatas are accurate and musical amps that manage difficult speakers with ease and have enough power to convince even the otherwise relaxed Martin Logans to step it up a notch.

Specifications

• Number of channels: 1

• Power output (8 ohms): 200 watts RMS

• Power output (4 ohms): 400 watts RMS

• Total harmonic distortion: 0.09 %

• Signal to noise ratio: 95 dB

• Damping factor (50Hz): 600

• Frequency response: 1 Hz - 100,000 Hz

• Slew rate: 25 V / uSec

• Power consumption: 800 watts max / 65 watts (idle)

• Dimensions: (w)43.18 cm, (h)14.68 cm, (d)38.70 cm

• Weight: 19.5 kg

  (1987 - 1990)

Having trodden down the path of audio exploration for a number of years, I could see myself growing increasingly bored with the black box designs that held the marvels of electronics. Especially the identical-looking folded metal covers that served to house all kinds of gear, ranging from exotic streamers to run-of-the-mill multi-channel amplifiers, stood for the sordid lack of devotion of an industry increasingly sidelined by more versatile and interactive technologies. To the audiophile listener, however, this meant a lamentable loss of variety and aesthetics. In the 21st century, the general rule was that all Hi-Fi devices looked the same, unless, of course, prospective customers were willing and able to shed a few month's salary on the purchase of a single unit.

Turntables and tube amplifiers were among the few Hi-Fi devices that had largely remained untouched by the folded-metal-covers-syndrome. On these exalted units it was still possible to see and appreciate the raw technology in action and to recognise a distinct design philosophy. And perhaps this was also part of the reason for their returning popularity among a fresh new generation of listeners. For the new spawning social media generation, daily survival was about gathering tangible experiences and developing a unique and marketable personal image. Recognisable product features were an important means to underscoring and fulfilling that personal mission. Exquisite designs and mature personalities both needed to strike the fine balance between boldness and compromise.

I suspect that this longing for truth in character was also the reason why I was attracted to the Becker ST-200 amplifier in the first place: The possibility of seeing its electronics and the stunning simplicity of its design. At the time of purchasing the amplifier, I did not have any information about its specifications nor had I heard of the brand. Nevertheless, I suspected that the ST-200’s attractive features would also be supported by the choice of electronics inside. Was this a limited series amplifier perhaps, or a DIY kit similar to the Hafler and Heathkit amps? I really could not tell from looking at the amp from the outside, and my enquiries in the usual Hi-Fi forums remained without a useful lead.

I decided to play detective myself. Searching the Internet for clues, I found that the Becker ST-200 used four Hitachi J49 power MOSFET transistors, i.e., two J49 transistors per channel. With each transistor fastened to its dedicated heat sink, there was little need to worry about overheating. MOSFET transistors were silicone-based solid state devices that could run quite hot, especially if set at a high class-A level. They were said to offer tube-like performance in the sense that they produced a warmer and less technical sound. Such characteristics were usually given preference by audiophile listeners over regular transistors. I learned that one pair of these Hitachi MOSFETs per channel was capable of delivering 100 watts of output. If fully exploited, this would make the Becker a 100 watts RMS per channel amplifier into an 8 Ohm load. Not bad at all, given its relatively compact size and moderate weight.

Following the MOSFET transistors, the Coke-can-like blue capacitors attracted my attention. Rated at 61,000pF each, these powerful capacitors were able to store enough energy to offer strong peak power and drive even the most demanding speaker loads. Unfortunately, the same could not be said for the transformer that looked to be of rather moderate size, especially when considering the amplifier’s available power. Our Hafler XL-280, by comparison, housed a transformer that was at least double the size and weight. After switching on, the Becker's transformer rattled for a short while, until a relay switched the amplifier boards on in order to let the music play. Before connecting the speakers, I opened the amp to make sure that no parts had gone missing or come loose on the inside. What I found looking under the hood surprised me a little: The quality components that were on display on the outside did not seem to be matched on the inside. The amp's wiring actually seemed somewhat improvised.

I would have liked to see twisted and tinned Belden 9497 wiring leading to the speaker binding posts. Instead, I found the typical multi-stranded copper speaker cables that were household standard during the 1980s. I also observed that signal and power cables were at times laid out in close proximity to each other or even touching. This naturally had the potential of compromising the amp’s signal output integrity. To protect our speakers from an unnoticed malfunction, such as direct current output, I first measured the signal output using a multimeter. I found that the amp churned out up to 20 volts playing from a direct CD source and measured the amount of DC voltage to be zero. All the more, I was surprised that connecting our loudspeakers revealed 50HZ noise on both channels, as well as some nasty current-failing distortion during playback. It seemed that some relevant parts of the amp needed replacement, and I initially had a feeling that this just might be the large capacitors.

In my efforts to find the original designer of the amp, I had contacted Helmut Becker of AudioValve who, by his own descriptions, was known to have experimented with a wide range of design concepts before finally settling on tube amplifiers. Sadly, I learned that the owner of AudioValve had passed away in the week before my enquiry, so that my question could neither be negated nor confirmed by the company’s helpful customer service personnel. Considering the impact of AudioValve on High End tube designs, I will leave it up to the readers of this article to decide how plausible they deem the connection. In the written words of the friendly customer service agent: "Möglich wäre es."

I wanted to learn more about the exposed Bauhaus-style amp and consequently took the Becker ST-200 to be serviced by our trusted technician. By this time, I had already gathered enough items on my list of electronic bugs to justify a full service. However, to my surprise, I was handed back the amp just three days later and informed that no parts needed replacing. "These are some formidable components that have been very poorly assembled" was our technician's verdict. He had therefore repaired only the most obvious blunders and handed the amp back to me so that I had the chance to listen and decide for myself if further repairs would be worth the effort and cost.

Back in our listening room, I connected the Becker ST-200 to our Tannoy system that was controlled by a Dynaco PAS-4 tube preamplifier. After a few minutes of warming up, the music sounded huge with great tonality but also an audible noise floor in addition to the humming transformer of the amplifier. I was sure this could be done better and replaced the Dynaco with our dead-silent Restek V1 preamplifier. The noise floor dropped considerably, and even the humming transformer subsided with each hour of playing music. What I was left with sounded like pure magic to my ears. This amp produced the most naturally pleasing soundstage that I had heard on our Tannoys thus far. In combination with our affordable Belden 9497 speaker wires, the result even came close to the tonal and spacial realism I had felt when listening to the H&S Exceptional amplifier playing on the HMS Gran Finale speaker wires. In theory, there should have been no comparison at all, given the difference in price, quality, and effort.

However poorly assembled the Becker ST-200 may have been, it was certainly able to cause quite a stir with audiophile listeners like myself, simply because it was capable of reproducing that Jazz club feeling: The groovy stomping, the spacial accuracy of width and depth of the venue, the tonal appeal of real wood and metal, and even the lush and magnificent lead vocals in the stage centre. What had first looked like a promising DIY job gone south managed to produce more musical realism than some of our ultra-accurate amp classics such as the Hafler XL280. And while the Becker's specifications perhaps did not amount to much on paper, the amplifier certainly managed to capture our attention us in our listening room. I was reminded of amplifiers like the Dynaco ST-70 that, too, was capable of bringing the Jazz club atmosphere home. Therefore, when continuing our full refurbishment of the ST-200 amplifier in order to eliminate the remaining humming, we needed to pay special attention not to destroy its inherent magic.

[At the time of writing this, the ST-200 still suffers from repeated crackling and sporadic signal loss on either channel during passages of low input signal, especially coming from phono.]

(To be continued…)

Specifications

• Type: MOSFET power amplifier
• Power rating: 100 WPC (8 Ohms)
• Transistors: 4x Hitachi MOSFET J49
• Housing: 2x chromed metal sheets
• Dimensions: (W)220mm, (H)190mm, (D)345mm
• Weight without power cable: 9.5 kg
• Country of manufacture: Germany
• Year: 1980 (estimate)

The Citation twelve deluxe power amplifier was released to the public in 1972 and based on the 1970 Citation twelve stereophonic amplifier that had many of the same features. The facelift to the Deluxe version included a wooden case with brushed aluminum front and slightly improved specifications in terms of frequency response and distortion. Harman / Kardon’s previous amplifiers had been tube designs, and the original Citation twelve was the company’s first transistorized power amplifier. The Citation twelve’s relatively modern design was based on a design suggestion published in the RCA Solid State Handbook.

The Citation twelve deluxe features many of Harman / Kardon’s trademark design choices. On the one hand, it was one of the first truly dual-mono design amplifiers, featuring two transformers, two power supplies, as well as two separate amplifier circuits. On the other hand, Harman’s belief in the interdependencies of sound waves gave this amplifier the freedom to deliver frequencies from 1 - 100.000 Hz at +/-1 dB. In fact, not many amplifiers are given free reign to produce frequencies outside the spectrum of human hearing. According to ‘Absolute Sound’ the Harman / Kardon Citation twelve deluxe is “One of the twelve most significant amps of all time.”

Industrial grade components made sure that the amplifier would last for a long time. Harman / Kardon was so sure of this that there is very little on board to protect the amplifier from harm. There are not buttons, switches, or attenuators on the Citation that could have a negative effect on sound. In the original design there is not even a power switch to turn the amplifier off, and the standby power of 30 watts assures that the unit is always preheated and ready to play. The Citation presents its music in a straight forward, not frills fashion. It does not sound quite as robust and aggressive as a Quad 405, but it does not paint in beautiful colours like the small Hafler DH-120 either. From all the amps I have heard, I feel the Citation sounds the most accurate. Playing in combination with the Restek V1 preamplifier, the Citation manages to shine its light deeply into the room, sets an excellent soundstage and has that ever so slight touch of inviting warmth that is sometimes missing in more modern designs. The imaging and timing are smack on, and the panorama extends widely beyond the speakers. Still an absolute highlight after all these years.

On the unit shown here, changes to the original design include: a new Lapp power cord to replace the simple US version, a high quality power switch, new capacitors and gold plated cinch/RCA sockets.

Specifications

• Type: Class A/B power amplifier
• Manufacturer: Harman Kardon, New York
• Frequency response: 1 Hz – 100.000 Hz
• Total harmonic distortion: 0.2 %
• Signal to noise ratio: 100 dB
• Slew rate: < 2 US
• Damping factor: 40:1
• Phase shift: < 5 degrees at 20 Hz
• Intermodulation distortion: < 0.15
• Power rating (RMS, 8 ohms): 2 x 60 watts
• Power rating (music, 8 ohms): 2 x 100 watts
• Idle power consumption: 30 watts
• Dimensions: 430 mm x 155 mm x 370 mm
• Weight: 16.5 Kg
• Year: 1976

Dynavox is the brand name of Sintron Distribution, an importer of audio goods operating out of Iffezheim, just south of Karlsruhe in Germany. This is not to be confused with DynaVox, a manufacturer and distributor of speech-generating devices from Pittsburg, Pennsylvania. The Dynavox brand name first appeared on audio devices during the mid-90s, a time when more sophisticated audio products were becoming available from Asia, often for a fraction of the price of similar products from European or American manufacturers. With China and other Asian countries gradually opening their economies to invite private entrepreneurs, they also increased private wealth and brought about a local hunger for genuine high fidelity products, such as tube amplifiers.

To the western audiophile community, Dynavox is also a reference in name to the famous Dynaco audio brand founded by David Hafler. Similar to Mr Hafler, the importers of Dynavox products believed that genuine Hi-Fi engineering should be made available to the general public, rather than a select few. The name of the Dynavox VR-70 tube amplifier itself is reminiscent of the legendary Dynaco ST-70 tube amp. However, while modern renditions of the Dynaco sell for 2,000 - 3,000 EUR — far removed from Hafler’s dream of making Hi-Fi affordable — the Dynavox VR-70 hit the German market at just under 300.00 EUR. And, while the original VR-70 was clearly not in the same league as the revised Hafler tube amps of today, it did have a huge price advantage over its competition, offering about 90% of the listening pleasure. A warning shot to the established western audio royalty.

Its low entry price made the small VR-70 tube amplifier the entry ticket to audiophile listening for many starters to the genre in Europe. With more units being sold of this and other products, Sintron Distribution turned from importer to designer, in the sense of being able to influence the design process, based on the feedback they received from their customers either directly, or, more recently, through web-forums. To keep product prices down, Dynavox continued to keep their audio designs in simple boxes, apparently making concessions in exterior design rather than sound. With the continuous improvement of their products and growing general acceptance by the audio community, demand finally did begin to affect prices and customer expectations. Today’s VR-70 models sell at double the price of their early arrivals and are possible better engineered, rooting out some of the very early issues.

Dynavox, today, designs and imports tube preamplifiers, stereo tube amplifiers, and mono block tube amps, the PS-320 BT turntable, an assortment of cables and accessories, as well as noise-filtering power distributors. After 20 years on the German market, the company portfolio is still relatively limited, but the products are meanwhile well-established and have a reputation of offering value for money. While I am typing this text, I am listening to a Dynavox VR-70 E II stereo tube amplifier playing Jazz in its simple and inexpensive black powder coated cabinet. It has a reassuring red LED power indicator on the left and a not quite so reassuring volume knob on the right of its front panel. The tubes are barely visible through the grid enclosure. Only when I get closer, I can see them glowing and feel their heat radiating towards me.

I had bought the Dynavox VR-70 E II from a store called VinylNerds.de, and I had done so actually not for myself, but on behalf of my colleague from work, who had been looking for an affordable amplifier to power his speakers. I saw him looking at imports directly from Asia and suggested he might try the VR-70 with added the benefit of purchasing from a local distributor and shop. He agreed that this was a good idea, but some days later (as these things go) was reminded by his wife that there were currently more pressing issues for the family than Hi-Fi. This was understandable, of course, but I was still happy to have the opportunity of listening to the VR-70 E II. To be honest, I am meanwhile probing into the possibility of keeping it for myself. This is not a bad-sounding amp at all, even after having listened to some legendary names in the industry.

The Dynavox VR-70 E II weighs close to 15 kg and arrived here well-protected in a large and heavy triple-packaged cardboard box that was filled with thick foam interior profiles. All tubes and the protective cage were pre-installed. I saw that the left side of the grid cage protecting the tubes was unevenly painted, but since the amp was all-black and a full-metal design, this minor flaw in the paint coat was only visible if one took a very close look. Other than this, I was positively surprised that it measured only 35 cm in width and looked solid and clean. Since I had originally not intended to keep this amp for myself, I had not given its design and size much thought. But having spent some years in Hi-Fi, I have come to enjoy such deviations from the standard rack format. I loosened the screws of the cage to inspect the tubes and saw that they all had survived the journey to our house in one piece.

I had read somewhere that bias should be adjusted to 300-350mV for good result, but I could not remember if this was with the tubes being at full operating temperature. So, I decided to give the amp a listen with the factory settings in place. I gave our Hafler XL280 amplifier a final discerning listen, playing Diana Krall’s album “Turn up the quiet”, and then changed to the VR-70 E II amp. I left the room for four hours straight, while it was warming up from the trip. When I returned, I noticed that the music was less spacious than with our Hafler. Diana’s voice had a slight edge and graininess to it that made it less believable and more sibilant. Bass, too, was a little weak and compressed in direct comparison. The VR-70 also better transported the slight tube hissing coming from our Dynaco PAS-4 preamp or added some on its own. Given that the VR-70 E II is a 40 watts per channel beast (as far as tube power is concerned) that is perfectly capable of heating a room, I was a little disappointed by the flatness of its sound. The amp was not as engaging as I was used to. However, there was also a mild sense of fulfilment, because what I was hearing was not completely wrong either.

Our Hafler XL280 is a very good amp that has had plenty of time to run it. The Dynavox had just come in from the cold and was perhaps playing music for the first time. I understood that the factory tubes used on the pre and amp section had been chosen for their bang-for-buck performance rather than their audiophile virtues. The same was probably true for some of the components inside the amp. If my present listening experience was really all that could be expected from this amp, I would need to send it back; but, with the potential for more, I was willing to give it some time and thought. My first step was to make an appointment with our specialist for tube amp designs to discuss the merits of the amp's basic layout and components. I also began to search the net for opinions on upgrading it to audiophile level.

When I arrived at our tube amp specialist, I was curious to see what would await us under the hood. While the stock tubes seemed to be of decent Chinese quality, we were met by a worn-out screw on the amp's underbelly which we had to pry loose using pliers. It seemed that the white bottom plate was without proper electrical contact to the chassis, a circumstance that could be improved. Once inside, we also noticed that the legs of one capacitor had been twisted during assembly and nearly touched, a flaw that we quickly corrected. The parts on the inside appeared to be of decent quality for audio devices at this price point, and yet, there was clear potential for improvement by replacing them with more capable components. I suggested that the general layout of this little amp seemed well thought out, and the tube specialist agreed that there was potential in this design. He said he would gladly assist me in making this an audiophile amp. We agreed to first focus on the refitting of the interior parts and to then listen to the results for a while, before ultimately deciding on which tubes to change to.

Continue Reading - Part 2

Note for non-EU citizens: The type VR-70 E tube amplifier is also sold through the “Affordable Valve Company” in Britain, under the brand of ‘Audio Institute’. To my knowledge it is essentially the same amplifier that has been optimised for the British market.

Mod suggestions

• removing the input caps and bypassing the volume control
• upgrading the power supply caps and rectifier diodes to Wolfspeed Z-Rec 1.2 kV, 10 A, 11 nC
• upgrading the 70 V circuit by adding Mundorf MCaps Supreme 0.1uF 1400V
• replacing the negative feedback caps (C5 on PCB) with Charcroft Audio Silver Mica 47pF 500V
• adding a switch and circuit to change between ultra-linear and triode mode

Specifications

• Power output (RMS, 8 ohms): 2 x 40 watts
• Input impedance: 20 kOhm
• Pre-amplifier tubes: 2 x 6F2 (ECF82)
• Power amplifier tubes: 4 x EL34 (ultra-linear)
• Tube bias: 300 - 350 mV
• Frequency response: 10 - 40,000 Hz
• Total harmonic distortion: 0,1%
• Signal to noise ratio: >88 dB
• Damping factor: N.N.
• Output terminals: 4/8 Ohm, gold plated, for spades or bananas
• Dimensions: (W) 35,0 cm x (D) 30,0 cm x (H) 18,5 cm
• Weight: 14,5 Kg
• Year: 2013 - 2022

When building our first signature power amplifier for eiaudio, the developer Winfried Echle and I were looking to fulfil four basic demands: First, to make minimal use of components, basically following the audiophile rule of less-is-more. Second, to assure sufficient back current stamina to power complex loads. Third, to achieve superior agility and musicality. And, finally, to create some visual understatement in the shape of a sleek and modest-sized enclosure.

eiaudio’s first dedicated power amplifier was to be designed on the basis of an earlier project that had involved four Sanken 2SC-3519A bipolar transistors per channel. To improve power handling, it was decided to increase the capacity of the supply by upgrading to a toroidal 500 VA transformer paired with two 10,000 mF capacitors instead of the original 250 VA transformer. We were aiming for the larger transformer to assure more power on demand while the fairly modest capacitors would preserve the amp’s agility.

The four Sanken 2SC3519A transistors per channel were able to handle currents of 15 A at high operating temperatures, although chances of this particular amplifier ever running hot were rather slim, since bias current was only set at 5 watts per channel output into 8 Ohms. To prevent the amplifier from producing the typical popping sound from the magnetisation of the transformer, a resistor-relay combination was put in place behind the power supply. As I later found out, this simple circuity was quite effective during the power-on phase, but it did lead to a mild popping sound about 30 seconds after the amplifier was turned off, most likely from the relay switching off.

The housing for the amplifier was sourced from the Chinese eBay-seller Douk Audio, at a time when imports from China were particularly pricey due to multiple disruptions to world trade that reached from pandemic measures to high petrol prices and border closures for political reasons. All this drove non-EU import prices up and lead to more competitive local offers, e.g., coming from the France-based electronics trader Audioholics. However, in the end, it was the list of specifications and not the more competitive pricing that led to our decision in favour of the Douk Audio amplifier enclosure.

The housing offered plenty of interior space (W) 220mm, (H) 112mm, (D) 300 mm to allow for some distance between the two amplifier boards and the power supply. This would help to reduce the likelihood of audible transformer humming to be heard on the loudspeakers. At 6.5 kg, the cabinet was sturdy enough to help further suppress mechanical vibrations on the HiFi rack. The massive aluminum face plate was of symmetrical design and featured a solid, polished aluminum knob for gain adjustment as well as a machined aluminum power switch. The sides were two massive heat sinks that would offer more than enough cooling under any circumstances.

The power switch felt firm and solid during switching. Paired with the amplifier’s soft-start circuit, it made for a high quality user experience. The same could be said for the aluminum volume control. Input gain could be continuously adjusted between 0 to 1.4 volts via an Alps Blue series attenuator. This, too, gave excellent haptic feedback. The housing needed to be assembled upon arrival which turned out to be an easy task. We used gold-plated cinch/RCA sockets for line input and gold-plated, low-mass binding posts for use with bananas or spades for the output to the speakers. We also decided to keep the small rubber feet that had come with the cabinet and to later place these on additional isolation pads for acoustic decoupling from the rack.

Winfried designed the two circuit boards (one per channel) so that they would house only the most essential amplifier parts, strictly those that were necessary to maintain and amplify the source signal in as pure a fashions as possible. And, sure enough, with the measuring equipment we had available, the amplifier showed a deviation of 0 dB across the relevant frequency spectrum from 20 - 20,000 Hz. Although Winfried had previously built amplifiers with very high damping factors, I suggested that musicality was more important to me than absolute control. Hence, the LF-3519 was designed with a relatively low feedback in mind. Signal damping was rated at 600:1, which is still low enough not to be overly analytical.

When I first heard the LF-3519 perform, I was immediately drawn into the music. Winfried had connected his revised Tang-Band W8-2314 with open-baffle dipole, and I could feel an intriguing mixture of strong command in the bass notes and softly breathing vocals. There was a pleasant fullness and warmth, a nice sense of tonal colour that I could enjoy. On that day I could not wait to take the amp home with me to test on our electrostatic system. One requirement had been for the amp to perform well on difficult loads and to have the power to drive our Martin Logan electrostatic speakers.

Upon first connecting the LF-3519 on our system at home, I heard the hissing of our Dynaco PAS-4 tube preamplifier. I then dialled the input attenuator back, until the system was near silence when standing right next to the speakers. With the LF-3519 set in this position, I saw that our regular listening volume was achieved when setting the PAS-4 volume dial between nine and twelve o’clock which was considered the ideal operating space for any attenuator. When I started listening to my familiar Jazz and Vocal Jazz albums on vinyl and CD, I heard a new firmness and agility in the music. The LF-3519 drove the Mylar diaphragms far more effortlessly into the higher frequencies than any of our previous amplifiers. Bass was quick and punchy with a swift decay. Vocals were a luring combination of rawness and softness. 

When required by the music material, the LF-3519 would have the Martin Logans deliver bass runs that were astounding each time, both in volume and extension. The point being that there was usually no trace of this quality until the bass started to kick in. Although I am not that interested in bass performance, it was on these occasions that I turned to look at my wife just to confirm that she, too, had heard what I had just heard. While some of these qualities were already present a few hours after construction, proper tonality matured over the next few days and weeks.

One tendency we did notice was the amps readiness to pick up and amplify random noises from our household. And so it happened that just two days after our absolute listening bliss, the music began to sound harsh and constrained. At first I thought that something might have broken on the LF-3519 itself, or that this was perhaps an unpleasantness in character I had missed in my earlier listening. As it turned out, our LED-Christmas light transformer was emitting obnoxious waves into the grid. We eliminated the noise source, but we soon noticed other issues, for instance when our children placed their nightlights on the charger. The result usually was an unpleasant hissing and brightness resulting in listening fatigue. 

Our Martin Logans are particularly sensitive in this area, because their Mylar Diaphragm has practically no weight on its own. My next exploration in audio will be to take the LF-3519 to our upstairs system and check how it does on our dynamic speakers.

Too much of a good thing?

After three weeks of listening to the new amplifier on our Martin Logan system, I noticed that I was taking a growing amount of ear ringing to bed every night. Although our listening volume was only at around 70 dB, a sensation of brute force on the ears remained. In my attempts of solving the problem, I replaced the worn out tubes from the line section of our Dynaco PAS-4 preamplifier. This helped to lower the noise floor, but the ear fatigue remained.

I found then another source for noise on our system: Our Apple TV with HDMI audio exctracor was plugged into the wall outlet at the other end of the room. When I plugged in the cinch connector, I could see a tiny spark and even feel the difference in ground potential in my hand when I touched the preamp housing and the cinch/RCA plug. When plugged in, I could hear a slight humming coming from the speakers. I consequently bought a line signal transformer to place between the HDMI audio exctracor and the preamplifier. This helped to stop the small humming and only marginally changed the sound coming from the Apple TV, but the unpleasant feeling of brute force on the ears remained.

I then carried the LF-3519 amp to our upstairs system with our Epicure EPI 500 speakers in place. The first impression was better, given the Epicure's slightly more forgiving nature, but when I changed from Jazz to Rock & Pop, the amplifier appeared to be screaming at me once again. I finally decided that we would need to look at the design again to see how we could better harness the amount of available power to produce a sweeter, more enjoyable, and less-fatiguing sound. Among the ideas that came to mind were:

• increasing transistor bias (less switching noise)
• reducing amplifier gain (less amplitude)
• eliminating the attenuator circuit (less signal noise)
• cutting ultra-high frequency response (less amplifier oscillation)

As our explorations have repeatedly shown that everything is a theory, until it has been heard in live action, it is impossible for me today to predict, if these measures will lead to the desired result. However, I will gladly report on any new development.

Beyond the Initial Frustration

(Edit: 21. Feb 2023)

In order to combat our initial frustrations of ear fatigue with this amplifier, three of the four steps described above were taken, which lead to a satisfactory and even rather pleasing result: By eliminating the attenuator circuit, humming decreased to almost inaudible levels, even with one's ear held directly in front of the tweeter. By capping ultra-high frequency response, amplifier oscillation was stopped to produce a much smoother top-end. We also increased transistor bias to the point at which the heat sinks became moderately warm under normal operation. We did not limit amplifier gain.

First listening sessions showed the amplifier to sound less raw and jumpy, although some of the initial force remained. Although the Echle LF-3519 was still a fast-sounding amplifier, it was now easier to listen to music at greater volumes without feeling overwhelmed. The LF-3519 still had the ability to cast individual notes deep into the room, however, more than before it also managed to maintain coherence. The high amount of energy and control would make the Echle LF-3519 an excellent companion for speakers that needed a little boost to sound involving. I would have loved to pair it up with somes of the larger Tannoy models, such as Windsor, Arden, etc.

Specifications

• Type: class A/B power amplifier
• Transistors: 4x Sanken 2SC3519A per channel
• Transistor type: bipolar (BJT)
• Transformer type: toroidal, 500 VA
• Power output (RMS, 8 Ohms): 145 WPC
• Power output (RMS, 4 Ohms): 230 WPC
• Frequency range: 1-100,000 Hz (+/- 3 dB)
• Signal damping: 600:1
• Input type: cinch/RCA
• Input sensitivity: 1.4 volts variable, Alps Blue
• Signal to noise ratio: 112 dB
• Total harmonic disortion: <0.01 %
• Rise time: (to be determined)
• Slew rate: (to be determined)
• Dimensions: (W) 320mm; (H) 130mm; (D) 335mm
• Weight: 10.75 kg
• Country of origin: Germany
• Year: 2022

The H&S Exceptional is an ultra-linear MOSFET power amplifier that is capable of pumping 200 watts per channel into 8 Ohm loads and double this amount into 4 Ohms. Usually, doubling the power-rating as impedance halves works in theory, but here it also does in practice. At the heart of the amplifier is a large toroidal transformer able to extract a maximum of 1000 VA from your household grid. The amp’s sturdy body is constructed out of 2 mm steel sheets, and an additional inner steel cage serves to protect the delicate audio signals from harmful EMF that are generated by the power section. The outer cover is chromed. This mirrored-surface helps to accentuate the amp’s modest size of just 36cm in width and 16.6 cm in height. When I first chanced upon it, I had been sitting in the same room for a while and had hardly noticed the amp in the rack. However, the modest first impression was quickly forgotten, when I carried the amp for the first time. Its body felt ultra-solid, as if the unit was cut from a single block of metal. This effect was supported by the use of high-quality materials, right down to the stainless steel screws that were perfectly integrated with the chassis.

There was no popping, traceable vibration, or humming when the H&S Exceptional was switched on. Even with our periphery attached, there was no hissing or noise in the absence of signal. And, yes, even with my ear held to the speakers, the amp remained dead-silent. This did take me by surprise, because both our B&K ST-140 and Hafler XL280 amplifiers produced at least a faint amount of hissing, despite being well-made and excellent-sounding devices. My first impression therefore was that the H&S was an exceptionally well-behaved amplifier. Could this have been the reason for its ‘Exceptional’ name?

The H&S brand was originally created by the German Ortofon service technician Eugen Stöckl and his partner, first as a side-project next to their jobs and then as their main occupation. Over a period spanning more than 20 years, H&S developed and built a range of small-series Hi-Fi components for audiophile listeners. Among these products were the phono preamp H&S ‘Exact’, the ‘Iceblue’ phono cartridge, and three consecutive versions of the amplifier that is presented here. The main difference between the amp versions rested in the designs of the housing with the heaviest specimen weighing up to 38kg. Through the increase in sales of their products to audiophile customers, H&S was beginning to get noticed. When, in 2011, the leading international Hi-Fi magazine “The Absolute Sound” listed the H&S Iceblue among the world’s best phono cartridges of all time, Eugen Stöckl was able to receive this considerable honour in person, before his untimely death from a heart attack in the following year.

When reading about his sad demise on Markus Kannewischer’s website, I was reminded of the tragic fate of Peter Snell who had similarly died of a heart attack shortly after the launch of his popular C-Series loudspeakers. And, while men dying of heart failure was not unheard of, the idea of them dropping dead at the height of success did feel rather tragic to me. Hi-Fi had once again lost one of the industry’s humble contributors. Eugen Stöckl had been a staunch believer in the synergy of measuring and listening and spent lots of time doing both. His investment and stubborn diligence had paid off, and H&S was able to offer some true highlights to the audiophile community. The phono-preamp H&S Exact, for example, is considered to rank among the best of its kind until this day.

As the H&S Exceptional was a heavy amplifier, it took some 30-40 minutes warming up before displaying its full potential. With the original cost of the amp having been well in the five digits, Mr. Stöckl could be certain that the original amp owners would neither mind nor notice the increase in their electric bill while waiting for their amps to reach operating temperature, especially, as they were anticipating to experience a musical performance that would make them feel as the amp’s name suggested.

From one Solid State to another:

I began my exploration of the H&S Exceptional by hooking it up to our main system. This consisted of our Restek V1 preamplifier (previously upgraded by Restek and featuring a quality power supply by Mr. Kassel) and Martin Logan SL3 electrostatic loudspeakers. A Sansui SR-525 turntable with AT-VM95 ML cartridge and a Rega Planet 2000 CD player served as music sources. All units were interconnected with solid-core silver cables with copper-mesh shielding. I had a choice of loudspeaker cables and decided to start with our trusty Belden 9497 in bi-wiring (and connected to a single point of contact on the side of the amp for improved response). I chose a range of music and styles to focus on various aspects of performance, but will use just a few examples to highlight my findings.

Transitioning to the Exceptional from our trusty B&K ST-140 workhorse, I measured a 6 dB increase in effective volume when driving the H&S at the usual setting on the stepped Restek dial. I attributed this difference to the fact that the Exceptional had close to twice the power of our B&K but nearly the same input sensitivity. To avoid the criticism of comparing apples with pears, I made sure to set the volume at our usual listening level. Yet, even with the volume dialled back, the Exceptional sounded more focused and cleaner whilst playing stronger and more determined than our ST-140. In combination with our Martin Logan electrostatic speakers, the H&S achieved superb spatial and tonal separation of music events. The amp’s agile power output was driven by a total of 120,000 mF in supply capacitors which facilitated a rise speed of 300 V/μS. And, in combination with its formidable damping factor of 800:1, this resulted in an ultra-hard grip on the speakers. Amps like this are a valuable asset when listening to classical music and other scenarios in which many instruments play at once with multi-layered spatial and tonal character.

The Exceptional was capable of superb bass-punch and ultra-abrupt decay while holding simmering high hats suspended for eternity. In an all-solid-state setup (CD, Restek, H&S) this much command could at times sound overly dry and tight-fisted, stressing accuracy over musicality, but even exchanging one part of this signal chain could result in magic. Switching from our Planet 2000 CD player to the Sansui turntable, for instance, highlighted the amp's more musical side. Vinyl could easily benefit from a highly accurate amplifier by receiving a bit more transparency, drive, and punch than usual. Due to the relative absence of overlapping frequencies, of the kind that came from time-lag issues on the part of the loudspeaker drivers, the H&S Exceptional would not on its own be deemed as a 'warm' and soulful amplifier. It is relatively free of such effects. But, when paired with a turntable and tube preamplifier, it could well contribute to a superb mixture of musicality and detail, in addition to offering the welcome flexibility of being able to drive even the most difficult loads.

From exceptional amps to exceptional cables:

On 19 January 2022, just two days after writing the previous chapters of this review, I exchanged our standard Belden 9497 speaker cables (which work excellent on tube amps, etc.) for a pair of monsterous Madrigal Mark Levinson flat solid-core copper cables. The result was truly magical with the H&S Exceptional amplifier sounding perfectly balanced. It seems that the increase in capacitance and the uniquely crafted solid-core design of the Madrigal cable served well to bring out the amp's true merits. After all, the H&S Exceptional was targeted at owners of Krell or Mark Levinson amplifiers who were seeking to move upward. More information on this subject can be found in my Madrigal cable review.

Specifications

• Power output (RMS, 8 ohms): 2 x 200 watts
• Maximum power consumption: 1,000 watts
• Transistor Type: Power MOSFET
• Frequency response: 4 - 150,000 Hz
• Total harmonic distortion: 0,03%
• Signal to noise ratio: >100 dB
• Channel separation: 105 dB
• Input sensitivity: 1.3 Volts, max.
• Input resistance: 27 kOhm
• Damping factor: 800:1
• Rise speed: 300 V/uS
• Rise time: 0,5 uS
• Dimensions: (W)360mm; (H)165 mm; (D)310 mm
• Body: 2 mm steel casing + 2.2 mm steel shielding
• Finish: polished chrome, silver-matt faceplate
• Weight: 19,5 Kg
• Years: 1990 - 2011 (Series 1-3)

The David Halfer Co. was founded in Pennsauken, New Jersey, in 1972, but at the time of its founding, David Hafler had already made history as one of the world's most iconic audio engineers. Born in 1919, Hafler was a graduate in mathematics from the University of Pennsylvania who served for some time as a communications specialist in the Coast Guard during World War II. In 1950, he and his friend Herbert Keroes founded Acrosound, a specialist manufacturer of audio grade linear transformers for tube amplifiers. From building transformers it was just a small step to building the tube amplifiers around them, and in 1954, David Hafler left Acrosound and partnered with an audio engineer named Ed Laurent to found the Dyna Company, a name that was later re-branded as Dynaco.

Throughout his career, David Hafler focused on engineering audiophile products at affordable prices. Acrosound had built transformers primarily for home electronics hobbyists, and Dynaco was to take the idea of DIY audio to a whole new level. Ed Laurent had designed a new type single-tube driver circuit for a power amplifier before joining Dynco, and Hafler was intent on marketing this as an affordable choice for a large number of enthusiasts. Because of the high quality of Dynaco’s tube audio designs, the name quickly became synonymous with great sound at affordable prices. During the 1950s and 60s, setting up an audio system was still considered mostly an engineering hobby with the best sounding gear being built by its owners. Dynaco’s first product was the Mk. II, a 50 watts tube power amplifier. The unit was available both as a DIY kit and as a pre-assembled unit. After 2 years of successful sales, the Mk. II was succeeded by the Mk. III which was slightly stronger and offered 60 watts of power. These ‘Dynakit’ amplifiers were assembled by hundreds of thousands of audio enthusiasts at their homes. During the 1990s, the famous Dynaco Mk. II was featured in the Smithsonian's Museum of American History in Washington as a groundbreaking piece of American communications history.

Several Dynaco products of this time are still regarded as among the best audio designs ever made. This certainly includes the Dynaco ST-70, a 35 watts per channel stereo tube amplifier with a highly efficient push-pull output circuit. In fact, the ST-70 was designed so well that it was to become the prototype for many similar products that followed from other manufacturers. More than 350,000 ST-70 amplifiers had been sold by the time production finally ceased, making the ST-70 the most popular tube power amplifier in history. Although Hafler sold Dynaco to Tyco in 1968, he remained in an advisory position until 1971. By the time that David Hafler founded the company bearing his own name in 1972, he had already exercised an enormous influence on several generations of audiophiles and music lovers. With his mission of manufacturing high quality audio products at affordable prices being unchanged, the Hafler Company's first two designs were the affordable DH-101 preamplifier, followed by the DH-200 companion power amplifier, both offering exceptional music reproduction in that price range. Another notable product was the DH-500 stereo amplifier which was rated at 255 watts per channel and found great success in home, studio, and live environments. All units were available as DIY kits and as fully assembled products.

The Hafler DH 120 is a bridgeable 60 watts per channel transistor amplifier. It is of sturdy build quality with two amplifier boards hooked up to a single transformer. The 4 Hitachi MOSFET transistors per channel are mounted on two large heat sinks that constitute the sides of the amplifier. The specifications of the amp still read excellent by today’s standards, and the high quality of components assures a long life expectancy. Due to the relatively small number of parts and the well thought out circuit design, the DH 120 is a dynamic and musical piece of equipment showing that sought after Dynaco signature. In direct listening comparison, I even preferred the smoother and more colourful sound of the DH 120 to Hafler’s larger DH 220, a 110 watts per channel amplifier. Size is not everything, certainly not when it comes to the DH 120. The amplifier has got charme and is able to power most types of speakers just fine. For electrostatic and magnetostatic setups, the amplifier’s 60 watts per channel rating is most likely not enough.

Specifications

• Power output (RMS, 8 ohms): 2 x 60 watts
• Transistor Type: Hitachi Mosfet
• Frequency response (60 watts, +/-0.5 dB): 10 - 40,000 Hz
• Frequency response (1 watt, -3 dB): 4 - 200,000 Hz
• Signal to noise ratio: >100 dB
• Damping factor: 100:1
• Crosstalk: 85 dB
• Rise time: 2 uS
• Weight: 9 Kg
• Year: 1984 - 1990

There was a time when my good friend Luigi was bringing HiFi gear by our house for testing on a regular basis. And although there were lots of interesting discoveries to be made, somehow the devices did not strike a chord with us to the extent that we actually wanted to own them. One day, as I was climbing up the staircase from an evening teaching classes, I could hear music playing in the living room that sounded very realistic, even from a distance. Whatever this is, I was thinking to myself taking the last few steps, this is going stay. The system Luigi had set up for us was a Hafler combo consisting of the DH-110 preamplifier and the 60 watts DH-120 power amplifier. And its musicality was beyond anything we had heard at the time. When I later asked my wife at which point she knew that this would stay, she said that she had already heard it was very special from the kitchen - which is about thirty feet down the hall.

There are not many amplifiers capable of winning over our hearts from 30 feet away with such unanimous vote and certainly not at a price tag that most people are able to afford. Because of the obvious qualities of the Halfer, Luigi decided to purchase the 115 watts DH-220 and had it readjusted and fitted with new caps. The class-A portion of the amplifier was increased in the process, which has a positive impact on sound and leads to greater heat dispersion. I think you can literally fry an egg on this unit. At twelve kilos, the little amp feels like a solid piece of metal. The heat sinks are massive, and with this much class A-power that is probably good as it is. For an amplifier of this caliber, distortion figures are very low at any frequency. The below specs show THD at 1 kHz.

From my own experience I know that the DH-220 can be quite a princess, in the sense that it does not play with everybody. Some time ago we had borrowed it from Luigi to test it on our smaller system. In this scenario it had to play with some mediocre preamp and mid-fi speakers. The result was less than pleasing, and we soon returned the amp to look for something more appropriate. I was therefore surprised when Luigi insisted that I give this amp a second chance, now that all our other components had gradually been upgraded. In the current scenario the DH-220 was to replace the Citation Twelve Deluxe, a power amp that we have come to enjoy. And the playing partners were a Lenco L75 turntable, the Restek V1 pre, and Tannoy DC6t speakers at 8 ohms.

We gave the Citation a final listen and then hooked up the DH-220 for comparison. The improvement in this scenario was immediately audible even though the amp was still warming up. The slight dreaminess of the Citation was gone, music now had a more intense and realistic dimension to it which became especially striking when playing live recordings. Whereas the Citation had caressed the listener, the Hafler had a straightness and insistence to it that was familiar to me from some Quad amplifiers. The DH-220’s midrange is tonally very accurate and at that pleasingly broad. Its bass lines are powerful and controlled which develops into a pleasing fullness of sound. Spatial representation is highly accurate and piano notes are flung deep into the room. The Halfer played so well that we were able to remove the weights that I had placed on top of each speaker for better imaging and could pull the speakers further into the room without losing foundation. We will certainly keep this amp around for a while to enjoy the new dimension in sound. The Hafler DH-220 is well worth exploring. Wherever this amplifier fits in, it is going to be very hard to beat.

Specifications

• Power output (RMS, 8 ohms): 2 x 115 watts
• Transistor Type: Hitachi Mosfet
• Frequency response (15 watts, +/-0.5 dB): 6 - 60,000 Hz
• Frequency response (1 watt, -3 dB): 2 - 160,000 Hz
• Total harmonic distortion: 0,0025%
• Signal to noise ratio: >100 dB
• Damping factor: 300:1
• Crosstalk: 85 dB
• Rise time: 2,5 uS
• Weight: 12 Kg
• Year: 1984 - 1990

The XL-280 stereo power amplifier is arguably one of the best devices the Hafler has ever made. Offering 145 watts RMS into 8 ohms, it runs stable down to just 1 ohm and is thereby capable of driving even the most challenging speaker loads without having to fear instability, overheating, or the amplifier going into circuit protect mode and shutting itself down. The XL-280 was therefore predestined as a work horse to power the magneplanar and electrostatic speakers of the 90s, but also served more demanding conventional designs, such as some Infinity models. 145 RMS may not seem like a lot of power at first glance, however, this perception might change, if we consider that the watts nearly double as the ohms are cut in half, if the architecture and power supply permit. Thus, at 2 Ohms the XL-280 delivers 360 watts per channel, whereas many more conventional amps will simply throw in the towel.

The XL stands for Excelinear, which—according to Hafler—means that it excels in linearity. The aim was to build an amplifier that would have the linear properties of a single straight wire. The benefit of such an amplifier would be that it neither adds or takes away from the signal it receives from the audio source. Hafler writes that “In phase, amplitude, transfer characteristic and other distortions, the XL-280 sets new standards for accuracy. It is so close to perfection that for the first time you can make a meaningful comparison of this amplifier with the classic zero distortion: a straight wire. (...) An Exclinear amplifier enables the ‘golden ear’ who demands the absolute in system linearity to move one step closer to perfection.” The operating manual goes on to describe that with the addition of the XL-10 switch box, A/B comparisons in distortion differences to a straight wire are possible, and that the XL-280 offers built in controls for load adjustment to accommodate specific speaker loads. To allow for this adjustment while the amp is closed, the top panel has two small holes that are sealed by rubber plugs through which a screwdriver can be inserted.

Halfer, like Harman Kardon, believed that musical bandwidth should not be restricted for the sake of music integrity. The XL-280’s exceptionally wide bandwidth is demonstrated by the specified 1 watt output performance of ± 3dB from 0.1Hz to 500kHz. Impressively, phase shift within the conventional audio band (20Hz to 20kHz) is specified at less than 0.5°. In terms of build quality, the XL-280 is very similar to its predecessor, the DH-220, although it is actually 25mm wider. The black case consists of four construction units: 2 pressed steel sections which form the chassis and lid and 2 large anodized heat sinks—one on each side—to which the amplifier modules are attached and the 6 output transistors are screwed for passive cooling.

