Explorations in Audio

Karsten Hein

Are you ready to Explore?

In 'Explorations in Audio' I aim to share some practical insights on setting up and optimising an affordable HiFi system. Although one would think that, really, all has been said about HiFi, some surprisingly simple questions still remain, e.g.: 'Is digital superior to analogue?' 'Do cables matter?' 'Can digital cables pick up interference?' 'Should speakers be placed on spikes?' 'Has evolution in HiFi made older gear obsolete?' 'Where should I place my sub?' 'Which room correction works best?' - On the other hand: 'Are these really the right questions?' - We shall see.

What's new in eiaudio?

While the entries in this blog are divided into the three distinct categories above, you will find a mixed listing of the most recent postings below. The most recent article is shown first. If this is not your first time visiting, the listing below is a good place to quickly check if anything is new.

Your input is more than welcome, as long as you follow the basic audiophile rule of ‘ear over mind’. This means that you do not comment based on what you think you know, but only on the basis of your own listening experience. Please feel free to suggest gear for testing as well as leave comments on the descriptions provided here.

  • Symphonic Line RG2-MK3

    Symphonic Line RG2-MK3


    Author: Karsten Hein

    Category: Gear & Review

    Tag(s): Pre-Amplifiers

    More Room for High End

    The RG2 MK3 is a preamplifier designed by Rolf Gemein and hand-crafted at Symphonic Line in Duisburg, Germany. Rolf Gemein was among the first audio designers in Germany to adopt the term ‘High End’ for his uncompromising audio products. He soon teamed up with other German developers of exceptional audio gear to form the ‘Deutsche High End Society’ and went on to initiate the High End audio fair in Munich, which has since become the largest event of its kind in the world. 

    The RG2 preamplifier in its third (MK3) iteration deserves to be thought of as a High End product in multiple ways. Its heavy body is made of 2mm-thick sheets of brass for superior RF protection. Its 10mm-strong face plate with turned full-metal knobs feels as though it was made for eternity; a quality impression that is underscored by its chrome-plated Aranja (or grapefruit) tinted-mirror shine. Everything about the look and feel of this preamp suggests that it is of exceptional quality. And those who have come in contact with Symphonic Line products would expect no less.

    Connoisseurs of the brand will also appreciate that the RG2 MK3 is housed in the same enclosure format that already served well in its legendary integrated amplifier cousin, the RG9 MK3. In fact, the preamplifier section that works so well in the RG9 MK3 is also used in the RG2 MK3. Symphonic Line even employs the same large mumetal transformer to supply the stand-alone preamplifier section with lots of clean and fast energy. And, with the two 140 Watts per channel power amplifier boards of the RG9 missing, this transformer’s output is more than generous for the unit.

    Having experienced the RG9 in our studio for a few weeks, I found myself much more at ease with the handling of the RG2’s front panel controls. While I had initially been taken aback by the power switch, input selector, and tape monitor knobs all having the same look and haptics, I meanwhile understood the principle of operating the unit from left to right: 1. turn on, 2. select source, etc. The only item that I still missed was a stepped attenuator for improved orientation when adjusting the volume.

    The RG2 MK3 offers cinch/RCA input sockets for Auxiliary, Tuner, CD, and Tape. The MM/MC phono stage offers two pairs of sockets, of which one can be used with adaptors to increase input capacitance (where necessary for tonal adjustment). An oversized gold-plated turning clamp right next to the phono inputs assures that excellent phono grounding is always close at hand. When turning the unit on via the power switch, large internal relays can be heard clicking into place. A similar relay-clicking is heard when moving the toggle switch from MM to MC or back. There is one pair of cinch/RCA outputs available to connect to the external power amplifier. All cinch sockets are sufficiently far apart to accommodate all types of cinch/RCA plugs.

    Without the need for internal power amplifier boards, the RG2 MK3 could potentially offer a reduced noise floor, improved dynamics, and possibly better protection from internal stray currents and rail fluctuations, which could all have a degrading effect the RG9’s preamplifier section. In other words, the stand-alone preamplifier unit had the potential to offer greater signal integrity than the combined unit. Its resulting overall performance would depend on how well it was matched with an external power amplifier, the loudspeakers, and the room, of course.