In their review of the Hafler XL-280, stereo-amplifier.net writes: “Set up for Quad ESL-63 loudspeakers the Hafler XL-280 gave a truly exemplary performance. The bass was absolutely firm and seemingly more extended than I am used to hearing, despite the fact that my preamplifier has a built-in LF roll-off. The treble was crystal clear and wide open sounding, with no trace of sibilant 'splash' and the overall stereo sound stage rock-solid regardless of the dynamic activity of the music used. Some of the more subtle subjective differences one hears in top-end hi-fi equipment are terribly difficult to quantify, sometimes even to express, but my overriding impression of the Haller XL-280 is that it neither adds to nor subtracts from the source material fed to it. The word that kept coming to mind as I listened over a period of weeks was 'authority' and I can't think of a power amplifier that I've used, or for that matter heard, which demonstrates that quality more convincingly.”

In my own listening so far, I can well relate to the relative authority which the amp attributes to the music. There is no halo, no trace of uncertainty in the representation of voices or piano notes. The amp rather seems to have an ultra-tight grip on the music that is truly fascinating. I cannot yet confirm the bass extension that we have come to know and enjoy from the DH-220, however, a fact that could mean that the capacitors in our unit have dried up over the years. While this would not be surprising for a unit that has been playing music since the 80s, it does mean that there is still some work ahead of us to reveal the XL-280’s full potential. Considering its fresh-from-the-shop condition, I would assume that this particular Hafler has been stowed away in the basement or attic for a long period of time, which is generally bad news for capacitors. Since we have already fallen in love with this amp, restoring it to mint condition will be well worth it.

Specifications

• Power output (RMS, 8 ohms): 2 x 145 watts
• Transistor Type: Hitachi Mosfet
• Frequency response (1 watt, -3 dB): 1 - 500,000 Hz
• Total harmonic distortion: 0,007%
• Signal to noise ratio: >100 dB
• Damping factor: 300:1
• Rise time: 0,7 uS
• Weight: 12,25 Kg
• Year: 1987 - 1990

“Have you ever tested a digital amplifier in your blog?” my favourite audio technician asked as I was leaving his shop. I stopped at the door and shook my head, grinning widely. I knew that Winfried was a seasoned developer of HiFi equipment ranging from network filters, CD-players, network players, pre and power amplifiers, all the way to loudspeakers. His more recent gear was usually packaged in inconspicuous-looking black boxes of visual understatement. And I knew that his digital amplifier designs had already been tried and tested in his own laboratory and in combination with the various HiFi gear of his customers. This particular Class-D amplifier had a higher-than-usual power output of 350 watts per channel into a 4-Ohm load.

“Will it work on the Martin Logans?” was my return question. We both knew that the Martin Logan electrostatic speakers produced some destructive dips in resistance, especially in the higher frequency spectrum. Winfried was confident that low resistance should not be problematic with his Class-D amplifier and assured me that there was built-in protection against overstraining of the circuits. I said that I would be thrilled and honoured to give his unit a try in my own testing environment. He handed me the amplifier, and, holding the little black box in just one hand, I was again reminded of the most obvious virtues of such a design: weight and size. At under 2.5 kilos, it was five to ten times lighter than a conventional 350 watts power amp would have been, even when considering some weight-stripped PA gear. I was thinking of such classics as the Dynacord PAA 880 power amplifier weighing 23 kilos.

As I had already experienced the Eichmann Bullet Plug’s advantage of equal mass ratio and also been witness to the benefits of solid-core connectors in eliminating Eddy currents, I was intrigued to learn about WBT’s 0210 CU Nextgen Plasma-protect sockets. What a positive surprise that Winfried should have chosen these plugs for the Class-D amp’s line inputs. The reassuring first impression continued when I turned the amplifier on for the first time. The integrated power switch on the IPC socket felt smoother and firmer than the many similar looking ones I had experienced before. The small black box looked sleek and sophisticated on our bamboo amplifier base, however, I could detect the slight ringing from the switching power supply that was emanating from the amplifier housing itself. It is no secret that I was no fan of trailing edge supplies and tried to eliminate them in our house wherever I could. On the other hand, I was prepared to keep an open mind towards the advances of technology.

During the warm-up phase of our equipment, the Class-D amp’s protective circuits detected a small amount of DC leakage coming from our tube preamplifier and switched the amplifier ouputs off repeatedly. This effect subsided once the Dynaco PAS-4 was at full operating bias. As our old Hafler XL-280 dinosaur had not featured such sophisticated circuitry, it had not revealed the small but not insignificant error on the side of the PAS-4. It took about 20 seconds for the Dynaco to stabilise, and the unpleasant switching noise stopped. Relieved that all was in good order, I assumed my listening position and noticed that the Class-D amplifier was itself quiet except for the small amount of familiar tube hissing coming from the Dynaco preamp.

When listening to Robby Williams’ album “The Christmas Present” on our Rega Planet CD player, I noticed that the Class-D amp played louder than our Hafler. It was quite typical for American amplifiers to have lower input sensitivity than their European counterparts. I could also hear that Winfried’s amp pushed the Martin Logans’ electrostatic panels into the higher frequency range more effortlessly. The resulting sound was accurate and smooth with great natural dynamics. The high frequencies sounded clean, and I felt that the tonality presented was natural. I was pleased with the amount of bass slam and control, and it was obvious that this amp was running stable enough to handle complex loads. Our hybrid Martin Logan speakers certainly qualified as complex loads due to their combination of panels (electronically similar to a capacitor) and dynamic bass driver. In this scenario, less able amplifiers than Winfried’s Class-D tended to struggle keeping control of the woofers.

The combination of the amp’s high damping factor 4,000:1 and its low internal resistance of less than four milliohms actually made it an excellent companion for our Martin Logans’ needs. I noticed that sonic events had their own spaces and sizes, without any apparent influence on each other. This was a great amp for analytical listening. The Hafler, on the other hand, seemed to paint with a single brush. It produced great cohesion in the music, but it could not match the Class-D’s superior bass control, extended high notes and effortlessness. While the Class-D design was able to produce growling bass that was deep and extended, the music could seem strangely disconnected at times. When playing music from digital sources, I sometimes felt a lack of emotion, a certain emptiness that was similar to the effect that is perhaps familiar from an LED cob light. While the light might be bright and also set at the specified colour temperature, there is also a sensation of emptiness when compared with a halogenic light source. And while this is just an analogy, the emmotional impact on the spectator was the same.

Playing music from an analogue source, however, was a completely different story. Here the amplifier’s additional detail and drive worked very well. The music sounded richer, fuller, and more satisfying. Phono benefited from the increase in agility coming from the Class-D design, and in contrast to digital sources, phono did not produce any feeling of emptiness. It instead sounded rhythmical, smooth, and full.

In conclusion, I could report that Winfried had built an inconspicuous-looking Class-D amp that packed many of the Class-D advantages but could not eliminate all possible design weaknesses associated with Class-D. In combination will digital devices, this particular amp could sound overly exact with some speakers and result in music information that was more interesting for the listener’s head than satisfying for the heart. In combination with analogue signal sources, however, the superior exactness had some obvious advantages. I could not help but wonder, if a linear power supply would not have resulted in an even better amp, but then this might just be my long-harboured personal suspicion of switching supplies.

Specifications

• Damping factor: 4,000
• Output power: 220 WPC (@ 8 Ohms), 350 WPC (@ 4 Ohms)
• Amp-internal resistance: 4 mOhms
• Switching power supply: 2x 600 VA
• Total harmonic distortion: <0,01 %
• Signal to noise ratio: 110 dB
• Channel separation: >115 dB
• Output impedance: 2-16 Ohm
• Line input sockets: 2x Cinch/RCA 
• Input socket type: WBT 0210 CU Nextgen Plasmaprotect
• Speaker binding posts: FineTech, gold plated
• Total weight: 2.44 kg
• Dimensions: (W) 165mm; (D) 260mm; (H) 93mm
• Country of manufacture: Germany
• Year: 2015

Having previously reviewed the Kenwood KR-9400 receiver of the mid 1970s, with its posh-looking brushed aluminum face plate, solid aluminium buttons and switches, all housed in an assembled metal frame that had originally been flanked by wooden sides, the black box design of the Kenwood Basic M2 with its thin, bent metal enclosure of the mid 1980s, was a bit of a let-down. The M2 shared this aesthetically reduced, light-weight design with most of the competing products of its time. Where, just ten years earlier, innovation had been in the machining and assembly of parts, this next phase was mostly about experimenting with the electronics inside to eliminate the shortcomings of the earlier circuit designs.

The 1980s were also a time of increased price competition. With more companies entering the market in the lower and mid-price segment with gear that fulfilled the basic demand of the average consumer, material and shipping costs needed to also come down on some of the established brands in the market. Kenwood was such an established brand, and the M2 Basic chassis offered 100 watts per channel more than the KR-9400 receiver and, proving the point, weighed five kilos less. Five kilos of net savings in materials and shipping weight would have made a considerable difference in the cost planning of a company that could sell thousands if not millions of iterations of each product.

In terms of assessing vintage equipment, the modern mass-market approach often lead to the immediate depreciation of value once the manufacturer’s warranty period had expired. However, this did not necessarily mean that the sound quality itself was compromised or that the inner circuitry similarly reflected the mass-market approach of the chassis. In fact, the 1980s were still a time of HiFi innovation, and the M2’s Sigma Drive introduced an all-new solution to the age-old challenge of handling the dynamic back current running from the loudspeaker to the amplifier. Instead of simply offering ultra-low internal resistance and measuring signal damping at 1,000 Hz, the Sigma Drive took into account the real feedback of the loudspeakers, regardless of the frequency.

In the tradition of decent High End power amplifiers, the Basic M2 used a separate power supply for each stereo channel. This was to lower the noise floor by eliminating cross-talk between the channels. The two heavy transformers were placed to the left side of the amp, thus leading to an uneven distribution of weight within the unit. The main board holding the two large capacitors per channel was located in the centre of the unit, culminating in the power transistor section with one large heat sink and a large cooling fan to the right. In domestic operation, the cooling fan would not play much of a role, but for owners willing to drive their M2 at full capacity, the fan would provide a safety net for the survival of the transistors.

The Basic M2 employed two pairs of transistor ICs: one set of DAT1521P / DAT1521N and one set of DAT1018P / DAT1018N, all of them fast switching 5-pin power MOSFETs made by Sanken. Especially the DAT1018P/N variety saw repeated supply shortages in recent years which would have made repairs of the amplifier section more difficult. The choice of fast switching ICs would have provided the Basic M2 with greater resistance to high frequency feedback which would otherwise have exceeded the slew rate of the amplifier. The new Sigma Drive circuitry would have similarly benefitted from the choice of ICs.

The Sigma Drive was designed to integrate the physical behaviour of a dynamic driver and the resulting dynamically unpredictable back current within the circuitry of the amplifier by monitoring the resulting deviation right at the speaker terminal and converting it into a mere current variation. As amplifier output constituted a voltage surplus, the ability to maintain voltage deviation at zero, by means of adaptive damping, led to exceptionally low harmonic distortion of just 0.004% measured across all frequencies. Effective back current damping was rated at above 1000:1 beyond the audible spectrum. With the new Sigma Drive feature on board, Kenwood introduced a new dimension in noise control that had the audio press of the 1980s interested for some time.

Kenwood was not the only HiFi manufacturer attempting to improve back current handling. Yamaha introduced “RO Control” on their B-4 and A-9 amplifiers, Aurex called their version “Clean Drive”, and Fidelix referred to their concept as “Remote Sensing NFB”. However, none of these technologies went as far as that of Kenwood which included measuring the whole loudspeaker from the voice coils to the speaker cable. This would have given Kenwood the upper hand in achieving the most accurate readings, if it had not been for a few issues that involved the use of two strands of speaker wires which needed to be connected in a fashion that was somewhat counter intuitive.

For the Sigma Drive circuitry to work its magic, two sets of wires needed to be connected between the amplifier and each speaker. Next to the common red and black binding posts per channel, there were two additional binding posts on the amplifier that were labelled as Sigma Sensor. Therefore the second set of wires ran from the Sensor posts, quite counter-intuitively, to the same binding posts on the speakers. This feature was only available for the speakers A and not for the speakers B. This meant that owners of the amplifier had to study their operating manuals carefully in order not to misconnect and destroy their amp. When connecting the amp for the first time, I therefore asked my wife to look over my shoulder and assure that all instructions in the manual were followed.

When connected correctly, the rather power-hungry Basic M2 offered a spacious and clean sound that was tonally rich and slightly dark in true Kenwood fashion. Hooked up between our Dynaco PAS-4 preamplifier and Martin Logan SL-3 electrostatic speakers, the music sounded soothing and voluptuous rather than exciting or sharp. This was an amplifier for easy entertainment rather than analytical listening. For an amplifier of this size and caliber, I was surprised by the amount of control it held on the flow of the music and on the rhythm. Where the Kenwood receiver sounded overly eager to tell the whole story all at once, the Basic M2 seemed to hold back, occasionally to the point of stomping and drudging. This may have been the effect of transients being cut short, and it sometimes took the fluidity from the music event.

I was generally pleased with the Basic M2’s performance. Connected to a difficult load as the Martin Logan SL-3, the Kenwood could really show its back current handling abilities. In combination with the two sets of OFC multi-strand speaker cables that I had available to test the Sigma Drive, I would hesitate to brand it audiophile material. However, it was well possible that a different combination of wires and preamplifier would have led to a more revealing result. Tonally rich and dark, the Kenwood followed the preferred sound signature of American customers of the time and thus offered a welcome contrast to the established European brands.

Specifications

• Type: Stereo Power Amplifier
• Special features: High-damping, Sigma Drive
• Power output (8 Ohms): 2x 220 WPC
• Power output (4 Ohms): 2x 324 WPC
• Frequency response: 1Hz to 200kHz (-3 dB)
• Total harmonic distortion: < 0.004%
• Dynamic headroom: 1.5 dB (8 Ohms)
• Damping factor: 1000:1
• Transistor-ICs: Sanken DAT1521P/N, DAT1018P/N
• Transistor type: Power MOSFET (5-pin)
• Rise time: 1.8 uS
• Slew Rate: 100 V / uS
• Input sensitivity: 1.0 V / 47 kOhms
• Signal to noise ratio: > 120dB
• Speaker load impedance: 4 to 16 Ohms
• Power consumption (max.): 1.350 watts
• Dimensions: (W) 440mm x (H) 158mm x (D) 373mm
• Weight: 15.5 kg
• Country of manufacture: Japan
• Year(s): 1983-1985

This rather pretty looking Dual CV 1260 integrated amplifier was handed down to my daughter from her recently deceased great aunt. It came along with a Dual CS 630Q direct drive turntable, a Dual CT 1260 tuner that was connected via 5-DIN plug, and a Denon DCD 660 CD player. There was even a Dual C 816 tape deck that I had some trouble finding worthwhile cassettes for in these days. Two Canton GLX 100 bookshelf speakers served to wrap up the Mid-Fi ensemble. Before surrendering these new arrivals at our house to our 9-year-old daughter, I had to test them and make sure the were safe to use, of course. Any publication of these test results is purely incidental, of course.

I must confess that there was something exciting and liberating about reviewing gear at this price level. After all, unless developers were asked to add intentional flaws to their designs, there was no reason why lower-priced gear could not sound as good or even outperform higher priced contenders. Proper acoustics had very little to do with the price of the components and was more reliant on the ingenuity of its designers. The speaker manufacturers Elac and KEF had demonstrated numerous times that audiophile listening pleasures were possible even at modest price points, and examples of purposefully poor designs were not difficult to be found in the industry. Rotel, for instance, had given their RC-9608X preamplifier a plastic floor board that sacrificed the pharadeic cage that the full metal enclosure would otherwise have offered. Manufacturers need to make sure that their devices perform according to the relative position that is reserved for them. 

Therefore, I did not know what to expect of Dual’s 1984 amplifier. For one thing, it had a larger brother, the CV 1460 Class-A amplifier of the same year that offered 95 watts per channel into an 8 Ohm load. And then, both devices were no longer built by Dual in Germany, but rather by the Japanese manufacturer Denon. As I unwrapped the 1260 from its protective bubble foil, I noticed how positively sturdy and heavy the unit felt. At just over seven kilos, the moderate-sized amplifier did not feel puny at all. Turning the Dual on for the first time, I was positively surprised by the elegant look of the softly illuminated output level meters. I made a mental note to capture these in my photos of the unit. I did not want to test the CV 1260 in combination with the Canton speakers, and so I hooked up our Epicure 3.0, half expecting the little amp to fail miserably.

I began my listening explorations with Carla Bruni’s 2014 live album A L’Olympia that I played on our trusted Denon DCD 1420 CD player. Our Epicure 3.0 speakers were connected via 2m runs of Belden 9497 as single wire. As both the speakers and the Denon amplifier had spring-loaded binding posts for small diameter speaker bare wire, I had to clip off my usual banana plug terminations. The idea that speaker cables need to be terminated to be of higher quality is relatively modern, of course. In reality, fewer material transitions and less mass in the signal path should have a positive effect on sound. The tinned Belden snapped into place, and, as these cables had already seen many hours of use, the resulting sound was pleasant and balanced from the very first minute. It was the instantly familiar sound signature of excellent receivers, such as the Harman Kardon 730, that surprised me most about the Dual. 

In combination with the Epicure 3.0, the midrange sounded warm and alluring. The soundstage was clean and well-ordered, and there was a surprising amount of space around each music event, especially when considering the relatively moderate power of approximately 2x 90 watts into 4 Ohms. Rated at 44 watts power consumption at idle and labelled as Class-A amplifier, it was safe to assume that average household listening volumes were served by pure Class-A transistor power. This certainly showed in the music performance. While the Dual presented a realistic amount of detail, the top-end never felt detached or edgy. There was wonderful cohesion and flow in the music, although the dynamics did not quite reach the level of a Luxman L-10. 

Bass performance was in balance with the rest of the music. It was not as tight-fisted as on the Luxman L-10 and also not as boomy as on the Pioneer SX 850. Complex bass sounds were better layered than on the Harman 730. The more I listened, the more I fell in love with the abilities of this integrate amplifier, and as the sun set, I started to enjoy the illuminated front with the level meters waving consistently at under 1 watt. The piano keys on Carla Bruni’s album sounded deliberate and simmered naturally, and I was once again reminded how good the Epicure speakers really were, even when powered by an inconspicuous mid-Fi Dual amplifier from the early 1980s such as this one. What a delightful discovery this was. My daughter would be spoiled from the onset by beginning her journey into music with this Dual.

Specifications

• Type: integrated solid-state amplifier
• Principle: Class-A amplification
• Output power (RMS): 2x 60 watts
• Frequency range: 10 - 45,000 Hz
• Signal-to-noise ratio (line): 88 dB
• Signal-to-noise ratio (phono MM): 68 dB
• Channel separation: input 70 dB / output 55 dB
• Signal damping: >70
• Number of audio inputs: 5
• Phono (cinch): 2.5 mV / 47 kOhm (MM)
• Tuner (cinch): 200 mV / 47 kOhm
• Tape1 (DIN): 200 mV / 47 kOhm
• Tape2 (cinch): 200 mV / 47 kOhm
• Monitor (cinch): 200 mV / 22 kOhm
• Number of audio outputs: 3
• Rec-Out Tape 1 (DIN) / Tape 2 (Cinch, Ri 470 Ohm)
• Headphone socket (jack-type): 6.3 mm
• Tone control: bass and treble (+/- 6 dB), loudness
• Bypass of the tone controls: not available
• Filter: subsonic
• Loudspeaker terminals: two (8-16 Ohm)
• Power consumption: 680 watts (max.), 44 watts idling
• Features: two combined VU meters, illuminated
• Dimensions: (W) 440mm x (H) 97mm x (D) 265mm
• Weight: 7.1 kg
• Country of manufacture: Japan (Denon)
• Year(s): 1983 - 1985

For far too long, I had harboured the suspicion that integrated amplifiers were ill-equipped to captivate our imagination to the same extent that separate units could. However, I must confess that this was mostly true in the years before I had ever heard a well-constructed integrated amplifier at work. Perhaps my misguided opinion had originated from the fact that I had mostly known integrated amplifiers from the run-of-the-mill gear sold by electronics superstores or your average online discounters. Since this had mostly been price-driven equipment of the kind that followed current market trends, audiophile pleasures had been hard to come by.

Luckily, the sleek-looking Italian amplifier that is the subject of this review had an utterly different story to tell. Instead of having been a mass-market product, the Performance 1.0 was designed and manufactured by Fase Evoluzione Audio in Italy, towards the end of the 1990s. It was, to a great extent, based on the craftsmanship and engineering philosophy of Fabio Serblin. Fabio himself was the nephew of the legendary Sonos Faber founder Franco Serblin and had previously designed the rather successful QUID amplifier for the Sonos brand. Fase Audio products, too, were created for the audiophile market, manufactured in small numbers, and of higher-than-average quality.

The Performance 1.0 was based on a simple circuit board design that was in keeping with the audiophile 'less-is-more' philosophy. The unit’s 60 watts per channel came from a decent-size, low-noise toroidal transformer and four high-quality Phillips capacitors. The pair of power transistors per channel were of the Mexican-made Motorola 'MJ15022' type. The unit's front panel featured input and recording selectors, as well as a high-quality Japanese-made Alps 'Blue Series' potentiometer for volume adjustment. The Performance 1.0 offered excellent RIAA correction for phono and was even capable of handling higher output MC cartridges. The rear panel featured solid speaker terminals for spades or bananas, a convenient IEC power socket, and a ground-lift switch that could come in handy in case of humming or similar grounding issues in connection with other equipment.

The unit’s sides were tastefully flanked by solid wood panels, a measure taken to dampen the effect of transformer humming on the electronics and housing. The overall design was of Italian understatement and crude simplicity. For example, the screws that secured the top and bottom of the cabinet were visible from all sides. Even the wooden panels themselves had visible screw heads peeking through. Perhaps this was done with the aim of highlighting a Bauhaus 'design-follows-function' philosophy, or it was simply to keep production costs down during the assembly in Italy. Even when I was not listening, I could not help but glance over to the position where the Performance 1.0 was standing from time to time, wondering what Fabio Serblin had been contemplating when he designed this unit. And so it happened: I had finally come across an integrated amplifier that did captivate my imagination.

I would have normally started my listening journeys with CD as source and then turned to phono once I had developed a feeling for the dynamics and dimensions. However, this time around, I started out by connecting our trusty Dual CS 505-3 to the Performance 1.0. The Dual, with original Ulm cartridge, had just been revised and fitted with cinch/RCA connectors, improved isolating feet, and new drive belt. I loved this simple Dual player for the no-frills attitude with which it presented music and really did not expect too much from the Performance 1.0. All the more, I was surprised how well the little amp highlighted the Dual’s inherent strengths by contributing to its clean and honest sound. If at all, the Dual seemed a little smoother than before, and it also seemed to pack more punch. Despite its modest dimensions, the Italian did not sound tiny or frail at all. It presented its music with great tonal richness. Bass was full, perhaps a little more on the thumping side than deeply extended, but nevertheless instantly amiable.

Katie Melua’s “Album No. 9” was presented with a slightly fuller voice than I was otherwise used to. This actually served to make the sometimes overly revealing and at times even harsh and sibilant recording more enjoyable. On the downside, vocals did sound less alive, realistic, and airy. Bass notes had a slight thickness to them and were more soothing to the ears and body than analytical to mind. This effect may have been accentuated and accumulated by our choice of low-capacitance silver solid-core interconnects and Belden 9497 speaker cables or by the resistance combinations of the devices. In and of themselves our Tannoy XT8f speakers and Dual CS 505-3 turntable were not known to be lacking in top-end or transients.

The impression of a mild top-end congestion, perhaps for the sake of reaching a fuller sound, remained unchanged when I made the transition from vinyl to CD. One thing struck me as particularly odd: On our current testing system, we were running a Cambridge DacMagic 100 in conjunction with a Marantz CD-17. All connections were based on solid-core silver cables. The DacMagic had an output impedance of 50 Ohms, and this simply did not match the Fase Audio’s expectations. Taking the DAC out of the equation, I was able to raise output resistance to 250 Ohms. The improvement was instantly noticeable, however, I made the mistake of also changing from our silver solid-core interconnects to an older pair of Fast Audio interconnects. For direct comparison, I should have just changed on thing at a time. Finally, changing back to our silver interconnects, I found that this created an even more natural top-end with vastly improved transients. The result was highly enjoyable, although I now noticed that the stage still seemed a little flatter and more recessed than I was used to. Such is the nature of our hobby that when one phenomenon is understood and put aside, the next one pops up from underneath, thus presenting another riddle to be solved.

However, further exploration will have to wait for another day. This particular Italian is going to play its tunes at Landon's house. Landon has been doing the proofreading for eiaudio and has been waiting for a proper amp to power his system for the longest time. Given some further exploration and clever matching, I can see the Performance 1.0 becoming the trusted heart of a passionate home Hi-Fi setup. With four line inputs and one very capable phono input, as well as lots of cross-recording functions, the elegant Italian offers the looks, power, and tonal richness that one would expect to result from a family production that has long since become royalty in Italian Hi-Fi. And although Fase Evoluzione Audio closed its doors some years ago, Fabio continues to manufacture Hi-Fi equipment under the brand of Serblin & Son. His uncle Franco of Sonos Faber died in 2013 leaving behind a flourishing loudspeaker manufacturing business. His life and achievements are commemorated by Serblin and Son’s through their current range of Hi-Fi equipment that is simply called — ‘Frankie’.

Note: Before handing the Performance 1.0 to Landon, I had the chance to test it on our newly acquired vintage Epicure EPI 500 loudspeakers. Playing in conjunction with the 4 Ohms EPIs, the Fase Audio seemed instantly more at ease and was able to drive them with superior tonal balance. The formerly punchy bass blended more seamlessly into the music. Following this experience, I would personally give preference to a 4 Ohm speaker to reach the Performance 1.0's full potential.

Specifications

• Type: integrated MOSFET amplifier
• Signal to noise ratio (line): 98 dB
• Signal to noise ratio (MM): 70 dB
• Signal to noise ratio (MC): 65 dB
• No. of input(s): 4x line; 1x phono
• Volume control: Alps ‘Blue Series’
• Outputs: 1 pair speaker terminals (bananas or spades)
• Power output (8 Ohms): 60 WPC
• Power output (4 Ohms): 100 WPC
• Features: ground lift switch
• Dimensions: (W)42.5 x (H)7,5 x (D)32 cm
• Country of manufacture: Italy
• Weight: 7.5 kg
• Year(s): 1995-1997

Just as I found myself suspended in audiophile bliss over our Becker ST-100 amplifier, Luigi dropped by our house on a casual visit carrying a small integrated amplifier under his arm and insisted that I give it a try at that very instant. I had long since understood that Luigi’s product demonstrations were nothing short of exceptional, and yet I was feeling more than just a little sad to dismantle my blissful setup of Restek V1 + Becker ST-100 separates to make room for a smallish-looking 55 watts integrated amp.

Being a great fan of separate pre and amplifier combinations to better match the sound of a system with the loudspeakers, it was only a small consolation to me that the integrated amplifier in question had been manufactured by Luxman in Japan, a company famous for creating some very exceptional designs back in the heyday of High-Fidelity. However, my impression changed considerably when I picked the Luxman up from the table where Luigi had placed it. At a weight of 10.5 kg, and featuring visible, shielded toroidal transformers for its two separate power supplies, the look and feel did seem more promising than I had first expected.

When positioned on a shelf, little about the Luxman L-10 demanded immediate attention. This was certainly not the type of amplifier that would start a conversation with a casual visitor to the house. However, for those interested in superb sound with knowledge of the industry, the L-10 would easily be accepted as the perfect understatement. 55 watts per channel might not seem like a lot of muscle judging from the figure alone, but when this was paired with a mindful internal layout, some exceptional components, and superb high current abilities, the result had the potential to be pure magic.

The L-10 is a member of the well-received Luxman ‘Laboratory Reference Series’ and steeped in the tradition of the 5C50/5M20 and C12/M12 amplifiers. It employed a clever DC amp configuration for both its pre and power amplification stages. The power amplifier was of dual-mono design and featured shielded toroidal transformers and large caps that facilitated high-current output and low-impedance drive capability. Its original Sanken 2SC1445/2SA765 output transistors were laboratory matched and of exceptionally high quality. Factors that made the L-10 both quiet and true to the music source. At the time of writing this, the special Sanken transistors were no longer in production, which had the potential of making replacements difficult. However, I did read that NOS offers could sometimes be found online.

The Luxman L-10 featured a newly designed volume control that kept channel imbalances to a minimum, and it had some attractive features to improve usability and connectivity. For example, the built-in preamplifier could be used separately in order to feed an external power amp, but also to serve as a headphone amp via the frontal headphone jack. All amp outputs offered the option of monaural down-mixing, a convenient feature when checking for channel imbalances or playing back monaural recordings. Another convenient feature was the stereophonic reverse playback switch that could invert the left and right channel inputs.

Instead of the usual +/- 6 dB tone controls that mostly had a degrading effect on sound quality by introducing phase shifts and signal loss, the L-10’s tone compensator allowed for +2 / -2.5 dB adjustments run through a passive circuit. The idea was for the owner to be able to mitigate tonal balance variations between different recording studios without sacrificing signal integrity. The variable control frequencies for bass were 50 Hz, 200 Hz, 700 Hz; and for treble 700 Hz, 3 kHz, 10 kHz. To protect the speakers from accidental harm, the amp output featured a protective circuit that would turn the amps off in the event of DC current output.

Listening to the L-10 play our favourite Jazz albums, I was surprised how seamlessly the integrated amplifier managed to pick up where the Restek V1 + Becker ST-100 separates had left off. In fact, the L-10 had nearly the exact qualities that had attracted me to the Becker ST-100 in the first place: It was tonally rich with a strong mid-bass presence and, at a mild damping factor of 80, it allowed the system to breathe. Layering of bass provided a tonally rich sound that made listening very enjoyable from the very start. While Luigi insisted that the Luxman had a tonally neutral approach to the music, our Tannoy speakers revealed a highly musical and juicy character.

Voices were depicted accurately and in an instantly pleasing manner, much like with the Becker amp. During vocal passages I would not have been able to tell the difference between the two, they were that close. Despite the slightly bloomy mid-bass, I was not able to detect a thickening of voices. Treble was focused, delicate, and elegant, just as one would expect from a well-protected signal path. Higher piano notes managed to free themselves from the speakers and take presence in the room. I was, indeed, very pleased with the performance I was being given by an integrated amplifier.

I must confess that under normal circumstances I would not have made any comparison between some of my favourite separates and the Luxman integrated amp. However, in this special case, having listened to the two so shortly after each other, I can say that the L-10 managed to hold its own very well. The differences were more or less a matter of personal taste. Luigi, for instance, gave preference to the Luxman’s slightly more controlled and agile sound, whereas I felt more drawn to the larger spacial representation, airiness, and punch of the separates.

The highest highs and the lowest lows were just a little more present on the beafier Becker ST-100 amp. There was also slightly greater physical separation between the instruments on the larger amp. On the other hand, the L-10 brought more speed and agility to the table that gave preference to faster music. For those looking for an integrated amplifier, the Luxman L-10 is most certainly worth considering. Refurbished models, such as the one presented here, are playing in a class of their own and can even compete with separate units at an audiophile level.

Specifications

• Type: dual-powered integrated stereo amplifier
• Features: Super-Class-A(/B), Realtime Processed
• Power consumption: 230 watts, max.
• Inputs: Phono MM, Tuner, Tape 1+2, AUX, Monitor
• Power output: > 55 WPC @ 8 Ohms; 75 WPC @ 4 Ohms
• Phono response: 20 Hz to 20 kHz (< 0.2 dB)
• Filters: Subsonic (10 Hz, normal, 20 Hz)
• Line response: 0 Hz to 100 kHz (< -1 dB)
• Total harmonic distortion: < 0.015%
• Damping factor: 80 (@ 8 Ohms, 1 kHz)
• Tone controls: bass, treble (+/- 2.5 dB, passive circuit)
• Variable control frequency: Bass (50 Hz, 200 Hz, 700 Hz); Treble (700 Hz, 3 kHz, 10 kHz)
• Phono input sensitivity: 3mV (MM), 300mV (line)
• Phono input impedance: 50k Ohms
• Signal to noise ratio: > 90 dB (phono), > 100 dB (line)
• Channel separation: > 85 dB
• Output: 300mV (line), 0.3V (Pre out)
• Dimensions: (W) 438 x (D) 363 x (H) 78mm
• Weight: 10.5 kg
• Country of manufacture: Japan
• Year(s): 1976-1982

Following the Japanese Luxman L-10 and the Italian Fase Performance 1.0, the British Musical Fidelity A1-X was my third integrated amplifier. It was handed to me for review by my namesake Karsten from Bad Vilbel (north of Frankfurt), who had recently transitioned to a whole set of Naim components to power his Altec speakers. The A1-X had been sitting in storage, until Karsten suggested that I could take it home for review.

Looking at the power rating of 25 watts per channel, I thought it best to hook the A1-X up to our system in the main listening room, which still had the Shure 701 Pro Masters set up. Rated at 102dB, the Shures would be forgiving of a slight lack of power on the side of the amp. However, when I tried to set up the A1-X in place of our Dynaco PAS-4 tube preamp and Hafler XL280 amplifier, I realised that I would need a preamp output to provide music to the subwoofer. In keeping with most integrated amp designs of the 80s, the Musical Fidelity did not offer this connectivity feature.

When considering our second system for compatibility, I was reminded that this had only recently transitioned from the more sensitive Tannoy XT8f speakers to the Epicure EPI 500 which had a modest sensitivity of just 88dB. Would this be enough to be powered by the A1-X? Well, there was only one way to find out. And so, I carried the small Musical Fidelity amp upstairs and disconnected our Restek V1 preamp that had been running to my great delight with our Dynavox VR-70 tube amplifier.

On paper, the change from a 35 watts to a 25 watts amplifier may not seem like a big deal. And yet, 35 watts of tube power were a completely different story, especially in comparison with transistor power. I meanwhile had lots of experience listening to the Restek & Dynavox combo and especially enjoyed its ability to develop the music from the bass notes rising upwards. This is a characteristic that tube amplifiers manage to do so well. In Hi-Fi forums and reviews, I had read that the A1-X was capable of a ‘tube-like’ sound, and I was eager to find out just how much truth there was to this claim.

I began my explorations by listening to Tony Bennet & Diana Krall’s 2018 album ‘Love is here to stay’. This album’s timbre was a bit darker than was typical for Diana’s other albums (with the obvious exception of ‘Rag Doll’, which turned out to be a slip in many ways). While being rich in musical information, ‘Love is here to stay’ had a strong centre-stage focus with channel separation being of less significance. There was lots of natural bass from the instruments but also from the performer’s feet moving and stomping on the floor. 

While the technical specifications of the Musical Fidelity A1-X my not seem impressive on paper: 25 watts per channel, 0.5% total harmonic distortion, 80 decibels of signal-to-noise ratio, the A1-X sounded neither weak nor distorted. On the contrary: My initial impression was that this was a perfectly clean sounding amplifier. There was lots of tight control, even when the amp was still heating up. For the first couple of minutes, I had a slight sensation of a channel imbalance and was wondering what was causing it, especially since I had taken extra care not to move the speakers. However, this imbalance disappeared after 3-5 minutes and may have had to do with the preamplifier taking power from the right channel, as was described in Mark Hennessy’s exceptional essay on the A1 and its derivatives. (Have a look for it, it is worth reading.)

Having been freshly connected to phono, the CD player, and the Epicure speakers all at the same time, the A1-X sounded a bit thin at first. Given some time to settle in, however, this impression changed. I appreciated the fact that the Musical Fidelity proved to be tonally accurate with lots of natural timbre. Where the Dynavox tube amp had laid timbre on quite thick, smothering the listener with tonal colours, the A1-X kept it strictly real. In this aspect, it was closer to the more balanced-sounding Luxman L-10 integrated than it was to vintage tube gear. 

Imaging was accurate, but instruments seemed slightly more recessed and smaller with more well-defined space around them than I was used to. This tendency became more apparent when I changed over to the 2Cellos 2012 album by the name of ‘In2ition’. It was in moments that demanded superior dynamics and authority that an increase in loudspeaker sensitivity would have produced better results with this integrated amplifier.

The A1-X was the European version of the A1 and released to the public in the mid-1980s. Just like the A1, the A1-X was based on an electronic design created by Hi-Fi legend and long-time Musical Fidelity engineer Tim de Paravicini. The European version already featured the revised design with open cooling vents on both sides. At the same time, the top-cover consisted of two large heat sinks that would easily reach temperatures of exceeding 60 degrees Celsius. The front controls were designed in a way to facilitate accidental touching of the heat sink, which only served to highlight the fact that there was some robust power handling involved.

As Mark Hennessy pointed out, it has been discussed with some controversy just how much power this amp was able to produce. In conducting some measurements and applying basic mathematics, Mark arrived at the conclusion that the A1-X produced an output of 8 watts in class-A before switching to A/B operation. Some, including the designer Tim de Paravicini himself, argued that class-A power output should be calculated differently, in that it more resembled that of tubes in a push-pull design. This would have placed class-A output at closer to 16 watts per channel and served to explain the amp’s continuous power consumption of 90 watts. Another such indication was that heat sink temperatures had been reported to fall by 10 centigrade at full output capacity. Fearing for our speakers, I decided not to confirm these measurements myself.

Mark measured that the output stage was biased at around 800mA, which was quite high, and did at times lead to thermal problems, especially on the first units that were sold without side ventilation. Similar to the Fase Performance 1.0, the Music Fidelity A1-X only offered the most essential controls: an input selector, a volume control, one power and one tape-monitor switch. In this context, it is noteworthy that the A1-X’s phono stage offered enough clean amplification for MC phono cartridges. The internal preamp was able to produce 200mV in gain. An additional switch in the back of the unit allowed owners to switch between MC and MM operation. The quality of the phono stage and the ability to switch to MC would have made the A1-X an instant favourite with audiophile listeners. It was sometimes reported that the large amount of gain on the preamp could lead to unwanted noise, although I did not notice any such issues myself.

Similar to the Fase Audio, the A1 series used a toroidal transformer as power supply. Following the transformer, the amplifier was of a double-mono design, with components mirrored along the central power rails that were supporting the heat sinks. There were a number of smaller facelifts in the versions of this amp from 1984 to 1990, starting with the A1 and the A1-X, which was succeeded by the MKII. There was also a version called ‘David’ that was made (and tuned) for Germany, and a ‘Final Edition’ which featured a MOS-FET output stage. The early designs had their power supplies built inside the main amplifier housing, whereas later specimens featured external supplies that increased power output to nearly 50 watts per channel.

In his discussion of the A1 amplifier, Mark explains that this design was not made to be worked on excessively. Not only was the cabinet too small to house bulky components (the power supply caps were laid sideways to account for the limited height), the large heat sinks were also tricky to remove, with lots of fresh thermal paste being needed on repositioning the sinks. It seemed that some portion of the A1-X’s superb sound quality could be attributed to its simple amplifier design philosophy of 'less-is-more'. Although the amp used some higher quality parts, the output devices themselves were relatively standard for the time: a set of 2N3055/MJ2955. Mark suggests replacing them with more durable Motorola MJ15003 and MJ15004, if they should ever be in need of repair. Later versions of the Motorola transistors (e.g. MJ15022) could also be found on the Fase Audio Performance 1.0, if I recall correctly.

When I was first handed the A1-X for review, Karsten told me about an issue that he had experienced with the volume attenuator having become unpleasantly noisy, but on the day of my arrival, he had not been able to reproduce the phenomenon. This reminded me of a similar issue I had once had with our DB Systems DB 1 preamplifier. In the case of the DB1, there had been a slight amount of DC current running through the quality Alps attenuator during line operation. I believe this stemmed from a broken part on the side of the CD player which resulted in the current. It was quite possible that the reason for the volume control having been noisy on that occasion had been the result of a similar issue with an external device, although Mark did suggest that the A1 design also encouraged small amounts of DC current to pass though the Alps control.

In any case, the Alps Blue potentiometer that was used on the A1-X was also built into the Fase Performance 1.0 to positive affect and did have a good name in audiophile circles. The combination of internal preamp and power amp section served to create the A1-X’s specific sound characteristics. However, it was the high gain of the preamp that also led to the lower-than-average signal-to-noise ratio of 80dB. As, during my listening tests, I did not detect any noise and could appreciate the sonic characteristics of the amplifier, I would be inclined to leave the A1-X in its current configuration. The relatively large amount of class-A amplification made the A1-X an excellent companion for higher sensitivity speakers.

Musical Fidelity Company History

Musical Fidelity is a British Producer of high-end audio equipment with a long line of amplifiers, ranging from power amps via phono and headphone amplifiers to integrated amps (such as the A1), and pre-amplifiers. When the company was founded in 1982, their first product was called “The Preamp”. It already featured an MC/MM switch. The founder, Antony Michaelson, was a clarinettist and Hi-Fi enthusiast who had a knack for unconventional industrial design.

Musical Fidelity’s second product was the “Dr Thomas” power amplifier that bore the name of its designer Dr Martin Vaughan Thomas. With a formidable output of 100 watts per channel, the Dr Thomas amplifier was already quite a beast for a first design. Among the designs that followed, not few went on to become genuine Hi-Fi milestones.

The A1 and all its variants and successors were designed by Tim de Paravicini who died in December 2020. Tim had been friends with Antony Michaelson since 1978 and also through the time when Michaelson was a partner with Michaelson & Austin. In the grassroots fashion of many start-ups, Tim de Paravicini had built the prototype design for the A1 in the private workshop of his home. He was proud to show his invention to Antony Michaelson who had in turn just started Musical Fidelity. Following a difficult time of further development of the design, the A1 would become one of Musical Fidelity's highly regarded products.

Specifications

• Type: integrated stereo amplifier
• Features: high class-A output
• Power output: 2x 25 watts, 8Ω (stereo)
• Class-A output: 8-16 watts, 8Ω (stereo)
• Power consumption: 90 watts continuous
• Frequency response: 20 Hz to 20.000 Hz
• Output stage transistors: 2N3055/MJ2955
• Total harmonic distortion: 0.5%
• Volume control: Alps Blue attenuator
• Inputs: (3x) line, (1x) tape monitor, (1x) phono
• Sensitivity (phono): 0.2mV (MC), 2mV (MM), 
• Sensitivity (line): 200mV
• Output terminal: 1-set (bananas/spades)
• Signal to noise ratio (phono): 55dB (MC), 60dB (MM), 
• Signal to noise ratio (line) 80dB
• Surface temperature: 55-65 degrees Celsius
• Weight:  5.8 kg
• Dimensions: (W) 408mm ; (H) 68mm ; (D) 258mm
• Year: 1984 - 1992

Watch this space. Full review of the RG9 MK3 coming up shortly.

The story has it that Sidney Harman and Bernard Kardon were co-workers in the higher levels of David Bogen & Co., a telegraph and communications specialist, before they both resigned to form Harman / Kardon in Stamford, Connecticut, in 1953. From the very start, the company focused on designing integrated receivers that would merit the definition ‘high fidelity’. The first Harman / Kardon high fidelity receiver, the Festival D1000, was among the world’s first AM/FM compact receivers and already featured what would later become HK trademarks, such as a copper plated chassis. Although Bernard Kardon soon after retired, in 1953, he sold his interests in the company to Sidney Harman, who consequently named his company Harman International. Perhaps out of respect for his retired colleague, but perhaps also because he did not want to again change a brand name that customers had just gotten used to, the company has continued to carry the double name Harman / Kardon on all their receivers, tuners, and amplifiers to this day.

The company’s strategy of building the highest quality product at any price level sometimes meant the omission of nice-to-have features for the sake of clarity and for the sake of being able to afford higher grade components, which may have alienated some customers in the shops. On the other hand, it has been this focus on the essential that has helped the company build a strong base of followers to keep it alive over the years where many others have failed. The iconic HK 330 receiver was introduced to the public in 1968. It is an excellent example of the Harman design philosophy and was very well received. The HK 730 shown here was the most powerful model of that product range and was built from 1975 - 1978. Its solid 50 watts per channel into 8 ohms may seem relatively unimpressive by today’s standards, however, one needs to consider that this unit was built before the receiver wars, in other words, before high watts figures were considered to be an asset. Instead, the unit was engineered for sonic performance, and the components were chosen to perform musically and effortlessly at common listening volumes. On the basis of the components used, higher output ratings would easily have been possible, if this had been the intention.

Harman / Kardon believed that limiting frequency response outside of human hearing would negatively influence the harmonics found in frequencies within the scope of human hearing. Hence the HK 730 attempts a linear performance from 4 Hz to 40.000 Hz. As is the case with all of Harman’s twin powered receivers, the unit features a double-mono amplification unit, each side with its independent power supply, as well as a third power supply for the preamplifier. Both the preamplifier and the power amplifier can be used separately, by removing the bridge at the back of the unit. All frontal elements are made of solid metal and have been placed on high quality switches and attenuators. Given Harman’s attention to detail, it is a little surprising that the treble and bass controls cannot be cut from the signal path. A small blunder that is easily forgiven once you hear the unit sing. The tuner and phono stage are truly excellent. The copper plated body helps to keep away interference, and the components are well chosen and well placed.

The unit shown here needed some re-soldering. Especially the cinch/RCA connectors on the back can come loose with time. The original US power cord has been replaced with a high quality Lapp cable, and the clamps for the two sets of speakers have been replaced with banana jacks for convenience and to be able to attach larger diameters of speaker wire. The sonic performance is life-like and natural with plenty of control over the speakers. Its quality, features, and performance make the HK 730 one of the best classic receivers ever built.

Specifications

• Type: Post World War 2 AM/FM receiver
• Tuning range: FM, MW
• Power output: 50 watts per channel into 8Ω (stereo)
• Frequency response: 4 Hz to 130 kHz
• Total harmonic distortion: 0.1%
• Damping factor: 30
• 2x Phono inputs: 2.5 mV, 47 kOhms
• Auxilliary and tape inputs: 150 mV, 30 kOhms
• Input sensitivity: 2.5mV (MM), 150mV (line)
• Signal to noise ratio: 72dB (MM), 77dB (line)
• Dimensions: (W) 432 mm x (D) 368 mm x (H) 140 mm
• Weight: 13.7kg

The Kenwood KR-9400 was the third receiver presented in this blog. It was given to me for testing by Luigi, who had previously purchased it from a collector in Berlin. At the time it was handed to me, the Kenwood had already been fully serviced and technically restored where necessary. Due to some obscure event, however, this receiver had lost its original wooden sides. The wood applications would not only have looked nicer and potentially prevented children from reaching inside, but they would also have served to absorb some of the mechanical vibrations, e.g., from the extra-large transformer. Rebuilding the unit's American walnut flanks at first seemed like an attractive idea, but I soon found that it would take some professional support because of the sheer size of each of the two surfaces. After all, the Kenwood KR-9400 was a very large receiver, a fact that partly remained concealed because the overall proportions seemed natural enough.

Taking a first glance under the hood, I could see that some effort had gone into designing the power supply. Where Harman Kardon had taken the path of separate power supplies (one for each channel of their HK 630 and 730 receivers) both the Pioneer SX 850 and the Kenwood KR-9400 had to draw their energy from a single supply. On the Kenwood, the transformer and filter capacitors were of impressive size in order to allow for an effortless flow in music, even when playing in combination with more challenging speakers. And, in true power amplifier fashion, the two amplifier circuit boards were placed upright, directly to the left and to the right of the large power supply. Two over-sized heat sinks successfully kept the four NEC 2SD287 bi-polar transistors per channel cool through all operating conditions. NEC 2SD287-type transistors were considered run-of-the-mill power transistors and would ensure long performance and serviceability.

Similar to Hafler amp designs, the KR-9400 did not use coupling capacitors that would prevent direct current from reaching the output stage. This sort of concept could potentially kill speakers, but audiophiles tended to describe direct-coupled amplifiers as sounding more direct and revealing, possibly due to having one less part in the signal path. Given the time of its production, this Kenwood receiver did produce a relatively low level of total harmonic distortion and was rated at less than 0.1%. Its output power was class-leading and unrivalled in the world of receivers until 1974. In fact, its sheer power is sometimes said to have spawned the Receiver Wars. After all, 120 watts RMS per channel into an 8 Ohm load, and 150 WPC into 4 Ohms made this receiver a truly versatile companion to power most available speaker concepts and a rival even to separate pre and amplifier combos.

The KR-9400 was the most powerful receiver of Kenwood’s 400 range. Beginning from the pretty KR-1400, Kenwood's lowest-powered receiver with 10 WPC at 8 Ohms, the company counted up the first digit of their receiver names to reach the model that is presented here. I did find references to all the receiver models from one to nine online, with the exception of the KR-8400, which seemed to have been sold in small numbers to customers in North America only and had since become rare. But the number scheme did not only pertain to amplifier power. Higher numbers also stood for increased connectivity, along with lots of useful features. This might come as a surprise to audiophile listeners today, who are so used to being sold little more than the bare necessities at the higher echelons of the market. By modern theory, musicality and purity are sacrificed when there is more than a power button and volume control on board. But, after listening to the Kenwood KR-9400 extensively, I was starting to have my doubts about the validity of such claims.

I set the KR-9400 up in our upstairs listening room, where it was to compete with a duet consisting of Restek V1 preamplifier and Dynavox VR-70 tube amplifier. The speakers were still our formidable Epicure EPI 500, of 4 Ohms resistance and built from 1973 to 1981. It was not unlikely that the paths of these two legends should have previously crossed in some Higher-Fi household. I liked the idea of making this encounter possible once again. In our summer-heated upstairs apartment, most amplifiers had a tendency of overheating. — Not so the KR-9400. Even after hours of performing at higher or lower volume, the unit's surface temperature never rose above 40 degrees. This was not bad at all, especially for a combined unit that had lots of clean power to offer. Heat could be an issue with MOSFET and tube amplifiers, and the KR-9400 was neither.

The most obvious strength of the Kenwood was its ability to produce natural bass and not the intellectual bass that we had all come to accept as linear, truthful, etc. No, it was rather the kind of bass that was present in all natural events but that microphones and studios were unable to capture well. And this is not to say that the KR-9400's bass was in any way too much, overpowering, imprecise, or smothering. A fact that was hard to believe, as I had been taught to distrust the engulfing presence of bass. Supposedly, it was not 'linear' or unfit for audiophile listening. And reading these lines in an article by another blogger, I might still have my doubts. But with the KR-9400, bass was an asset and did not come across as fake or nonlinear at all. This impression was aided by a sufficient amount of layering and exceptional speed.

When I listened to the Kenwood play music for the first time, I wrote to Luigi that I could not believe the speed with which it presented the music. It almost felt overly eager to tell the whole story, as if it all had to come out at once. After a few minutes of listening, this early impression of shock changed into genuine admiration for a machine that obviously had great potential in terms of dynamics, rhythm, and speed. Although I first began with Jazz albums, as usual, I soon found myself exploring different genres to see how the increased speed would affect the music. I was pleasantly surprised by the agility of our EPI 500 speakers that now seemed to be more nimble on their feet than was usual with our other equipment. In Hi-Fi listening, bass-slam and speed were often mutually exclusive. This was not at all the case on the KR-9400 that made bass and speed appear to be natural and effortless occurrences.

And yet, there was another contradiction that the top-of-the-line Kenwood managed to overcome. In Hi-Fi, we naturally assumed that excessive bass would negatively affect our ability to detect nuances in the mid-band or treble. Since humans only had a single eardrum to handle all frequencies of music, greater excitement of the lower frequencies had the potential of smothering over the more delicate upper frequencies via the single diaphragm. Yet, somehow, this did not seem to be an issue while listening to the KR-9400. I admit that this positive impression may have been supported by our spacious listening room, in which our actual listening set-up occupied less than one fourth of the available space. Since there were no parallel walls, reflections were naturally kept to a minimum. In this scenario, bass frequencies were not at all in conflict with those produced by the midrange or treble. In a boxy room, on the other hand, the amount of bass attack might have led to a different assessment.

The KR-9400 offered two Phono inputs for MM cartridges with excellent sensitivity and highly accurate RIAA correction. The phono inputs shared a single ground screw which could make changing the connections a bit iffy. The AM/FM tuner section was of excellent quality and considered to be above the Marantz models of the period. There was one Auxiliary input to connect a CD-player or streamer, as well as a 6.3mm Microphone jack that was located on the front panel. Microphone input could be added to the music source by turning on the 'Sound Injection' function, and the microphone level could be adjusted to suit the general volume level. Two tape loops were available via separate switches. Recording from one tape to another was possible even while listening to a different music source in the process.

There were separate connectors for a Dolby Noise Reduction unit called the Kenwood KF-8011 'De-Noiser' and for an oscillator unit called the Kenwood KC-6060 A. Another convenient feature was the 6.3mm Headphone jack. Tone controls for Bass, Midrange, and Treble allowed for basic room correction, and a Tone Defeat button made sure that the signal path stayed untouched by such obstacles to the signal if needed. Additional High and Low Filters as well as a button for Loudness served to complete the extensive control package. All controls and switches were of very high quality with volume attenuator offering 40 steps that clicked into place on each turn. Everything about this receiver showed that cost considerations were last on Kenwood's list when building their flagship model.

The active signal source was indicated by an LED light on the left side of the large tuner scale, and another LED served to indicate if Stereo reception was possible. The LEDs made it possible to check basic settings from a distance. I did not so much appreciate the fact that the volume control was of the same design and perched between the Balance and the Input Selector. This would make it more difficult for casual users to operate the receiver with confidence, especially in low light conditions. As was typical for receivers of this period, playing music from a (high output) CD source made the volume attenuator very sensitive. Even with our EPI 500 speakers that were rated at 88dB, full listening volume was reached with the attenuator set in 9 o'clock position.

To close off my listening sessions, I put on Boris Blank's album 'Convergence'. First released in 2014, and with its strong focus on collected samples and computer generated sounds, the album was quite different from the albums found in the 1970s. To my delight, the KR-9400 presented Mr Blank's songs in a joyful, harmonically rich, and forward-sounding fashion with a lush midrange, full bass, and a slightly grainy but sweet-sounding treble. Kenwood clearly had produced a powerful and lively sounding receiver that would work well with many genres of music. Although the KR-9400 did not put its main focus on presenting the subtleties of music, there was still plenty of nuance to satisfy that end of the market. Instead, it excelled in speed and bass-slam. This certainly brought the aspect of joy back into the music. I could easily see myself listening to this receiver for hours on end and would personally give it preference over the two models I had previously tested.

Specifications

• Type: Post-WW2 AM/FM-receiver
• Tuning range: AM, FM
• Power output (8 Ohms): 2x 120 watts
• Power output (4 Ohms): 2x 150 watts
• Frequency response: 5 Hz to 40.000 Hz
• Total harmonic distortion: > 0.1%
• Damping factor: > 50 (8 Ohms)
• Speaker impedance: 4 to 16 Ohms
• Inputs: 2x Phono, 2x Tape, 1x Aux, 1x Mic, 1x Dolby NR
• Input sensitivity, line: 150mV
• Mic sensitivity: 2.5mV
• Phono sensitivity: 2.5mV for MM
• DIN sensitivity: 150mV
• Signal to noise ratios: 65dB (mic), 70dB (mm), 93dB (line/DIN)
• Tone controls (+/-10dB): 100 Hz, 800 Hz, 10.000 Hz
• Loudness (+5/+8 dB): 100 Hz, 10.000 Hz
• High filter (-5 dB): 10.000 Hz
• Low filter (-8 dB): 100 Hz
• Tone control bypass: bypass-defeat
• Outputs: 2x Tape, FM quad radial, 6.3mm headphone jack
• Line Output: 150mV (line), 30mV (din)
• Power consumption: 750 watts (max.)
• Dimensions: (W) 557 x (H) 166 x (D) 395 mm
• Weight: 20.6 kg
• Country of manufacture: Japan
• Year: 1974-1976

Accessories

• Oscilator: Kenwood KC-6060 A
• Noise reduction: Kenwood KF-8011 (de-noiser)

When I think about audiophile listening pleasures, my first association is a meticulously set up stereo system, including at least one tube stage, with its loudspeakers carefully placed in a dedicated listening room. I imagine the listening position to form an equilateral triangle with the speakers and a high-floor carpet to counterbalance a high ceiling. I see myself in this position alone and understand that absolute soundstage and tonality perfection can only be enjoyed by one listener at a time. And while this could be seen as a selfish vision, I can assure you that in most households, there is only one single person who cares about the subject and is willing to set up a HiFi system in this way. Audiophiles are a rare species, and achieving proper sound balance takes years of experience.

When I first met our next door neighbour Alexi, I was therefore surprised to learn that he had purchased some HiFi components that had been specifically designed to break these rules. His Duevel Planets loudspeakers, for instance, were of an omni-directional design using two metal spheres to radiate the sound full-circle into the room. This concept allowed listeners to receive a fully realistic stage impression from various listening positions in the room. My review of these speakers recognised the benefit of the Duevel Planets in the ability to share the music experience with more than one listener at a time. Because, even if the other family member did not care so much about sound stage and tonality, the ability for them to share in the experience was still an improvement.

The other component to challenge established audiophile rules was Alexi’s DAD M-10 music streaming-amplifier. First released in 2019, the compact NAD claimed to offer 100 watts per channel of continuous music output into an 8 Ohms load. Weighing around 2.5 kilos, it was equipped with a large LCD display that covered the whole front of the unit. Alexi had not yet pealed off the protective film, a measure that slightly showed on the photos. There were no visible buttons or lights, except for the illuminated NAD logo on top of the unit that signalled operation. It could not have been a sleeker and less pretentious looking device. And coming from large and heavy separate vintage components myself, I was not sure what was to be expected from such a design.

Upon my first visits to Alexi’s house, the combination of M-10 streamer-amplifier and Duevel speakers had sounded rather frail and disorganised. When I later tested the Duevels in our listening room and on our system, this frailness was gone. I felt that the NAD amplifier might be the culprit and gave Alexi our Tannoy XT 8f speakers to test. Different from the Duevels, the Tannoys sounded bass heavy and overly boomy in Alexi’s house. Looking at the listening room, and following my explorations on the subject of room modes, I understood the room dimensions to be responsible for the repeated unbalances sound. In marked contrast to our one hundred year old building with high ceilings and masonry walls, modern buildings had much lower ceilings and open plan kitchen & living room layouts with lots of hard concrete being used.

Low ceilings in spacious rooms that are paired with concrete walls make setting up proper stereo systems almost impossible, because they excite an unbecoming combination of high and low frequency room modes, creating a discordant boxy impression. We can probably all relate to this sound when we imagine speaking or clapping in an underground carpark or in the pedestrian tunnel leading underneath railroad tracks. In addition to these attributes, the necessary furniture in the room also did not allow us to freely set up the Duevels or Tannoys in their ideal positions. Without knowing it, Alexi and I had found the perfect room to explore the full potential of the NAD M-10 that came with Dirac live room correction. We decided to be serious about getting it right and made a proper appointment for the purpose of setting up his system.

On the day of our exploration, I packed my best Manfrotto tripod that would allow us to set the microphone up in the exact positions that were prescribed by the calibration software. I had meanwhile read that Dirac had started as a research project at the Signals & Systems group at Uppsala University of Sweden during the 1990s. The project objective had been to revolutionise the world of sound through digital signal processing. The researchers found that all components of a sound system contributed to a degradation of sound and that the listening room was one such component. The algorithms developed by the team had finally lead to the founding of the Dirac audio company in 2001. Dirac room correction technology can today be found in audio gear from well-known names in the industry: Arcam, Dynaudio, Emotive, Focal, Integra, JBL & Lexicon Harman, Marantz, Monoprice, NAD, Onkyo, Pioneer, Quadral, Hotel, and others.

Alexi downloaded the Dirac software to his laptop computer, and we proceeded to set up the tripod and microphone in his preferred listening position on the sofa. We started the analysis with Dirac running a few frequency sweeps. The resulting graph showed the low frequency hump at 80-90 Hz. It also showed the rest of the bass frequencies to respond unevenly, with a dip at 40 Hz and a peak at 50 Hz. A slight hump between 6-10 kHz was followed by a sharp drop from 12 kHz onwards. Our first measurements were followed by eight adjacent microphone positions that formed a three-dimensional cage around the central listening position by moving the microphone 50cm diagonally in each direction. Dirac ran a number of sweeps in each position. The Manfrotto tripod allowed us to meet each required position exactly.

Once all nine positions had been measured, Dirac suggested the optimal digital adjustment to the curve from 19 Hz to 500 Hz. The NAD M-10 could also have run the calculation for the higher frequency spectrum, however, Dirac would have required us to pay 100 EUR extra for this service. Since the Tannoys had most obviously been suffering from a boomy bass, we decided that we would first give the bass correction a listen. Alexi transferred the new curve to the M-10 and we listened to some of the same songs that we had listened to before the correction. The improvement was immediately audible. The boomy bass had given way to a well-defined, controlled, and refined bass. As a consequence, Diana Krall’s voice was louder, clearer, and tonally more accurate than before. What was left was the sensation that some significant high frequencies were missing from the music. This had the effect that the aura around instruments was missing with the music sounding slightly stale and lifeless.

Satisfied with the result, I think we both would have liked to experience the correction of the upper frequencies as well, however, we decided to leave this for a later day. Even with just the bass frequency adjustment, the NAD M-10 had been able to show the benefit of room correction in circumstances that prohibited the ideal placement of loudspeakers. I could appreciate the positive effect on bass and voice performance and for the first time would have liked to stay and listen for longer. There were some genuine qualities to the music that had been missing before. I enjoyed the deeper and tighter bass that was free of unwelcome resonances throughout the listening room.

Room correction algorithms proved to be immensely useful wherever the room and the loudspeakers were in unfavorable relation to each other. And this did happen more often than one might think, especially in private households and rooms of mixed use. The NAD M-10 and Dirac offered a, not exactly cheap but very effective, method to harmonise the HiFi system with the listening room. In this respect, the two manufacturers NAD and Dirac together offered some real-world listening comfort to many people who would otherwise have had to settle for a rather mediocre result.

Specifications

AMPLIFIER

• Continuous power output: 100W (4-8 Ohms)
• Frequency response: 20 - 20,000 Hz (±0.6 dB)
• Total harmonic distortion:  <0.03 % (20 Hz – 20 kHz)
• Signal-to-noise ratio: >90 dB
• Clipping (8/4 Ohms): 130/230 W (@ 1 kHz, 0.1 % THD)
• Dynamic power (8/4 Ohms): 160/300 W
• Damping factor (8 Ohms): >190
• Treble adjustment: ±6.0 dB @ 20 kHz
• Bass adjustment: ±6.0dB @ 60 Hz
• Channel separation >75 dB (1 kHz)
• Input sensitivity line: 1.0 V
• Digital input: -6.2 %FS
• Standby power: 0.5W

DAC

• Audio formats: MP3, AAC, WMA, OGG, WMA-L, ALAC, OPUS
• High-resolution audio: MQA, DSD, FLAC, WAV, AIFF
• Sampling rate: 32 bit/192 kHz PCM max.
• Bit depths: 16 – 24

BLU-OS

• Supported operating systems: Microsoft Windows XP, 2000, Vista, 7, 8 to current Windows Operating Systems, and macOS versions
• Mobile operating system (BluOS): Free Android and iOS App
• Supported cloud services: Spotify, Amazon Music, TIDAL, Deezer, Qobuz, HDTracks, HighResAudio, Murfie, JUKE, Napster, Slacker Radio, KKBox, Bugs
• Free internet radio: TuneIn Radio, iHeartRadio, Calm Radio, Radio Paradise
• Bluetooth standard: Bluetooth aptX HD (built-in)
• Bluetooth connectivity: bi-directional, receive and headphone
• Network connectivity: Gigabit Ethernet RJ45, 802.11 b/g/n WiFi

PHYSICAL

• Dimensions: (W)215 mm (H)100 mm x (D)260 mm
• Unit weight: 2.5 kg
• Country of manufacture: N.N.
• Year(s): 2019-2020

Paionia Kabushiki-gaisha, a Japanese company henceforth referred to as Pioneer, has evolved to be the heir of a long legacy of outstanding professional and domestic electronics. And although receivers made up only a small fraction of the company’s success story, they did serve to promote the Pioneer brand in Europe and the USA. Pioneer is sometimes said to have spawned the infamous ‘Receiver Wars’ during the Golden Age of audio in the decade spanning from 1971 to 1981.

The ‘Golden Age’ of audio is sometimes referred to as such, because consumers in this era were willing to spend a considerable portion of their income on advances in Hi-Fi, thereby giving manufacturers the financial resources to incorporate long-lasting quality components, and the freedom to conduct intensive research in order to build the best devices they possibly could. In those days, the market was still dominated by privately owned and research-driven companies that were fighting for pole position in the newly emerging Hi-Fi magazines.

Pioneer was a case in point. Owned and operated by the Matsumoto family, the company already had a thirty-year history in manufacturing audio electronics by they launched the SX 850. The concept of an all-in-one control unit that included tuner, preamp, and power amplifier had originally been invented by the American Harman Kardon corporation during the 50s. However, Japanese manufacturers, such as Marantz, Sansui, and Pioneer, followed suit and soon rivalled Harman Kardon in terms of quality, performance, and especially cost.

Despite having established a strong manufacturing base in Japan, Hi-Fi receivers continued to be mostly manufactured for and sold in the United States and Europe, as Japanese audio enthusiasts preferred the sound and versatility of separate units over the combined package. Customers in western countries, on the other hand, enjoyed the fact that they could get very close to the performance of separate units while having to put up with less than half the fuss. It may have also helped sales that most receivers featured large illuminated scales and fancy looking front-panel designs that increased the wife-acceptance-factor.

On the downside, receivers usually offered less power than separate amplifiers. Or at least this was the case before Pioneer, staying true to their name, released the world’s first genuine 100 watts per channel receiver. This was even certified by the United States Federal Trade Commission (FTC) that had started to regulate the audio market, due to an increase in false promises on the side of manufacturers. Released in 1974, the SX-1010 was Pioneer’s (then) flagship receiver and out-performed the competition by almost 40 watts per channel. Unfortunately, the glory turned out to be short-lived. In August of that same year, the Japanese Marantz corporation followed suit with their legendary 2325 model that boasted 125 watts per channel. The receiver wars had officially begun, with each manufacturer aiming to out-perform the competition in terms of sound quality and power output.

Although the SX 850 fell into this time period, its moderate 65 WPC into 8 Ohms indicated that it was not a contender in the on-going war effort. This, however, could just as well be seen as a plus, because not all monster receivers turned out to be well-equipped for audiophile usage or were in it for the long-haul. In a real-world scenario, 65 honest watts into eight Ohms (and 85 watts into four Ohms) were perfectly capable of driving most conventional 2-way or 3-way speakers on the market. And, while the Receiver Wars did go on to produce true monsters capable of powering even electrostatic speakers and other unruly designs, the SX 850 was most fitting for dynamic speakers of medium to high sensitivity from 4-8 Ohms.

The specimen shown here had been restored to its original splendour in the weeks prior to our listening tests. Its switches had been cleaned in an ultrasound bath, the capacitors had been checked and replaced where necessary. The relays had been cleaned, and the offset calibrated according to factory standard. The original lamps (that were prone to failing) had been replaced with longer lasting LED lights. The real-wood case had been freed from scratches and re-polished to its original shine. To improve connectivity, an IEC socket had been installed that replaced the original US cord, and four banana/spade terminals had been added in position of speaker output “A”. The SX 850 had been restored to better than NOS condition. Its look and feel made it seem as if no time had passed since 1976.

The SX 850’s impressive width and weight would have served to give it a noticeably prominent position on any Hi-Fi rack or piece of furniture. And working on the buttons and switches felt more like operating the control panel of a submarine than those of a common household radio. In fact, I was so surprised by the Pioneer’s weight and haptics that I felt compelled to open the unit in order to see where this impression originated from. However, in my explorations I could neither confirm the large transformer nor the wooden casing or chassis to be the sole cause of its weight and solid feel. It was rather the sum of all quality choices that in the end led to this unit’s close to 20 kilograms of weight and its superb rigidity. The 850 was seven impressive kilos heavier than even the twin-powered Harman Kardon 730.

Recently refurbished units often had a tendency of sounding a bit stale until the new components had been sufficiently run-in to become part of the greater scheme. And it was difficult for me to say in which phase of the running-in process our specimen really was and how much of my sonic impression was affected by this condition. However, having been present during the break-in of many devices, I felt sufficiently knowledgeable to identify areas of potential. If some units will feel a bit light-footed and short-winded during the first couple of weeks, this particular receiver greeted me with a huge sound stage spanning from far left to far right, a solid and dependable center image, and a thick and musky sound. It was as if it was painting with a broad brush.

Even coming from our Restek V1 and Becker ST-200 separates, I could not help but be drawn in by the SX 850’s colourful and engaging sound. Similar to the Becker, the Pioneer was more about the sensation of listening to musicians playing their instruments live than it was about being present in the highly accurate mastering room of a recording studio, especially during passages of instrumental Jazz. Brushes sounded convincingly metallic and still had a pleasant softness about them. I enjoyed this quality a lot on Tony Bennett & Diana Krall’s album “Love is here to stay”. Similarly, both nylon and steel guitars had a natural timbre with a pleasantly soft top-end, as I experienced listening to José González album “Local Valley”.

The SX 850 certainly understood about music and, in connection with our silver solid core interconnects and Belden speaker wires, offered the stomping and airy bass presence of a live venue. While bass was perhaps not nuanced, multi-layered, or controlled, I personally preferred this type of 'musical' bass to the sterile impression left by some more recent amp designs with damping factors well above 200. In its current state, the Pioneer was perfectly suitable for extended listening sessions, even for listeners who have high expectations regarding their choice of audio entertainment.

Both male and female vocals sounded lush and full-bodied with an aura of slight restraint. There was just not as much air and space around the singers as I was used to from our Restek & Becker combination. When it came to vocals, I could not shake the feeling that I was sitting in a recording studio. This is not to say that there was anything unpleasant in the way vocals were depicted, they simply sounded less live and had less of a physical aura than (strangely enough) the instruments did. It seems that the mid-band was not able to breathe as freely (yet) as some of the higher and lower spectrum. This may have been a result of the still ongoing running-in phase, but it could also have been caused by the unit's design. In the end it does not matter too much, because, if we consider that my benchmark was my favoured combination of separate audiophile units, the SX 850 already put up a formidable performance.

For audiophiles in search of a classic solution for their second or third system who do not shy away from the cost of a (by now necessary) refurbishment, Pioneer sure has some worthwhile receivers from the Golden Age to consider. And the SX 850 was certainly a specimen that I could personally grow attached to. Its colourful and engaging sound, its superb musicality and impressive stage width made it an endearing companion for long and joyful audio sessions any day. Equipped with two MM phono inputs with excellent RIAA correction, two tape monitors, a microphone input and headphone output jack, it is well suitable for most applications. It even features a very convenient -20dB muting switch by which the volume dial can be adjusted to accomodate high input devices, high sensitivity speakers, or both.

Pioneer Company History

The world famous electronics company was founded by the Japanese inventor and entrepreneur Nozomu Matsumoto. Born in 1905, the son of a Kobe missionary family showed an early interest in electronics and was among the first to recognise the potential of recorded music in the context of addressing people’s emotions and felt that this could aid the promotion of the Christian faith.

Therefore, in 1936, he started what was to be the precursor to Pioneer, the “Fukui Denki Shokai Seisakusho”, which translates into the “Gospel Electric Works” in English. His small company took up operations in his hometown Osaka and specialised in the research and development of dynamic loudspeakers.

Matsumoto’s inspiration had come from western companies that still held the lead in entertainment electronics and shipped them over to Japan. However, Matsumoto had a vision of making this a Japanese technology and, in 1937, his early experiments came to fruition with the introduction of the A-8. It was the company’s first large series speaker driver and Matsumoto referred to it as the “Pioneer”. This speaker was the first to feature the ‘omega sign and tuning fork’ that were later to become the company’s trademark.

In 1938, Fukui Denki Shokai Seisakusho moved its operations from Osaka to Tokyo where the growing family business specialised in the construction and repair of loudspeakers. Nozomu Matsumoto made sure to involve his family in the operations and was fully supported in this by his wife Chiyo and his two sons Seiya and Kanya. Following his university studies, Seiya took over Marketing and Sales and went on to become the president of Pioneer in 1982.

The company with the long and difficult Japanese name changed its brand to “Pioneer” in 1962 in an effort to create stronger international brand awareness and went on to become one of the world’s leading developers of first audio and later also video equipment. Pioneer made major contributions in the research and development of loudspeakers, was the driving force behind the development of the laser disk, and next to Sony and Marantz, was one of the first companies to manufacture CD players.

Pioneer stayed true to Matsumoto’s initial mission statement which had been to develop and manufacture audio products that would speak to and captivate people’s emotions. Perhaps it was this deep focus on the true essence of listening that has earned the company a loyal base of followers until this day.

Specifications

• Type: Post WWII AM/FM receiver
• Tuning range: FM, MW, AM
• Power output into 8 Ohms: 65 WPC
• Power output into 4 Ohms: 85 WPC
• Frequency response: 10 Hz to 50.000 Hz (+0 dB, -1 dB)
• Total harmonic distortion: 0.1% @ 8 Ohms
• Damping factor: 25
• 2 Phono inputs: 2.5 mV, 50 kOhms (MM)
• Input sensitivity: 150mV, 100 kOhms (line)
• Microphone sensitivity: 6.5mV
• Signal to noise ratio: 70dB (MM), 90dB (line)
• Signal output: 150mV (line), 30mV (DIN), 1V (Pre out)
• Bass control (100 Hz):  ±10 dB
• Treble control (10 kHz):  ±10 dB
• Speaker load impedance: 4 Ohms (minimum)
• Semiconductors: 3 x FET, 3 x IC, 56 x transistors, 36 x diodes
• Dimensions: (W) 52.7 cm x (H) 17.3 cm x (D) 41.15 cm
• Weight: 19.1 kg
• Accessories: FM T-type antenna
• Country of manufacture: Japan
• Year(s): 1976

Music is a multi-dimensional event, and its re-creation through loudspeakers is understood to be an approximation at best. The most obvious dimension is ‘volume’, and the vast majority of listeners will be able to point out the difference in impression created by sounds played at low or high volume. The juxtaposition of silent and loud opens a space in which a listener’s associations range from soft and friendly to powerful and threatening. Human hearing is usually most comfortable when listening to music at volume levels ranging from 50dB to 80dB.

The second dimension is ‘frequency’. Most people will be able to tell the difference between a lower and a higher frequency sound. This is especially true, if the sound created is between 500Hz and 3,000Hz, where our our hearing is most sensitive. The space that is made available via the frequency spectrum offers a vast playing field to musicians and their instruments, ranging from ultra-low bass to the highest notes of the piccolo flute. Lots of engineering has been done in extending the linear frequency range of loudspeakers in an effort to capture the aspects of natural instruments and beyond.

A third dimension is timing. It describes the ability of a music source to emit its sound waves in a synchronous manner in order to capture the speed and rhythm of an original event. Accurate timing will be supported or hindered by the placement of the music source in the room. The overlapping of music frequencies bouncing back from walls and ceiling can usually best be eliminated by the listener's brain when there is sufficient time-lag between direct and reflecting waves. Loudspeaker manufacturers have developed different solutions to address the issue of timing. Tannoy and KEF, for example, have adopted coaxial designs, whereas others have pursued single driver concepts, such as electrostatic and magnetostatic diaphragms.

And, listening to the Pata Acustica, I was reminded of a fourth dimension, one that is often forgotten in comparisons between loudspeakers, especially in a country like Germany where my fellow listeners habitually rely on facts and figures and are often deeply sceptical when it comes to trusting their emotions: I am referring to tone and timbre. That is to say, the ability of a loudspeaker to stay true to the tonal colour of the physical material of an instrument. This quality is especially important when listening to Classical Music, Jazz, Folk, etc., in which the simultaneous presence of many instruments requires a space in which each can be recognised by its own individual character.

To musicians, instruments are often as recognisable as the voices of friends and lovers. They will discern and often prefer one manufacturer over another, solely on the basis of how the instrument makes them feel when playing and listening to it. Loudspeakers that are able to maintain some of this difference in character are thereby capable of opening a huge (and additional) space in which a multitude of instruments and voices can be separated by their specific tonal character. And, most likely, it was this tonal correctness that set the Pata Acustica apart from many other loudspeakers in its class and aroused the interest of the people at Auditorium 23 in promoting it to their audiophile disciples.

During the 90s, Auditorium 23 was approximately ten years into business. Its founders believed in the sonic integrity of single-ended tube amps and simple Class A designs that would feed their sweet and soft signals into horns for amplification. The Pata Acustica was obviously not a horn and as such an exception in their lineup of exquisit loudspeakers. Retailing at just under 4,000 DM, it was considerably cheaper than folded horn designs, and it was also smaller than most of the other speakers. Manufactured by ATD in Italy and rated 91dB at 1 watt, the Pata Acustica played both loud and tonally correct on smaller tube amps. And this made it a real gem in the Auditorium's special circle of listeners.

When it first came into our house for auditioning, I knew close to nothing about the Pata Acustica. As usual, I prefer to conduct my listening assessment before digging deeply into the subject, simply because I do not want to bias my exploration towards a certain result. All I had heard from Luigi was that it performed well on tube amps. If I had any bias, it was that I feared the smallish speakers would sound hopelessly lost in our spacious listening rooms. I dug out our two stands that we had constructed for the KEF iQ30s, dusted them off, and mounted them on spikes towards the hard-wood floor. I then stuck 5mm felt pads to the four corners of the stand tops and placed the Patas on them. In my previous explorations, felt pads had always proved beneficial in taking the edge off a cold electronic top-end.

Our test system was made up of a Technics SL1310 turntable with AT VM540 ML cartridge hooked up to a Dynaco PAS-4 tube preamplifier that was feeding into a Hafler XL280 power amplifier. All interconnects were made of solid-core silver, such as the HBS4, with copper mesh shielding. The speaker wires used were a pair of Belden 9497 that I had terminated with beryllium hollow bananas. At the time of listening, all connectors had been sufficiently run in to reach sonic maturity and proven themselves over the course of many months. I was familiar with this system performing with our relatively modern Tannoy XT8F tower speakers.

Switching to the Pata Acustica, I noticed that I had to dial back the volume a little. This was surprising to me, as I would have expected the larger Tannoys to play louder. I later checked and found that both speakers were rated the same 91dB at 8 Ohms. My only explanation for the Patas playing louder was that they did not extend as deeply as the Tannoys, thereby losing less energy on the fringe of the audible spectrum. And this brings me to my second immediate observation: the lack of bass extension. Since the Pata’s woofers were built into the closed cabinet of a bookshelf-size loudspeaker, they quite understandably could not compete in the discipline of bass with a ported down-firing floor-stander of nearly tripple their size. Strangely enough, this lack was only apparent on first comparison, because, soon after, other aspects gained greater importance.

Instead of the ultra-low growling of bass extension, the Patas produced the dry snarling so familiar of some wooden instruments. The result was a more grainy and wooden texture that was predestined for Classical Music, Jazz, and Folk. Katie Melua's “Album No. 8” was presented with a wonderfully large and solid phantom centre. Her voice was lush with only the slightest hint of the recording’s original metallic ringing. While the highs were not overly detailed, they were wonderfully nuanced with great timbre. It was the most enjoyable rendition of this particular album that I had heard until that point. There was great channel separation with the stage extending wide across the room. Stage depth, on the other hand, was less impressive. It suffered from the need to place the speakers close to the wall. This need can be a blessing and a course. However, I decided not to mind and rather marvelled at the warm wooden tones of concert guitar and piano. The Patas managed to highlight the sweetness inherent in the music, perhaps slightly thickened with an small and endearing mid-bass hump.

I decided to step it up a bit and put on Ted Poor’s “You already know”. The saxophone never sounded so sweet to my ears. Drums, especially kettle drums, were presented with great realism regarding their respective material composition. I noticed superb transients and great separation between tonal colours of each instrument. If I were to describe the effect, it would be: “total immersion in the music”. While there were moments in which the Pata Acustica’s small dimensions became apparent, I found myself genuinely perplexed by what these loudspeakers were capable of. I especially enjoyed the fact that I could listen to them and, while doing so, completely forget that I was listening. Walking across the room, I was pleased to find that much of the Pata's musical attraction remained. Well done!

Also see: ATD Pata Acoustica (Auditorium 23, 1995) Audio Demo

Specifications:

• Design: 2-way bookshelf, closed cabinet
• Drivers: (1x) 20 mm soft-dome tweeter, (1x) 200 mm paper cone
• Nominal impedance: 8 ohms
• Sensitivity: 91 dB
• Power handling: 6-60 watts RMS
• Terminal: originally Speakon (here: modified to banana sockets)
• Dimensions: (H) 470 mm x (W) 270 mm x (D) 250 mm
• Year: 1995

In 2013, not long before our daughter was born, my wife Sabina and I went out to search for a pair of loudspeakers for us to restart our journey in the appreciation of music. When it came to audiophile pleasures, we were both out of practice and felt unsure of what to aim for. Visiting some local HiFi showrooms around Frankfurt, we finally decided that we did not understand enough about loudspeakers to make a permanent decision. However, we did feel some attraction towards Canton speakers that outperformed the competition in terms of clarity. We finally settled on a pair of used Canton Vento 890 DC that we bought from a vendor in Günsburg, Bavaria, unaware that the company was actually located very close to our home in Frankfurt am Main.

Canton was our entry ticket to audiophile listening, even before we fully grasped what this might mean. The 890 DC were revealing speakers that could show the merits and flaws of a system in an instant. They led to us gradually improving our front-end from the music source, via the preamp and amplifier, to the cables connecting the devices, until we noticed a flaw in the Ventos themselves: No matter how hard we tried, we could not get those speakers to sound tonally balanced. The treble, and perhaps also the upper midrange, simply sounded too bright to be natural and did not match the otherwise commendable sophistication of the speakers. Listening to the Ventos could easily become tiring because of this effect and we ended up selling them.

Exactly ten years had passed since our original purchase, and I found myself listening to a pair of Canton speakers once again. Instead of being large floor-standers, however, the GLX 100 were small and inconspicuous bookshelf speakers. They were finished in modest anthracite rather than our Vento’s shiny silver, and the soft fabric dome tweeters made me hopeful that the resulting sound would be less harsh than I had previously experienced with or 890 DCs. And I was sure to give the GLX 100 bookshelf speakers the royal treatment by putting them on our MDF loudspeaker stands and taking good care when positioning them in the room to get the tonal balance right. The GLX 100 had been a gift to my daughter from her great aunt, and I was glad to have the opportunity of auditioning them here first.

As usual, the Cantons opened with a wide soundstage and even gave the impression of proper stage depth when placed a little deeper into the room. Their depiction of female vocals was penetratingly transparent, thus creating an instantly engaging experience that kept the ears at high alert. I also noticed a raspiness in the upper midrange that I had trouble identifying. It could be that there was some competition between the midrange and the tweeter that was causing it. Just to be sure, I removed the front metal grille which, to my ears, made matters worse. These speakers had obviously been designed for the grille to be in place. To achieve greater tonal balance, I moved the GLX 100 closer to the front wall. This gave them improved bass foundation, however, it did not lessen the energy of the treble which proved to be too much for my ears.

I reluctantly turned on the tone controls on our preamplifier and dialled back the treble by 2-3 dB. This was my last resort when speakers were obviously off balance. The silvery and over-accentuated treble subsided and revealed a pretty decent speaker underneath. Without this measure, the GLX 100 were obvious candidates for ear fatigue, if they were driven with a semi-revealing front end. Engineered for the point of sale, the Cantons would have dazzled shoppers in the 1980s and have enjoyed the ride home more often than they deserved. There was no question that Canton knew how to build great speakers for those who had the money and interest in learning about them, but I could easily see that they also knew how to sell speakers to those still new in this territory.

Specifications

• Type: 3-way bookshelf speaker
• Principle: closed, with dynamic drivers
• Frequency range: 28 - 30,000 Hz
• Crossover frequencies: 800 / 5000 Hz
• Low frequency slope: 12 dB per octave 
• Midrange slope: 6 dB per octave
• Tweeter: 20 mm, fabric dome tweeter
• Midrange driver: 28 mm, fabric dome tweeter
• Woofer: 220 mm, paper cone
• Nominal impedance: 8 Ohm
• Power handling (RMS): 65 Watt
• Resonant frequency: 69 Hz
• Terminal: spring-secured for 2mm cable
• Number of terminals: single wire
• Dimensions: (W) 245mm x (H) 370mm x (D) 215 mm
• Country of manufacture: Germany
• Weight: 5.5 kg
• Year(s): 1983

Married audiophiles will confirm that you can tell you are onto something special, when your wife comes home and—without prior talk on the subject—leaves you baffled with a congratulatory comment regarding your new loudspeakers. I cannot remember the exact words, but they were something along the lines of: “By the way, I saw the new speakers. They look absolutely fabulous! Are they here to stay?” With us, the latter is a valid question. Because, more often than not, the speakers are only with us for testing, before they are given back to their owners.

The loudspeakers on display were a pair of Dahlquist DQ10, and they were given to me for sampling by my friend and fellow audiophile Luigi. This is nothing unusual, and those who have followed my reviews will know that I have tested much of Luigi's HiFi equipment over recent months. And—to my surprise—my wife was not the only female showing instant affection regarding the Dahlquists. My sister in law, someone who is aware of my hobby but does not stop by our house on a regular basis, marvelled at the new speakers when she noticed them in the room. I think you will agree that this is not something that women usually do, regardless of how much money you have spent. It is pretty much the equivalent of a guy commenting on the beauty of a girl’s makeup or shoes. Normally that doesn’t happen, right? And yet, with the Dahlquists, it happened twice within a very short timeframe.

The Dahlquist DQ10 was the first loudspeaker manufactured by the Dahlquist company, then based in Hauppauge New York. Among the company’s founders were some famous names in audio, such as Jon Dahlquist and Saul Marantz, Irving M. Fried and Werner Eymann. The DQ10's design was first exhibited at a New York audio show in 1972. It was revolutionary, because it parted with the traditional boxy shape of conventional speakers. Dahlquist had instead constructed a cabinet that suspended its drivers freely in an open array and in correct phase alignment. From the DQ10 onwards, the term 'Phased Array' became the Dahlquist trademark.

The design idea was loosely based on the popular Quad electrostatic speakers of the 60s and, among Dahlquist enthusiasts, is said to have successfully achieved a marriage between the powerful bass slam of conventional cone drivers with the low refraction, high transparency, and phase accuracy to be expected from electrostatic speakers. The resulting loudspeaker had a square and convex frontal face that was covered in dark cloth and flanked by slim sides of natural wood. To play at ear level, the speakers were then positioned on slender stands that, at their base, matched the wood colour of the speaker sides and held each unit suspended on three black columns or pillars.

In combination with the speaker stands, the DQ10 looked light and non-technical from the front and slim from the side. It arguably held greater resemblance to a radiator than a loudspeaker, an aspect that made it both stand out as a design element and an understatement in terms of technology. Strangely enough, its appearance fits into a modern household just as well as it did back in the seventies. It is not surprising, therefore, that close to 60,000 pairs of Dahlquist DG10s were sold between 1973 and the end of its production in 1988. And the Dahlquist remains popular among audio enthusiasts until this day, reaching 4.8 out of 5.0 stars on audio-review. With more and more units going out of service due to their advanced age, used prices of this speaker have been on the rise over the past 15 years.

The DQ10 featured a closed bass cabinet with angled sides and an asymmetrically positioned 10” cone driver. It had a dedicated 5” mid-bass driver to support the woofer and provide the Dahlquist’s legendary mid-bass punch. The midrange was produced by a 1.75" soft dome driver, much like the tweeter, which was of 0.75" dome design. A super tweeter served to extend the upper frequency band using piezo technology. With the exception of the woofer, all drivers were held freely suspended by metal brackets and radiated both towards the front and the speaker's open back. A 5-way crossover made sure that each driver only played a limited frequency band and cut off from mid-bass to super tweeter at 400, 1000, 6000, 12000Hz, respectively. The crossover components played such an important part in the Dahlquist’s overall performance that there were many specialists in the market offering upgrades.