    Setting the Stage

    For my first listening setup, I connected the RG2 MK3 to a Dynavox VR70E-II tube amplifier using my trusted HBS1 Silver Solid Core cinch/RCA interconnects. The Dynavox amp offered 40 Watts per channel via EL34 tubes into an 8 Ohms load. The loudspeakers were a pair of Tannoy XT-8f with Tannoy's trademark dual-concentric drivers and a sensitivity rating of 91 dB at one Watt. In my initial setup, the speaker cables were Belden 9497, which tend to perform well with both vintage equipment and tube amplifiers. The Tannoys, however, were not exactly vintage speakers. I was therefore open to giving some alternative cables a chance if need be. 

    My music sources were a Denon DCD 1420 CD player, paired with Cambridge DAC Magic via HiViLux Reference cable,and a Sansui SR-525 turntable with Audio-Technica VM540 ML cartridge. The Cambridge DAC had a massive 100VA linear power supply at its side. As you can see, I was no stranger to the idea of oversized supplies and could appreciate Rolf Gemein’s approach in beefing up the RG2 with a high output transformer.

    The DAC was connected to the RG2 by means of a twisted two-strand type of silver solid-core interconnect that had been sent to me by Marc Stager in New York for auditioning. My initial impression of the cable had been positive, and so I decided that it could stay in this first setup. As silver offers superior conductivity to copper (check out the Annealed Copper Standard Table here), the prevalent choice of silver cables on my setups has usually served to support a fast, dynamic, and engaging sound. As usual, the loudspeakers had been positioned using the room mode calculation sheets handed to me by Peter English and had then been fine-tuned by ear. The final stereo-matching was done using a laser distance measure.

    There were no cables touching or crossing behind the rack as to negatively affect the tiny signals passing through them by means of induction. Sadly, it has not yet become common knowledge that this step is essential for the music signal to pass the cables uncorrupted. However, as my childhood friend Alec likes to tell from his days he was running a PA firm in Frankfurt: “We used to watch the power cords of our large QSC amplifiers dancing to the beat when they were hanging close to each other behind the PA rack.” The trouble is that our ears will notice cross-induction long before our eyes see the power cables dancing with the beat.

    Construction on our 70 square meter listening room had been completed only recently. An assortment of carpets, rugs, drapes, and acoustic panels helped to reduce reverberation times to a realistic-to-live level. I was quite happy with the result. It felt bold and natural to be working on music-related subjects in this new dedicated space. And the first titles I was about to listen to were from Helge Lien’s 2008 Jazz LP “Hello Troll”. 

    First Impressions

    Opening with ‘Gamut Warning’, I was instantly greeted by the superb depth and width of the RG2’s phono stage. Knut Aalefjoer’s drums, albeit sharply rendered, were slightly set back and smallish in the left third of the stage, whereas Frode Berg’s bass lines could be found in life-like dimension to the right. Helge Lien’s often delicate and sometimes highly dynamic piano keys were lingering freely suspended across the room, thereby holding the stage together. Although the Tannoys were connected in bridged mode (i.e. wired to the treble and jumpered to the bass driver by using the same Belden cable), I was pleasantly surprised by the amount of bass control and contour.

    The RG2 MK3 presented individual instruments in a wonderfully separate and yet cohesive manner to preserve the individual playing styles of each artist. This was a Symphonic Line characteristic that I had already enjoyed immensely on the RG9. I was reminded that the Sansui SR-525 is a well-engineered direct drive turntable, even by today’s standards. It had once been far ahead of its time and could fully demonstrate its prowess in combination with the RG2. It probably also helped that the AT VM540 phono engine with ML stylus makes for an excellent-sounding MM cartridge.

    There were two aspects, however, that I did not find instantly fulfilling: First, the dynamics of piano keys could have been slightly stronger to be absolutely realistic. And, second, the tonality of this HiFi system did not captivate me emotionally to the same extent as the two HiFi systems (using Epicure 500 and Martin Logan SL3 loudspeakers) in my RG9 tests had done. I suspected that the reason for the perceived lack was to be found in the wiring either between the turntable and preamplifier or perhaps between the VR70E-II tube amplifier and the Tannoy XT8 loudspeakers. 

    Adding Tonality to Music

    Looking for a remedy, I first swapped the Belden speaker cables for original Symphonic Line Harmony HD ones that Heinz-Peter Völkel had given to me with the preamplifier for testing and added 4mm-thick solid-core copper jumpers to connect to the bass drivers. I then left the system playing random music for a while in order for the new gear to settle in. When I came back into the room, I could hear that the tonal balance had shifted towards a slightly softer treble and richer, more powerful low bass. There was still sufficient detail preserved in the music, however, the shift towards darker colours did not automatically translate to into a greater separation of tonal events as I had hoped. I noticed that the system played louder somehow, and I suspect this impression was caused by the superior conductivity of the Symphonic Line cables.