The Dahlquist was rated at 8 Ohms and appeared to be easy to drive, and yet, the phased array design required lots of clean power from the amplifier to sound at its best. 150-200 watts paired with high-current ability went down well with the DQ10. In many ways, its demand for power and its overall performance were similar to Martin Logan, Magnepan, etc. speakers that were of electrostatic or magnetostatic design. The positive aspect was that the DQ10 was also able to compete in this range and that the investment into a decent amp was poised to be rewarding. I hooked the Dahlquist up to our Hafler XL-280 power amplifier to satisfactory result, however, Luigi was quick to assure me that the large Audio Research D-115 tube amplifier (which I had already returned to him) would have been able to bring out even greater effortlessness and transparency in the DQ10. This was well possible, as the Dahlquist liked to be driven a little harder to achieve greater musical coherence.

Although the speaker was positioned relatively low for many seating arrangements, its height became less of an issue when sitting further away from the speakers. Generous distance to the speakers was essential to minimise phase differences resulting from the spacious array design. In our less than perfect listening room under the roof, I was sitting just two meters from the speakers with a huge space opening behind me. I was positively surprised by how full and consistently lush they sounded, both in my listening position and when walking across the room. The DQ10 produced a spacious, intense, and full soundstage that was in many ways similar to a live-event. The thumping of the mid-bass, the space between instruments, and its timbre when playing Jazz and Vocal Jazz resembled the sensation of being at a dingy small-club concert. The speakers produced the most realistic audience clapping that I had ever heard coming from a two-way system. The highs were detailed and spread out as you would expect from an electrostatic speaker and they were non-aggressive at all times. Voices were affectionate and full with a slight leaning towards throaty.

Also see: Dahlquist DQ10 Audio Demo

If you like your music to sound lush with rich harmonics, and if you enjoy full-bodied vocals and a live-feel when playing music from acoustic instruments to be found in Jazz, Folk, Singer-Songwriter, etc., and if you own a beefy high-current amp to pair them with, the Dahlquist DQ10s just might be the right speakers for you. Give them a bit of time to settle in and some space to breathe on all sides, and they will make music for you like few other loudspeakers today. And let's not forget the wife acceptance factor, of course.

Specifications

• Type: 5-way phased array, open baffle
• Frequency response: 35 Hz — 27,000 Hz
• Recommended amplification: 150 to 200 Watts
• Crossover frequencies: 400, 1000, 6000, 12000 Hz
• Nominal impedance: 8 Ohms
• Bass: 1 x 25,4cm (cone)
• Mid-bass: 1 x 12,7cm (cone)
• Midrange: 1 x 4,45cm (soft dome)
• Tweeter: 1 x 1,9cm dome
• Super Tweeter: 1 x piezoelectric
• Dimensions: (h) 99cm x (w) 77cm x (d) 33cm
• Weight: 22,7 kg
• Years: 1973-1988

As human beings, we are natural collectors of information and ultimately become the medium through which this information is digested and passed on. This is especially true for those of us who, against all odds, have nurtured the childhood urge to explore. The reward is often little more than a brief and fleeting moment of enlightenment, a story to tell and perhaps a few bruises to heal. And the exploration is always incidental. Just when we think we have it figured out, it lights up, jumps sideways and makes its way across the paddock. Imagination, which is exploration, is an ever-elusive beast, and what is to be gained can therefore be little more than a relative aspect of truth. After all, who knows what will come next.

My background in sound exploration had brought me into contact with Alexi, who was eager to have his omni-directional Duevel Planet speakers reviewed. Pleased with my article, Alexi's colleague Michael asked me to review his Teufel M200 loudspeakers. On the day I returned the Teufels to Michael, I was introduced to Matthias, who had brought along his Devialet amplifier for a listening test. Looking at the way Matthias connected the amplifier to his MIT speaker cables and experiencing the sonic improvement the amplifier brought to the equation that is music, I was curious to see what else Matthias had in store. It turned out that he owned a pair of Duevel Bella Luna Diamante speakers. Now... Alexi had already told me about them.

The four of us made an appointment to test Matthias’ setup at his house a few weeks later. As it turned out, the Duevels were mostly stored in some private room most of the time and had to be brought out into the living room for the occasion. As setting up loudspeakers properly can be quite tricky, Matthias asked for some time to complete the project. In the meantime, I was looking forward to experiencing the combination of the large and lush-sounding Devialet amplifier with the majestic Bella Lunas. I was therefore prepared to accept that good things come to those who put in the time. Waiting, by the way, is an important skill for any explorer.

On the day we were summoned for the audition, we found the Bella Lunas positioned down the long walls of a deep and narrow living room. Three chairs were placed near the centre of the room with the speakers forming an equilateral triangle with the listening position, roughly in the lower third of the room. This meant there was plenty of space behind the speakers. The HiFi rack and system had been set up to one side behind the loudspeakers with the MIT Terminator 5 cables of 3.60m length easily reaching both channels and forming a long-sweeping curve towards the farther of the two speakers. I could see that Matthias had given some thought to the decoupling of his Bella Lunas and had decided on a combination of 3cm thick 40x40cm wide granite slabs coupled with dedicated speaker coasters made of high-grade steel and acoustic beads for a solid stand and effective vibration cancellation.

The latter had obviously also played a role in Matthias’ choice of audio rack. Finite Elemente of Brilon, Germany, had designed their legendary ‘Spider’, a versatile rack system that could be adjusted to accommodate many sizes of HiFi equipment and provided excellent cancellation of mechanical vibrations, both from the floor of the room and from the other devices inside the rack. The Spider rack housed (from top to bottom) a Thorens TD 320 MK II turntable with Ortofon Vero MC cartridge and an improved linear power supply, and a Pro-Ject CD Box RS transport paired with one Power Box RS Uni 1-way supply. A shiny silver Devialet D-Premier served as DAC and power amplifier. Matthias explained that this Devialet D-Premier, the first amplifier ever made by Devialet, had been technically upgraded to the specs of an Expert 250.

All cables presented were of carefully selected audio quality. For example, a Mogami Neglex 2549 microphone cable was used between the turntable and the Devialet, and a 110 Ohms Inakustik Exzellenz XLR cable was used for the CD transport. Matthias also used a MacBook Air M1 running Audirvana and Qobuz to stream music to the amplifier. It was obvious that this system had been set up with great care, and during the listening tests that followed, it never occurred to me that there was anything amiss that the use of a different cable or a more capable rack could have fixed.

As we began with our listening exploration, Alexi and Michael were kind enough to offer me the chair that was in the centre of the room and in the musical sweet spot. Michael sat on the opposite side of the room, behind the speakers and facing us. I closed my eyes to better concentrate on the music. Right from the start, I could hear that there were, indeed, large speakers playing in the room. They confirmed the tonal balance I had already enjoyed on Alexi’s Planets. Duevel speakers do not just hint at bass, they fully execute it, with attack and decay just like an instrument would. The Devialet Expert 250 added an extra layer of control to the music that, on lesser speakers and in smaller rooms, had sometimes been described as too much. However, in the few setups I have heard the Devialet, I have always found it to be one of the best-performing amplifiers I have ever heard.

After about two minutes of listening, I noticed a slight horn-like curvature in the midrange which surprised me. Could the open horn design of the Duevels produce some characteristic compression of the midrange, or was it perhaps the specific distance from the walls that produced this effect? As my eyes were scanning the room, I noticed that the MIT loudspeaker cable of the rear channel was laid out to cross itself and one of the power cables. There were also two power cables crossing behind the rack. I asked Matthias to help me free the cables and was relieved to find that the initial compression had disappeared and did not reappear for the rest of our session. It was yet another reminder of the absolutely sensitivity of the music signals passing between the components of a system.

Given the choice between the Pro-Ject CD transport and the MacBook M1, I surprisingly preferred the MacBook with Audirvana and Qobuz. The Pro-Ject had a much sharper top end and seemed less balanced and musical. It is possible that this verdict was the result of the pairing of two powerful and analytical components. However, the exact reason for the harshness was difficult for me to judge in the time available. To my ears, the Thorens TD 320 MK II turntable with Ortofon Vero MC cartridge sounded more pleasing and musical and, for a turntable, was extremely well-behaved. I would have expected nothing less from Matthias. On the other hand, vinyl did not offer the impressive dynamics of the M1 laptop. Hence, we decided to play mostly music from the Mac that afternoon.

Paired with a capable amplifier, such as the Devialet Expert 250, the Duevel Bella Luna had the potential to amaze. Although the room layout and furnishings were less than ideal, and only one of us could sit in the sweet spot at a time, the speakers offered a high degree of lifelike imaging and balanced tonality throughout. The levels of bass, midrange, and treble seemed just right for the occasion. Their ability to present plenty of musical detail quickly exposed the Devialet amplifier's digital SAM speaker optimisation software. Although SAM was said to correct bass performance right up to 150 Hz, it also took some of the realism of the vocal frequencies, leaving us hungry for the ugly truth rather than the artificially flattened curve. The timbre of instruments and the occasional traces of hesitation in vocals were naturally preserved by the Duevels, making for an entertaining and engaging listening experience throughout the afternoon.

With the possible exception of our Martin Logan electrostatic speakers and the elusive Snell C4, perhaps, the Duevels played more flawlessly than most of the loudspeakers I had heard, and they were able to do so without sacrificing homogeneity for the sake of detail where the source material allowed. Like all good speakers, the Bella Luna benefited from careful positioning in the room and from impeccable source material and amplification. When paired with aggressive sounding equipment or material, they were only too happy to follow suit. Given their size, they benefited from larger rooms and some distance from the walls. And although omnidirectional speakers were more forgiving with respect to the listening position, the apex of the stereo triangle remained by far the best spot for listening.

To preserve the afternoon’s exploration for posterity, Alexi, Michael, and Matthias allowed me to make a recording of the setup. The material chosen for the recording was Seal’s CD album Best 1991 - 2004 and the acoustic version of ‘Killer’.

< Horn Milling Process | Audio Test Sample >

Specifications

• Type: floor-standing 2-way loudspeaker
• Design: omnidirectional, vented cabinet
• Frequency response (±3dB): 40 Hz - 23,000 Hz
• Power handling (RMS): 150 watts
• High-frequency driver: 4,4cm titanium dome tweeter, horn-loaded
• Midrange-to-bass driver: 22cm dynamic, kevlar diaphragm
• Woofer specifics: die-cast chassis, M-roll surround
• Diameter of horn diffusors: 280mm
• Gap between diffusors: 47mm
• Crossover frequency: N.N.
• Crossover design: phase-linear
• Power sensitivity (SPL): 91 dB
• Nominal impedance: 6 Ohms
• Dimensions: (H) 1050mm x (W) 325mm x (D) 325mm
• Weight: 30 kg
• Country of manufacture: Germany
• Year(s): 1999 - 2023

When I first met Alexi, this was during our role as fathers of elementary school children. However, it did not take long before we discovered our mutual interest in home audio equipment. I was intrigued by the fact that he was a seasoned technician in electronics who had preserved the heart of an explorer and did not, on principle, object to the significance of interconnects. As I found out, he even ran a pair of single-wired Kimber cables from his NAD streamer amplifier to his speakers. From this combination, I took it that there was likely to be some room for meaningful conversation.

As it turned out, Alexi's speakers were a pair of smallish-looking omnidirectional 2-way towers with down-firing bass ports. They had the words ‘Duevel Planets’ printed on them and each cabinet held two shiny spheres suspended above its upwards-pointing drivers. The woofer-to-midrange driver featured a kevlar diaphragm, whereas the soft-dome tweeter was recessed behind a horn construction. The otherwise non-frills cabinet had a clean anthracite colour coating and was raised 40mm off the ground by four rubber absorbers. These also served as acoustic decoupling from the floor.

However, no matter how long I looked and pondered over the design, I did not have the faintest idea of what to expect from these speakers, especially, because they came from a small German manufacturer of whom I had never heard. Alexi informed me that Duevel was the founder’s family name and that the Lower-Saxony-based company specialised in building omnidirectional loudspeakers, most of which were larger and also heavier than the Planets. He further told me that the Duevel Planets had been praised as unrivalled in the sub-1,000 EUR category, and performed near the level of this manufacturer’s far more expensive models. I was hard-pressed to believe this account and fully expected their sound signature to resemble their physical appearance: small, airy, slightly metallic and tonally thin, perhaps.

When Alexi first started his convenient NAD streamer amplifier, my impression was that the music sounded a little thin and disorganised. I had trouble discerning an accurate center stage image but could also see that the distances from the speakers to the front wall and the distance between the speakers and the listening position were not the same for both channels. The speakers had clearly not been set up taking into account the specific resonance frequencies resulting from the room's dimensions. Although the NAD amplifier offered on-board software for room-adaptation as well as a microphone for calibration, this feature had not yet been fully employed. The random overlapping of frequencies and heavy smearing of running times I could have easily taken as confirmation of my suspicions towards the design.

I spoke to Alexi about my concerns regarding the positioning of his speakers in the listening room and also offered to lend him a power amplifier from my stock in order to test his speakers with this. However, we agreed to first swap loudspeakers for a few days: He would get my Tannoy XT8F, while I would audition his Duevel Planets. At the time, I thought that he was getting the better deal for sure, but I think we were both excited to get new insights and gather experience with different loudspeaker designs. As it turned out, dragging the large and heavy Tannoys over to Alexi’s house in our children’s handcart proved to be quite a challenge, whereas the eleven kilo Duevels could easily be carried and pulled over to our house. This was the Duevels' first obvious benefit.

We decided to set his Planets up in our upstairs listening room, which was of considerable size and had slanted walls that helped to deflect some of the reverberations. The Duevels were going to replace a pair of Epicure EPI 500 that had been my favourite speakers due to their natural bass and tonality for some time. We gave the Epicures a final audition, playing tracks from 2Cellos, Diana Krall, and Norah Jones and then placed Alexi’s Planets in the exact same position. We played the same tracks again and were both more than a little surprised at how tonally similar the Planets sounded. Alexi remarked that the Duevels had slightly sharper imaging than the Epicure, and I noticed a mild leaning towards analytical and technical sound on the side of the Duevels.

In this first position, the Planets were positioned directly on our hardwood floor with one meter distance kept between the bass driver's central axis and the room’s front wall. Happy with the findings of our first listening session, Alexi and I parted ways. Over the next few days, I came back to the Planets to experiment with different placement options. I noticed that bass response and depth of soundstage strongly depended on the triangular relation between the speakers, the room’s front wall, and the listening position. And although I did realise that this was the case with all speakers, the effects seemed more pronounced due to the omnidirectional nature of the design. The front wall became an integral part of the listening experience, and differences in shape, texture, and firmness of that wall would have an effect on how the music sounded.

Bass became stronger as I moved the Duevels closer to the front wall. I found that imaging stayed remarkably sharp until about 50cm distance. Whereas at one meter wall distance I had been lacking bass punch and the lower frequencies of vocals, the speakers sounded tonally richer and fuller when nearer to the wall. Of course, the wall distance will affect room resonances and bass modes relative to the seating position, and I was glad to see bass increasing again once the speakers were positioned further than one meter from the front wall. In one instance, I moved the Planets to a position half-way between myself and the listening position and was pleased with the immense depth of stage I was experiencing.

Judging from their looks alone, I would have thought that the upward thrust of the drivers paired with the two spheres would make the Planets susceptible to imbalances caused by the room dimensions. In our upstairs listening room with slanted walls, the left speaker only had about 50 cm of air above, whereas the right one had about three meters of empty space above it and also plenty of room to the right. However, my concerns were unfounded, because the spheres served as fixed points of first reflection, radiating the sound around the speaker rather than up. As a consequence, the Duevels sounded just as balanced as all the loudspeakers I had auditioned before them. If anything, the center image felt more natural.

As I was still feeling a little bothered by the Planets’ accurate and technical sound, I experimented with pads and carpets that I placed under the speakers. This helped shift the balance from listening to the character of a microphone towards hearing the voice of a human singing. I would suspect that the best option would have been to place a thick board underneath the speakers and to decouple this via felt pads. But since the Planets were not mine, I did not want to make the investment. Instead, I achieved good results by placing felt pads or floor matts underneath the four feet. Either way, the speakers benefitted from some form of additional decoupling from the hardwood floor. The floor matts had the advantage of keeping the bass reflex at the prescribed distance.

I found that the Duevels were capable of creating a naturally-sounding sound stage that was both deep and wide. This impression grew stronger with increased distance to the room wall. Given their relatively small size and shape, however, placing these speakers midway towards the listening position would make them stumbling blocks in most listening rooms, exposing them to the risk of being toppled over to one side. Their more monumental brothers and sisters, on the other hand, would present more obvious obstacles and also resist the occasional collision without the immediate risk of damage. This could be worth a consideration when deciding to make a purchase.

At the correct relative distance to the wall and seating position, the Duevels produced a tonally correct sound that was neither thin nor boomy. Vocals sounded clean, open, and realistic once the correct coupling towards the floor had been achieved. Imaging was surprisingly sharp for an omnidirectional speaker system, and the developers Annette and Markus Duevel were obviously in control of the relevant acoustic dimensions when they designed these speakers. I was surprised by the accurate phantom center despite the uneven layout of the room. And I was even more astonished by the persistent stage effect as I was walking through the room. Similar to a living room concert—and we have had some of those—the stage did not change position. It seemed as if the Jazz combo was still playing in the exact same position, no matter from where in the 70 sqm room I was listening.

From the listening impression alone, it was difficult to believe that the Planets were entry-level speakers that had been sold for under 1,000 EUR. With my eyes closed, I would have assumed that I was listening to far taller speakers with a heftier price tag. With the eyes open, there were some indicators that the price was perhaps justified. Inspecting the Planets from the floor upwards, I first stumbled over the affordable-looking rubber feet that kept the speakers suspended without the addition of a defined base plate with spikes towards the ground. The binding posts, too, were designed to only take one set of bananas or spades without the option of bi-wiring. Given the limited mass of the woofer, I did not feel that there was need for bi-wiring, however, the absence of this option did not strike me as state-of-the-art.

The cabinet itself was a simple box of medium density fibre that had been neatly colour coated. Although my wife rather liked the look, I would have preferred a more reassuring instrument-like appearance using real wood veneer. The font and style of the lettering did not exactly scream High End design, either. Instead of well-seasoned and sophisticated, these speakers looked young and cool. And this coolness-factor was further accentuated by the two seemingly cold spheres hanging suspended above the drivers. Since both of the drivers were pointing upward, keeping them clear of dust might prove to be a challenge. The mouth of the tweeter’s horn had a metal grille to protect it from children’s fingers, however dust and cleaning liquids passing the grille would remain out of reach. Non of this, however, appeared to have been an issue on my test specimens that still looked clean and in great shape. Perhaps a testament to Alexi’s good care.

In my listening tests, I enjoyed how the Planets maintained stage size and instrument location. The fact that some of the music was reflected upward gave string instruments a life-like appearance. The speakers did not betray their position nor the materials used on the cabinet or spheres. They did not sound wooden, boxy, or metallic. Even in our large listening room, playing music at volumes of between 60 and 80 dB was possible without audible compression (measured from the listening position). Duevel rated the Planets at 50 watts RMS per channel, and our Dynavox VR-70 tube amplifier had no difficulties driving them. Low-bass presentation was sufficient and even surprising given their size. I could not detect any phase issues, and their timing was excellent. Rated at 85 dB (1W / 1m), the Planets would benefit from large amplifiers despite their relatively low power tolerance.

Although I could not find any information on frequency response, the thought that anything was off or amiss never once crossed my mind while listening to them. Sonically, the Planets were close to some well-regarded classic speakers and did not follow the path of so many modern showroom squeakers. Astonishingly, this character remained largely in tact when walking though the room. On very rare occasions, I missed the piercing power and attack of piano keys, especially when the Planets were standing further away from the wall. And I did notice that the full extent of tonal balance needed at least 60 dB of volume. Below this, the treble seemed slightly dominant. This did play a role at least once when we had guests for dinner, and I was looking for some mild background entertainment. In this scenario, I would have wished for stonger bass foundation to support tonality.

I never played music at volumes where the size of the woofer seemed to matter. And after listening to Jazz albums by Diana Krall, Helge Lien Trio, and Jamie Saft (among others), I was pleasantly surprised how well the Duevels played Jörg Hegemann’s fast and furiously dynamic CD album “High End Boogie Woogie” that included some wonderful double bass runs. Due to their omnidirectional characteristics, experiencing the music with friends and sharing a similar experience, all at the same time, was possible for the first time. Audiophiles will agree that sharing the pleasure of listening is often a challenge, because, given the narrow sweet spot, we can only guess what the other person is hearing.

While a sceptic at first, I could see that omnidirectional loudspeakers such as Alexi’s Duevel Planets had a deserved place in the heart of HiFi enthusiasts. Given Annette and Markus’ command of this technology, it was fair to say that the Planets shared some highly audiophile characteristics and were fun and easy to listen to over extended periods of time. Omnidirectional speakers had the potential to create a more natural stage that maintained its realism in many positions of the room. For those of us who prefered to listen to acoustic instruments played by small combos, these speakers provided the perfect setting. As all audiophile speakers, the planets had been designed to perform best at living room volumes. Any deviation from this (be it higher or lower) would produce less-than-ideal results.

For my part, I decided to hold on to the Planets for a few more days and enjoying the music before returning them to their rightful owner. I was also looking forward to helping Alexi in calibrating his own NAD system to his listening room, first with my Tannoys and then with his Duevels. I now knew that they were well worth the fuss.

Test system: Marantz CD-17 via HiViLux Reference SP/DIF cable on Cambridge DAC Magic 100 via HBS Silver Solid-Core Interconnect on Dynavox VR-70 via Belden 9497 in Y-wiring on the loudspeakers

Specifications

• Type: floor-standing 2-way loudspeaker
• Design: omnidirectional, vented cabinet
• Frequency response: N.N.
• Power handling (RMS): 50 watts
• High-frequency driver: soft-dome tweeter, horn-loaded
• Midrange-to-bass driver: dynamic, kevlar diaphragm
• Diameter of spheres: 98mm and 58mm
• Distance between spheres: 48mm
• Crossover frequency: 4,100 Hz
• Power sensitivity: 85 dB
• Nominal impedance: 4 Ohms
• Dimensions: (H) 840mm x (W) 260mm x (D) 156 mm
• Weight: 11 kg
• Country of manufacture: Germany
• Year(s): 2012

Shortly after the turn of the century, some twenty years ago, the audio technician and car-Hifi store owner, Winfried Echle, came across the review of a Dynamic 16cm bass-to-midrange driver with Kevlar diaphragm when leafing through one of the last issues ever printed of the German electronics magazine ‘Funkschau’. The chassis was made in Thailand and, as it turned out, was difficult to obtain from a German supplier. This prompted Winfried to contact the Thai embassy in Frankfurt to establish direct contact with the producer in Thailand. When he finally received a response, it was to inform him that the minimum order quantity was at 100 pieces. Winfried took a deep breath and made the purchase. “I was feeling put under pressure, but what I should have done, would have been to place an order for 200 units instead.” he told me laughingly, “How could I have foreseen how successful these little drivers would become.”

His first serious bookshelf-size loudspeaker was of a two-way design, with a front-ventilated bass port that was placed in one corner right next to the tweeter. The passive crossover cut the tweeter off at 1,500 Hz and at a 6dB slope per octave. Early models featured a 2.5cm Peerless soft-dome tweeter, which Winfried ended up replacing with a Vifa XT-300/K4 ring radiator on later models. The ring radiator did not play as loud as the soft-dome tweeter, but it introduced a new sweetness to the sound and offered a more pleasant drop-off in the treble. The crossover parts, internal wiring, and wire terminals were of a high quality, and the pass port was fine-tuned to be as linear as possible, preferring tight control to the usual 60 Hz hump. Winfried spent some time listening, measuring, and adjusting the crossover parts and bass port until he was pleased with the result.

Showing his new prototype speakers to friends and visitors to his shop, some of whom were industry specialists themselves, Winfried received excellent feedback on his design and ended up selling over one hundred of these bookshelf speakers. In fact, he sold more speakers in the given price category than the local HiFi shop did at the same time. To the owner of the HiFi shop, this did not come as much of a surprise, as Winfried’s unique price-performance ratio even impressed his friends at Hessischer Rundfunk who bought two pairs of speakers for proper installation in their broadcast vehicles. But, was this just a lucky punch, or a replicable show of skills? Listening to the story made me curious, and I just had to find out for myself.

Ever since hearing about his monitor speakers for the first time, I was tempted to take them home with me for a trial run. But it was not until our impending relocation from Frankfurt am Main to Marne, Schleswig-Holstein, and when our weekly meetings in Aschaffenburg were slowly coming to an end, he let me know that he would actually be honoured if I still found the time to write a review. Of course, I did not have to think twice about this and brought along a large Eurobox for transport, into which the pair fit perfectly. On my drive back home, I contemplated which amplifier to test them with and decided that I would go with our Dynavox VR-70 tube amplifier, unless this would prove to be problematic due to some unforseen mismatch in capacitance or resistance.

I gave our EPI 500 floor-standing speakers a good listen and then set up Echle’s bookshelf speakers in that same position. The DIY stands I used had originally been designed for our KEF iQ series speakers, and they were made of sturdy PDF boards perched on spikes with coasters that were in turn placed on felt cushions for decoupling towards the ground. The finished stands weighed about as much as the speakers themselves and gave them a firm position while preserving their ability to sufficiently free themselves from the floor not to excite ghastly resonances. With the Vifa tweeter being mounted off axis, I was puzzled for a bit whether to have the tweeters on the inside towards the listening position or to rather have them on the outside, away from the listening position with the bass port on the inside. I decided to listen to the set with the tweeters on the inside first.

The resulting musical image was accurate yet somewhat thin-sounding. The center image was super sharp, and voices seemed slightly thickened and throaty with an alluring touch. There was lots of bass texture, even if low-bass extension was not great. The speakers performed in a well-behaved manner with a sensible top-end. The midrange was insightful and homogenous. Piano keys sounded warm enough but were lacking some of the treble bite and bass punch. On occasion, I noticed a little time-smear and could sense more than the usual sibilance. Looking at my setup, with the vertical radiation axis of the speakers merging about 50cm behind my head, I could see that I had brought the tweeter coils relatively closer to my ears than the woofer coils.

Since the woofer coils were usually positioned deeper inside the speaker cabinets than the tweeter coils, swapping the left and right speakers to position the treble outward would help to correct this issue by increasing the distance between the tweeter and the ears. The result was less time-smear and sibilance and an increase in stage width. The midrange remained the strong point with accurate tonality. The initial lightness of sound had disappeared. The result was vocal credibility and a kind of no-fuss reporting of musical events. The term understatement came to mind, an impression that was even enhanced by their their ample use of build-depth rather than height or width.

From Nick Cave’s live-album ‘Idiot Prayer’ I then changed to Boris Blank’s studio album ‘Convergence’. I also turned up the volume from Cave’s natural-sounding voice to moderate disco. Boris Blank has been a long-time favourite among tech-minded people, and on its basis the speakers could show their ability to keep the separate layers of samples apart. I was impressed with the insightful positioning of bass-events from left to right and from top to bottom as well as the lack of tweeter aggressiveness I would normally have expected from smallish speakers playing loud music. I did notice, however, that the higher excursion of the woofer of +/- 8mm did lead to to a certain breathiness in the treble. I am not convinced that the Doppler effect would have been as pronounced if the bass port had not also been positioned between the tweeter and the listening position.

I enjoyed listening to these speakers being played loud, especially because their treble was a little more forgiving than on our other models. Michael Patrick Kelly’s live album “ID” came to mind, and the speakers did not disappoint in terms of speed, agility, and, to some extent, even dynamics. The kick drum sounded hard and firm. These loudspeakers would work equally well playing Rock music and Jazz, and that combination was not all too common. Rock music requires for the music to be kept together rather than taken apart, and this was certainly the case.

To round off my exploration, I put on some Norah Jones. “Feels like home” was presented with musky vocals and amber keyboard notes. It sounded at once exciting and spacious as well as refined and well-proportioned. The soft top end that had served so well when playing the speakers louder here resulted in a slight lack of crispness in piano notes. In the end it seemed as though we cannot have it all, or at least not in the still affordable price categories. I wonder, how many of us would get up to tweak the sound coming from a real live event, if we were given the power to do so. As around speakers and for serious listening Winfried’s speakers were certainly able and enjoyable tools. When it came to mixing music and discerning listening, on the other hand, the somewhat relaxed treble presentation might make problems in this area seem less dramatic than they really were. For monitoring vocals, these speaker were truly excellent.

Specifications

• Type: 2-way bookshelf speaker
• Speaker principle: vented cabinet
• Crossover 1,500 Hz (@6dB per octave)
• Application: entertainment, monitoring
• Tweeter: 25mm Vifa XT-300/K4 (Tymphany)
• Tweeter principle: ring radiator
• Bass driver: 16cm dynamic, Kevlar diaphragm 
• Dimensions: (H) 320mm, (D) 350mm, (W) 210mm
• Country of manufacture: Germany
• Designer: Winfried Echle
• Year: 2002

When my good friend Luigi called to say that he had come across a pair of Epicure 3.0 speakers in Berlin, I was at first a bit puzzled why he was telling me this. The German capitol was located five car hours from Frankfurt, and I could not imagine how I might transport two 30kg tower speakers over a distance of 550km in any other way than by driving to Berlin myself. Nevertheless, I thanked Luigi for keeping me posted on new opportunities and said that I might consider these Epicure speakers for review someday. In the days that followed, I did some research on the 3.0 model and became even more interested in listening to them perform. I also remembered that we had good friends in Berlin who just might be spontaneous enough to pick them up for us, until we could find a way of transporting them to Frankfurt.

In a spur of the moment decision, I contacted the seller in Berlin and bought the speakers. That same evening, I wrote to our friend Enrico in Berlin telling him about my purchase and the difficulties involved. Luckily, Enrico said he would be interested in supporting me and the eiaudio project by picking up the speakers. I was relieved to hear this, because I knew that the Epicures would be in good hands with him. As it turned out, Enrico had to drive from Berlin Bernau in the north all the way across town to Steglitz in order to pick them up. To both our surprise, the Epicure were on sale from their original owner and came with all the documents relating to the purchase. The owner himself informed Enrico that he had bought these speakers at a time when he was still a university student, long before starting his career and, later, his own business. He had simply enjoyed listening to them for the greater part of 40 years. That was a good sign, indeed.

Once the Epicure 3.0 were safely stored at Enrico’s house it took me another month or so to find a professional carrier who would pick up the speakers and deliver them to our doorstep, labelled as ‘additional cargo’ as part of a larger delivery. I had found out that the Berlin-based freight company ‘KLTransporte’ organised regular transports between Berlin and Frankfurt that made additional cargo loads possible in most weeks of the year. To assure a safe journey, Enrico wrapped each speaker in multiple layers of bubble foil and indicated the exact positions in which the speakers could be touched and carried. It was due to his mindful preparation and support that the moving company was able to take all necessary precautions and deliver the Epicure 3.0 in one piece. I was truly grateful to all involved for making this new exploration possible.

On the images I had found on the Internet, but also in the photos that Enrico had sent me, it mostly looked as if one side of the Epicures’ truncated pyramid shape was off balance somehow. I am not sure what might have caused this first impression, but unpacking them at our house provided me with affirmation that they were indeed perfectly balanced. And although I had used a folding ruler to check the speakers’ approximate size and position in our room, I was surprised by how monumental and accomplished they looked in real life. The rounded edges, the unconventional pyramid shape, but also the high-quality waxed American walnut surface on all sides suggested that these loudspeakers were not to be taken lightly.

Similar to our EPI 500, the 3.0 were decoupled from the floor by means of a wooden base. But different to the EPI 500, the base itself was decoupled from the floor by means of four scantlings, with one scantling placed in each corner. In my attempts to get the EPI 500 to sound right, I had applied the same method of raising the base with great success and was pleased to see this confirmed. As the speakers of this era were mostly designed to be placed on American living room carpets, I achieved the most natural tonality by placing them on 5x40mm felt pads, sometimes in combination with 8mm thick steel plates. The base itself served to raise the bottom of the cabinet off the floor and allowed for the binding posts to be hidden from sight underneath the speakers, thus contributing to Epicures’ clean look from all around.

For those of us conducting lots of experiments with loudspeakers, the hidden position of the binding posts could become a bit of a nuisance, and I was further surprised to find that the supposedly original G.R. plugs had been upgraded (most likely by the company itself) to more convenient wire clamps that sadly were too puny to accept the hollow beryllium-gold banana plugs of my confectioned Belden speaker cables. In search of a quick solution, I grabbed a disused run of Belden 9497 cables and simply clipped the bananas off at one end. I then slipped the tinned copper Belden wires directly into the clamps. This did the job of connecting the speakers to our Hafler XL280 power amplifier, and, as usual, the initial sound emanating from the speakers proved to be quite horrible. With the cables and speakers having been dormant for many months prior to my purchase and with one end of the cables having freshly been clipped, there was obvious need for homogenisation of materials and perhaps fluids. 

Another aspect leading to the at first poor sonic impression was the positioning of the speakers in the listening room. At first, I had simply placed them at the markers that had worked well with our Martin Logan electrostatic speakers, and this was obviously not the perfect position for the Epicure 3.0. In this position, the speakers were standing too far apart, far from the room’s front wall, and toed in towards the listening position. On the Epicures, this placement led to an over-accentuation of treble and lower bass with a complete absence of bass punch. It was clear to me that the room was interacting unfavourably with the speakers, and I was reminded of an Excel spreadsheet that I had received from a fellow audiophile called Peter Englisch. This spreadsheet permitted the calculation of favourable speaker placement positions simply from entering the room dimensions. It seemed that the process of placing the Epicures would present a good opportunity for me to work with this new tool. Based on the dimensions of our main listening room, I received the following values:

Speaker-to-wall distances in centimetres:

• Front Wall: 70 / 112 / 252
• Side Wall: 59 / 94 / 212
• Floor-to-Woofer: 35 / 56 / 126

The Front Wall distance was measured from the room’s front wall to the woofer-plain (near the voice coil); the Side Wall distances were measured from the left and right side walls to the centre-axis of the bass drivers, and the Floor-to-Woofer distance was measured from the room’s flooring to the centre-axis of the woofer. Speaking to Peter Englisch about how to best work with the values, I was reminded that, while the front wall distances should be identical between the left and the right channel, the side wall distances should not be the same. The need for different distances between the side walls resulted from the listening position normally being located midway between the speakers. If the speakers were also positioned symmetrically within the room’s walls, the result would be a cancellation of frequencies in the listening position.

I ended up with a front wall distance of 70 centimetres (which was 10-30 cm less than I usually positioned our speakers at) and a right channel to wall distance of 94 centimetres. The floor to woofer distance was naturally at about 56 centimetres with the Epicure 3.0. On the left channel I could not quite match the prescribed value, because of a door being in the way. I added round 5mm high and 40mm wide felt pads underneath the four scantlings to decouple the speakers from our hardwood floor for more tonality. The speakers were placed in parallel to the front wall to improve channel separation and bass agility. The Epicure 3.0’s freestanding invert-dome tweeter provided linear frequency response over a super-wide dispersion angle and was said to show variations by 3dB over a 180° angle only. This resulted in the speakers sounding relatively balanced anywhere across the room and even outside the listening room. When standing right next to the speakers or grabbing a cup of coffee from the kitchen, the emanating sound remained natural and balanced, more so than we were otherwise used to.

The Epicure 3.0’s unusually wide dispersion angle and its flat frequency response over the whole bandwidth was accompanied by excellent phase linearity resulting from the front plate being slanted backwards towards the pyramid top. Earlier models of manufacturers such as Cabasse, KEF, B&W, etc., had added additional cabinet boards under the bass and midrange drivers to reach a similar effect, but Epicure’s soft edge, soft slope approach would also lessen the unpleasantness caused by sound waves hitting on sharp edges. The pyramid structure had the advantage that the reflecting surface around each driver was proportional to the driver’s size, thus minimising harsh refractions. The tweeter and the midrange driver were housed in their own separate compartments, and there was little interference between the chassis that would jeopardise acoustic integrity. This resulted in low distortion, reduced time-smear, excellent transient response, and, above all, natural tonality.

On the 3.0 model, Epicure made use of a relatively large 140mm ferrofluid damped midrange driver that was allowed to mechanically roll off at 6 dB per octave from 75 Hz towards the woofer. Its potential high frequency content was kept from interfering with the tweeter via crossover at 2,600 Hz and 18 dB per octave. The bass driver was kept clear of the midrange by sloping at 12 dB per octave. Next to the active ferrofluid damping of the tweeter and midrange drivers, the model 3.0 eliminated internal resonances through a combination of bracing and anti-resonance matts. The resulting effect was a linear frequency response from a very low 32 Hz to 10,000 Hz over an impressive 180° angle. Needless to say, shoppers today would be hard-pressed to find loudspeakers that deliver a similar performance. And measured from the sweet spot, frequency response over the whole spectrum of human hearing was quoted at 32 to 20,000 Hz with a mere 3 dB variation towards the fringes.

With their high level of resonance absorption, the Epicure 3.0 turned out to be power hungry. Sensitivity was rated at a low 83 dB, which would have made them a companion for beefy amps. I did achieve good results driving them with a 40 WPC Dynavox VR-70 tube amp and with a 145 WPC Hafler XL-280 solid state amp. Epicure actually recommended amplifiers from 30 to 500 watts, and I can confirm this to be realistic, if the lower watts amplifiers are tube driven. Ferrofluid cooling made the speakers withstand even high levels of continuous power without any immediate danger of them overheating. Their impeccably flat impedance curve at 4 Ohms made the choice of amplifier relatively easy. With the foam grills in place, especially those covering the tweeters, listening at slightly elevated volumes proved to be more rewarding. However, for greater musical detail and nuance, the grills needed to be removed. Sadly, removing the frameless frontal grills without running the risk of breaking them in the process had long since become a challenge on my specimen. Perhaps to compensate for its wide dispersion angle, the tweeter’s output could be attenuated in -3dB steps. This could be a practical feature, for instance when highly reflecting side walls contributed to the amplification of the output signal in an undesirable fashion. 

In my extensive listening tests, the Epicure 3.0 played all kinds of music program, film score, and effects with ease. While their specific sonic character was not immediately noticeable and would be difficult to spot by the casual listener, these speakers certainly had the potential to surprise. Their linear response made them sound rather inconspicuous until the music program itself demanded attention. From the beginning, I was perplexed by the Epicure 3.0’s bass response and extension to which there was no warning. While other speakers would let you guess their intrinsic abilities by the sound signature they produced, the Epicure were capable of dishing out bass attacks without even the faintest hint of having this ability. And these bass moments could either be surprisingly low or astonishingly loud, depending on the music chosen. I would have expected this kind of bass from a subwoofer, perhaps, but I had never actually heard a subwoofer that was so well integrated with the music and not once seemed misplaced.

In our setup, the Epicure 3.0 performed well in terms of smoothness, balance, and natural tonality. They were not the most exciting sounding speakers in and of themselves, but they were always ready to accentuate the music when this was called for. I enjoyed the natural sound and kick of percussions and the many tonal layers by which the music was presented. In the field of tonal separation, the model 3.0 was similar if not superior to the EPI 500 series. Stereo imaging was not as wide and crisp as on the EPI 500 when sitting in the sweet spot, but it was far superior to the EPI 500 when listening from almost all other positions in the room. In my nightly sessions I noticed that the model 3.0 took the whole room into the acoustic equation which had its advantages when it came to maintaining lots of musical nuance. Some listeners had described the Epicure’s freestanding tweeters to have an ambience effect, however, this was something that I did not notice as outstanding or even care for so much.

Listening to the performance of the Epicure 3.0, it was difficult for me to imagine that these had been relatively affordable speakers at the time that could be purchased by a university student. But then again, the 70s and 80s were still about showing customers what was possible in HiFi, and the Epicure 3.0 did strech those boundaries.

Specifications

• Type: 3-way tower speaker
• Design: acoustically damped, closed-cabinet
• Bass driver: 320mm paper-cone woofer, dynamic
• Midrange driver: 140mm, paper-cone, dynamic
• High-frequency driver: 25mm, paper inverse-dome
• Ferrofluid damping: on tweeter and midrange
• Crossover frequencies: 475 Hz and 2,600 Hz
• Frequency response: 32 Hz - 20,000 Hz (+/- 3 dB)
• Tweeter level attenuation: -6 dB, -3 dB, and flat
• System resonance: 32 Hz (-3 dB)
• Nominal sensitivity rating: 83 dB (1 Watt, 1 m)
• Practical power sensitivity: 3,6 Watts (91 dB, 1 m)
• Nominal impedance: 4-Ohms
• Amplifier requirements: 30 (min) - 500 Watts (max)
• Solid-state amplifier: 100 WPC recommended
• Speaker terminal: G.R. plugs, base-plate mounted
• Grille material: acoustic foam, frameless
• Cabinet finish: hand-rubbed American walnut
• Dimensions: (H) 105,2cm; (B) 2x42cm; (T) 2x21,6cm
• Weight: 30.00 kg, each
• Country of manufacturing: United States
• Year(s): 1978-1986

Although the brand has largely been forgotten by today’s Hi-Fi enthusiasts, there are few names in vintage Hi-Fi that make the audiophile heart grow fonder than that of Epicure. The company’s focus in loudspeaker design was on providing natural tonality and imaging, and it often went to great lengths in the pursuit of this aim. Its founder, Winslow Burhoe (a former apprentice at Audio Research), had originally set out from a 2-way speaker design, which he named ‘the module’, and designed a whole range of loudspeakers around this. The Epicure 'Model 20', for instance, used two sets of 'the module', which were positioned invertedly to form a dipole and resemble live-stage characteristics. The idea was to incorporate the listening room’s front wall for acoustics effect. A similar design was also used in the EPI 'M 201' loudspeakers. These early specimen were well-received by the audio world and aimed at the higher end of the market.

The EPI 500 were among the first Epicure loudspeakers to break with the traditional module design. Instead of being based on Epicure’s tested 2-way principle, the EPI 500 were a classic 3-way tower speaker featuring specialist drivers to cover: the high notes, the critical midrange, and the bass frequencies. While essentially being of a closed-cabinet design, the EPI 500 extended their cabinet volume with the help two passive radiators, one placed on each of the speakers' side walls. These served to absorb the woofer’s inward energy and also supported it in the area of low-frequency extension. (Passive ratiators have again become attractive in modern times, in the sense that they provide considerable bass extension to Bluetooth convenience gadgets made by JBL, Bose, etc.) The Epicure's top-end was based on their signature inverted-dome gold ring tweeter. Where other high frequency drivers would have their domes facing outwards, Winslow Burhoe had made a name for himself using an inverted face-plate design, which gave the tweeter some horn-like compression characteristics. The tweeter on our specimen was of the second generation air-cushioned, oil-dampened design, a fact that would have placed the most likely construction year of our pair in the mid to late 1970s.

I purchased our EPI 500s from a private vendor in Nürnberg, who had in turn bought them a few years earlier in order to listen to his extensive vinyl collection. Having had troubles with the engine of our car on the way to Nurnberg, I arrived there in some disarray, kept wondering about my risky journey home, and therefore found it rather difficult to focus on the music. We listened to two or three songs, I held my ear on the drivers to check for potential noises that should not have been there, and concluded that they worked just fine. I did notice that one of the midrange drivers showed a slight smell of burnt coil-resin, but since I could not detect any scraping sounds emanating from it, I decided to trust the seller’s own verdict that he had not noticed any faults with the speakers himself. Epicure speakers were well known to stand the test of time, unless they had been over-driven for extended periods. The 40-something-year-old woofers looked as though they had been re-coned, and I was relieved to see that the work had been done with care.

While heaving them into the car for my ride back to Frankfurt, I noticed that—despite their modest size for tower speakers—they were surprisingly heavy, and I was grateful for the helping hand offered by their previous owner. 250 kilometres distance could seem long when seen from the perspective of a broken car that was blowing black diesel fumes out its back. As one might imagine, I made good use of my time going through different scenarios of having the car and speakers towed home that day. Luckily enough, I managed to make the journey back with the engine in its last twitches and unloaded the speakers before finally taking our vehicle to be serviced. This was commitment to the cause all the way through, of course. But then again, I was confident that the Epicures deserved no less.

When I finally returned home to further investigate the EPI 500, I noticed that they had one additional feature that I had noticed in the very beginning of my research and then somehow forgotten about: There was a wooden base screwed in place that formed a closed acoustic frame underneath the cabinet. This raised each speaker off the ground by about 8.6 cm. The base was needed to elevate the tweeter to ear-level, but it also prevented the speaker terminals from touching the ground. There may have been a number of reasons for positioning the terminals underneath the loudspeaker, e.g.: to make the back of the speakers look cleaner; to allow for the attachment of invisible sub-floor cabling; or simply to make unobstructed use of the cabinet's resonances. Holding my hand to the side and rear walls of the EPI 500, I could feel that this cabinet had been designed to naturally incorporate resonances with its sound signature, instead of bracing against internal and external vibrations in the way modern speaker designs would.

Understanding how the EPI 500 dealt with inherent resonances would be vital to finding the correct placement and integration in the room. However, with the whole cabinet and passive radiators set in motion at once, I also saw that success would not come easy. I would have to put myself in the position of the designers and imagine the most probable environment that they had envisaged for their speakers to perform in. This, of course, was likely to have looked and sounded differently from our sleek office with white high-gloss furniture and scant carpeting. Luckily, the underlying architecture of our building itself was not all too different from the typical American home of the 1970s and 80s, in the sense that our room was located under the roof of the building and of poorly insulated wooden beams that were planked with gypsum and plywood boards. This would most likely help to absorb some of the excess bass energy, if needed. I also discussed the matter with my audiophile friend Luigi who reminded me that the base had probably been designed with American highfloor carpets in mind.

The base of the EPI 500 had a small hole describing a semicircle towards the floor through which one was to run the speaker cable. To keep the base from touching the ground, some previous owners had glued small rubber pads of 1mm thickness and 20mm width into all four corners. I did not know if this had been found a good idea and decided to listen to the speakers in this condition first. Our testing system consisted of the Restek V1 preamplifier with upgraded Kassel power supply and the B&K ST-140 power amplifier. As sources, I used our Technics 1310 turntable and Marantz CD-17 player paired with Cambridge DAC. The interconnects were of solid core silver, and the speaker cable was our affordable but effective Belden 9497. This was a Hi-Fi setup that I could trust in terms of sonic integrity, having listened to each of the components in many different constellations. Naturally, I was intrigued to learn what the EPI 500 would add to or take away from the balance of sound.

Perched on the hardwood floor with the 1mm thick rubber plates in place, the speakers sounded dull and lifeless. I felt compelled to visually inspect the tweeters just to see if they had perhaps been damaged during transport. They looked fine. I also noticed that the ground in our office was not perfectly even so that the base did not manage to press down firmly enough on all sides. As I had expected, the smallish pads could neither offer a defined coupling nor decoupling from the ground. They somehow did both, and this confusion was audible. To learn more about the situation, I scraped off the pads and placed the speakers directly on the floor. With wood piled ontop of wood, the whole floor was turned into a resonator, and the resulting sound was overly wooden and muddy. To experiment with the opposite direction, I then placed our ultra-hard metal ball Aucharm absorbers underneath the base. This did serve to accentuate treble, but, consequently, the EPI 500 now sounded overly analytical and were lacking bass.

At this stage, I could already hear that the speakers had some potential, and that the optimum solution would need to provide the right mixture of dampening and stability. To make this possible, I lined the bottom of the base with felt towards the floor. This improved tonality, but I still had problems with imaging, possibly resulting from the slightly uneven floor. Thinking about how to address this issue, I added three 5mm-thick and 40mm-wide felt cushions: two on each side at the front, and one in the back. The hole for the speaker cable got in the way here, but I decided that a few centimetres off axis would not matter to the rear support. I then sat down to listen and was relieved to find that both soundstage and tonality had much improved. The EPI 500 produced a full and open sound that was also tonally rich. The double-bass on Diana Krall’s album “Turn up the quiet” now had lots of zest and dimension. I was not yet happy with the depiction of Diana's voice which was represented softer and less assertive than I was otherwise used to. Placing a second felt cushion on the other side of the speaker cable hole in the back went some way of solving issue. Possibly, the enhanced sound could be attributed to the improved balance in the support between the speaker's front and back.

In positioning the speakers, I found them to work well with the mouth of their drivers at 109cm distance to the front wall of the listening room. This was a placement that should also be possible to achieve in most listening scenarios. The speakers were placed just under two meters apart, measured from axis to axis, and my listening position was similarly at around two meters distance measured in diagonal. I found the tweeters and midrange to work best with the tweeter’s output axis crossing at least one third behind the listening position, instead of being pointed directly towards the listener. I have found this to be the most enjoyable setup with many speakers, but this might just have to do with my own listening tastes.

In this setup, I found the EPI 500 to offer a highly natural and informative mid-band. Their ability to reveal lots of nuance and layering in this tonal segment would have made them an instant darling with audiophile listeners. More generally speaking, the Epicure’s ability to incorporate their cabinet's resonances and passive radiators into the music output made them an excellent companion for natural instruments as found in Jazz, Folk, Country Music, etc. However, I found that the obvious strengths of the mid-band did not automatically translate into an outstanding depiction of voices. From my own perspective, our more modern Tannoy XT8F managed to offer the tiniest bit more in terms of believability in the midrange. I would have had to run further tests to learn if voices could be improved by adding solid steel plates inbetween the base structure and the felt pads in order to increase stability. I had a strong feeling that structural instability towards the ground might have been the culprit here.

Going through forums, I had read that some people suffering from tinitus were complaining about listening fatigue in connection with Epicure speakers. This phenomenon may have had to do with faulty coupling to the ground, with high feequency infiltration, but also with the shape of the inverted-dome tweeter itself. I noticed that this could produce a slight compression effect and thereby make the music seem quite dense in the treble. I also noticed that I tended to listen to music louder than I would have done with our other speakers. It was easy to get carried away while listening to these speakers, as I found out when putting on our 2009 pressing of Fleetwood Mac's 1977 album "Rumours". I simply enjoyed listening to the intense tonal richness that I had sometimes missed before.

In comparison to my first experiments with the EPI 500, bass performance had trippled, thus providing me with the realistically full sound and satisfying punch of an excellent tower speaker. Imaging was excellent, with a naturally wide and unconstrained center image. The music was well-spaced: from front to back and from left to right. Voices were still a touch on the sweet and soft side, but we would need to see about this aspect in the long run. From my experience, the EPI 500 should be easy to drive from a 20 watts tube amp, as well as a beefy solid state amp. They took some time in setting up properly, but the additional effort was well-worth it. Perhaps the aspect that I enjoyed most about them was their ability to provide a Jazz club atmosphere with freely breathing natural bass—but without the smell of cold cigarettes and stale beer.

Sound Sample on Youtube

Specifications

• Type: 3-way dynamic speaker
• Design: closed cabinet with passive radiators
• Impedance: 4 Ohms
• Power handling: 250 watts (max.)
• Power sensitivity: 88 dB (1 watt, 1 meter)
• Frequency range: 45 Hz - 20,000 Hz (+/-3dB)
• Tweeter: EPI gold ring (2nd generation)
• Tweeter principle: 2.6cm invert-dome, air-cushioned, oil-dampened
• Midrange driver: 10.5cm, paper cone (1st generation)
• Bass driver: 25.4cm, paper cone
• Passive radiators: 30.4cm
• Crossover freq.: 750-3,000 Hz
• Cabinet finish: walnut
• Dimensions: (H) 91.44 cm, (W) 30.48 cm, (D) 35.56 cm
• Weight: 28.12 kg (each) 
• Country of manufacture: U.S.A.
• Year(s): 1973 - 1981

It seems that from the 1950s right up to the 1990s, adventures in Hi-Fi were about exploring the limits of what was technically possible in terms of faithful sound reproduction. Size, look, and cost seemed to be of lesser concern to Hi-Fi manufacturers and the proud owners of the gear at the higher end of the market. Monstrous receivers, such as the Kenwood KR-9400 of 1974 to 1976, and loudspeakers the size of wardrobes, such as the Electro Voice Patrician 800 of the mid-70s to early 80s, all stood testimony to this fact. The primary music source of this period was the vinyl record, of which Hi-Fi enthusiasts tended to own impressive collections.

With the advent of more compact music formats, such as the CD (Sony 1982; Philips 1983), the DAT (Sony 1987), and ultimately the MP3 player (Saehan 1997), the audio market was intrigued to learn what else could be made smaller and more convenient. After years of bigger and better devices, the focus of the new millennium was about the question of how much size, weight, and cost could be sacrificed, before the magic of what once was music was lost. Mainstream Hi-Fi engineering therefore began building smaller and lighter gear. Loudspeakers became tall and slim to hide in the living spaces rather than dominate them. Consumers were attracted to smaller speakers that would offer much of the sound of their taller cousins. 

Speaker cables first disappeared into the walls, before they were ultimately replaced by WiFi or Bluetooth and disappeared altogether. The KEF LS-50 and 'LS-50 wireless' of 2012 to 2022 are cases in point. The LS-50 are compact bookshelf loudspeakers that can best show their sonic virtues when positioned on proper Hi-Fi stands, taking into consideration the dimensions of the room, etc. The wireless version, which is slightly more expensive, offers the added advantage to the Hi-Fi newbie that nothing can go wrong in terms of grounding, interconnects, and loudspeaker cables. It is no surprise that, at the time of writing this article, the versatile and unobtrusive KEF LS-50 have been in production for over 10 years. And yet, the LS-50 is still a conservative home speaker design. Other manufacturers that have taken versatility to the next level.

The JBL 'Xtreme 2' were the second generation of JBL’s Xtreme Bluetooth speakers, and the pair that is on display here, was owned and given to me for testing by my long-time friend Thomas Kubalsky, who had previously helped me with a number of Hi-Fi issues. He had originally bought them that he could listen to music on his lengthy bicycle tours. To Thomas, the advantages were that the JBL’s canister-shaped body could easily be attached to his load-carrying bicycle, that they were water-proof, and that they had quick-charging batteries that would provide a playback time of up to 15 hours. Bluetooth connectivity had been a positive asset to him as well, but not an absolute must, given the close distance between cellphone and speakers when attached to his bike. By the time these photos were taken, his JBLs had already accompanied Thomas and his bicycle on numerous trips for at least 10,000 kilometres through excessive heat, dust, and rain.

On the day I decided to take the JBL Xtreme 2 home with me, they had already played a few hours of music at our children’s summer fest at the kindergarten. Thomas had shown me how to pair two Xtreme 2 speakers with my smartphone to create a small array. Although the JBLs had two sets of loudspeakers built in to each unit to allow for stereo playback, the intelligent Bluetooth profiles allowed for left and right channel allocation, when two Xtreme 2s were present. In fact, the profiles allowed for the inclusion of up to 100 loudspeakers in a single array. This amount of speakers should have been enough to power any cocktail or beach party. What really attracted me, though, was the opportunity to learn about the sound quality of such a versatile system with Bluetooth connectivity. How would this hold up in a listening comparison with some real Hi-Fi speakers?

Similar to other small cabinet designs, the JBL Xtreme 2 used passive radiators to suggest a larger cabinet volume and to improve the bass extension of the two smallish dynamic drivers. This was not a new principle but had been used on many famous speakers, such as the KEF Calinda, built from 1975 to 1976, and the Epicure EPI 500, built from 1973 to 1981. And while the Calinda had one passive radiator at its front, the EPI 500 used one radiator on each side of the cabinet, just like the JBL Xtreme models. And since I still had the EPI 500 set up in our second listening room and was perfectly happy with their sound, what better place to set up the small JBLs. To allow for quick A-B comparison, I placed the Xtremes on top of each EPI speaker with their drivers being flush with those of the EPIs.

In setting up the EPI 500 speakers, I had taken special care to achieve the perfect balance of dampening and support. By placing the Xtreme 2s directly on top of the Epicures, therefore, I was sure to benefit from that same advantage. During my listening tests, I made sure to raise or lower my ears to the level of the tweeters when switching between speakers. At the time of the test, the EPI 500s were still powered by our Kenwood KR-9400 receiver, a combo that offered an agile and forward sound with lots of natural bass slam. At the same time, the Epicures’ natural timbre was maintained, which made this combination quite enchanting, especially when it came to the playback of real-life music events. It would be interesting to learn, just how much of the original music event would be transported through the smallish JBL Bluetooth speakers. I was fully prepared to believe that this was just another convenience gadget with few other merits than being small and portable.

When comparing equipment, I tended to listen to the same albums played over and over again. Tonality, agility, transients, and natural bass were just some the characteristics I was interested in. The Epicure speakers could sound anything from muddy to sharp, depending on how they were positioned, supported for stability, and decoupled from the floor. If these aspects were in harmony, they were capable of superb tonal balance, and natural bass. Although with the Epicure bass was not extremely structured, I enjoyed that it was neither laid on too thick nor too lightly when paired with a good amplifier, such as our Becker ST-200, Dynavox VR 70, or even the Kenwood KR-9400 receiver. I put on Diana Krall's album 'Turn Up The Quiet' and listened to this via the EPI 500s first.

When I switched over to the JBL Xtreme 2s, I again had to wake the Bluetooth connection from its sleep and noticed that the unit I had paired as slave woke up only five seconds later. There was also a small amount of lagging and crackling involved, before the connection was perfectly established. At the same time, I was impressed with the palpable image that the JBLs created smack-centre between the speakers. This effect was instantly familiar to me from well-conceived wired connections. The next aspect that caught my attention was the great similarity in tonality between the EPI 500s and the Xtreme 2s. Both speakers presented Diana's voice in a highly believable fashion and with very similar timbre. The Epicure speakers did manage to separate the vocals from the upper bass a little better and therefore sounded slightly less muddy in this area. This difference, however, was much less than I would have expected.

The JBLs remained particularly faithful to the source material during slower and more organised passages of music. The louder and faster the music became, the more the speakers began to reveal their natural limitation. This is not to say that they sounded at all bad or poorly designed, it was just that some of the attack and order of the Epicures was not present when listening to the same track via the JBL speakers. To be honest, I would not have thought that portable Bluetooth speakers would even merit such a comparison, but with the JBLs, it did not seem all too far-fetched. This impression was also reflected back to me by my colleague Landon, who walked into the office smiling, saying: "Karsten, I would not have thought to see the likes of them in this office" while pointing at the Xtreme 2s. Upon giving him a demonstration, however, Landon seemed perplexed and, like me, had to confess that he would have assumed the difference between the speakers to be much greater. "So, they are really not bad, huh?" Landon said as he walked over to his desk.

When pairing the two Xtreme 2s for the first time, they were automatically set to 'Party Mode', which meant that each speaker was playing the full stereo image. This had the advantage that they could be positioned far apart, without sacrificing music information at the point of listening. To set them up in 'Stereo Mode', I had to first download the 'JBL Connect' or 'JBL Portable' app from the App Store. Switching the devices into Stereo Mode only took a few seconds, however, I did experience an issue by which I had some trouble in trusting the music information to be intact. This impression may have stemmed from sudden changes in channel volume that I consciously noticed on a few occasions. The stereo image also seemed overly emphasised at times with a strong but rather unpredictable three dimensional effect and a slightly hollow sound. [This was possibly due to a timing issue between the two channels called Hass effect. Thank you, Jens.] In consequence, there was a slight strain on my ears, which I had not experienced with the speakers set in 'Party Mode'.

Hence, I switched the speakers back into 'Party Mode' (or mono, in that case) and instantly felt much happier with their performance. In conclusion, I was able to report that the Xtreme 2 were acoustically well-engineered loudspeakers with excellent tonality, whose merits remained sadly concealed by a rather unstable Bluetooth connection. In 'Party Mode', with each speaker playing the full stereo signal, some aspects of vocal and instrument playback were similar to the better speakers of this world. In 'Stereo Mode', however, Bluetooth made the speakers lose all sense of proportion, flinging individual notes at random into the room. The occasional drop in volume, or even the disappearance of one channel altogether, put a strain on the listener and took away from the relaxing and reassuring aspect of the music. In short: A better connection would have turned these into far better speakers, because, physically, they really had a lot going for themselves.

Specifications

• Type: portable stereo loudspeaker
• Connectivity: bluetooth version: 4.2
• Features: speaker array integration
• Profiles: A2DP V1.3, AVRCP V1.6, HFP V1.6, HSP V1.2
• Tweeters: 2.0 cm x2
• Woofers: 6.99 cm x2
• Passive radiators: 800mm x2 
• Rated power: 2 x 20W RMS; bi-amped
• Frequency response: 55 Hz – 20.000 Hz
• Signal-to-noise ratio: > 80 dB
• Power supply: 19V, 3A
• Battery type: Lithium-ion Polymer 36Wh
• Battery charging time: 3.5 hours
• Music playback: up to 15 hours
• Inputs: 3.5mm headphone jack
• USB output: 5V, 2A (maximum)
• Transmitter power: 0-12.5 dB/m 
• Transmitter range: 2.402 – 2.480 GHz
• Dimensions: (H) 136 x (W) 288 x (D) 132mm
• Country of manufacture: China
• Weight: approximately 2.4 kg
• Year(s): 2018 - 2022

Where do I begin? Perhaps best with an apology. Because, up until this point, no other speakers had captivated my attention and imagination more than these little bookshelves. And, in my attribution of positive and negative qualities to these loudspeakers, I may not always have been fair. It actually took me quite some time to find this out, and, in the end, it took the whole journey to get to the truth of things.

We had originally bought the KEFs as unobtrusive bookshelf speakers to play background music in our home office. This was well before I began contemplating to set up a second audiophile system to use when the kids where blocking our main listening room. As usual,I had studied reviews on entry level bookshelves that punched above their weight, and KEFs were mentioned repeatedly in this context.

In our office they had to replace some ageing Denon bookshelves that were left over from my old F-07 midi system. Driving these was an entry level Rotel preamp and amplifier combo rated at 2x 60 watts. The match was actually pretty decent in retrospective, as the Japanese combo had been designed with the affiliated Bowers & Wilkins in mind and is said to be following the philosophy of ‘British sound’. This, to my understanding, is characterised by accuracy, tonal balance, and a warm midrange.

While the Denons with their soft dome tweeters had been forgiving of flaws and therefore easy to integrate, the KEFs immediately revealed the sonic weakness of our cheap glass and aluminium speaker stands. Hence, we replaced the stands with a simple DIY design (using 4 cm MDF boards) and immediately noticed a shift from a harsh and technical sound towards a more pleasing and natural performance.

Another aspect revealed by the KEFs was the lack in bass response from the listening room. Our office is situated under the roof of the building and has many acoustic disadvantages: slanted gypsum walls all around that absorb much of the lower frequencies, lots of hard furniture surfaces that reflect higher frequencies, and an extensive room depth of 13 meters with the listening position located at just 2.5 meters from the speakers.

In my attempt to make the KEFs sound well-balanced, I brought in a range of preamplifiers and amplifiers, spanning from Rotel, via Hafler, to Harman Kardon. But the KEFs, to various degrees, remained harsh and bright sounding. I looked at the Uni-Q driver’s sharply pointed wave guides and could not help but wonder whether KEF had somehow got them wrong. Just like I had found my earlier Canton Ventos to have accentuated highs, which, as I later read in a test, actually turned out to be true.

Unable to get the iQ30s balanced in our office, I gave them to my brother for listening and switched to Tannoy DC 6t tower speakers instead. With an additional dedicated bass driver, the Tannoys offered more direct bass punch and sounded more balanced at short distance. Yet, on listening to the new speakers for longer, I realised that they, too, were struggling with the size and structure of the room.

Last week, I received the KEFs back from my brother. And—as during their absence I had started wondering if there was not something I had missed in setting them up—this time I decided not to take them to the office upstairs but rather to hook them up in our main listening room. To be honest, my expectations were not too high, as their rivals downstairs are not some old Denon bookshelves but rather the formidable Martin Logan SL3 electrostatic speakers.

I started out by playing a few songs on the Martin Logans. Jazz and Folk that I know well and enjoy listening to. Then I switched to the iQ30s, half expecting to have a big laugh. Surprisingly, this is not at all what happened. The KEFs set in at similar volume and almost identical sonic characteristic, so that at first, I looked over at the Martin Logans in disbelief. With the tweeter on axis and the wave guides to cast the highs deeply into the room, the KEFs displayed a similar energy and authority when setting the stage.

The SL3s strength lies in the accuracy and subtlety of voices, the iQ30s play voices well, but do not reach that same level of subtlety and intimacy. And yet, they come very close. If the Tannoys love piano keys, the KEFs caress the guitar. Nils Lofgren’s playing was thrust into the room much like I am used to from listening to the Martin Logans. Notes linger a little shorter on the KEFs than on the SL3s, which is no wonder considering the exceptional lightness of the Martin Logan’s Mylar membrane.

The KEFs now sound balanced in our main listening room. None of the former harshness is still present, so that listening for long hours is now highly enjoyable. Bass is full and present and at times even punchier than on the SL3s. However, when it comes to playing very low notes, these are still present on the Martin Logans and simply missing on the KEFs. This should not come as much of a surprise, considering the 30 cm woofer size on the SL3s as opposed to a small 16 cm full range speaker on the iQ30.

The KEFs present a wonderful stage and—like the Martin Logans—can play loud as well, creating a wonderful live atmosphere. The Martin Logans can play louder, of course, but personally I never listen to music at volumes where this would really matter. Considering the size of the KEFs, their ability to fill the room is a respectable. Doing so with accuracy and authority to take on much lager and more expensive floor standing speakers is incredible. Hence, my apology. When the KEFs did not perform well at first, it was obviously not a design flaw of the speakers. It was the room.

Specifications

• Frequency response: 45 - 40000 Hz
• Sensitivity: 89 dB
• Impedance, average: 8 ohms
• Crossover frequency: 2500 Hz
• Recommended power: +15 Watts RMS
• Weight: 6.45 kg
• Dimensions: 36.5 cm x 22.0 cm x 32.7 cm

Gayle Martin Sanders and Ron Logan Sutherland had been interested in developing their own electrostatic loudspeakers ever since working together in a High End music store in Lawrence, Kansas in the late 1970s. Sanders was working as the store manager and had a background in architecture and advertising, and Sutherland was an electrical engineer. Both men were convinced that electrostatic loudspeakers had the greatest potential in providing High End audio performance, despite the fact that the electrostatic speakers that existed at that time still showed very limited performance in terms of frequency response and dispersion angle. Many of them became famous as amplifier killers, due to their troubling impedance curve nearing a shorted circuit. In addition to their lack of treble and bass response and the difficulty of finding a potent enough amplifier, electrostatic speakers produced a very narrow sweet spot for listening, sounding wrong or unbalanced in most places of the room. Among the few successful models of the time were the Quad ‘ELS’, mildly mimicking the design of an electric heater, and the huge KLH ‘Model 9’. While the Quad was able to reproduce chamber music in its fine and delicate tones, the limitations of its design became apparent when listening to louder performances, such as rock or classical music. The KLH on the other hand was very capable of producing all kinds of music, but its sheer size resulted in very low sales.

Sanders and Sutherland began constructing prototypes, some of which went up in flames when driven at higher volumes, until they found the materials composition that would enable them to play their speakers without fear of destroying them. Improvements included the development of an ultra-light Mylnar diaphragm and two horizontally curved stators made of perforated steel that would allow charges of up to 10.000 volts. According to the company website, Sanders and Sutherland exhibited their speaker concept at the 1982 Consumer Electronics Show in Chicago with only a mock-up and some photographs. The design was so radically new that it became an instant hit in the industry and was honoured with a CES Design and Engineering Award. While the ideas presented at the show were still in the design phase, Sanders and Sutherland had already developed their first working electrostatic speaker based on more conventional designs. It was called the ‘Monolith’, and dealers who heard it play during product demonstrations were more than eager to sell this to the public. Given the early acceptance of their ideas, the two men felt ready to start their own business. Having to come up with a brand name, they decided to combine their middle names to MartinLogan in 1983.

Despite many initial setbacks, including the departure of Ron Logan Sutherland from the company, the manufacturer managed to secure its foothold in the High End loudspeakers market. In the 1990s, MartinLogan created many now famous classics, such as the SL3, the smaller Aerius, and the Quest. The SL3 that is featured here is said to be the ‘rockiest’ of the 1990s range. It features a tall and slender stator panel that is flanked by blond oak rails. The Mylar membrane is almost completely translucent, inviting the application of soft back lighting to the front wall for optical effect. The SL3 is a hybrid speaker in the MartinLogan ‘Sequel’ series tradition and offers a 10” paper cone woofer for bass extension. The woofer is housed in a closed cabinet that also includes the 250 Hz 12 dB crossover and the high voltage transformer needed to generate the static electricity driving the Mylar membrane. The panel is open towards the front and the back of the speaker, and it is curved at the MartinLogan typical 30 degree angle to allow for optimum high frequency dispersion. The SL3 features dual binding posts for bi-wiring, as well as a Bass Control Switch to lessen bass response by -3 dB. This can be quite convenient, if the speakers are to be placed in smaller rooms in which bass response is accentuated. Although each speaker must be connected to a power source for high voltage generation, energy consumption is very low, and the speaker switches into standby if no signal current is detected on the binding posts. A small red light at the front of the speaker indicates when the speaker is switched on.

The MartinLogan SL3s is best driven with a strong amplifier that is built to handle high current feedback, because the impedance curve of the speaker shows some very low dips down to just 1,5 ohms at 20.000 Hz. Due to their bipolar panel design, placing the speakers can be a little more challenging than this would be the case with conventional designs. If placed well, the SL3 is perfectly capable of performing a disappearing act that is amazing to experience, in that the precise location of the speaker becomes difficult to trace and the music appears three-dimensional in the room. The sound is sonically balanced, and bass integration works very well on the hybrid design. At 0,37 sqm panel surface, the SL3 are capable of presenting a huge sound stage, both at low and high volumes. Bi-wiring is of the essence, as control over the woofer becomes sloppy when bridged. This may have to do with the hybrid design and the inherent electric characteristics of the drivers. When connected correctly, the SL3 is capable of lots of punch and a quick decay when needed. Because the panels themselves are of considerable size, listening to music at close distance can be quite overpowering. Some people have stated that they feel as if they are being grilled by them. To lessen this effect, but also to integrate the speakers more effectively into the room, the panels can be tilted backward. Overall, the SL3 provides a great basis for a high quality sound experience, as well as lots of room for experimentation.

Also see: Martin Logan SL3 Audio Demo

Specifications

• Frequency response: 30-22.000 Hz +/3 dB
• Dispersion angle: 30 degrees
• Sensitivity: 89 dB
• Impedance, average: 4 ohms
• Crossover Frequency: 250 Hz (12 dB)
• Impedance, minimum: 1,5 ohms at 20kHz
• Power handling: 200 watts RMS
• Weight: 29,5 kg, per speaker
• Dimensions: (h) 163 cm x (w) 33 cm x (d) 36 cm

Our family had just returned from living in the United States and was coming to terms with the adjustments of living in Germany, when a friend of mine introduced me to Mr Beyersdorffer’s infamous Orbid Sound loudspeaker company. Seeing that I had an interest in audio gear, he handed me a brochure that seemed to give away lots of secrets regarding the production and sale of loudspeakers. In this, Mr Beyersdorffer claimed that the established audio companies were ripping off their customers by packaging cheap drivers into fancy-looking boxes, hoping that enough paying customers would be attracted by their paid-for (and therefore always positive) reviews in the audio press.

Mr Beyersdorffer explained that Orbid Sound could work with superior drivers at a far lower price point than the audio establishment, since his company did not advertise in expensive magazines, and instead had built its reputation on word-of-mouth from its happy customers alone. His claims were not without truth, of course, with Hi-Fi stores selling speakers based on their high wattage figures, increasingly dubious frequency curves, and accentuated treble response—the latter being directed at affluent pensioners who were happily smiling that they could once again hear the upper ranges of the frequency spectrum. These were the days in which low-budget speaker manufacturers would paint large shiny rings around their smallish drivers in the attempt to make their speakers look more impressive through the cloth.

However, these brands—mostly from mail-order outlets and department stores—were not the primary target of Mr Beyersdorffer’s campaign. His rantings were directed at established Hi-Fi stores, and in his audience were emerging audiophiles on a tight budget. If he could convince the youth of the day that they could play with the big boys by being cleverer than the audio establishment, he would be able to earn enough money with his company to make a living for himself, and perhaps even some more. As it turned out, my friend, my younger brother, and myself ended up buying our first ‘real’ loudspeakers from Orbid Sound.

To save money, my brother and I chose assembly kits from the company. My brother’s Pluto kit came with prefabricated cabinet parts and was easy to assemble. I decided to go one step further by building the speaker cabinet from scratch. With more than 30 years having passed since then, I have forgotten what my loudspeakers were called, I just remember that they had four small woofers each, instead of one larger one. And these woofers were paired with the Pluto’s midrange driver and tweeter. Although I liked the idea of benefiting from the reduced time-lag of four smaller bass drivers and could even follow Mr Beyersdorffer’s ideas on this, I found that the concept did not work so well in practice—perhaps due to differences in timing between the drivers—and so I sold my speakers again, just a few weeks after finishing them.

My brother, on the other hand, kept his Orbid Sound Pluto kit speakers and finally left them behind at my parents’ house when he moved out in 2006. This is precisely where I found them just the other day. I called my brother to ask if I could take them home for a listening test on our system, to which he agreed. There was a moment of pause in which we both had to snicker at the improbability of running Orbid Sound speakers on a 'grown-up' stereo system. How would they compare against the high musical standards set by our vintage classics, let alone the modern Tannoy XT8f dual-concentric towers, the Epicure EPI 500, or even the Martin Logan SL-3 electrostatic speakers? We decided that we could not know until we tried, and I took the Plutos home with me later that evening.

Upon further inspection, I could see that the cabinets and drivers were still in surprisingly good shape, even if the glue of the veneer edging had become a little brittle in some corners, revealing plies of multi-ply underneath. This came as a surprise to me, as I had misremembered them to be made of cheaper pressboard. Multi-ply had the added advantage that it was not as sonically dead as the MDF board that is typically used these days. So, I whipped out a bottle of Ponal wood glue to solve the issue. The drivers themselves were still sonically sound, and I could not detected any scraping when moving them by hand.

Some people had reported that Orbid Sound designed their crossovers without using coils, simply by combining resistors. However, with the crossovers being cast in hardened resin, it was difficult for me to find out how much truth there was to this claim without breaking them. In my early youth, I had also built speakers without coils in their crossovers and learnt that such designs could actually be beneficial to phase correctness in some setups. Without the low pass function of a coil choke, the woofers were simply allowed to play lower midrange frequencies. And while this may have been an option on a two-way system, I was a little suspicious in respect to a 3-way design. Some sceptic listener had even x-rayed the crossovers and suggested in an online forum that they were in fact quite conventional. Be that as it may, in the end, I decided that it was worth finding out what Orbid Sound had cooked up thirty years ago.

Following some time listening to our Epicure EPI 500 speakers, I connected the Plutos to our Dynavox VR-70 tube amplifier, which had already been well run-in at this time. The music source was our Marantz CD-17 paired with a Cambridge DAC. I positioned the Plutos in the exact position where our EPI 500 had been, with the chassis at about 105cm distance from the room's front wall, only to find that this practically eliminated all bass frequencies from the rear-ported speakers. As intended book shelve speakers, the Orbid Sounds had been designed with the room's front wall to act as bass support. This itself was not necessarily a shortcoming in real-world applications; hence, I slowly began moving the stands closer to the room's front wall. As the chassis were approaching 62cm distance, bass notes finally began to sound right.

And yet, there was a second quirk that I had noticed right from the first minute of the speakers performing. Something was off balance in the Plutos' midrange. Female voices sounded squeakier and more compressed than I was previously used to, from our other speakers (and from real-life). At first, I had thought that this effect would lessen once the bass had locked in with the room, but sadly this was not the case, and I began to wonder what the level attenuation panel at the Pluto cabinet's rear wall was actually used for: the tweeter or the midrange? When first setting the speakers up many years ago, my brother and I had chosen to install a simple wire bridge, instead of using one of the included attenuation resistors. (I think there had initially been two, but who knew where they were now?) Listening to the Plutos today, this proved to have been a mistake. I admit that back in the 90s, we used equalisers to augment speaker performance, a practice that would be seen as an unspeakable blunder in the world of audiophile listening today.

Another phenomenon that I had noticed upon first listening to the Plutos was their eagerness to cast frequencies deeply into the room. This could have even been considered a positive effect if it had also served to create a stage impression with identifiable width and depth. For some reason, however, the Orbid Sounds did this at random and with no apparent coherence. This made only three basic stage positions discernible: left, centre, right. Snare drum, high hats, guitars, and piano notes found themselves loosely afloat in the listening room, strangely devoid of all form and position. Of the Plutos' three difficulties, this last one would probably be the most difficult to fix, as it seemed to stem from timing issues between the three chassis.

If tonality could be fixed through midrange attenuation, this might be a step in the right direction. To find out, I would first need to confirm that the attenuation clamps had actually been attached to the midrange. If they had instead been connected to the tweeters, it would probably be best to give up on these speakers. But if the midrange could be reduced in volume, this might actually reduce the midband squeakiness and create some listenable speakers. The rear terminal looked large enough to house a standard Visaton attenuator. The next morning, I unmounted the woofer to have a look inside. My findings were twofold: The midrange driver really was connected to the attenuator clamps, and, even better, it was housed in a separate internal cabinet. Feeling reassured by the results of my exploration, I ordered two Visaton attenuators, thus hoping to rein in the sqeaky midrange.

The Visaton LC57 attenuators arrived just three days later and easily slotted into the existing cabinet holes of the resistor clamps. I connected pins two and three of the L-pad, thus reaching maximum resistance (minimum midrange volume) with the attenuators turned left, as was described on the face plate. And yet, a first listen to the Orbid Sounds with the new L-pads in place reminded me of an issue from first placing the fixed resistors thirty years ago: There was hardly any difference in sound...! — But how was this even possible? Normally, one would think that taking the midrange drivers out of the sonic equation should also affect the speakers' ability to perform in this area. Were the Plutos' woofers perhaps allowed to extend into midrange frequencies after all? And what may have been the point of having dedicated midrange drivers, if their presence would be hardly detectable?

Over the course of the next few days, I experimented with various distances to the listening room's front wall and also tried different settings on the attenuator dial. Even in their most becoming position—out75/in70cm front wall distance, 2/3 midrange-volume, placed at 2m distance to form an equilateral triangle with the listening position—the Pluto (kit) speakers still sounded compressed in the midrange. And although the applied attenuation did produce a mildly positive effect in terms of tonal balance, this proved less significant than expected. Granted, the Plutos were capable of producing excessive amounts of sonic information. However, they presented this in an overly eager and in-your-face fashion that would take some getting used to. Considering their entry-level priced competition of the 1990s, the Plutos' capability to present a great wealth of musical detail may even have been a welcome feature. Their ability to radiate notes deeply into the room surely was perplexing, until it also became apparent that this mostly came at the expense of losing precise musical dimension. From their very beginning, Mr Beyersdorffer's Orbid Sound had banked on the notion of setting themselves apart from the Hi-Fi mainstream, and these speakers certainly lived up to the expectation.

Note: Martin Beyersdorffer died on 1 November 2020, just a few days before reaching his 87th birthday, and the company is currently maintained in its second generation by his son Daniel Beyersdorffer and Thomas Feil.

Specifications

• Type: 3-way dynamic ported speaker
• Features: midrange adjustment via resistor
• Frequency range: 33 Hz - 20,000 Hz
• Impedance: 4 Ohms
• Power handling: 60 watts (RMS)
• Tweeter driver: 3.0 cm, soft-dome 
• Tweeter model: Peerless of Denmark, SKO10 DT
• Midrange driver: 10 cm, coated paper
• Midrange model: WDH of Germany, BMT 130/19-120
• Woofer driver: 15 cm, poly-compound
• Woofer model: Peerless, 830228 (dual voice coil)
• Cabinet: Laminated multiply wood
• Cabinet volume: 27 litres
• Dimensions: (W) 23.5 cm; (D) 24.5 cm; (H) 52.5 cm
• Country of origin: Germany (kit)
• Weight: 11 kg
• Year: 1992

“What on earth…!?” you might be thinking when stumbling across this article, and even more so if you have been following this blog and perhaps thought you had me pegged as a straightforward audiophile who just happened to be into vintage gear. What on earth is a pair of Shure 701 Pro Master (that was obviously built for public address) to do on an audio blog that is dedicated to the enhancement of domestic listening pleasures? Well, to be absolutely honest, I was a little surprised by this acquisition myself. I guess, some little voice had whispered to me that these anno 1979 PA speakers would be worth the effort of exploration, simply because they would yield new experiences on many levels.

For one thing, the Pro Masters featured a 15-inch paper-cone woofer that was similar to some highly relevant Tannoy and Altec classics. From experience, I had learnt that paper was a decent enough construction material to build natural sounding dynamic drivers. On the other hand, more often than not, I had been warned by my audiophile friends that 15-inch drivers would be far more difficult to integrate with the room, as their greater dimensions could more easily excite room modes that would in turn limit placement choices. I had therefore thought it best to first experiment with speaker placement on the affordable level of the Shure Pro Masters before finally taking the plunge on their more expensive domestic cousins.

In addition to the new bass experience, the Shures featured a radial horn driver with adjustable angle that would offer fresh insights into horn-loaded designs as they were found on many renowned Hi-Fi and studio loudspeakers built by Altec Lansing, JBL, TAD, Electro Voice, Fostex, among others. Horn designs offered the benefit of high sensitivity output even at the low voltages produced by small tube amplifiers. In fact, the Pro Masters’ 102dB in sound pressure (measured at one watt power input and at one meter distance from the speakers) could mostly be attributed to the horns of the high frequency drivers. While the Shures’ horn principle may not have been the most delicate on the market back in the 1970s, it would allow me to learn more about the sonic characteristics of horns in terms of minimum distance, sweet spot, room modes and reflections, and other parameters which would be difficult to judge without first-hand experience.

For the pair of 1979 Pro Masters presented here, I ended up driving all the way up to the infamous Marburg “Hinterland”. Their previous owner Micheal was an ageing audiophile and collector of loudspeakers himself and in the advertisement had described the speakers as being fully functional. Hence, I was quite optimistic when I arrived. I found the speakers set up in a furnished garden hut, in which Micheal had compiled his third or fourth system. A quick listening tests showed them to play music. However, neither the positioning on a table nor the room itself allowed for a deeper tonal analysis. There was pretty much a lack of everything, and so I decided to trust his verdict that they were still fully intact. We carried the Pro Masters to my car and spent the next few minutes listening to his current basement horn system.

Back at home, Sabina helped me carry the heavy speakers up our winding stairwell. I quickly found a spot for them, and we ended up parking them there for a few weeks to finish some other projects. When I finally came back to the Shures, I quickly set them up on two stubby stepladders. I connected them to our Dynavox VR-70 tube amplifier which was fed from our Marantz CD-17 and Cambridge DAC on Restek V1 combo. Having been fully broken in, the Dynavox VR-70 (still with original Chinese tubes) was capable of producing a tonally and spatially accurate musical image. The big question was, if the amp would be able to offer the same dexterity with the Shure Pro Masters connected instead of our EPI 500 loudspeakers. Having limited experience with PA speakers myself, I really had no idea what to expect next, but I was prepared to keep an open mind.

Our upstairs listening room was a little special in terms of dimensions. It was almost 13 meters deep, 10 meters wide, and over 4 meters high in its centre. There were no two walls running in parallel. With all this space available, it may come as a surprise that the only area reserved for listening was a unilateral triangle of about 2 meters in length with a thick piece of carpet laid out at its centre. Somehow the juxtaposition of short listening distance and the massive delay of the room made it relatively easy for the brain to filter out reflections from the music source. Hence, this was usually not a poor choice of venue for testing loudspeakers. However, when setting the Shure PA horn-loaded speakers in motion for the first time, I realised that listening at this short range would be a real challenge.

The horn’s design principle naturally caused high levels of compression at short range that could easily overstrain the ears. Luckily, some previous owner had added Visaton LC57 attenuators to dial back the horns. This worked quite well, indeed. I then started experimenting with the horns’ dispersion angles and adjusted them from formerly 120 to now 60 degrees. At short range, this made the treble sound less bloated and more musically effortless. It was possible that this observation would have been different at greater distance from the speakers or other room dimensions. To my utter surprise and delight, the Shures’ horn drivers did not only sound large and impressive but were also tonally sensitive and dimensionally accurate. The Pro Masters were capable of natural transients and even tonal nuance despite delivering the output to entertain an event.

A lot has been said (and written) on the discrepancy between the relatively small size of horns in relation to their 15-inch woofer companions, as found on many professional audio and domestic designs. This naturally takes us to the subject of bass performance. It seems that on PA loudspeakers, 15-inch drivers with rippled cone surrounds were used as 'midrange' chassis that were also capable of extending into the upper bass frequencies. This was a significant finding when it came to the expectations one might have towards such designs. Coming from domestic speakers, I would have suspected a 15-inch driver to act as a subwoofer that would only with great difficulty reach the higher crossover frequencies when coupling to the horn. However, listening to the Pro Masters perform, I quickly understood that I would have to dial down my expectations in terms of bass extension. 

The Shures played an excellent treble and even created a believable midrange, perhaps as one might expect from listening to a home concert, and yet bass was more hinted than it was fully executed. This was also the moment when I started to feel confined by my up-close listening position. I wanted to have a solid back wall behind me to more fully appreciate the slapping of the large cones. In order to find out more about the Shures’ tonal balance, I would need to give them an audition in our main listening room in which my listening distance was at five meters, with the back wall about 90cm behind me. To make this happen without getting in trouble with my wife for aesthetic reasons, some dedicated stands would need to be built first. I drew up a quick design and went to buy some wood and paint from a local DIY store. On my way home with my bundle of carpenter board and solid wood beams, another question came to mind: What made these horns sound so great, and what was the crossover design for the woofer?

Back at home, I decided to first open the speakers to find out what was inside. The large woofers were held in place by eight screws that were professionally countered from the inside by threaded drive-in nuts. This would make woofer replacements an easy task, and I could already see why. As it turned out, one of the woofers had a crack in the cone and had already been taped from the inside. The crack had hardly been visible from the outside, and I had a strong sensation that Michael the pensioner and loudspeaker collector from Marburg's Hinterland had in fact sold me a damaged loudspeaker without telling me about it. In my years in Hi-Fi, I have come to understand that there is a generation of people who have learned to twist the truth in any way they like, even to the point where they start to believe it themselves.

Luckily for me, the damage did not render the bass driver useless. With a fresh strip of black tape in place, the driver could still be trusted to perform for a number of years. And, to my surprise, I saw that the woofer was attached straight to the terminal without passing any kind of crossover. While this would leave it up to the driver's cone and its spider's mass and tension to reduce unwanted high frequencies, it also lessened the likelihood of phase issues, as long as the drivers were positioned correctly to begin with. I was strangely reminded of the Orbid Sound Pluto's (kit) design, which seemed to go by the same method, even though their much smaller bass drivers had great difficulty in losing the higher frequencies and therefore contributed to a squeaking midrange.

Following the inspection of the woofer (seemingly a 15" Eminence-type with the typical square magnet and three magnet screws), I unmounted the Shure's horn driver and noticed that a number of audiophile improvements of the crossover and mounting had been made in comparison to the original design. The capacitors had been replaced with modern audiophile foil caps. In addition, a variable Monacor DSP-1 resistor had been installed to protect the horn from damage in the event of unintentional power spikes. The horn was no longer screwed onto the cabinet's rear wall. It was instead placed on a wooden support with foam cushion. This would minimise some of the back wall resonances and prevent these from afflicting the horn's diaphragm.

Some prior owner had also attached self-adhesive bitumen mats to the interior walls; however, they had already become loose in many places and had begun to slide down the sides. I decided to take them out completely in order to once again reach that warm, vintage, cabinet sound of a resonating wooden box. If the original intension had been to reduce cabinet resonances, some simple internal struts would probably have done a better job anyway. I decided to hold on to the bitumen mats just in case I would change my mind upon hearing the speakers perform.

Building the stands for the Shures was a simple enough task. We started out from two 16mm carpenter boards that would form the bottom plates of the stands (32mm in thickness) and to this attached three 360mm beams of 80x55mm in strength in a triangular position. We then screwed the top plate onto the beams, again made from two sheets of 16mm carpenter board. I was hoping that this construction would allow for more freedom on the side of the speakers which would in turn result in a more pleasant tonal representation. Three spikes would isolate the stands towards the floor. And, on the side of the speakers, I would replace the four original plastic feet with three rubber cushions made for professional music gear. I had already noticed that three supporting points often produced a better defined coupling between materials and was therefore easier to execute than four spikes or cushions on which the weight distribution could be less than ideal.

When I set up the speakers in our main listening room just a few days later, I was actually feeling hopeful that the combination of greater listening distance and better stands would also lead to superior imaging, and that the boxy shape of the room would do well to accentuate bass response. To my surprise, however, the Shures did not sound any more bass-heavy than they had done before. Unless they were used for public address, where they would be called upon to transport vocals over a great distance, these speakers needed a subwoofer in order to capture all aspects of natural instruments. My next task would be to find a sensible sub to pair with the speakers, and thus I found myself crawling even deeper down the rabbit hole. In order not to get lost on the way, I decided to see an expert on professional audio solutions, hoping that he would aid me with my difficulties.

As I found out from running a few web searches, there was an audio enthusiast by the name of Rainer Weimann who operated a part-time sales office southeast of Darmstadt in which he sold affordable audio gear to small-time local musicians, entertainers, and organisers of events. Over the years, he had established a reputation as distributer for the Chinese brand Dragon Audio. Founded in Shenzhen in 2004, Dragon Audio had grown into a major OEM producer of audio gear with over 1,400 staff working in 14 factories. I was specifically interested in an active Hi-Fi subwoofer made by DA that Rainer had listed on an auction site. The other product I had seen on sale in Reiner's shop was an active 15-inch Vonyx PA subwoofer. Vonyx was another audio company that had made a name for itself serving the lower end of the market. Ideally, it would be possible for me to listen to the two subs in direct comparison.

Upon arriving at 'ProSchall', as Rainer's shop had been named, I was given a warm welcome and invited inside. I immediately recognised some of the products I had seen offered online. The two subwoofers were standing side by side, right next to some even larger specimen. Rainer explained that the 15-inch Vonyx PA subwoofer was designed to power public venues and would sound best when driven at high levels of sound pressure. It had a rigid suspension that could handle high volume music program but would sound flat and overly dry when played at living room volume. The Dragon Audio woofer, on the other hand, had been designed to be played in a household environment. It had a softer suspension that would allow the driver to operate accurately even when played at low volume.

Seeing that I was not yet fully convinced, he quickly connected the 12-inch DA woofer for me. The sound it produced was instantly familiar from listening to Hi-Fi gear. I could imagine that this would play well with many types of speakers. Rainer then connected the 15-inch Vonyx woofer, and immediately the room sounded too small for the hard and dry bass of the woofer. The music could be physically felt in the room more than it could be heard, and it was easily conceivable that the neighbours would derive greater benefits from the output of this woofer than we could in the listening room. It was at that moment that I could quite literally feel the difference between Hi-Fi and PA speakers. Either of them would perform like a fish out of water if it was employed outside of its intended venue. I thanked Reiner for the wonderful experience and, with a deeper understanding of the matter (and one Dragon Audio subwoofer called 'The Art of Sound' in the trunk), I made my journey back to Frankfurt.

From Reiner, I had also learned that professionals often preferred to have the vocal section separate from the bass drivers, because this would reduce the load on the amplifiers, decrease the likelihood of damage to the delicate top-end, and allow for the perfect number of bass drivers in relation to the size and sonic characteristics of the venue. This made sense of course, considering how long it took me to integrate simple 3-way speaker systems in our listening rooms. PA speakers could be used for a whole range of venues, from outside gigs on which massive amounts of bass were needed, to boxed-in basements in which low frequency waves were accumulated from being reflected back from the walls. In our living room, the 12-inch DA woofer turned out to be more than sufficient for filling in the Shures' missing bass. For the first time, the tonal balance was as one would expect from speakers of this size. As you might imagine, the following movie night turned out to be a real treat for the whole family, with the Pro Masters effortlessly rising to breath-taking volume at an instant and the subwoofer giving the sound effects their palpable bass dimension.

< Watts, Sound Pressure, Decibels | Shure 701 in Public Application >

Specifications

• Type: full-range public address speaker
• Principle: 2-way, front-ported bass reflex
• High frequency section: radial horn driver
• Low frequency section: dynamic 15-inch woofer
• Special features: 60° / 120° adjustable horn
• Power handling: 150 watts RMS / 55V peak
• Sound pressure level: 102 dB (at 1W / 1m)
• Frequency response: 50 Hz to 15,000 Hz
• Crossover frequency: 2,000 Hz, 18dB
• Nominal impedance: 8 Ohms
• Horizontal sound distribution: 60° or 120°
• Vertical sound distribution: 90°
• Operating temperature: -7°C to 43°C
• Cabinet: 15.9 mm multiply wood, vinyl coated
• Original weight: 26,4 kg per speaker
• Dimensions: (H) 700mm; (W) 585mm; (D) 405 mm
• Country of manufacture: USA
• Year: 1979

Updates

• Terminals for bananas and spades
• Visaton horn volume attenuator
• Audiophile horn crossover
• Monacor DSP-1 resistor

I first heard Peter Snell’s C IV loudspeakers perform in the dining room of a Wiesbaden townhouse and was instantly taken in by the realism with which the club atmosphere of Christian McBride’s album “Live at the Village Vanguard” was recreated. The spacious room boasted a ceiling height of nearly 5 meters and was sparsely furnished, with a massive dining table and chairs dominating its centre. The speakers were positioned far away from the walls, approximately two meters from the front wall and 1.5 meters from each side. They were driven with a Dynaco ST70 tube amplifier. Everything in their sound—stage depth, width, resonances—suggested that we were were listening to the actual event, rather than a recording of it. I could literally smell the scent of stale beer and cold cigarettes.

I learned two things that day: The ultimate goal of HiFi does not lie in deeper bass or higher treble, nor in clearer sound or greater dynamics, but rather in the sum of all parts to recreate the authentic event. And second: The room and positioning of the loudspeakers play a major role in making the illusion of a performance become reality. And once we have heard it, once that vision has been installed in our minds, it is very difficult to listen to anything less. Most newbies in HiFi have been taught to dissect music rather than achieve homogeneity. Data, rather than feeling, is the message conveyed by the audio press. Hence, new arrivals to the HiFi scene will look for the right specs on their gear rather than make sure to get the right sound. One can spend a lifetime in HiFi and still have very little clue of what it is actually about.

It is probably fair to say that the Dynaco ST70 tube amplifier played a major role in the recreation of the authentic event. Neither the wattage of this amplifier nor its channel separation, damping factor, signal to noise ratio, etc. indicate the amount of realism this amplifier is capable of. Hence, it is no surprise that, in a world run on facts and figures, it took me close to 50 years and some repeated nudging from fellow audiophiles to finally be able to listen to and comprehend the merits of a performance that deserves the term ‘high fidelity’, i.e. as close to the original as possible. That day, “Live at the Village Vanguard” really felt live. It prompted me to purchase the vinyl record and write a review on it. And it also got me interested in the C IV speakers.

Snell Acoustics was founded in Haverhill Massachusetts in 1976, and the company soon made a name for itself selling audiophile loudspeakers at reasonable prices. After sales service was exceptional, as Peter Snell was a perfectionist and made sure that each of his speakers measured to spec with deviations below 0.5dB per chassis. The same was true of all the replacement parts the company sent out, often many years after the original date of purchase. Audiophiles constitute a small and intimate circle, and especially bang for buck producers often benefit from word of mouth and manage to build up longstanding relations with their thankful customers.

Launched in 1983, the Type C series was among the last loudspeakers actually designed by the company founder himself. Peter Snell died from a heart attack in his factory in the following year. Despite the absence of its original owner, the company continued to evolve and, in 1990, joined forces with Lucasfilm to design its first line of THX loudspeakers. In 2003, the by then renowned Joe D'Appolito joined Snell as chief engineer. In 2005, Snell and Boston Acoustics were purchased by D&M Holdings—which also owned Denon, Marantz, and McIntosh—and Snell would continue to build loudspeakers until 2010. Throughout its existence, the loudspeaker manufacturer stood for great customer service, tonally accurate acoustic designs, and great attention to technical detail.

The Type C IV series are said to have been heavily influenced by the methods and measuring philosophies of the National Research Council (NRC) based in Ottawa, Canada. Typical characteristics of speakers developed in conjunction with the NRC are steep crossover slopes, wide dispersion, smooth off-axis response, and special focus on a speaker’s interaction with natural listening rooms. The C IV has fourth-order crossover slopes, a very flat frequency response that varies very little off-axis. A rear tweeter was added to compensate for the front tweeter’s increasingly narrow beam at high frequencies. It can be turned off with a toggle switch to accommodate smaller listening rooms. The C IV boasts what the company called a “Zero Diffraction” grille. The idea was to wrap the removable grille’s wooden frame around the speaker front in order to minimise the distance between cloth and divers and decrease diffraction.

The additional tweeter at the rear comes in at around 6kHz with a first-order slope. It contributes to the front tweeter’s energy and helps to create a stage impression that is both wide and deep. Depending on the distance to and material of the front wall, the additional tweeter can cause some harshness. To turn the speakers to the room, the C IV’s front tweeter can be regulated. Alternatively, a switch at the back allows us to turn the rear tweeter off completely. To make full use of the C IV’s abilities, it should be placed in a large room with approximately 1,20m distance to the front wall and some distance to the sides. Set up in this way, the rear tweeter supports the illusion of the music breaking free from the source with the speakers themselves becoming invisible. Toe-in helps to correct the stage impression. I must confess that, given the peculiar shape of our room, I did find it difficult to get the stage as perfect as I had heard the speakers capable of in the Wiesbaden townhouse, but I can say that I came quite close.

With the rear tweeter switched on and the right distance to the walls, the C IV created a broad and open stage. And with the grille cloth in place, they produced a pleasantly soft treble, even at short range. For those sitting at a distance of 3 meters or more from the speakers, there is some treble fall-off, and listening without the cloth might be preferable. Despite Snell’s “Zero Diffraction” promise, the difference between open and closed operation is quite audible. In our listening room, the C IV produced an open and spacious top end and a natural and fully integrated bass. The speakers sounded tonally accurate and presented the music nice and full with great timbre on the lower piano keys. There was sufficient presence of the higher piano keys as well, however, in direct comparison they were missing some of the attack of our electrostatic speakers or even our more recent Tannoys. Male vocals sounded natural with a slight tendency of thinning when the rear tweeter was switched on (e.g. Nick Cave). Female vocals showed much of the same effect (Nora Jones, Come Away with Me), especially when playing music from digital sources.

Also see: Snell Acoustics Type C IV Audio Demo

The Snells showed convincing overall dynamics and, due to their large bass driver and ported design, they were capable of swelling in volume quickly. When set at 75dB volume, my wife reported that she felt quite overwhelmed by the music and that she would have preferred to sit farther away from the speakers. It was the first time that I had heard her comment on loudspeaker in this way. I would think that the effect was caused by a combination of the sonic impression and the speaker’s design. Standing far into the room, nearly 120cm tall and 40cm wide, with their black grille cloth in place, the physical image alone was quite intense, indeed.

Specifications:

• Type: Four-driver dynamic loudspeaker
• Drivers: 10" woofer; 5” midrange; 1” front tweeter; ¾” rear tweeter
• Crossover frequencies: 275Hz; 2.7kHz (@24dB/octave)
• Nominal impedance: 8 Ohms
• Sensitivity: 88.5dB
• Dimensions: 37cm (W); 117cm (H); 30cm (D)
• Weight: 39kg
• Year: 1983-1991

My explorations into the TEAC LS H255-MA bookshelf speakers was purely coincidental. A friend of ours had left them at our house having heard about my interest in audio gear. Puzzled about how to put them to good use, I decided to pass them on to a work colleague of mine who was looking into setting up his own system. The thought of passing them on came easy to me, as I had never considered them to be candidates for an audiophile listening session. When they had first arrived at our house, I had done some quick research and found out that they had originally been sold with TEAC’s CR-H240 DAB compact-HiFi system, which was known for decent entry-level performance. I could not find any indication of the H255s having being sold separately — usually not an indication of serious speakers.

The CR-H240 DAB was a combined unit with a CD drive and radio unit built into a single compact receiver. The trouble with such all-in-ones, especially at this price point, was that many concessions to sound quality had to be made on multiple levels: from the vibrations of the CD drive to the performance of the DAC, from the circuit board layout and the single power supply, right to the smallish amplifier to power the loudspeakers. In such a scenario, even the best of speakers would perform poorly and — consequently — only low-cost choices could be made in terms of speaker design. And yet, the H225s offered a robust front plate of low-resonance materials, a real wooden cabinet (made and assembled in China), a relatively large for their size 2.5 cm soft-dome tweeter, and what looked like a kevlar midrange/bass driver. After some tweaking, the sturdy screw-down binding posts on their backs were even able to take hollow banana plugs or large spades, just as one would find on far more pricy designs.

A knock on the cabinet revealed that this was still capable of some warm and woody sounding resonances, similar to the body of a guitar. That the H225s were rear-ported only highlighted this quality and made me wonder, if this type of cabinet was going to be an asset or a liability to them. Most modern manufacturers try to eliminate all cabinet resonances through MDF or HDF and strong inner bracing. Either way, nothing about the chosen materials gave away that these speakers had been carelessly designed. I therefore decided that I would hook them up to our upstairs system, which I had just fitted with an all-new Audioplan PowerCord S to very good results. I wanted my colleague to listen to the speakers perform at their best, before handing them over to him, and, quite naturally, I was also curious of what would become of my own mixed impression of the H225s.

They almost had to fall behind when compared with our speaker legends from the past, such as ATD’s Pata Acustica or the Tannoy XT8F towers. The only questions was: How much exactly? I was half expecting to have a good laugh at their miserable performance. But, we can never be sure of the performance of HiFi equipment, unless we have auditioned it ourselves and witnessed it play our favourite tunes with our own ears. In my test setup, the H225s were running on Belden 9497 cables and hooked up to our Hafler XL280 power amplifier. This in turn was powered by our Dynaco PAS-4 tube preamp fed through Audioplan’s PowerCord S. All interconnects used were of the solid-core silver type. The Audioplan cord had recently brought a sense of dimension and urgency to our system that proved to be a priceless upgrade from what we previously heard. I was therefore looking forward to learning how much of this quality would remain.

I tested the H225s with three CD albums: Diana Krall’s “Turn up the quiet”, Jörg Hegemann’s “Foot Tappin’ Boogie”, and Helge Lien’s “10”. All three albums offer outstanding recordings throughout, with excellent timbre, rhythm, and dynamics. I began with Helge Lien’s album and was surprised by the width, depth, and dimension that the H225s were capable of. Placed on our homemade MDF stands and cushioned on felt pads at about 60cm from the front wall, they immediately sounded much larger than their actual size. There was bass in abundance, much more than I had heard on the closed Pata Acustica. On the H225s the bass lines were not as well-contoured, of course. And yet, bass seemed natural and blended in well with the music. Metallic sounds from the drum-set were presented in a real and life-like fashion. Instrument separation and stage depth were still in tact, more so than on the Pata, showing the effects of the Audioplan cord even through these entry-level speakers.

On Diana Krall’s album, the impression of natural instrument colours and space remained largely the same. However, the concessions to price and size did shine through in the critical midrange discipline of female vocals. Diana’s voice was not fully in balance showing a bit of crisp harshness around the top-end that would take a little getting used to, especially coming from a more pricy system. Sibilants were a bit forceful and the natural timbre suffered a bit. Once again, I was taken in by the sense of dimension and presence that these smallish bookshelves were capable of. Just to think that these were all beautiful traits that the H225s had never received credit for, simply because their usual play friends were unable to highlight or even grasp their full potential. It was the sad old tale of a huge talent hanging out with the wrong crowd.

The TEAC LS H255-MA are solid entry-level speakers that will perform at near audiophile level when driven with powerful and precise electronics. As rear-ported speakers, they will need space to breathe and will sound convincing when placed on stands with their front plate at a minimum of 50cm distance from the front wall. The TEAC engineers deserve some credit for outperforming any Sonos and similar convenience products by a long stretch, if given proper amplification and source signal. To my colleague, I recommended that he should purchase a nice tube amp for them, as this would continue to make them sound large with great flow and musicality.

And this brings me to perhaps the most important lesson to be learnt from the H255s: the role of the source in the equation that is called music. From now on, whenever there is a debate on what is more important - the source or the speakers - my answer will be: “The source!” After all, many of today’s speakers are able to follow the source signal quite faithfully, often making differences in performance secondary and a matter of personal taste. It has often been stated that speakers cannot play correctly what the source gets wrong in the first place, and, listening to the TEACs perform on our system, has made this clearer to me than ever before.

TEAC Company History

The Japanese company that became known as TEAC had two original sources with separate founding dates: First, there was the Tokyo Television Acoustic Company, founded in August 1953 and, second, the Tokyo Electro-Acoustic Company, which was founded in 1956 and provided its name following the merger. TEAC is also the story of two brothers: Katsuma Tani, who was an engineer in aviation and aeronautics and employed by the first company, and Tomoma Tani who joined his brother in the creation of the second company in an effort to improve reel-to-reel and cassette recorders. Both brothers' ingenuity helped the company to establish a solid reputation for HighEnd reel-to-reels, cassette decks, turntables, and CD players during the 1970s and 80s. In 2013, Gibson took over the company but was forced to sell again during its bankruptcy in 2018. The TEAC company has continued to manufacture products in three categories: computer peripheral devices, professional audio products (with their brands TEAC and TASCAM), and information products that are used for in-flight entertainment, monitoring, etc.

Also see: TEAC LS-H255-MA audio demo

Specifications

• Speaker type: 2-way, rear-ported
• Frequency response: 60 Hz—22,000 kHz
• Power handling: 50 W RMS
• Impedance: 6 Ω
• Sensitivity: 86 dB
• Mid-range / Bass driver: 1x 130 mm meshed cone
• Tweeter: 1x 25 mm, soft-dome
• Finish: maple
• Dimensions: 170 x 270 x 235 mm
• Weight: 3.7 kg
• Year: 2007

It may not be immediately obvious from looking at the photos, but I had to think long and hard about how and if to present loudspeakers on this platform. For one thing, loudspeakers are vertical objects, whereas I have made a point in maintaining a 16:9 horizontal picture format in my presentations. Secondly, it was clear from the start that I would not be able to offer a look inside the speakers, for the simple reason that this might cause damage to the cabinet or drivers and thereby lower the resale value – a significant consideration, if I want to continue our Explorations in Audio on a reasonable budget. And, lastly, loudspeaker performance depends to a great extent on the environment in which the speakers are placed.

I finally decided that, due to the significant role speakers play in our systems, I would double-layer my photos based on the current listening environment that the speakers are in and to fade out the room features. My intention in doing so was to lessen the prominence of the room and to thereby give you the opportunity of imagining the same speakers placed in your own environment. The advantage is that you see the speakers at the toe-in angle and distance that is most realistic to real life.

Tannoy was founded by Guy Fountain as the Tulsemere Manufacturing Company in England in 1926 and ranks among the oldest manufacturers of loudspeakers in the world. The name is an abbreviation of ‘tantalum alloy’ a material that was used in electrolytic rectifiers that were developed by the company. The Tannoy trademark was registered in 1932. With its original headquarters in London, Tannoy soon became famous as a manufacturer of public address speakers and professional speakers for the military in World War II. Since the name was shown in bold letters on the speaker grills and thereby frequently visible to the general public, to ‘Tannoy’ an event became synonymous with providing amplification for it. In fact, older Englishmen can still be heard referring to public address systems as Tannoys, despite the fact that, more often than not, these systems today come from a wide range of manufacturers.

Following economic pressures, Tannoy moved to Coatbridge, Scotland in the 1970s, where it has remained. Today, the company belongs to the Uli Behringer MUSIC Group, that has pledged to preserve the brand and to keep the Scottish location. In recent years, with mainstream buyers turning away from High Fidelity for the sake of cheap USB & wireless gadgets, Tannoy has been struggling to keep their foothold. Tannoy did not invent coaxial driver designs, but they certainly were among the pioneers of this technology. The Tannoy signature Dual Concentric driver was invented in 1948. It boasted a design in which the tweeter was set deeply inside the center of the woofer. The on-axis position had the advantage of improved time and phase alignment and was originally intended for microphone measurements. The original pair ended up being used in Decca’s FFRR studios, and then EMI ordered some for Abbey Road (source: whathifi.com), a studio made famous by The Beatles, among others. Form there it was only a short way to stardom.

The Tannoy DC6t of 2010 comes in a slender modern design with an excellent wood finish. Despite its trapezoid shape, the overall impression is still that of a box, even if it is a relatively pretty one at that. For added stability, Tannoy has mounted the cabinets on an additional and wider floor plate. This is quite effective and has allowed me to place felt pads under the spike coasters without the speaker becoming too rocky. Connection is made via bi-wiring terminals which are quite solid and conveniently located close to the floor. A bit unusual perhaps is the polarity arrangement, with the two positive and the two negative posts being located next to each other on a horizontal line.

The tweeter has a titanium dome, and, like all hard surfaces, this can be rather unforgiving if something is not quite right. Clean energy is therefore of utmost importance to this type of speaker. An additional woofer is positioned directly underneath the 6-inch Dual Concentric driver, and the speaker does have an intensional three dB increase in bass response. The cabinet is rear ported but can be placed relatively close to the front wall of the room despite of this. The sound is very precise and the stage is both wide and deep. Instruments reach deep into the room and piano has just the right timbre and attack to be realistic.

On the 35 watts HK730 the speakers performed very well, however, only the 60 watts Citation provides the necessary boost for piano to attack. Since the DC6t are 8 ohms speakers, the amplifier power will be exactly as presented. The speakers are ideal for small to medium sized living rooms and will survive an occasional party. 6-inch woofers have their limits of course, especially when it comes to fullness of sound and punch. If you have the room and budget for it, I would suggest that you try the next larger versions DC8 and DC10.

Specifications

• Cabinet design: floor-standing, ported
• Drivers: 1x 1-inch titanium dome tweeter, 1x 6-inch paper cone midrange (dual-concentric, 1x 6″ paper cone woofer
• Freq. response: 34 Hz – 35 kHz, – 6 dB
• Nominal impedance: 8 Ohms
• Sensitivity: 89 dB
• Crossover Frequency: 1.7 kHz
• Power handling: 87 watts RMS
• Dimensions: 950 x 226 x 225mm
• Weight: 14.9 kg (each)
• Year 2010

My original intention was to sell off a pair of speakers and not so much to purchase a new one. But when a caller expressed interest in my pair of KEF iQ30 bookshelves, somehow I could not help but enquire more deeply about the reason for his interest. It turned out he had a small listening room, and that his current speakers were simply too large for the job. To my surprise, these were of the exact brand and model that I had been running a web search on for some time. We consequently agreed that he would bring his current speakers along when auditioning mine. What a strange coincidence that was.

To replace our KEF iQ30 bookshelves, I had originally purchased a slim pair of Tannoy DC6t floor-standing speakers. And, although these sounded fuller, I could not rid myself of the sensation that they, too, were lacking the muscle to fill our 70 sqm office with music. While being articulate and pleasant in their presentation, their performance mostly inhabited the space right up to the listening position (at about one-fourth of the room’s depth), rather than filling it completely. Granted, the pair of Tannoy DC6t was better suited than the KEFs for this location, but it still seemed a little light on the bass, not terribly underperforming, but not impressive either.

Replacing the DT6t with even larger speakers was not going to be easy. The trouble is, when your listening space is a sleek and modern office, this does set some limits to the possible speaker choices in terms of colours, shapes, and sizes. And since the DC6t had already been approved by the other household dwellers, I tentatively set up a web search on the next larger (and more recent) model, the Tannoy XT8f. Hence my excitement when I heard over the telephone that there now was a pair of XT8f on offer — and that this was even going to be brought to our house, instead of us having to take the trip.

As you might imagine, our double-interest in each other’s speakers created a strange scenario, in which either side had something to gain and something to lose. I could see that it would be a challenge for us not to let this get in the way of enjoyment. Upon his arrival, I helped our guest by carrying up one of his Tannoy XT8f speakers, and I immediately noticed how large and heavy they were in comparison to our present DC6t. Although they were only wrapped in thin blankets and not stuck in bulky boxes, I had to take especially good care not to scrape them along the inner walls or banister of our stairwell.

Since the original reason for his visit had been the KEF iQ30s, we decided that they should be auditioned first. I had them hooked up to our DB Systems DB1 + B&K ST140 system in our main listening room. We had a choice of vinyl, CD, as well as the possibility of streaming via Amazon Music available, but we ended up only playing CDs, some of which he had brought along as his reference. It is always fun to listen to other people’s music, and so I simply sat and listened to new sounds or enjoyed playing some of my own. The KEFs do play well in our main listening room, and there were moments in which I forgot the original purpose of our meeting and was simply taking in the music.

Without a final decision on whether he would purchase my KEFs, we proceeded to our office upstairs. Here, our Tannoy DC6Ts were still connected to the Restek V1 + Hafler XL280 combo. With everything perfectly set up from hours of listening, I asked him to sit down and listen to these first. I know how our system sounds, so I simply stood aside and let the music play. My impression was that he enjoyed what he was hearing, however, the second purpose for his coming to Frankfurt was for me to decide whether I was interested in the larger Tannoys that he had brought for me. We therefore quickly took the protective blankets off and connected the XT8Fs to our system.

My first impression was that the sound was muddled and massive, resonating far too chaotically in the large office space. Would I be able to make them blend in with the room, and what was it worth to me to find this out? After all, where the DC6T had been articulate and refined, the larger speakers now seemed disorganised and colossal. However, since this forum is called ‘Explorations in Audio’, you can probably guess my final decision, although it was not one that resulted from a positive first impression. That they already had some bumps and bruises on the finish only contributed to this sensation. What consoled me was the fact that the whole room was energised by these new speakers. And this was the one thing the smaller Tannoys had been missing. We both made our respective purchases, content with each other’s offers, and the buyer went on his way.

I have learned not to judge new gear arrivals too quickly. Some of the best devices I have ever owned, have taken me weeks, if not months to set up well. New speakers can be tricky in this way, because many factors come into play: distance to the front and side walls, width of placement and toe in angle, listening position, and system matching, to mention just a few. These factors are hardly solved within a day’s work, as even one centimetre difference will have a pronounced effect on the speaker’s ability to perform. While this is true for all speakers, larger speakers tend to be more difficult to place, especially when taking interior design considerations into account.

Given some time to experiment, I came up with a placement that allowed me to keep my accustomed listening position at about one-fourth of the room’s depth with only minor adjustments. The XT8F are positioned about 20cm further away from the front wall than the DC6T had been, and my listening position had to be moved 10cm back. This way, the toe-in could remain unchanged with both speakers directed just past my ears instead of straight at them. This has a positive effect on sound stage and reigns in the highs which are a bit overly pronounced when played on axis. During the placement I listened to Bruce Springsteen’s Song "Tougher than the Rest" from his live on-Broadway performance. This way I could be sure that there was a real stage to be recreated. In fact, I listened to it so many times in an endless loop, I have been humming it ever since.

The XT8f have a full and rich sound, in comparison with the DC6t, but also more generally speaking. At close distance, the sensation is one of bathing in music. There is plenty of good quality bass, and due to their 91dB performance at just one watt, they play loud with ease. Although they look chunky and provide plenty of tonal depth, they play voices intimately, as if listening to a cozy living room performance. This contrast of mighty roar and delicacy is highly addictive to my ears. Due to their concentric construction, the XT8f are very exact when it comes to locating instruments. Perhaps not quite as exact as the DC6t but still industry-leading at this price level. If the DC6t sounded as though one was taking part in a studio session, the XT8f invite you to the jazz club. Both speakers are insightful enough to be entertaining at all times, but if the room is right, the eights appear just a bit more rounded, especially towards the lower end. I now understand that in a smaller room this much bass can be overwhelming.

Also see: Tannoy XT8f Audio Demo

When the music is subtle, the XT8f will play this with delicacy and insightful detail, and when the orchestra swells, their excellent dynamics generated from a 50 litre corpus with down-firing bass port will thrust forward with a vengeance. I could not detect any compression when going loud, which is new to me and wonderfully pleasing. It quickly became clear that this is a completely different beast. Those who purchase the XT8f hoping for an upgrade to their DC6t might be disappointed that their room is simply too small of a playing companion. But those who have ended up with the DC6t in error, like myself, have a real chance of being very happy.

Specifications:

• Cabinet design: floor-standing, ported (down-fire)
• Drivers: 1x 1-inch titanium dome tweeter, 1x 8-inch paper cone midrange (dual-concentric), 1x 6″ paper cone woofer
• Frequency response: 34 Hz - 32 kHz, -6 dB
• Nominal impedance: 8 ohms
• Sensitivity: 91 dB
• Crossover frequencies: 250 Hz & 1.8 kHz
• Power handling: 100 watts RMS
• Dimensions: 1080 x 317 x 345mm
• Year 2016

In November 2022, I tested a pair of Duevel Planets loudspeakers. They were of omnidirectional design and surprised me with tonal accuracy and excellent stage imaging. When their owner, Alexi, shared my test with his audiophile friend at work, Michael wondered if I might be interested in testing yet another German HiFi legend, namely, the first loudspeakers ever sold by the German loudspeaker manufacturer Teufel. Since I only knew the Teufel brand from the mid-Fi gear sold in department stores, I was a little sceptical at first. However, this changed when Michael sent me a German HiFi Vision magazine test from August 1988, in which the small Teufels were put up against massive floor-standing speakers from HiFi royalty: Cabasse (model: Brigantin VI), MB Quart (3200 S), and Pilot (Concorde MK IV). It may have helped the test a little that the M200 were played in conjunction with their 56 kilos M6000 compound-bass module. On the other hand, reaching top scores among these speaker manufacturers was more than impressive for a newcomer.

Founded by Peter Tschimmel in 1979, the Berlin-based Teufel had established a name for itself as speaker kit manufacturer, offering selected combinations of crossovers, drivers, and cabinets to its customers. The M200 Basic Module and M6000 Bass Module were the first ready-to-play loudspeakers by the young company. In them, Peter Tschimmel combined the best of what he understood about crossovers with top-of-the-line driver technology. Tschimmel knew that phase alignment and natural tonality were key criteria to be addressed in loudspeaker manufacturing. He was a relative pioneer with his idea of keeping the subwoofer separate from the Basic Module to allow for easier placement of all units in the living space. The M6000 subwoofer itself sacrificed some of its sensitivity to a new compound design that positioned one channel’s bass driver behind that of the other channel to create a pneumatic buffer between them which served to cut the output frequency in half. Due to this effect, the M6000 naturally cut in just under the rated 50 Hz drop-off frequency of the M200 Basic Module, thus extending its range down to 20 Hz.

The M200 were cleverly constructed, reducing cabinet resonances through internal bracing and still not suffocating the sound by using MDF all around. While the front plate was made of MDF, the rest of the cabinet was constructed with 22mm chipboard in support of natural tonality. The midrange-bass and sub-bass drivers were made of paper by the German components specialist Isophon which had not too long before been taken over by Bosch/Blaupunkt. Isophon was among the most innovative speaker driver manufacturers of its time, and the M200 / M6000 chassis still have a good reputation in the HiFi industry. Tschimmel's understanding of crossovers was excellent, and the M200 showed some welcome features for serious bookshelf speakers of the time: 1. proper binding posts that were able to take bananas or spades, 2. a single diameter of allen key screws to fasten all driver chassis as well as the grille, and proper loudspeaker stands to support the Teufel's High-End claim, especially to those customers who were willing to look for and experiment with the ideal room placement. 

The frameless speaker grilles were made of rigid perforated sheet metal and allowed for ultra-wide dispersion. Depending on one’s listening tastes, one might find that the speakers sounded better with the grilles taken off. The act of taking the grilles off, however, could be a little tricky because of the four spacer sleeves keeping the grille from touching the speaker front. One had to be careful not to loose them while the grilles were removed and stowed away. After all, the spacer sleeves were made of simple black plastic and, especially when found out of context by some other member of the household, did not look like anything worth keeping. 

When Michael and I first set up the M200 Basic Module in my listening space, I was a little confused by the fact that the familiar stage impression of a singer in the middle and the instruments placed around did not want to materialise. Instead, it sounded as if there were two singers simultaneously singing the same song. Inverting the polarity of one channel changed the impression only slightly. It was not until Michael had gone home that I opened both speakers to have a look inside. While one of them looked to be in original condition, the other seemed to have been repaired along the centric spider. The polarity had been handwritten on the magnets by Tuned Systems in Frankfurt am Main. In doing so, the service technician seemed to have confused the poles, and, since they had been given only one of the two speakers for repair, had been unable to notice their error.

I corrected the polarity and found that the sound stage had much improved. When I called Michael to tell him about my findings, he remembered the story of the repair, and we both laughed at the improbability of such a mishap from a professional speaker repair service. And, as Michael had only been running the speakers as rear channels on his surround system following their return, he had never had the chance to notice the inversion, believing that the resulting sound was part of the rear channel effects. Needless to say, the polarity inversion of one midrange-bass cone had contributed to an elimination of bass frequencies and an over-representation of treble, a fact that would have remained hidden on most surround systems that use an additional subwoofer for this job and cut low frequency output on the rear speakers.

I first hooked up the M200 Basic Module speakers to our upstairs system that consisted of a CD source, DAC, solid-state preamplifier and a tube power amplifier (see details below). The Teufel 2-way bookshelves had been given to me for testing without the M6000 subwoofer, which was deemed too heavy for transport and not worth the hassle. In fact, the original HiFi Vision testers of the Teufel system had come to the conclusion that the Basic Modules alone did a splendid job, even when playing without the bass. I did, however, receive the original Teufel stands, which should have been well-matched with the properties of the speakers. My first impression was that the stands looked a little frail to properly support loudspeakers of 14 kg with strong bass drivers. Their center column only consisted of four sheets of MDF with bent metal grilles between them on front and rear that would also act as cable duct for the speaker cables.

Resonances from the speakers could be felt along the front grille and all the way down the shaft of the stands, even when the speakers were playing at moderate volume. Michael had placed four thin rubber pads under the stands which I would have preferred to replace with spikes and coasters. I did, however, notice that the M200 could all too easily sound light and analytical if proper coupling towards the ground was not assured. Placing the M200 on our own DIY-MDF stands did not produce a desirable result, which was most likely due to the felt pads that I had placed on top if the stands. The M200 surfaces were a little too slippery to be fully stabilised by felt. Michael had installed rubber pads on top of his original stands which worked better in this position. Yet, somehow, I could not shake the feeling that improved stands and coupling towards the ground would also have produced better-sounding speakers.

The M200 were of a closed cabinet design and needed to be placed relatively close to the front wall of the listening room to assure natural tonality (without the aid of a subwoofer). When I started out in the original position of our EPI 500 speakers, the M200 sounded too airy. Moving them closer to the wall improved the bass foundation. I ended up sufficiently happy with the drivers being 70 cm from the front wall, forming an equilateral triangle of 200cm with the listening position. Although moderately rated at 87 dB, these speakers had the ability to easily entertain a large room. Measuring 9 x 11 meters, our upstairs listening room was such a large space, and the M200 sounded controlled and present in the whole room and even in the adjacent rooms downstairs. I have always been able to judge the quality of a system from outside the listening room and have presented many examples of this phenomenon in my articles. The M200 were yet another case in point, by making music sound similar to a live event when I was not in the same room with them.

Having critically listened to loudspeakers for some years, I had come to prefer Vocal Jazz for basic analysis. The human voice was an important component of music, and speakers that excelled in this discipline were usually instant favourites in audiophile circles, even if other categories were not as convincing. The M200 rendered vocals faithfully, albeit with a touch of Teutonic soberness that, at times, bordered on analytical. The Teufels were able to present a wealth of acoustic information, if soundtrack and speaker alignment permitted. However, I never had the impression that this was at the cost of musical cohesion. Whilst painting in slightly cooler tones than our Epicure speakers, the music still seemed sufficiently rich in colour.

The Teufels depicted drums and brass sounds in natural colours. When it came to double bass and string instruments, I preferred the subtler, slightly less frontal sound of our Epicure and Martin Logan speakers. Listening to live music worked great with the M200. In faster passages they could show the agility of the paper cone within a closed box. Bass was try and punchy where the music required it. Some passages would have benefitted from the Bass Module for improved realism. However, in this respect, the Teufels did not really lack in terms of bookshelf speakers. In fact, they did not sound much like bookshelves at all. With my eyes closed, I would have imagined them to be much larger and more complex. It was a real surprise to have this much vigor coming out of a relatively small speaker system.

To my ears, the M200 sounded better at greater distance than at close range. The treble appeared to be most natural with the tweeter axis directed to a spot at about 1/3 past the listener’s head. The M200 did not benefit from parallel placement with the room’s front walls and, in my setup, sounded most balanced at a slight toe-in. In terms of soundstage, I found the Teufels to play wider than I was used to from our previous speakers. While this might speak for exceptional channel separation from our system in the eyes and ears of some listeners, I was a little concerned about the obvious lack of stage depth. Although I moved the speakers around the room to try different positions, I was not able to eliminate this phenomenon. At times, the singer seemed to trail off to either side, as if there was some unforeseen bending of phase involved.

I did not listen to the speakers without the metal grilles in place, and it was possible that the lack of stage depth was somehow caused by the grilles interacting with the direct sound waves from the drivers. It was also possible that the plastic tweeter refractor ring interacted unfavourably with the tweeter’s direct energy, or that the resulting time-smear was a result of both. As the tweeters were ferro-fluid cooled, hardened ferro-fluid could have been blocking the propagation of the dome in some undesirable way. And, finally, it was possible that the stands themselves would have required better support in order for the speakers to remain still.

I decided to test the Teufels in other combinations and will report here. Michael suggested that I try a beafy solid-state amplifier with them, instead of our 2x 40 watts tube amp. Well, we shall see...

Test system (1): Marantz CD-17 CD-Player via HiViLux Reference SP/DIF cable on Cambridge DAC Magic 100 via HBS Silver Solid-Core Interconnect on Restek V1 preamplifier via HBS Silver Solid-Core Interconnect on Dynavox VR-70 tube power amplifier via Belden 9497 speaker cables in single-wiring on the loudspeakers.

My second upstairs system consisted of similar components as the first, using a CD player as source and feeding into a pre and power amplifier combination. Only, this time around, the individual units, as well as their interconnects, were of a more basic quality. In fact, the power amplifier was the only exception in the line-up, having been especially designed for eiaudio and the purpose of audiophile listening. It offered excellent signal damping, had low-Ohms capabilities, and was able to churn out 150 transistor watts per channel into 8 Ohm loads on the basis of a 500 VA power supply. I was eager to find out how changing the electronic and physical environment would affect the M200's musical performance.

Both the Rotel preamplifier and the speaker cables were more forgiving components, which worked in favor of the more analytical Echle LF-3519 transistor amplifier, which could be ruthless when it came to uncovering faults in the system. The resulting mix of properties had worked well on our Epicure 3.0 speakers which had previously played in the same position. At this end of the room, there was a sloping wall behind the speakers that made for a mild horn effect. This was arguably not the best possible placement, but the best I could do for comparison.

In this new position, the M200 could show that they were more than ordinary bookshelf speakers. I was happy to find that they managed to work nearly as well in front of a sloping wall as they had done in front of a straight one. The Echle solid state amplifier offered almost four times the power reserves of the Dynavox tube amp, and yet, the speakers still sounded very similar and recognisable. The tubes had presented the music with a little more gravitas, whereas the Echle LF-3519 amp sounded a little tighter in the bass and offered generally more bass control. The treble seemed a bit cleaner and crisper on the Echle amp, but tonal colours were more enchanting on the tube amp. Both amps made for a musical experience on the M200 speakers.

The one aspect that still troubled me, however, was the impression of mono-signals trailing off to the sides at times, thus adding a slight stereo artifact around the singers vocals. Being unused to this phenomenon, I automatically found myself turning my head towards the respective speaker each time it happened. One could shurely get used to it, and less discerning listeners might not even have noticed. However, it did affect stage depth, and it would have been interesting to find out what was causing the phenomenon. Irrespective of this, I would have liked more listening distance to the speakers to achieve a less sharp-sounding sound image. In my listening tests, the M200s became really interesting from a diagonal of 3.00 metres.

Test system (2): Denon DCD-1420 CD player via Wireworld Luna 7 on Rotel RC-960BX preamplifier via HBS Silver Solid-Core Interconnect on Echel LF-3519 power amplifier via Oehlbach standard 4mm copper speaker cables on the loudspeakers

Specifications

M200 (Basic Module)

• Type: 2-way bookshelf loudspeaker (MK-I, 1988)
• Principle: dynamic drivers in closed cabinet
• Cabinet: 22mm fine chipboard and MDF, internally braced
• Nominal impedance: 8 ohms, without M-6000 subwoofer
• Power handling: 200 watts (RMS), 500 watts (peak)
• Recommended transistor amp (min): 60 watts into 8 ohms
• Power efficiency: 87 dB
• Frequency response: 50 Hz - 22,000 Hz (-6 dB)
• Crossover frequency: 1,600 Hz
• Slope: 12 dB per octave (phase aligned)
• High-frequency driver: 25mm dome by LPG, titanium (ferrofluid cooled)
• Midrange-to-bass driver: 20cm Isophon, paper pulp
• Connection panel: single, for bananas or spades
• Dimensions: (W) 270mm; (H) 460mm; (D) 280mm
• Weight (each 2-way basic module alone): 14 kg
• Accessories: M6000 subwoofer module (< 50 Hz)
• History: first ready-made loudspeaker by Teufel
• Development and construction: Peter Tschimmel
• Country of manufacture: Germany, Berlin
• Year(s) of manufacture: MK-I 1988 - 1992 (MK-II 1992 - 1996)

M6000 (Bass Module)

• Type: stereo subwoofer in ported cabinet (MK-I, 1988)
• Principle: 2 dynamic drivers in compound position
• Cabinet: 22mm fine chipboard and MDF, internally braced
• Nominal impedance: 4 ohms, with M-200 basics
• Power handling: > 200 watts (RMS), 500 watts (peak)
• Power efficiency: 87 dB
• Frequency response: 20 Hz - 50 Hz
• Recommended transistor amp (min): 80 watts into 8 ohms
• Upper crossover frequency: 50 Hz
• Slope: 12 dB per octave (phase aligned)
• Sub-bass driver: 2x Isophon PSL 320/400, paper pulp
• Connection panel: single, for bananas or spades
• Dimensions: (W) 410mm; (H) 630mm; (D) 520mm
• Weight: 56 kg (70 kg with one basic module)
• Accessories: M200 basic module (> 50 Hz)
• History: first ready-made subwoofer by Teufel
• Development and construction: Peter Tschimmel
• Country of manufacture: Germany, Berlin
• Year(s) of manufacture: from 1988

M200 (Speaker Stands)

• Type: loudspeaker stands
• Dimensions: (W) 275mm; (H) 500mm; (D) 300mm
• Base plate: (W) 275mm; (H) 500mm; (D) 30mm (MDF)
• Top plate: (W) 220mm; (H) 2mm; (D) 220mm (metal)
• Column, hollow: (W) 100mm; (H) 46mm; (D) 100mm
• Weight (each stand): 4.4 kg
• Development and construction: Peter Tschimmel
• Country of manufacture: Germany, Berlin
• Year(s) of manufacture: 1988 - 1992

Born in the early 1970s, I grew up listening to music on mono and stereo Mid-Fi systems. Our Grundig TV was still black and white with an oval wide-band driver mounted to the right of the tube. And while I was looking forward to my father purchasing a colour TV, improvements in sound were the last thing on my mind. We listened to records via a Dual turntable and simple Grundig RF240 system, on which one speaker could be detached for improved stereo effect. This also had a built-in radio tuner, but I much preferred the warm and fuzzy midrange-focused sound of our Saba tube radio. It never once occurred to me that we needed more bass-slam or that our movies were lacking in cinematic effects in any way. Being visually and acoustically sensitive myself, I found that a great number of movies showed more than enough realism, even when shown in black-and-white and with mono sound.

The first HiFi systems I purchased and built for myself during the 1980s and 90s were simple stereo setups with records, cassette tapes, and CD player as source. In those days, it was common to tweak the sound with multi-band equalisers which usually involved increasing the bass and treble response of the speakers. The resulting sound curve was either V-shaped or similar to a bathtub. In 1987, Bose introduced the Acoustimass series which I heard play at a friend’s house. This featured one separate bass unit and some smallish-looking satellite speakers. The system had been ridiculously expensive, and my friend’s family was very pleased with the result, but I could not hear the benefit of this design and felt that this had been engineered to improve the visual appearance rather than the sound stage.

I continued to explore the potential of stereo listening, even when the cost of multi-channel systems using subwoofers began to fall. Whenever I did hear multi-channel systems play, I felt that something was not quite right in the integration of the subwoofer, unless they were for the purpose of listening to music score or for the enhancement of sound effects. I was surprised to find that this was even true for some professional setups using large Bowers & Wilkins loudspeakers with a front-firing subwoofer. Perhaps it was due to these early and continuous experiences that I did not consider delving into the subject more deeply, until I purchased a pair of Shure 701 Pro Master PA loudspeakers and later discovered that they had been designed as mere tops to work with a subwoofer. This meant that I suddenly had an acoustic gap to fill and that a subwoofer would be the only way to fill it.

Remembering the performance of the less-than-impressive B&W setup, I decided that I would make a list of requirements and then simply choose the subwoofer that fit my list at the most affordable price point. It needed to be actively powered and fitted with a low-level cinch/RCA input. I was also looking for a vented front-firing design with volume level control, cut-off frequency adjustment, and simple 180° phase correction. And I finally found all these features combined from a vendor in Darmstadt who had established a reputation as a distributor for the Chinese brand 'Dragon Audio'. Founded in Shenzhen back in 2004, Dragon Audio had grown to become a major OEM producer of audio gear with over 1,400 staff working in their 14 factories in China.

Their ‘Dream 2 Sub’ model came in glossy piano black lacquer and housed a front-firing 30cm woofer with soft a suspension. Two large rear ports served to minimise air noises but did demand a greater distance to the walls of the listening room, as the wall distance should be at least twice that of the total port diameter. At around 40 cubic centimetres, the outer dimensions of the Dream 2 were still considered to be about average in the world of subs. Looking at the Dream 2, one could see that the lacquer could have been applied more evenly and thicker and that the built-in amplifier could have been given a sturdier base plate and cooling socket, perhaps. However, when I factored in the low price, I was still impressed with what Dragon Audio had visually achieved. When it came to sound and overall performance, I was not yet sure what to expect.

Turning the Dream 2 Sub on for the first time, I heard a mild humming noise coming from the woofer. This noise remained for as long as the integrated amplifier was in operating mode. The noise was just bearable enough for me not to follow the impulse of returning the woofer to the vendor. Another issue I noticed was that the internal amplifier would switch into standby on quiet movie scenes. While this effect did not usually occur during music playback, it could be bothersome when watching movies late at night, especially because there was an audible popping sound on each event. I also noticed that the smallish heat sink could get quite hot during longer listening sessions. As I was otherwise happy with the subwoofer, I decided to ask my trusted service technician to have a look inside with me.

As we opened the Dream 2 Sub by taking out the amplifier board, I was pleased to find a closed wood cabinet around the amplifier that would protect it from vibration. The cabinet itself was of sturdy build quality. I was, however, a little disappointed with the amplifier itself. While it featured a conventional linear transformer, this was relatively small for the task, at around 30 watts, and placed too close to the main circuit board. The audible 50Hz humming was a natural result of this close placement and would be difficult to resolve. In addition to this, the power supply capacitors were also relatively small for the job of eliminating noise. The Dream 2 Sub’s high sensitivity of around 90 dB at 1 watt meant that the amplifier’s power would still be sufficient to enjoy music at household volumes. The sound output was generally acceptable, although we could detect a slight mismatch between the upper and the lower sine waves, especially when the unit was driven at low input volumes.

While the issues detected were not necessarily a deal breaker when purchasing an entry-level sub, the Deam 2 was just barely sophisticated enough to be the protagonist in my planned subwoofer placement explorations. I could only marvel at DA's ability to employ 1,400 factory workers based on this relatively low level of quality and performance.

Specifications

• Model: Dream 2 Sub
• Type: active Subwoofer
• Principle: front-firing, dual rear-ported
• Driver: dynamic, 12-inch
• Frequency range: 20-200 Hz
• Power handling: 100 watts RMS
• Phase adjustment: 180° inversion
• Volume control: full range on input
• Low-level input: cinch, stereo
• High-level input: speaker wire, stereo
• Amplification type: class A/B
• Sensitivity: >90 dB
• Features: automatic standby
• Finish: piano black, removable cloth grill
• Dimensions: (H) 370mm, (W) 370mm, (D) 400mm
• Weight: 11 kg
• Year: 2012

When my good friend Thomas Kubalsky suggested that I try a 5.1 set of loudspeakers and receiver that he had recently been given by his brother-in-law, I was a little hesitant at first. Being a child of the 70s, I could not help but think of the first surround sound systems by JVC and the likes that all sounded pretty terrible, regardless of whether the multi-channel function was activated or not. Somehow, I had managed to get by without hearing a proper surround system for half a century. On the other hand, I also had the sensation that my hesitation was in conflict with the spirit of this blog, which bears the importance of venturing into the unknown in its title. 'Explorations in Audio' requires us to put our ears over whatever we think we know in order to test the validity of our beliefs. — For the times they are a-changin'.

If I was going to write a review on a 5.1 setup, I wanted to first prepare for the task. This was especially so, as I was lacking experience in the placement of subwoofers. Hence, I asked Thomas to hold on to the set for me to give me some time to prepare. In the period that followed, I started the category of subwoofers and wrote my analysis on subwoofer placement. Feeling sufficiently prepared, I contacted Thomas again, and we packed our children's handcart with equipment and pulled it the two blocks from Thomas’ place to our apartment. The set consisted mostly of plastic components and, although quite bulky, weighed in at just above 10kg. When comparing this to much of the gear tested here previously, the low weight did not exactly scream quality. However, I did not want to jump to conclusions and was prepared to be surprised.

The name HTB-7590-D (see edits below) alone suggested that Philips had not intend this equipment to become the beacon of their audio engineering. It is far too long and clunky to be casually dropped at a dinner party. We might assume that the “H” stands for home and the “D” for digital, but these letters could also be internal code for some other purpose. In fact, the name was so inconspicuous that I continued searching for it long after I had found it. I simply could not imagine that this was its name. Running a web search, I could see that there were a number of similarly named Philips devices with higher and lower numbers, none of which had found much attention in the press. On the back of these HTB-7590-D units, one could read that they had been designed and engineered by Philips in Europe. However, there was no mention of a manufacturing country.

I set the system up with my four-year-old son Max, who had no trouble carrying the tower speakers into the room with me. The speaker wire was firmly installed on the side of each speaker and exceptionally thin in diameter. It was, however, sufficiently long for our 5.60m x 4.70m listening room. The rear speakers had longer wires attached to be positioned further away from the unit. Each wire was colour-coded to indicate the correct pair of clamps on the back of the receiver unit. The speakers themselves were narrow plastic satellites perched on hollow plastic tubes. The tubes became slender towards the base plates, and four rubber foam cushions were employed to couple the speakers towards the ground. The satellites consisted of two full-range drivers each. Between them was a bass port which had been designed to resemble a tweeter when seen from a distance.

The subwoofer was of side-firing, rear-vented design, and the cabinet material appeared to be simple plywood. Coming from the Dragon Audio subwoofer, the 4kg Philips looked like a toy. Of the four attached rubber foam cushions, one had already been lost. The 6.5-inch driver was stuck behind a non-removable speaker cloth. I had never come across a cheaper-looking woofer design but decided to be open-minded. Our ears do not look especially fancy either, and yet they are precision instruments capable of tremendous tasks. The Philips receiver had all the electronics necessary for processing the information and sending the amplified signal to each loudspeaker in one single box. Its power consumption of 105 watts looked rather dismal in the face of having to drive five-plus-one loudspeakers. All the more, I was surprised to find the total output power RMS rating to be at 800 Watts with all channels driven at <10% distortion.

Max and I turned the HTB-7590-D on for the first time, and I slipped in Mark Knopfler’s remastered version of the Dire Straits “Brothers in Arms” album. The room instantly sounded as if we were trapped in an underwater fish tank, and I quickly understood that many parameters had to be off at the same time in order for the performance to be so dismal. A look at the owner’s manual revealed that the front speakers had been designed to be positioned relatively close to the TV-set. When bringing them closer, I noticed that of the four existing rubber foam pads there was always one that was suspended in the air. To give all speakers a more stable stand and a well-defined coupling toward the ground, I placed each of them on three 5mm rubber pyramids. This took the remaining uncertainty out of the sonic equation and instantly resulted in a fuller more assured sound.

Since the HTB-7590-D receiver did not have a proper display, I connected an old computer monitor to it via HDMI. In the audio settings, I found that all speakers’ volumes had been raised to +6 dB. My first task was to again set this to neutral. I also found that some tonal adjustments had been made via the internal equaliser and also reset this to flat. It was only later that I also found where to turn the function ‘Audio Improvement’ off completely. The next listening test showed that the system was beginning to sound tonally more realistic. With all the superfluous emphasis turned off, it was also easier to hear the problems in timing that still existed. Luckily, the internal sound processor (DSP) offered six sliders to set the distance of each speaker towards the listening position.

I used a simple laser distance meter made for room measurements to determine the distance from my head to each speaker. To do so, I held the meter over the top of my head and pointed it on the main driver of each speaker. I set the corresponding slider to the nearest approximation and then proceeded to move the speaker to correspond with the set value. This also allowed me to perfectly align the subwoofer. In order for the subwoofer not to overly excite room modes in my listening position, I had set this up first. Although side-firing subwoofers are more forgiving to place, I preferred a more direct sound and turned the woofer with the driver pointing towards the listening position. This way, I was sure to benefit from the punchiness and agility of the woofer and get better bass layering. I had then set up the satellites to be phase-aligned with the woofer. The rear loudspeakers were set as far behind and wide away from the listening position as possible.

Following the phase alignment, the HTB-7590-D sounded pretty grown up. I was especially pleased with its bass performance, which was not only full and satisfying, but also clean, dry, and layered. To my surprise, this woofer-satellite combination worked better than our previous setup with the Dragon Audio subwoofer. This was probably the result of having more exact placement options with the smaller speakers in the room. The Shure-DA combination would have benefited from a larger room.

We decided to test the HTB-7590-D with Bruce Springsteen’s 2019 Blu-ray album “Western Stars”. I had heard much praise regarding the audio track and thought this might be a good starting point. Listening to Bruce Springsteen tell the old tale of fear, passion, and forgiveness in Dolby Surround (originally recorded for Dolby Atmos) made me feel that multi-channel sound was the ideal companion for concerts on Blu-ray. Especially the audience cheering and clapping had a wonderful effect in the room. Still, there were some moments in which I was not sure what to make of the feature. Should the strings really have played via the rear channels? Little things like these had such an effect that I snapped out of the sensation of being at the event.

On the small full-range satellites, Bruce Springsteen’s voice did not have the full depth that I was used to from listening to his songs on our usual equipment. There was generally a slight lack in tonal richness that is commonly associated with wooden materials. As Springsteen’s voice became lower in some passages of the performance, the satellites revealed inherent resonances caused by their cabinets of thin plastic. This effect was not apparent during the whole performance and only stuck out during two or three songs. Holding my hand against the speakers, I could really feel the resonance that extended nearly all the way down the shaft towards the ground. Improved internal bracing and better insulation could have lessened this effect but would surely have increased the sales price of the unit.

I would have liked to see proper buttons on the receiver’s front. The capacitive ones were poorly lit and very small which made it easy to confuse them in low-light conditions. Often, they did not immediately respond to touch commands, which at times led to a successive opening and closing of the disk-tray or to the unit switching on and then off again. The built-in LCD display was neither bright nor large enough for the information to be read from the sitting position. It also did not help that it was tilted upward. The remote control had lots of important and easy to reach functions. Sadly, the keys quite frequently failed to execute the command on the first or second push. Harder pressing of the keys resulted in bending sounds coming from the plastic housing of the remote. None of this felt very sophisticated or reliable.

No up-mixing options were presented for Auxiliary devices, which made 5.1 functions exclusive to the onboard features, HDMI or SPDIF devices and only if provided by the track. 2-channel operation of the HTB-7590-D was generally alright but not as full and tonally rich as we were used to from our previous devices. Channel separation and soundstage were reasonably good. Bass performance was generally excellent, especially considering the materials used, and the amplifier never seemed weak or unfit for the task. The full-range drivers of the satellites had their limits in terms of tonality, but also in frequencies above 20.000 Hz. This could make the music seem a bit stale occasionally. Resonances affected male vocals at times, indicating the cost-conscious build-quality of the cabinets.

All-in-all it can be said that the Philips HTB-7590-D is a worthwhile 5.1 system that is still going strong after 10 years of use. While it does not hide its concessions to the price-conscious consumer, it does deliver a solid performance, especially when listening to 5.1 recordings. It is musically solid enough to bring pleasure to most households, but only if it is set up by someone who knows what they are doing. Unfortunately, it is all too easy to get lost in the features and adjustments which will leave this particular, and actually most other 5.1 systems, sounding pretty useless. I have greatly enjoyed the opportunity to expand my horizon with a technology that was still new to me at the time, and I look forward to our next project.

Edited, 10 Oct 2022 As Landon has rightly pointed out to me upon reading this article, there is a blog entry on toenegel.net of 31 August 2012 that describes the new Philips naming scheme introduced that year. According to this, the HTB-7590-D was the best version of the mid-high-end 5.1 home theatre Blu-ray system that provided a docking station for use with iPod. — We live and learn.

• HTS = Home Theatre System
• HTD = Home Theatre DVD-System
• HTB = Home Theatre Blu-ray-System
• HTL = Home Theatre Loudspeakers
• HTM = Home Theatre Loudspeakers (with Mediaplayer)

---

• HT?3xxx = Series 3 (entry level)
• HT?5xxx = Series 5 (mid entry)
• HT?7xxx = Series 7 (mid-high-end)
• HT?9xxx = Series 9 (flagship models)

---

• HT?x1xx = 1.1-System
• HT?x2xx = 2.1-System
• HT?x5xx = 5.1-System

---

• HT?xx1x to HT?xx3x = “good” (of series)
• HT?xx4x to HT?xx6x = “better” (of series)
• HT?xx7x to HT?xx9x = “best” (of series)

---

• D = Docking Station
• K = Karaoke-Version

< Subwoofer positioning | Dragon Audio Dream 2 >

Specifications

Receiver

• Type: 5.1 DVD Blu-ray-disc receiver
• Power output (RMS): approx. 130 WPC
• Frequency range: 20 - 20,000 Hz (+/- 3dB)
• Signal-to-noise ratio (line): > 65 dB
• Analog audio input: Cinch,
• Digital audio inputs: S/PDIF (coaxial, TOSLINK)
• Radio tuner: 87,5-108 MHz (analog)
• Signal-to-noise ratio (tuner): < 50 dB
• Radio frequency range: 180 - 12.500 Hz (+/- 3dB)
• USB input: high-speed 2.0
• USB File systems: FAT16/32, NTFS
• Power supply: 110-127 Volts / 220-240 Volts
• Power consumption: 105 Watts
• Standby power consumption: 0,25 Watts
• Dimensions: (W) 435mm, (H) 56mm, (D)344mm
• Receiver unit weight: 3.3 kg

Front and rear loudspeakers

• Type: front-vented floor-standing loudspeakers
• Drivers: (2x) 3-inch full-range (7,63cm)
• Dimensions: (W) 96mm, (H) 1110mm, (D) 75mm
• Base plate: (W) 240mm, (H) 24mm, (D) 240mm
• Impedance: 5 Ohms
• Weight: 3.5 kg

Centre speaker

• Type: front-vented loudspeaker
• Drivers: (2x) 2.5-inch full-range (6,35cm)
• Dimensions: (W) 266mm, (H) 87mm, (D) 99mm
• Impedance: 3 Ohms
• Weight: 1 kg

Subwoofer

• Type: side-mounted, rear-ventilated Subwoofer
• Driver: 6.5-inch woofer (16.5cm)
• Impedance: 3 Ohms
• (W) 178mm, (H) 302mm, (D) 353mm
• Subwoofer weight: 3.9kg

Video

• Output Format: PAL/NTSC, HDMI 480i/576i, 480p-1080p24
• Output resolution: 1920 x 1080 pixels, HD (max.)
• Bitrate: 30 frames per second (max.)
• Formats: AVI, DivX, MP4/M4V, MKV, ASF/WMV, MPG/MPEG, VLF, 3GP
• Country of manufacture: China
• Year: 2012-2013

Similar to the nearly double-priced K712 Pro, the K702 were designed and engineered in Austria. But, instead of both models having been uniformly manufactured in Slovakia, the K702 were manufactured in China, which only served to highlight their low-price focus. Both headphones featured AKG’s patented flat wire voice coil for linear performance and increased responsiveness from 10 to 39.800 Hertz. Weighing in at a mere 290 grams, the K702 were 10 grams lighter than the K712 Pro — with neither model weighing the 235 grams promised on the packaging and in product reviews online. I guess nobody actually took the time to weigh them again once they were in production. The pictures show the K702 with protective plastic around their edges, because I had already decided to return them to the dealer at the time of taking the photos.

Both headphones were of the same open design and, by means of AKG’s patented two-layer diaphragm, offered extended frequency range and a spacious and airy sound. Whereas the K712 came with one spiralled and one straight orange cord, the K702 were equipped with a single straight and black cord. The mini-XLR connectors were the same on both units. This made it easier for me to change between the models during my listening tests. The colour scheme was different between them, too, with the K702 coming in (retro-)silver and black and the K712 Pro in orange and black. At first glance, I preferred the retro-silver design, as it looked more solid, but holding them in my own hands and realising that nearly all parts were of painted plastic, I found the orange to be more sincere.

It also found it interesting to read that both units came with pre-selected and matched transducers for improved performance consistency, and that each pair of headphones had been individually tested and numbered to assure for high quality following production. It seems that weighing them to assure that all parts had been included was not a part of this process at either factory location. It also seemed that the K712 Pro had been deliverd to another customer’s house for testing before coming to me, as the warranty instructions were no longer packaged in their original plastic sachet, and the protective seals around the ear pieces had already been removed. Neither pair of headphones seemed to have been designed to stand the test of time with the materials used being relatively thin and therefore seemingly fragile. AKG was no different in this respect from other companies, and yet it was never easy for me to acknowledge this trend. To prove my point, some customer reviews had already suggested online that there could be problems with individual channels loosing their connection. Another complaint had been about the sonic effect of the removable headphone plug and cord brushing over clothes. Although it was true that touching and rubbing the cable produced an unpleasant sound, I had no problems staying clear of my clothes and shoulders.

The K702 had received excellent reviews in the press for their highly revealing trans-lucid sound and excellent dynamics when they first came out at the end of 2008. Considering their entry-level price, I could easily agree with AKG that these were a pair of excellent headphones and would be useful “for precision listening, mixing, and mastering”. Their sound was light and agile, catching lots of transients and ambient noise. Perhaps this came at the cost of losing some of the lower end of the music. I had often found that it was relatively easy for equipment to sound revealing, as long as the lower aspects of the frequency band were omitted from the equation. If the eardrums were not too busy following the bass lines, there was more room for them to catch the detail at the top-end. It is a magic trick, as each one of us only has a single set of eardrums after all.

Comparing bass lines to natural instruments was not an easy feat with either one of the two headphones. The K712 Pro compensated for the natural bass-loss from their open-back design by raising lower-end frequencies by 3 dB. This was also not quite natural and correct, of course, because bass extension from loudspeakers came from room-interaction and the overlapping of frequencies, effects that were practically non-existent in the case of open headphones. However, I had some trouble with the ‘non-existing bass’ from open headphone designs being described as ‘honest’, because it was mostly the phenomenon of bass drop-off on open headphones, an issue to be addressed. From my experience with our Canton Vento 890 DC loudspeakers, many years earlier, I knew that over-accentuated highs and recessed lows - while perhaps interesting and exciting at first - could permanently spoil the listening pleasure.

And this was also the main reason for my decision to keep the more balanced K712 Pro headphones and to send back the bargain-priced K702 to the dealer. And, yes, I could also hear that the additional bass on the K712 Pro made them sound slightly less revealing and thickened singers’ vocals a little. However, I could appreciate this weightier sound as being more balanced and rounded. It certainly resembled more closely the sounds captured of all our speaker recordings and came closer to my understanding of live music. This is not to say that the K702 reproduced vocals wrongly. Singers simply sounded as if they had lost a few pounds in weight. And for listeners finding pleasure in an abundance of detail and a more penetrating presentation, the K702 will surely be the better choice.

AKG Company History

The Akustische und Kino-Geräte Gesellschaft m.b.H. was founded by Rudolf Hörige and Ernest Pless in Vienna, Austria in 1947. Rudolf was a physicist, and Ernst Pless was an engineer. The two men grouped their understanding of materials and mechanics to create loudspeakers, film projectors, and light meters. With the growing demand for media applications, AKG’s first microphone was used by Austrian radio stations, theatres, and Jazz clubs.

AKG achieved an international reputation for building excellent microphones with the launch of their D12 in 1953. This was far ahead of its time, and subsequent updates served to maintain its position. AKG also produced turntable cartridges during the 1970s and 80s.

The company established an American subsidiary in Los Angeles in 1985 and was taken over by the Harman group in 1994, which also operates Crown Audio. In 2017 the company facilities in Vienna (headquarters, manufacturing and engineering) were closed with most of Harman’s production facilities having been relocated to low-cost countries. At the time of writing this, Harman with its many brands is owned by the Korean conglomerate Samsung.

Specifications

• Driver type: patented 2-layer diaphragm, dynamic
• Design: over-ear, open
• Frequency range: 10 - 39.800 Hz
• Nominal impedance: 62 Ohms
• Sensitivity: 105 dB (1mWatt, 1.000 Hz)
• Power rating: 200 mWatts, max.
• Cables: 1x straight
• Connector: detachable via mini-XLR
• Cable length(s): 3m
• Plugs: 3.5mm + 6.3 mm jack
• Place of manufacture: China
• Weight: 290g (without cable)
• Year: 2008 - 2021

My interest in headphones did not stem from the desire to listen for pleasure or experience superior sound quality when travelling. Nor did I need to be especially quiet when our kids were asleep. They had grown up with music playing way past their bedtime and had hardly ever had trouble sleeping - at least not because of music playing. No, my interest rather resulted from the need to monitor the audio recordings of interviews, digitised records, and - more recently - loudspeakers. My aim was to find headphones that would not colour the music and step out of the way for the original event to shine through. The audio-setup of our two Hi-Fi systems had become of such high quality that it was increasingly difficult to find headphones to accurately monitor their output. Differences in the performance of loudspeakers could be very subtle, of course.

For various reasons, I would have chosen good loudspeakers over headphones any day. A loudspeakers’ ability to excite the whole human body and interact with the dimensions of the room, but also its ability to set a real stage along with physical depth and proportion, all these aspects were missing from most headphones today. Luigi suggested that I try AKG’s K1000 electrostats which could be folded outward to create a better stage impression. But I decided that simpler more versatile headphones would be more suitable for my intended use as studio monitors. Was this perhaps again the point at which I was to wilfully ignore the expert’s advice and regret this for the days to come? Possibly, but at least I had a choice between experts now.

When purchasing the Beyerdynamic DT 990 Pro headphones some weeks earlier, I had ignored Jens’ advice on buying AKG monitors, instead. The DT 990 proved to be inadequate for my purpose, and I have since auctioned them off online. For my second attempt at finding good studio monitors, I decided to follow Jens’ lead on the AKG. Since the original model he had suggested had been on the market for a very long time, I decided to try two of the more recent models: the AKG K702 and the K712. From the reviews of both models that I found online, I was unable to make a definite decision between them. Both were open-back headphones that allowed for ambient noise and offered a somewhat unconstrained sound. However, the K712 came with stronger bass response of +3dB above the K702.

Some reviewers found the K702 to be more linear and therefore realistic in sound, whereas other reviewers had the opposite impression. Since most open designs had a natural bass-drop in comparison with their closed counterparts, I had a strong suspicion that the reviewers’ verdicts depended on their previous listening habits. Since I was looking for headphones to accurately reproduce the sound captured from our loudspeakers tests, I was going to use the loudspeakers as reference and then determine which of the two to keep, depending on their tonal proximity to the original. Since my impression would also depend on the periphery driving the headphones, I decided to use three sources: The Douk Audio T-3 Plus tube amp, our Zoom H4n Pro recorder that we had used to create the sound files, and our MacBook with its internal sound card. Both headphones had an impedance of around 60 Ohms which made them sufficiently easy to drive, even from the on-board sound card of a computer.

The K712 arrived first, and I was surprised to find that they were made almost entirely out of plastic. The drivers and the leather headband were the exception. This led to the headphones being very light-weight. AKG’s self-adjusting headband even increased this sensation by automatically exerting minimal pressure to the head. On the other hand, the plastic made them feel a little over-priced at first. The ear-pads were large, comfortable, and spacious inside. The feeling of openness increased during the first soundcheck. Whereas our Sennheiser HD 580 Precision headphones made the music sound close and intimate (with a sensation of resonances that were not completely kept at bay), the K712 gave the instruments some dimension and space to breathe. The darkness in between did not feel as artificial as it had on the DT 990 Pro, but rather natural and even elegant. There was a laid-back sensation to the music most likely coming from the lack of body resonances and the superior impression of order this produced.

On the Douk Audio T-3 Plus with GE tubes, the K712 produced a full and balanced sound. Transients and bass extension were cut a little shorter than I was used to from our loudspeakers. It was quite possible that this was caused by our Chinese headphone amp, the Denon CD player, or the non-existing break-in time of the diaphragms, headphone cable, solder joints, and the new plugs. I confess that I was a little sceptical at first when I saw that the K712 came with a detachable signal cord (two, actually) which would introduce more mass to the signal path. But seeing the benefit of changing between cords, I was inclined to accept it as an advantage, too. Having listened to the Sennheiser DH 580 and the Beyerdynamic DT 990 Pro, the K712 clearly had the upper hand in terms of clarity, sound-field, dimensions, tonal balance, etc.

Diana Krall’s song “No moon at all” showed less sibilance than I had heard on other occasions. However, the tonal colour of the piano was more accurate and relaxed than exciting. The double-bass being plucked in the beginning of the song was well-presented, but it could have been slightly more impressive, perhaps. I had heard this passage many times on speakers, often to jaw-dropping effect. The K712 remained accurate and in control with no aspect of the music falling out of place. String sounds came across as both sweet, varied, and nuanced. Via the MacBook Air sound card, I had the impression that male voices were artificially composed of their high and low aspects. However, I was not able to reproduce this effect via the dedicated headphone amp. It is no secret that one could rarely trust computers when it came audio reproduction, unless they were dedicated machines designed for the purpose of music.

Jörg Hegemann’s “Rock Me Mama”, on which Thomas Aufermann sang the lyrics, showed a little less bass-slam than I had previously been accustomed to from our loudspeakers, but they produced the vocals fully and accurately. Metallic sounds from the drum kit could have sounded a bit more shiny and aggressive, perhaps. I noticed that, even during faster sequences with many voices and multiple instruments playing simultaneously, the K712 managed to keep these separate, without them drowning each other out or overlapping. This superior sense of order was perhaps the most significant character trait of the K712. If asked, I would neither have wanted for myself nor recommended to others, headphones with less bass punch than these, as this would have taken us too far from the actual acoustic event of live music. Both physically and sonically, these modern AKGs headphones could be worn comfortably over extended periods of time without causing listening fatigue. AKG labelled them ‘Reference Studio Headphones’, and I could see that this description was accurate, as it placed order and control above sensation and excitement. These were sober headphones for a sober job, and I decided that I liked them.

AKG Company History

The Akustische und Kino-Geräte Gesellschaft m.b.H. was founded by Rudolf Hörige and Ernest Pless in Vienna, Austria in 1947. Rudolf was a physicist, and Ernst Pless was an engineer. The two men grouped their understanding of materials and mechanics to create loudspeakers, film projectors, and light meters. With the growing demand for media applications, AKG’s first microphone was used by Austrian radio stations, theatres, and Jazz clubs.

AKG achieved an international reputation for building excellent microphones with the launch of their D12 in 1953. This was far ahead of its time, and subsequent updates served to maintain its position. AKG also produced turntable cartridges during the 1970s and 80s.

The company established an American subsidiary in Los Angeles in 1985 and was taken over by the Harman group in 1994, which also operates Crown Audio. In 2017 the company facilities in Vienna (headquarters, manufacturing and engineering) were closed with most of Harman’s production facilities having been relocated to low-cost countries. At the time of writing this, Harman with its many brands is owned by Samsung.

Specifications

• Driver type: patented 2-layer diaphragm, dynamic
• Design: over-ear, open
• Frequency range: 10 - 39.800 Hz
• Nominal impedance: 62 Ohms
• Sensitivity: 105 dB (1mWatt, 1.000 Hz)
• Power rating: 200 mWats, max.
• Cables: 1x straight and 1x spiralled
• Connector: detachable via mini-XLR
• Cable length(s): 3m
• Plugs: 3.5mm + 6.3 mm jack
• Place of manufacture: Slovakia
• Weight: 300g (without cable)
• Year: 2021

I must confess that I had a relatively late start into the subject of headphones, simply because I had rarely worn them professionally, never managed to feel comfortable wearing headphones in public places, and always preferred the soundstage of our loudspeakers at home. This is not to say that I had never paid any attention to headphones. The first proper set of headphones I remember were my dad’s Panasonic studio monitors. They were of a closed-back design and had a second and softer inner ear pad that felt very comfortable. They cost some 300 dollars in the 1980s which was a lot of money back in the day, and—at least in my memory—they sounded great. My first own set of headphones had been the open back Sennheiser HD 580 Precision, and I remember being disappointed at how little they could do for me in terms of accurate bass. The Panasonics, by comparison, had bass performance so strong, they could hover over your head. Granted, this was probably an unhealthy experience to have.

The HD 580 Precision ended up sitting on the shelf for most of their existence, and it was not until late autumn 2021 that I became curious about headphones once again. A friend of mine had asked me to digitise his records for him, and I needed a good pair of headphones for monitoring and mastering. One of the people I interviewed before making my purchase decision was Jens, a part-time music producer, who recommended a set of tried and trusted AGK headphones to me, but, reading through the reviews online, I went for the 250 Ohms Beyerdynamic DT 990 PRO instead. 250 Ohms was the pro studio and audiophile standard, and I had read that, for a solid sound, decent headphones would require lots of clean power. So I bought a Douk Audio T-3 Plus tube headphone amp for them, which I soon upgraded with a wonderful set of GE tubes and a decent linear power supply.

Sadly, the Beyerdynamic DT 990 PRO turned out to be a disappointment to my ears. There was lots of bass, width, and dimension, and the highs were sufficiently articulate; however, I could not get over the fact that the highs and lows did not harmoniously connect with the midrange, which sounded rather muffled and overly dampened. The DT 990 PRO sounded far from linear on any of my music sources and were sorely lacking even when compared with the company’s higher-end gear, such as their flagship T-1 headphones. The latter was also the reason I decided to return the DT 990 PRO to the shop. A few weeks later, I found myself sending back a pair of AKG K702 headphones that were so obviously lacking in bass that just two hours of listening had prompted me to again read through the return policy.

I finally found happiness with a set of AGK 712 Pro which had a slight bass-boost to compensate for their open back construction. This made them sound tonally correct and, indeed, very similar to the tonally balanced sound that I had achieved on our audiophile stereo systems. The AGK 712 Pro were a true benchmark in their price category and had been my yardstick when comparing the sonic virtues of other headphones. Tonal correctness referred to the listener's ability to recognise the specific sound character of an instrument or a material, and it allowed music differentiation on a scale outside of volume, frequency, and rhythmic agility. For discerning listening, correct tonality played an equally important role as the other three dimensions, and this was also my reason for recommending the AGK 712 Pro to friends seeking price-conscious audiophile headphones.

All the more, I was surprised when my brother informed me that he had done some research and bought a number of Beyerdynamic headphones for the video mastering in his education programs. Jörg explained that his team needed closed back headphones that they could simply plug into their laptops and tablets without the use of additional amplifiers, and that the Beyerdynamic DT 770 Pro in their 16 or 32 Ohms version were well-equipped for the job. Without having listened to the headphones myself, I could not shake the feeling that what had alienated me from the DT 990 PRO might simply have been the Beyerdynamic ‘studio’ headphone sound. Had my brother run into the same trap that I had so readily trodded into when I first set out to purchase headphones for my mastering adventures? I sure did not hope so, and we agreed that he would lend me a pair for testing some time soon.

32 Ohms headphones—while perfectly suited for a low-output computer sound card—were not exactly ideal for a high-output tube headphone amp. And, while I was still contemplating how to set up my test in order to be fair to the Beyerdynamics, a friend from up our street mentioned that he had owned a pair of 80 Ohms DT 770 Pro for a few years, which he was still happy with, and that he would be honoured to lend to me for a test. I felt flattered by Erik’s willingness to support the eiaudio project and accepted his offer. And I was feeling even more flattered when I later learnt that Erik had fitted them with brand new silver-velour ear pads for the occasion. He had worn his DT 770 Pro for so many hours, the original silver velour colour had completely changed on his set. — And the Beyerdynamics were great when it came to parts replacements.

The original DT 770 had come out in early 1981 and had since become standard gear in many professional sound studios and for many musicians. The DT 770 PRO followed in 1985 but did not replace the DT 770 completely. People who have owned both the 81 and the 85 versions of the headphones reported that, except for the branding, there was little difference between them. Professionals in music have enjoyed the fact that Beyerdynamic headphones did not break easily and—if they should break—could be fixed cheaply and without much effort. Labelled 'hand made in Germany', the headphones used a combination of spring steel headband and forks with ear cups made of durable plastic. A simple stepped mechanism allowed the user to adjust the length of the headband in increments by pulling downward on the ear cups. Head pressure was perceived to be just right for long listening sessions. Although, on my heavily-used headphones, the adjusting mechanism had become slightly loose, the pressure on the head was still just right.

As on the DT 990 PRO, I enjoyed the generous size of the ear cups. From experience, I knew that this particular velour material could feel slightly warm and sweaty, especially when worn on hot summer days, but for the relatively modest price of the DT 770 PRO this was still more than fair. The ear cup forks were also made of spring steel and perhaps one of the reasons these Beyer’s stood the test of time. They allowed the head shells to swivel both horizontally and vertically to comfortably accommodate any head shape. Although I was wearing glasses during testing, I never felt them to be an inconvenience with these headphones.

The 80 Ohms version of the DT 770 PRO came equipped with a generous cable of just over three meters in length. While this would be sufficient for most studio applications, it could become a hindrance when using these headphones on the move. As far as non-detachable cables go, I much preferred the DT 770 PRO’s long and straight cable over the DT 990 PRO’s spiral cord. I also liked the fact that the cable felt quite sturdy being covered by lots of protective rubber. It was fitted with the typical straight 3.5mm TRS jack connector and offered threading for a 1/4-inch screw-on adapter. When it came to headphone cables, I personally preferred detachable cords as they were found on most of the headphones tested in this blog.

When I started listening to the DT 770 PRO on our tube headphone amp, I quickly understood that they were completely different from the DT 990 PRO that I had sent back in frustration one year earlier. The DT 770 PRO did not suffer from a muffled and seemingly unconnected midband, instead they sounded more compact and held the music together nicely. Our GE tubes had a sweet and harmonious top-end, and I found the Beyerdynamics to render this nicely. It was well possible that listening to these headphones with a transistor or less powerful amplifier would have produced a harsher result. Bass performance came across as slightly accentuated, especially when coming from an open-back design such as my AKGs, and yet, bass was neither boomy nor overly resonant with the ear cups.

The midband was not particularly strong but also not sharp or edgy. I had a sensation of a subtle sweetness when listening to both male and female voices on these headphones. The spacial separation between instruments was good for closed back headsets but not outstanding as far as headphones go. When switching to our 250 Ohms AGK 712 Pro, I was surprised to find that there was only a minimal difference in loudness between them. My brother had probably been well-advised to opt for the lower than 80 Ohms version for mixing on the computer, as I could see computer sound cards struggling to pump enough life into the Beyerdynamics. The DT 770 PRO did not clamp down on the ears and head as hard as the Sony MDR-7506 had done that I had tested earlier, but they also did not reach the level of tonal correctness and nuance that I was used to from the Sony and other higher-end models.

Current Headphone Ranking

1. AKG K712 Pro (the most balanced and tonally accurate)
2. Beyerdynamic T1 (nothing to complain about, except for the price)
3. Stax New SR-3 (difficult to set up and operate, but sweeeet)
4. Sony MDR-7506 (good monitor functions and natural tonality)
5. Beyerdynamic DT 770 PRO (good monitor functions and cohesion)
6. HiFiMAN HE-400i (balanced but a little on the bland side)
7. AKG K702 (generally alright but unbalanced, leaning toward bright)
8. Sennheiser HD 580 (sweet midrange, lacking precision and bass)
9. Beyerdynamic DT 990 (pop-sound with muffled midrange)

While being sufficiently balanced and revealing for getting the mix right and for a joyful listening experience, the DT 770 PRO maintained a slightly closed-in soundstage and a tonal signature that was not quite on par with the more expensive models. The resulting shift could be described as transitory, perhaps. Considering how cohesively the DT 770 PRO performed on the whole, I could easily see this limitation as individual charm and would place the Beyerdynamics just under the Sony MDR-7506 from an audiophile perspective. However, if long-time wearing comfort or general studio usability also played a role in my rating, they would need to be positioned higher.

Further Reading:

< Douk Audio T-3 Plus & GE Tubes | Info on Linear Power Supplies >

Specifications

• Type: Stereo Headphones
• Design: closed back, bass reflex
• Ear coupling: Over-ear
• Frequency response (headphones): 5 - 35.000 Hz
• Nominal impedance: 80 Ohms (model tested)
• Available impedances: 16 - 250 Ohms
• Power sensitivity: 96,39 dB
• Power handling: 100 mW
• Harmonic distortion: < 0.2 dB
• Approximate pressure: 780 g
• Weight with cable: 350g
• Headphones without cable: 287g
• Cable type: single (straight), fixed
• Cable length: 315 cm
• Plug type: stereo jack, gold plated 
• Plugs size(s): 3.5mm + 6.3mm jack
• Place of manufacture:  Germany
• Predecessor: DT 770 (1981)
• Re-Design: DT 770 PRO X (2020)
• Year(s): 1985 - 2023

When my friend Charles asked me to digitise his record collection for him — the remaining pieces he had salvaged from the flooding in his basement — I needed a pair of headphones to oversee the process with. My last use of headphones had been so long ago that I could not remember who I had lent my Sennheiser HD580s to. Nor could I be sure that I still had them, considering they were from 1995. (I had originally written 2008, but this was not true.)

I contacted Jens, who is a composer and producer of music himself and usually quite knowledgeable about what is available on the professional studio market, to ask him for advice concerning reasonable headphones for my task. He mentioned that he was quite happy with his AKG K271 MK2 headphones. Jens referred to them as being “honest and revealing”. If I wanted even more honesty, he suggested, I might also consider the open K702. I thanked him for his prompt and knowledgeable support and bought the Beyerdynamic DT 990 PRO instead.

Do you have such moments, in which you know that you are getting excellent advice and then end up doing the exact opposite? In retrospect, I think it was the AKG headphone’s bulky look that put me off purchasing them. The two solid steel rods connecting the two ear pieces that remained fixed while only the head strap was lowered. This part was designed so much more elegantly on the Beyerdynamics and made me blind to some obvious disadvantages that should have got me thinking, especially with my prior knowledge in audiophile matters.

For one thing, the Beyerdynamic DT 990 PRO only had one single, non-detachable signal cord. A single cord had some disadvantages, when it came to signal integrity, because the two channels ran in very close proximity to each other over a longer distance. This could potentially cause inductivity that negatively affected the signal. The cable being curled like an old telephone cord only contributed to this phenomenon. In HiFi, cables touching cables was generally not a good idea and to be avoided.

I also could not help but wonder, if the two channels had cables of the exact same length, as one of them needed to be run over to the other side of the headphone to reach the other driver. The relatively poor center image of the 990 PRO, especially in comparison with the T1 of the same company, made me doubt that this was the case. One could argue that this should not have mattered on a short cable run such as this. But, if this had been the case, why did Beyerdynamic not simply use the same unequal cable design on their flagship T1 headphones? The answer was simple: Because in HiFi everything mattered.

The fact that the cable was not detachable could be seen in two ways: On the positive side, a soldered connection did not inject as much mass into the signal path as a plug would have done. But on the negative side, it meant that I was stuck with the cable it came with, even though I did not like it much. No upgrade was possible in this case, unless I was prepared to take out my soldering iron and get busy soldering new connections.

The DT 990 PRO were of light weight and did not press too firmly on the temples. I could see that wearing them for many hours would not present a problem. I did find that they could get warm with time and would not recommend them in areas of high humidity or temperature. However, all this I could have easily lived with, if they had offered greater tonal balance. This was the most obvious weak point of the DT 990 PRO headphones and made them rather undesirable for audiophile listeners. It was sometimes said that they were non-linear or ‘HiFi’-sounding — whatever that meant — but I do feel this to be an understatement.

Some frequencies of the mid-band strangely seemed suppressed, either by the driver or cabinet design, or by the thick acoustic foam-padding over the drivers, as to make voices sound thinner and sharper. I tested this with three different kinds of output: my computer sound card (only when digitizing records), our Denon CD player’s internal headphone amp (for comparison), and our Douk Audio T-3 Plus tube headphone amp (during an audition). The loss in frequencies remained similar, and this, although the treble was the harshest on our T-3. Since the latter had no difficulties driving high-resistance headphones and worked very well with the Beyerdynamic T1, I assumed that the effect of a recessed mid-band was built into the headphones themselves.

Given my narrow range of amplifier equipment, it was well possible that the DT 990 PRO would have performed better in combination with other devices. However, especially having the T1 as benchmark, I find it hard to believe that any differences in source design could paste over the general tendency of the DT 990 PRO to sound unbalanced, especially on vocals.

Specifications:

• Driver Type:  single, dynamic
• Design:  over-ear, open
• Frequency range:  5 - 35.000 Hz
• Nominal impedance:  250 Ohms
• Sensitivity:  96 dB (1 mWatt, 500 Hz)
• Harmonic distortion:  0,2% (1 mWatt, 500 Hz)
• Power rating:  100 mWatts, max.
• Cable:  Single (spiralled), fixed
• Plugs: 3.5mm + 6.3mm jack
• Place of manufacture:  Germany
• Year:  2021

Following my recent exploration of the affordable T-3 Plus headphone amp by the Chinese brand Douk Audio, I was left wondering how good this little amp actually was. At the time of my test, I was lacking a pair of headphones that would be revealing and balanced enough to allow me a definite verdict from an audiophile perspective. Dissatisfied with the open ending of my exploration, I kept pondering on how to proceed, until I remembered that my friend Michael owned a pair of top-of-the-line T1 headphones from the German manufacturer Beyerdynamic. I invited Michael over to our house and asked him to bring his headphones along. That evening, we set up a test to examine the merits of both: his headphones and Douk Audio’s T-3 Plus preamplifier.

As reference, we used Luigi’s Pata Acustica speakers driven by our Hafler XL-280 power amplifier and our Dynaco PAS-4 tube preamplifier. The latter had its focus on vinyl and a great phono stage. The signal source on this system was a Technics SL1310 turntable with AT-VM 540 ML cartridge. I knew this system to offer excellent tonal balance and dynamics while being revealing enough to be highly engaging. If there was room for criticism at all, this would be in respect to bass extension. The Pata Acustica bookshelf speakers had a natural limit when it came to bass that I generally did not mind but some hard-core bass-lovers might object to.

The test system consisted of our Philips GA212 turntable with Shure M 75 ED cartridge, connected via Fast Audio cables to Douk Audio’s T-3 Plus preamplifier. This had its noise-free energy coming from a new and dedicated linear power supply. By that time, I had already decided that I preferred the Douk’s phono stage abilities to those of its line input. I have not checked, but it is well possible that the line stage is passive on the T-3. On the evening of our test, we focused on three songs on vinyl: Seasick Steve’s minimalist “Hard Knocks” representing male vocals, Helge Lien Trio’s jazzy “Gorogoro”, and Katie Melua’s relentlessly swelling vocals on “Heading Home”. We started with Seasick Steve on the Pata speakers, then moved on to the T-3 Plus with my own Beyerdynamic DT 990 PRO headphones for comparison. Finally, we connected the Beyerdynamic T1. We paused to compare our findings following each step, and although we did not agree in all aspects, our basic assessments turned out to be the same.

The male singer's voice sounded tonally most accurate via the Pata Acustica loudspeakers and very similar to this via the Beyerdynamic T1 headphones. While the loudspeakers set a wider and highly accurate stage and sounded a little fuller, the T1 sounded more intimate and reached a little lower in bass. Slightly more detail was audible on the loudspeakers, with individual notes trailing longer. However, this was mostly due to our new Audio Technica cartridge, the particular cut of its ML stylus, and the greater ability of the Technics turntable. Our own Beyerdynamic DT 990 PRO headphones, in comparison, revealed a midrange dip and did not manage to hold the music together as well as the other two contenders. This made bass sound more boomy and treble more pronounced. Additionally, it seemed as if there was a cloak over some frequencies, an over-dampening of the headphone shells, perhaps. Individual high-notes, especially, were flung deeply and seemingly detached into the cloak of darkness that otherwise prevailed. Interesting, but somehow not useful for voices and acoustic guitars.

On Helge Lien’s Jazz piece, we began with our reference speakers that gave a formidable impression of the event. We then went on to audition the DT 990 PRO first. Our reasoning for changing the original order was that we did not want to fall into the trap of fulfilling our expectations. Without vocals present, the DT 990 PRO sounded natural and exciting, lacking some of the fullness of the instruments on the Pata speakers. While the rendition was engaging and entertaining, careful listeners could notice a lack of substance. The Beyerdynamic T1 brought substance back and held the performance together. Here, the stage seemed wider, and locating instruments on stage was easier, although the speakers prevailed in the latter aspect. There was sufficient musical detail in all three contenders, but the T1 and the Pata's sounded most accomplished.

We completed our test with Katie Melua’s “Heading Home”. The recording showed a slight metallic ringing to Katie’s microphone that might have added an interesting effect on a car stereo but seemed rather misplaced in audiophile listening. Therefore, any character trait during reproduction that highlighted this effect was unwelcome. Not surprisingly, the revealing nature of the Audio Technica cartridge brought out the metallic quality of the recording. The Pata handled this rather well by tonally integrating the effect without letting it break away. This did keep the listener engaged, if only to wonder when the treble would lose control of the moment. The DT 990 PRO brought about a more unfamiliar Katie Melua, accentuating some of the rougher aspects of her voice. Katie seemed more rocky, more like a younger Pat Benatar. I enjoyed listening to this rendition of her voice, until I started longing to have the familiar Katie back. The DT 990 PRO's suppressing of selected frequencies did not come without risk, of course. On the other hand, the T1 managed Katies voice very well, partly because they did not have to struggle with input coming from an over-sensitive ML stylus. The Shure’s elliptical diamond did not add any sibilance (as it sometimes did). Consequently, the performance seemed clear and solid, although not quite as suspenseful as on the Pata system.

Beyerdynamic’s T1s are tonally accurate sounding headphones with a solid sound stage that present the music performance as a homogenous whole. The excellent materials used pay off in creating a pleasant and entertaining musical experience. These headphones deserve a good amp that can deal with high capacitance output of 300-700 Ohms. To both our surprise, the small Chinese T-3 held its own during our test, if only after upgrading, tubes, power supply, and interconnects to an audiophile level. Following these significant upgrades, I can recommend both, even in this combination.

Company History:

Beyerdynamic has a long history in audio electronics. The ‘Elektrotechnische Fabrik Eugen Beyer’, as the company was first called, had its origins in Berlin, Germany, during the 1920s. Its first products were loudspeakers for use in the emerging film palaces. Beyer's first pair of dynamic headphones, model DT 48, followed in the 1930s. With Berlin having been severely bombed during World War II, many German companies left the city ruins to seek new opportunities elsewhere. Eugen Beyer finally found a new home for his operations in Heilbronn, a German city located about 600km south-west of Berlin.

Famous Beyerdynamic products where the DT 49 (1950s) hand-held headphone, used in record shops and popular record bars, the M 160 ribbon mic (1957), and the E-1000 microphone (1965). At the time of writing this, Beyerdynamic is still based in Heilbronn and operates an American subsidiary Beyerdynamic, Inc. in Farmingdale, NY. The company offers a range of products, ranging from headphones and microphones of conferencing and interpretation equipment.

Specifications:

• Driver Type: single, front-angled, dynamic
• Design: over-ear, semi-open
• Frequency range: 5 - 50.000 Hz
• Nominal impedance: 560 Ohms
• Sensitivity: 102 dB (1 mWatt, 500 Hz)
• Harmonic distortion: 0,05% (1 mWatt, 500 Hz)
• Power rating: 300 mWatts, max.
• Maximum output: 126 dB (300 mWatts, 500 Hz)
• Cables: 2x cloth-covered OCC 7N copper
• Plugs: 3.5mm + 6.3mm jack / XLR, mic jack (optional)
• Weight: 356g / 437g with cable
• Place of manufacture: Germany
• Year: 2016, 2. generation

The popular Chinese brand 'HiFiMAN' was founded by Fang Bian in New York. It evolved from an earlier company called 'Head-Direct' that had served as web-shop and Head-Fi sponsor. Among HiFiMAN's first products were the HE-5 planar headphones that were already launched in the founding year of 2007. Within a relatively short time, the new HiFiMAN brand became notorious for products offering excellent sound quality and advanced technology at affordable prices. Their widely successful HM-802, HE-560, and HE-400i headphones were released in 2014. Fang Bian’s design philosophy, as found on his HE-400i planar magnetic headphones, was loosely based on the much higher priced, and by then legendary, Stax electrostatic headphones. However, the planar magnetic principle never was in real-world competition with Stax in terms of sonic virtues.

In an effort to bring down production costs, HiFiMAN set up two small factories in China and moved its headquarters to Tianjin in 2011. Early HiFiMAN headphones, such as the HE-5, featured wooden ear cups that had two virtues: They looked exquisite and helped the young company to keep tooling costs down. Although the use of wood served the company well in establishing its reputation as a producer of high-quality headphones, the material was prone to cracking as it aged and dried. Some of the early HiFiMAN customers sent in complaints of cracked wooden ear cups. Hence, the revised LE-version of the HE-5 featured ear cups made of plastic and already boasted some typical traits of the company’s signature planar magnetic headphones that were to follow.

At 93 decibels sensitivity and low 35 Ohms impedance, the HE-400i headphones required only moderate amplification. In practical usage this meant that some listening pleasure could be derived, even when the headphones were connected to a smartphone or computer. This was in marked contrast to the company’s earlier planar magnetic headphones that required lots of clean power to operate, bearing some similarity to electrostatic drivers. Since affordable headphone amps with lots of power were still rare to find in those days, HiFiMAN also started to build their own dedicated headphone amplifiers, such as models EF-5 and HE-6, to power their fleet.

I began my explorations of the HE-400i planar magnetic headphones driving them with our humble Douk Audio T-3 headphone amplifier, which we had only recently upgraded with General Electric JAN 5654W tubes and an ultra-linear power supply. The interconnects used in the listening test were made of solid-core silver with copper-mesh shielding and could be unforgiving of flaws in both the setup and choice of song material. I set out listening to José González’s album “Local Valley”, which offered a mixture of male vocals, lovely guitar picking, and some minimal and delicate sound effects, such as birds singing and the occasional synthesiser support. The album provided tonal balance as well as subtle bass lines in vocals and guitars. In doing so, “Local Valley” skilfully juxtaposed the close and imminent with the vast and distant to achieve an acoustically pleasing and highly entertaining effect.

The HiFiMAN headphones had come to us packaged in a posh-looking black box clad with leatherette. In this box, the HE-400i were pressed so firmly and the cable rolled so tightly that I could not help but wonder if the box design would serve to protect its contents or rather damage the cable and ear cushions in the long run. I also noticed that the previous owner had lost or misplaced the additional 6.35 mm adaptor, because this was not enclosed it in the box. As the 3.5mm plug was angled, finding a replacement appeared to become a challenge. I put on the headphones, leaned back to listen, and immediately noticed that the original cable was too short for my sitting position. I could see how, at a mere 1.5m in length, the stiff and cloth-covered headphone cable could turn out to be too short for a whole range of applications. Replacement cables could be found online, of course. However, purchasing new cables of similar quality would drive up the price of these otherwise affordable headphones.

I thought it best to compare the HiFiMAN HE-400i with our similarly priced AKG K712 Pro headphones. According to my research, the HE-400i had initially been sold for about 400.00 EUR in Germany and then dropped in price to 200.00 EUR, before they sold out in 2018/2019. Our AKG K712 Pro first entered the market at about 300.00 EUR in Germany and then dropped to just under 200.00 EUR, following the Christmas sale of 2021. As they were similar in price and completely different in terms of technology, they seemed to be worthy opponents to me. In order not to be biased by my existing listening habits, I made sure to listen to José González’s complete album on the HE-400i first. This would give Fang Bian's planar headphones and myself some time to adjust, as I could not be sure how long they had been sitting on the shelf, before I arrived at their owner's doorstep to free them from their fate.

One of the first things I noticed was that the HE-400i planar magnetic headphones created a compact and focused image. The music seemed to be close and intimate, however, the impression was not so much of a lover whispering tender words in my ear; instead, it appeared slightly directive. The only exception to this being the birds on José González’s album, which seemed delicate and distant due to the recorded effects. There was a certain robustness to the presentation that took me by surprise and also some getting used to. And, although the ear cups were sealed with a tight metal grid that optically veiled the planar magnetic drivers underneath, the headphones provided little shielding from ambient noise. This made them ideal for critical listening in low-noise environments at home or in the studio. The fact that their music also radiated outward to considerable extent, as it did on most semi-open designs, could make them tricky to use in the monitoring of studio recordings.

The HE-400i presented lots of drive and a tonally accurate midrange, with both male and female vocals sounding natural and full-bodied. There was, however, a limited sense of spacial separation between the singer’s voice and instruments in the room. Surprisingly for planar magnetic headphones, the HE-400i more resembled our Sennheiser HD 580 in this respect. In terms of spacial and tonal separation, the conventionally driven AKG K712 Pro were far superior. Perhaps I would have expected a little more agility from planar magnetic headphones, simply because of their low-mass foil design. While the midband was quite solid and seductive, the lack of agility also showed in the treble, which cut back earlier than on the AKG. The HE-400i started dropping off at 35,000 Hz, which was almost 5,000 Hz sooner than the AKG. And, while treble extension above 22,000 Hz is considered a ‘nice-to-have’ by those pointing out the limits of human hearing, this much difference in treble performance naturally affected the ability of the driver to fully generate the impression of space and dimension in the music. On the positive side, neither the AKG nor the HIFIMAN suffered from an unpleasant accentuation of frequencies.

The HE-400i sounded less edgy when driven with sibilant music material, partly because they were less expressive in the high frequency range. They served well to highlight issues in the mid-band, where they were quite accurate. Bass performance was smooth and natural, showing a slight hump in the lower mid-bass that could have been caused by ear cup resonances interacting with the planar driver. This did contribute to a warmer and fuller sound and was not necessarily a negative aspect for music enjoyment, as it could be perceived as rather endearing. Bass roll-off was at 20 Hz, i.e., a full 10 Hz higher than on the AKG K712 Pro. While this was not a whole lot of difference, AKG did state in their sales material that the K712 Pro was designed with a +3dB increase in bass-extension. This served well to balance out the AKG’s spacious highs without being discernible as a bass-effect itself. The HE-400i seemed more compact in this discipline as well. On the whole, I found the HE-400i to be accurate and smooth-sounding headphones that lacked some refinement in terms of tonal and spacial presentation, especially in direct comparison with our highly engaging AKG K712 Pro headphones.

I had originally embarked on my tour of exploration aiming to learn about the merits of planar magnetic designs as opposed to headphones with conventional drivers. The HE-400i showed me that decent sound performance can be achieved using both concepts. HiFiMAN was still a relatively new contender on the market whose biggest contribution to Hi-Fi was to make planar magnetic designs accessible to the average consumer. However, this did not mean that conventional driver concepts needed to fear being outclassed. AKG, Beyerdynamic, and other experienced headphone manufacturers, were perfectly capable of competing from a sonic perspective and still had the upper hand in some disciplines. For planar magnetic headphones to achieve the acoustic performance of the electrostatic designs of AKG and Stax, it would take far better drivers and amplifiers than we had available with the HE-400i headphones and our humble Douk Audio headphone amp.

Specifications

• Driver type: single-ended planar-magnetic
• Design: over-ear, semi-open
• Frequency range: 20 - 35,000 Hz
• Nominal impedance: 35 Ohms
• Sensitivity: 93 dB (1mWatt, 1.000 Hz)
• Power rating: 200 mWatts, max.
• Cables: cloth-covered, Y-shaped
• Connector: detachable (mini-jack)
• Cable length(s): 1.5m
• Plugs: 3.5mm + 6.35 mm jack
• Place of manufacture: China
• Weight: 370g (without cable)
• Year(s): 2013 - 2018

In my recent article on the Beyerdynamic DT 990 PRO, I wrote that my reason for purchasing new headphones had been that I could not remember who I had given my old Sennheisers to. Some weeks later, I found them at my parents’s house, next to an unused field recorder. As it turned out, the Sennheisers were much older than I remembered (and had professed in my article). A faded and wrinkled receipt showed that I had bought them at Galeria Kaufhof in 1996. All the more, I was surprised to find them still in good shape, even after 25 years. And something else surprised me: Even before listening to them again, I still had a solid memory of their sound.

Before purchasing my Sennheiser HD 580s, I had listened to music with a set of closed Panasonic studio monitors that we had bought in New York during the 1980s for the pretty steep price of 250.00 USD. I remember that they had impressive bass and were able to lift the ear-pieces off your head. They also featured an otherwise decent sound. I carried them around until the cushions disintegrated and their black and flaky residue would be clinging to my hair for the rest of the day. At the time, I was reluctant to give them up. And switching to the open Sennheiser HD 580 seemed to be a sonic step back. Everything I had loved about the Panasonic headphones was gone. Instead, there was this barren new clarity, a quality that I had trouble warming up to at the time.

Perhaps this was partly due to the fact that the relatively high impedance of 300 Ohms made them more difficult to drive with the equipment I owned in the 90s. It seems that these headphones were directed at the professional market, where high impedance is less of a problem. And, since the Pioneer had been of closed design, the semi-open Sennheisers seemed far less punchy in bass. This made me miss the familiar fullness of the lower frequencies. However, dusting them off and listening to them again after so many years, with years of discerning speaker auditions having gone by, my taste in sound and music had also matured, and the Sennheisers left a much more balanced impression than they used to. I was able to see the advantages of such an open design. It all depended on the application.

On professional recording equipment, such as our Zoom H4n, the HD 580 did do quite a wonderful job in depicting voices and stage dimensions. I noticed this first when I played back a recording of my father playing the guitar. Both the guitar and my father sounded so realistic that I had to look up from the monitor to check if he had started playing again. I was amazed to find him sitting with his hands by his side, patiently waiting for me to finish my listening check. A simmilar effect happened, when I was listening to my recording of Luigi’s Snell C-IV loudspeakers playing the first song of Jörg Hegemann’s “Foot Tappin’ Boogie” album. I had set up two large-diaphragm studio mics, pressed record, and then walked across the room to turn on the CD player. Listening to this again during video production a few days later, I repeatedly looked up, fully convinced that someone was approaching me from behind. The impression was fabulously real.

When it came to voices, the Sennheiser HD 580 deserved the name ‘precision’. Tonal accuracy would have been an even better name. And this character trait did not depend so much on the equipment driving them, either. On the other hand, they were not particularly strong in terms of bass extension. For optimum bass, they required a strong dedicated headphone amp. On our T-3 Plus with GE tubes, the HD 580 showed a punchy mid-bass, but lower bass frequencies were still under-represented to the extent that it took some getting used to. At the higher end of the spectrum, the Sennheisers tended to focus on the essence only. Sadly, this meant losing some of the nuances and subtle transients of the music. This made them excellent companions for smaller recording studios to monitor the tonal balance of voices and guitars but also rather useless for genuine audiophile listening, which was perhaps not surprising given their relatively low price point.

As I found out when doing research on the specifications, there is a real HD 580 fan community out there. And, to my delight, I even managed to find a new replacement head-cushion for my Sennheisers online (not yet shown in the photos). They were well-worth keeping, if only for monitoring future studio sessions with our Zoom recorder. In this scenario, I could not imagine anything more useful.

Company History

Fritz Sennheiser set up operations in a farm house near Hanover in 1945 post-war Germany. His young start-up Laboratorium Wennebostel, or ‘Lab W’, soon became a supplier of measuring equipment to Siemens. In 1958, the company changed its name to Sennheiser electronic. Although Sennheiser’s MD 1 mic still borrowed heavily from existing microphone designs, the MD 2 mic was of the company’s own engineering. Other microphones soon followed, with the first Sennheiser wireless microphone system reaching the market in 1957. In 1960, the company introduced its famous MD 421 microphone, which is still available in stores today.

The company produced a range of successful products and soon expanded to form subsidiaries in over 20 countries. Famous headphones include the HD 25 (1988), the Orpheus electrostatic headphones (1991), the HD 800 high-end headphones (2009), and the electrostatic Orpheus successor HE 1 (2015). Both the Orpheus and the HD 800 are considered to be top-of-their-range products. At the time of writing this article, the company is run by the Sennheiser family in its 3rd generation.

Specifications:

• Driver type: single, dynamic
• Design: over-ear, semi-open
• Frequency range: 16 - 30,000 Hz (-3 dB)
• Impedance: 300 Ohms
• Sensitivity: 97 dB (1,000 Hz)
• Harmonic distortion: < 0.1 dB
• Plugs: 3.5mm + 6.3mm jack
• Weight: 260 grams
• Place of manufacture: Ireland
• Cable length: 3m
• Year(s): 1993 - 1997

I must confess that when my colleague returned from a family trip to the USA and happily reported that he had been gifted with a set of Sony MDR-7506 studio headphones, this did not immediately ring a bell with me. There were two main reasons for my ignorance: It had not been until recently that I had developed an interest in headphones, and my previous impressions of Sony gear had been mediocre at best. Sony used to be quite popular in the low to mid-price consumer market during the 80s and 90s, and this had given the brand the tag ‘OK for the price’, which is close to a death sentence coming from an audiophile, or, as the German pun on the brand name goes: So nie.

When Landon and I took a closer look at the headphones at our Frankfurt office, we found that the soft black imitation leather ear pads were starting to disintegrate from old age. I suggested they might still be available as replacement parts online, and Landon managed to find a reasonably-priced pair of red cushions. I later learned that all the parts used on the MDR-7506 headphones were easily serviceable and available from a host of suppliers. Serviceability has always played a major role in the maintenance of vintage gear, and the Sony studio headphones were certainly not lacking in this respect.

The serviceability and availability of parts would also have been an important aspect for professional users of these headphones. The larger studios of the 90s would own a large number of headphones that was often used by careless studio guests and amateurs alike. The possibility to replace a broken driver or ear pad right at the studio without having to send the headphones in to Sony for servicing would have saved the studio time a money. This also explained why so many MDR-7506 were still around.

Made for professional studio monitoring, the MDR-7506 were of a closed back design. This had two advantages: in the mixing room, the closed and damped shell served well to cancel out ambient noise, and noise radiating from the headphones would less likely find its way into the recording. Wearing the headphones for longer periods of time, I was surprised how well the lightweight ear cups worked in sealing me off from the outside world.

At 230 grams, the MDR-7506 were the lightest headphones I had tested. However this did not mean that they felt light or frail in handling or when wearing them on the head. The single headband was adjustable in size and held the ear pieces firmly in position. At first I was surprised to find that the cushions pressed my ears down flat against my head, but I soon did not notice it anymore. In fact, I was reminded of my dad’s old Panasonic Studio Headphones that had softer inner cushions to minimise the pressure. Wearing glasses with thick temples might be a bit of a challenge, however, I had no problems wearing my glasses with flat temples on the side.

I had mixed feelings about the mechanism that allowed the ear cups to be folded upward into the headband. On the one hand, I could see the advantage of being able to store the headphones in a smaller space. On the other hand, the ear cups continuously folded up in scenarios where this was neither needed nor desired. It was well possible that this feature had been a little tighter when they were new. The other aspect I did not enjoy so much was the non-detachable coiled up cable. Having accidentally rolled over the cable of my AKG headphones with our office chair a few days earlier, I could understand the obvious benefit of having a cable that kept itself short. However, as I was usually sitting quite far from our equipment, I would have prefer to be given a choice. For this reason, AKG offers cables with plugs on the side of the headphones as well as the source.

I began my listening explorations with Helge Lien Trio’s “Album 10”. This begins softly and slowly builds up in loudness and speed with each new song. The music source was our Marantz CD-17 CD player paired with a Cambridge DAC Magic. I could feel the little bit of pressure on the ears and heard the slight ringing from long day at the computer. I heard very little from the surrounding, which was a completely different starting point from my AKG K712 Pro headphones that basically incorporated the room in the listening experience and featured large open-back cups in which the ears could maintain their natural position.

I noticed that the MDR-7506 sounded less airy and more compact in terms of proximity to the listener and also soundstage. They played slightly louder than the AKG and offered a fuller sound with a slightly thickened bass. This more robust bass foundation would serve well when listening to Rock, Pop, or Metal music but most likely come across as emphasis in Jazz or Classical music. I did not notice any bothersome shell resonances as you will find on cheaper and less well-made headphones.

Paired with our Douk Audio T-1 headphone amp with GE tubes, the top end sounded sweet and pleasing. I must say that the JAN 5654W were some formidable tubes for this amp, and the Sony headphones did not take away from their magic. At low volumes, the MDR-7506 sounded a little robust with fast-decaying transients, but at higher listening volumes, the PET diaphragm managed to free itself better, and the music became more spacious and more accurate. Even when playing at higher volumes, bass frequencies did not dominate the music as I had initially feared.

In direct comparison, I found the AKGs to be tonally more accurate and revealing, especially when listening at lower volumes. There was just a bit more insight into the music that served well to gauge the depth and width of each recording. This is not to say that the Sonys were far off, however, which did come as a surprise given the 30+ years of material ageing and scientific advances. I actually found the MDR-7506 to be superior to the Beyerdynamic DT990 Pro and the AKG K702, both of which I have had here for testing and also seen in heavy use at various studios. If I had to come up with an adhoc ranking of headphones, my list for audiophile listening would look like this:

My Current Headphone Ranking

1. AKG K712 Pro (the most balanced and tonally accurate)
2. Beyerdynamic T1 (nothing to complain about, except for the price)
3. Stax New SR-3 (difficult to set up and operate, but sweeeet)
4. Sony MDR-7506 (good monitor functions and natural tonality)
5. HiFiMAN HE-400i (balanced but a little on the bland side)
6. AKG K702 (generally alright but unbalanced, leaning toward bright)
7. Sennheiser HD 580 (sweet midrange, lacking precision and bass)
8. Beyerdynamic DT 990 (pop-sound with muffled midrange)

Having listened to Helge Lien on CD, I started our Technics SL-1310 with Audio Technica VM 540 ML cartridge to play Fleetwood Mac’s album “Rumours” on vinyl. This made for an enjoyable experience. Returning to our AKG for a quick check, I was surprised how much thinner they sounded. The MDR-7506 here offered a strong and punchy mid-bass with a rhythmical forward drive. As before, they cut a little short in decay and offered slightly less tonal insight. As such, I was reminded of the sound of the 80s and 90s in which sonic finesse was reserved for the ultra-high end of the market. And still I found that the presentation worked very well with the music from the period.

I could see less discerning listeners enjoying the more robust sound of the Sony MDR-7506 more than the AKG, because it was generally more forgiving of the subtle differences in the recordings. Whereas the AKG invited the listener to look past each recording at the spaces that were not sufficiently covered or overly smothered by the music material, the MDR-7506 took the music more at face value and encouraged a more general appreciation of sound. This works quite well and places the Sony above some well-known competitors of its time and beyond.

Specifications

• Type: dynamic studio headphones
• Special features: foldable head band
• Earpiece: on-ear supra-aural, closed-back
• Driver type: 40mm dynamic, neodymium magnets
• Diaphragm: polyethylene terephthalate (PET)
• Nominal impedance: 63 Ohms
• Frequency response: 10 Hz to 20,000 Hz
• Power sensitivity: 106 dB/mW
• Maximum power handling:  1,000 mW
• Plug type: headphone 3.5 mm, TRS
• Connector: gold plated
• Cable design: fixed, coiled
• Cable Length: 1m to 3m (max.)
• Available color(s):  black
• Weight: 230 g
• Country of manufacture: Japan
• Year(s): from 1991
• Preceded by: Sony MDR-V6 (1985)

It all started when Luigi received a pair of 1971 to 1975 Stax headphones and dropped them off at our office for testing. I was just finishing up an article on Jörg Hegemann‘s "High End Boogie Woogie" recording sessions at Hansahaus Studios and could see that this would take some time to complete. However, Luigi suggested that he would not need the headphones back anytime soon and insisted that I give them a try. One reason for his curiosity may have been that I had just completed a series of reviews covering more conventional headphones, and the Stax were of electrostatic design, ‘ear speakers’ as Stax had lovingly christened them.

The most far-out headphone design that I had previously tested had been HiFiMAN’s planar magnetic HE-400i. The planar design concept had often been compared with electrostatic designs, and, I guess, Luigi and I were both eager to learn what the fuss was about. I was not a novice to electrostatic technology either, having run a pair of Martin Logan SL-3 loudspeakers on our main system for a number of years. There was much to suggest that—despite their biblical age—auditioning the New SR-3 series would turn out to be an enjoyable and worthwhile experience for us.

Following my article of a Thorens TD 320 turntable, I once again found myself with some time on my hands and connected the Stax converter model SRD-6/SB to the speaker terminals of our Hafler XL280 amplifier. The way the Stax input cable was designed, it needed an amplifier that had its binding posts for both channels in close proximity to each other. Since this was not the case on our other amplifiers, the Hafler seemed a given. Our input sources were a Technics SL1310 turntable with AT VM540 ML cartridge and a Marantz CD17 CD player paired with a Cambridge DACMagic with upgraded ZeroZone power supply. All peripheral components assured that we had excellent signal quality coming to the Hafler, the latter of which was a true ultra-linear MOSFET powerhouse in its own right.

It first seemed strange to power a small set of headphones with a 145 watts RMS per channel amplifier, however, such was the preferred playing field of the electrostatic design. The two stators in the headphones needed to bridge a gap of 300 microns by means of static electricity and this could take some time and power to build up. I noticed that for the first 20-30 minutes after switching on, the Stax New SR-3 still sounded dull and lifeless, character traits that are not commonly associated with nimble foil drivers. Once fully charged, however, the sound became more agile. Initial channel imbalances were soon forgotten. It was possible, however, that a hair got caught in the stator, leading to a popping discharge of stator bias. This could make the afflicted side lose volume for a few minutes, until the full bias charge was replenished. Our electrostatic Martin Logan loudspeakers, by comparison, did not (and could not) rely on amplification alone to charge their stators and were instead connected to the power grid for stable power potential on the stators. I could see the benefit.

Being somewhat used to our AKG K712 Pro headphones, the Stax ultra-balanced sound took a moment getting used to, before their true merits started to shine through, making me wonder how I had managed not to notice them right from the start. Let me be ultra-clear on this: With the Stax we are talking serious headphones, not some half-baked Bluetooth fashion article with fancy noise cancelling that also cancelled out half the music in the process, as I had heard plenty from both Sony and JBL headphones. No, the Stax SR-3 were, like the AKG K712 Pro, serious listening tools for those who were sensitive to how their music sounds.

Despite their advanced age, the Stax SR-3 offered superb tonal accuracy that allowed the differentiation between a myriad of natural instruments and playing styles. This became especially apparent when many musicians were playing their instruments at the same time, e.g. in Classical music or more complex Jazz arrangements. Instrument separation was the best I had heard and—due to the proximity of the drivers—even surpassed that of our Martin Logan SL-3 speakers. The overall impression was a combination of immediacy and attack, with the music at times crashing out of the headphones with a vengeance. And yet, the stage remained close and intimate, definitely not as spacious as I was used to from our K712 Pros. Similar to our AKGs the Stax excelled at providing lots of high resolution and nuance. Their special strength lay in a superior sense of order at very low noise levels. Natural instruments, piano keys, and metallic sounds benefited from the SR-3’s superb tonal colours. With the stators fully charged, there was a good sense of mid-bass punch, too, which made mid-size drums really come alive.

On the downside, bass extension could have been better, especially in direct comparison with our AKG headphones. From the model I tested, I would have to disagree with Ken Rockwell that this was simply the result of their superior linearity. Some aspects of the lower bass spectrum were simply missing from the music. Bass dynamics also could have been more pronounced on my test sample. This could have been a result of the physical age of the headphones, of course. Half a century must have had an affect on the materials, even if the electronics of the drive unit had recently been serviced and restored where necessary. Another factor to be considered was the Stax’s need for lots of clean amplifier power, which needed to be available at least 30min before each listing session for the stators to be properly charged. Not many people will be able to set aside such a formidable amplifier for the purpose of powering their headphones. And, although the Stax drive unit SRD-6/SB was designed to pass the amp signal through to the main speakers, permanently placing the small black box and its outdated terminal clamps in the signal path of your everyday system would probably not be a great idea.

The Stax offered what I would describe as tonal robustness, that is to say, they produced natural tonal colours that seemed more crude, raw, and realistic than on our more pleasant and refined sounding AKG headphones. In female vocals, there could be a trace of confinement and squeakiness at times, as if the vocals were conveyed via a public address system. I listened to this effect many times over, once even falling asleep during the analysis, and, in the end, I had the impression that the compression was the result of the closed back of the ear cups reflecting back the sound. As I did not conduct any measurements, there could be a host of other reasons for this phenomenon as well. Later Stax headphones had open back ear cups that allowed the inverted outward frequencies to disperse and fade into the environment more naturally, instead of being folded back through the diaphragm. In our listening room, the Martin Logan speakers are given at least three feet distance to the front wall to sufficiently delay the reflected sound.

The New SR-3 headphones presented a wonderful opportunity for us to experience the electrostatic design first hand. For those of us who do not mind having a spare power amplifier on standby, the SR-3 deliver at least 80% of what can be expected from electrostatic headphone designs, and this at a small fraction of the usual price. One needs to consider that, after half a century, the electronics might need looking at, and one needs to be sure to audition them before making a purchase. However, without directly comparing the SR-3 with modern headphones such as the AKG 712 Pro, they offer everything it takes to find great joy in listening to music. It is only in direct comparison that our AKG’s superb design managed to show a bit more of everything, perhaps with the exception of the Stax’s raw tonal colours, a discipline in which the SR-3 are difficult to beat.

Specifications

• Diaphragm: ultra-thin, approx. 5 microns thick*
• Stator electrode gap: approx. 300 microns*
• Input: Stax standard (230 V bias) 6-pin adapter energizer
• Impedance: approx. 130,000 Ohms* @ 10,000 Hz
• Capacitance: approx. 120 pF*
• Sensitivity: 95-100 dB @ 100V RMS*
• Frequency range: approx. 30 - 25,000 Hz*
• Cord design: straight, supple cloth-covered
• Cable length: 2.5 meters, 6 mm
• Weight: 290g without cord; 373g with cord
• Drive unit: model SRD-6/SB
• Drive unit polarity: (R) +red -black / (L) +white -green
• Country of manufacture: Japan
• Year(s): 1971 - 1975

*measurements and estimates by Ken Rockwell, 2011

“Is nothing sacred?” was the title of Salman Rushdie’s famous essay that he wrote in defence of his 1988 novel ‘The Satanic Verses’. As it so happened, his work of fiction had prompted Iran’s Ayatollah Khomeini to declare a worldwide ‘fatwa’ on Rushdie, which was, in essence, an order for the author to be killed. With his essay, Rushdie was hoping to mobilise sympathy for his train of thought, unfortunately, without much success. The author had to remain in hiding for years to come. As Rushdie pointed out in his essay, the question “Is nothing sacred?” is usually of rhetorical nature and posed in hope of reaffirming agreement or arousing mutual outrage, whenever an established system of belief is threatened by the careless non-believer: A church that is turned into a restaurant or discotheque. — Is nothing sacred?

This same question must have been on the mind of my friend and fellow audiophile Luigi, when he learnt that I was making preparations for an article on a cheap Chinese import preamp by the ‘eBay-brand’ Douk Audio. Considering the line-up of reputable audio devices presented on this website, my musings on the price-driven T-3 to the well-seasoned Hi-Fi connoisseur must have seemed like a wilful attempt at dismantling my credibility. “I don’t know anyone, who is serious about Hi-Fi and would consider making such a purchase” was his impromptu view of my endeavour.

I could understand his objections, of course. In purchasing audio legends from the past, we had the clear advantage of hindsight. Over their sometimes 40+ years of existence, the true gems of historical audio engineering stood out from the unworthy rest like beacons in the night. And, making purchases from one connoisseur to another, the true merits of each unit were mostl well documented, and the risk of making a financial loss was minimal. The sonic discoveries were glorious. Under the radar and far from the regular consumer claptrap, we found ourselves protected in the world of the informed. Why would I open Pandora’s box for a new and far away contender, when there was still so much of worthwhile history waiting to be rediscovered?

On the other hand, many of today’s legends started out as unorthodox price breakers in their own right. If you think of David Hafler, for example, and his affordable Heathkit audio gems, these, too, were in stark opposition to the more established (and pricier) Harman Kardon designs, and they were often frowned upon by the more established brands. Hafler’s designs earned their reputation and their eternal place in our hearts mostly based on their sonic virtues. In this context, it would be interesting to draw up a comparison between low-price engineering successes and their higher priced counterparts. There would ultimately be some surprises, because a product’s merits can best be gauged by how satisfactory it is to the owner over the course time. A point at which existing vintage models clearly have the upper hand.

I came across the T-3 Plus when I was preparing to digitise records for a friend of mine. Charles had seen his record collection flooded in the recent heavy rainfalls and had decided to leave what he could salvage with me for restoration and safe-keeping. In return, he had asked me to create CD-quality files for him that he could store and play on his computer. Suddenly faced with this new task, I realised that I did not have a headphone amp that would allow me to match our 250 Ohm headphones with the sound card of my computer. At the time, I still had limited experience with headphones, dedicated headphone amps, or digitising records. Not a great starting point, except for those with the heart of an explorer. And so, I set out to search the web for a reasonably priced headphone amp, taking into consideration new and used units alike.

The T-3 Plus caught my attention because it had a fashionable Steampunk look about itself. It stood upright and combined both dark-brown metal and wooden elements. The industrial look was further highlighted by the tube sockets being conveniently located along its top. It also featured built-in RIAA correction for MM and MC turntables, the combination of which was rare among the smaller tube preamps. I was pleasantly surprised that it also featured micro-switches that would allow me to adapt its input to the exact specifications of the phono cartridge in use. OK, and it probably helped my decision that, after looking at the T-3 Plus just once, it continued to be displayed to me during my following searches. I could have cleared my cookies, but I decided that I did not mind. When I made the purchase I was fully aware that this might be considered blasphemy by the hard-core believer. To me it was an act of inquisitive playfulness at most.

The T-3 Plus arrived here well-packaged in a foamed box of organic grey cardboard with the words “Transmit nature music” written on it. Except for the poor English, nothing about the packaging suggested that this had been designed carelessly. The box contained the preamplifier, a set of Chinese 6A2 825M vacuum tubes, a cheap 1.5 ampere switching power supply, and one 3.5mm to RCA auxiliary interconnect. Unfortunately, both the interconnect and the power supply were of such poor sonic integrity that they would work against Douk Audio’s mission statement of transmitting natural music. — I also had a suspicion about the quality of the tubes, but I was willing to give them a try before making a decision about them.

Although T-3 Plus was of satisfactory build quality, I noticed that it was delivered without rubber feet that would help the unit stay in place in the event of a accidental tugging on the headphone cord. I still had some anti-slip feet available and attached them to the base. The front of the unit featured the 3.5mm headphone socket and a single knob for operation. Although I liked the idea of the power switch being part of the volume control, I did find the dial itself fragile. A bit more resistance would have been desirable. If given a choice, I would also have chosen larger headphone jacks over the smaller ones. The back of the T-3 Plus featured RCA/cinch sockets for phono with a massive gold-plated ground prong. I would have liked to see the same RCA/cinch standard as auxiliary input as well, rather than having to purchase a dedicated interconnect for a 3.5mm socket. Additionally, a manual selector between the two inputs would have been desirable, instead of giving the auxiliary signal automatic priority when connected.

I began my listening adventure with our trusted Denon DCD-1420 player as music source. The T-3 Plus was connected via its original accessories: the cheap interconnect, tubes, and power supply. Unsurprisingly, the music sounded flat and stale, lacking rhythm, excitement, etc. I compared the sound to our Denon’s onboard headphone amp and found the Denon to be far superior. I then understood that some major changes would be necessary in order to get this little headphone amp to shine — if it was possible at all. So, in true explorer spirit, I scanned the web for a linear power supply. Many of the supplies I found had displays that showed the mains voltage and similar futile information. For audiophile listening, I had to make sure that our power supply was free from noise factors. I also contacted Mr Becker and asked him to manufacture a 3.5mm to RCA interconnect for me. I wanted to make sure that I was listening to the headphone amp rather than the cable. We decided on a solid core silver interconnect with Elecaudio’s silver-plated tellurium-copper on the side of the source, and Oyaide’s P-3.5SR silver-plated rhodium plug on the side of the amp.

The power supply and interconnect arrived about three weeks later. I decided that I would give all parts a break-in time of at least 80 hours. To do so, I let our DCD-1420 play for a few hours each day, mostly during working time, in order to monitor the sonic development at a certain interval. While the linear transformer did improve bass response right from the start, the new silver interconnects laid bare some strange metallic sibilance in the treble that, once identified as such, troubled me each time I listened. And, while the T-3 Plus had matured in bass and rhythm, the Denon’s internal headphone amp still had the lead in terms of spacial and tonal accuracy. I was starting to be a little frustrated and suspected the tubes to be the culprit. Some research on the subject brought to light that Chinese 6A2 825M vacuum tubes can be purchased for 3.00 EUR a pair, whereas audiophile vacuum tubes rarely sell below ten times this amount for a matched pair. I was willing to expand my experience in ‘tube rolling’ and contacted Douk Audio for advice. They wrote back to me the following day, giving me a list of possible replacements: 6J1, 6J2, 6J5, 6K4, 6*1N, and 5654.

Since I was still a relative novice in the subject of vacuum tubes, I conducted another web search and came across an article by Rainer Uhlmann published on the audionist.de website, in which Rainer, a musician, described how different tubes affected the music in his listening setup. He explains his findings in such vivid terms that I, too, managed to get a good impression of the potential differences between them. The tubes used in his experiments were:

• Western Electric WE 403B
• RCA 5654 Command
• Mullard CV4010
• Raytheon JAN-CRP-5654
• General Electric JAN 5654W
• Voskhod 6Ж1П-EB (= 6ZH1P-EV o. 6J1P-EV)
• Ericsson 5591

From Rainer’s description, I shortlisted three tubes: Mullard CV4010, General Electric JAN 5654W, and Ericsson 5591. Looking for the most versatile performer, I ended up purchasing a matched pair of JAN 5654W tubes. Unfortunately, this meant having to leave the Mullard and Ericsson tubes for another project. As to my order, I was not sure what to make of the branding of the JAN 5654W tubes as 'General Electric'. The vendor was the Chinese Hi-Fi seller 'Nobsound' who operated on a similar basis as Douk Audio, showing their products mostly on AliExpress, eBay, and Amazon. I doubted that General Electric still made tubes. And the tubes did not look as though they were 'New Old Stock' (NOS), either. I assume that they were instead manufactured in China (like everything else these days), using old General Electric tube patents and designs. If you know more about this, your comment would be much appreciated.

On the day the new tubes arrived, I started listening straight away with great apprehension and was deeply disappointed to find that the metallic sibilance in the treble still remained. It seemed as if there was a tonal up-shift that affected the complete spectrum and caused the sound to be unnaturally bright. Since burning in the tubes for 80 hours had shown no effect on my previous setup, I was not very hopeful that I would see much of an improvement this time around. Still, I decided to give the headphone amp a final chance to shine. I let it play music for five hours a day over a period of five days and made a point not to listen during this time. When I finally returned for auditioning, I found that the JAN 5654W tubes proved less resistant to burn-in and showed a much-improved performance. The top-end had meanwhile become softer and developed a teasing warmth and affection. During passages in which I used to fear being attacked with the harsh sibilance of female vocals, I could now feel a playful attraction. The space between individual instruments had increased, and there was now sufficient sonic width and depth. I could see myself listening for fun and relaxation in this setup without having to suffer any harshness.

Before reaching the technical limits of the T-3 Plus headphone amp, I was able to hear the shortcomings of my monitor headphones. These were the older 300 Ohm Sennheiser HD580 from 1996 and the more recent 250 Ohm Beyerdynamic DT 990 PRO from 2021. Both of these could be classified as entry-level headphones, although the DT 990 PRO could also be found in professional studio applications. While the Sennheiser managed to hold the mid-band frequencies together and gave a more solid-sounding performance, it lacked bass extension and lost most of the delicate transients. The Beyerdynamic, on the other hand, had wonderful bass extension but was lacking mid-bass punch. It gave lots of room to transients and managed great instrument separation, perhaps at the cost of losing the performance as a homogenous whole. It seemed as some frequencies were purposefully muffled in order to give others prevalence, which resulted in a somehow muffled sound in which room aspects where missing.

I ended my exploration of Douk Audio’s T-3 Plus with mixed emotions. While the basic unit was available at an entry-level price, I found that serious audiophiles would need to invest at least twice this amount on the periphery to raise its performance to an acceptable level. Connectivity, as well, entailed some compromises that made this unit a niche product for very specific scenarios. In order to give you a definite verdict on T-3’s full capabilities, I would have needed to invest in equally as capable headphones, a shortcoming that I had yet been unaware of. Therefore, be sure to consider these factors in application before making a purchase, and then decide for yourself, how deep into the rabbit hole you are prepared to crawl. I certainly enjoyed the trip, perhaps because it was unorthodox and almost forbidden. And while doctrine would force us to make a choice between good and evil, loyalty or blasphemy, the open road of exploration meanders freely and ultimatley becomes an amalgamate of the two sides.

Note: For further exploration of Douk Audio’s T-3 Plus see my article on the Beyerdynamic T1 headphones which helped shed more light on the subject.

Specifications:

• Type: Tube Headphone Amplifier / Preamplifier

• Audio inputs: RCA phono / 3.5mm Auxiliary

• Audio outputs: 3.5mm headphone / RCA stereo

  Auxiliary Input

• AUX input level: 1V

• RCA output level: 2V (max.)

• Frequency response: 20 -20.000 Hz, -1dB

• Total harmonic distortion: 0.01%

• Signal to noise ratio: 100dB

  Phono Input

• Phono input: 0.005V

• RCA output: MM = 530mW (max.) / MC = 5V

• RIAA correction

• Total harmonic distortion: 0.2%

• Signal to noise ratio: 89dB

  Headphones

• Headphone output: 130mW@32Ω

• Headphone impedance: 32-300Ω

• Operating voltage: DC 12V

• Dimensions:  v(W) 50mm; (D) 120mm; (H) 138mm

• Weight: 540g / 1.19lb

• Year: 2021