    In a next step, I exchanged my HBS1 Silver Solid-Core with a Symphonic Line interconnect. The music again seemed louder and became more tangible in a general sense. There was a stronger presence of tonal colours, and it was now more easily possible to distinguish between them. I cannot say for sure that the extent of tonal nuances was on par with the listening test I had previously conducted with the RG9, however, I was definitely getting very close. I would have liked to possess a second Symphonic Line interconnect to replace the only remaining HBS1 interconnect that remained between the RG2 and the tube power amplifier, as I do suspect that this would have taken my listening adventure to the next level. 

    Changing over to my Denon CD player and Cambridge DAC combo with Marc Stager cinch/RCA interconnects, both tonal balance and soundstage impressions remained very similar. Even the volume appeared to be on the same level. Heinz-Peter had also sent me some of the Live||Tape recordings he had made in cooperation with the former Radio Bayern sound engineer Andreas Sandreuter. The recordings were intended to cultivate analog reel-to-reel studio sound, and the only reason he had sent them to me on digital medium was the fact that I did not yet have so much as a cassette deck in the house. 

    Through Heinz-Peter’s concession to my analog media shortcomings, I was able to listen to local German music highlights, such as Bad As We, the Senior Jazz Trio, Anna Boulic, the Sunday Morning Orchestra, Alexander Möckl, and others. And while I was listening, I forgot that I was listening for a review or that I was listening to HiFi components. Much rather, I was listening to the musicians and their instruments, to the rooms, to the music, and occasionally to the audience. It was perplexing to think what would happen, if I had had an even better power amp, interconnect running to it, or superior loudspeakers. The RG2 MK3, surely had the potential to eliminate the boundary between the live event and the recording even further with each new improvement.

    Side Notes to History

    It has sometimes been said that the Dynavox VR70E-II is a well-built tube amplifier that can keep up with equipment many times its price. And I would have tentatively agreed that this is the case from my own limited experience. However, it was not until my experiments with the RG2 phono stage in combination with the Symphonic Line interconnects and speaker cables that I personally became witness to how far this little amp was willing and able to go. The Tannoys, too, did surprisingly well in this combination, exhibiting tonal skills and dynamics that I had as yet been unaware of. Having said that, I do think it highly unlikely that many owners will ever hear these speakers in this way. 

    My longtime HiFi companion Luigi has a short explanation for this: Modern speakers tend to do lots of things well, have lots of bass, treble, midrange, and dynamics. And more often than not they will sound cold and lifeless despite all their wonderful skills. At the point of writing this article, the Tannoy XT8f have been in my possession for just over four years. And the RG2 MK3 with all Symphonic line cables in place has made them sound properly for the first time. We are talking about equipment that is many times more expensive than the speakers themselves. But who is going to spend that kind of money on a pair of mid-of-the-market Tannoys?

    Both the Epicure EPI 500 and the Martin Logan SL3 loudspeakers delivered an excellent tonal performance based on the affordable Belden 9497 speaker cables, because they were designed to work well with small diameter cables. The same cannot be said for more modern speakers that tend to entice their owners to pay evermore for their equipment and periphery. I would therefore agree with my friend Luigi that modern HiFi love affairs tend to be rather calculated and run the risk of being unfulfilling.

    While I Have You Here

    Listening to Helge Lien’s album “10” has always been a treat to me. And, thus, I am still sitting here, listening to Helge’s performance on the RG2 MK3, wondering where this journey of discovery will take me next. At this moment it is difficult for me to imagine that anything could sound even more real. — Any ideas? Please feel free to share them with me in the comments section below.

    < Sansui SR-525 | Symphonic Line RG9 >


    • Type: Solid State Stereo Preamplifier
    • Transformer: 300 VA, toroidal with mumetal enclosure
    • Phono section: MM/MC with adaptable capacitance
    • Number of line inputs: 3 + Tape loop
    • Country of Manufacture: Germany
    • Dimensions: (W) 450mm x (H) 100mm x (D) 380mm
    • Weight: 17 kg
    • Year(s): 1992 -

    Jörg Hegemann
  • Duevel Jupiter, Series-1

    Duevel Jupiter, Series-1


    Author: Karsten Hein

    Category: Gear & Review

    Tag(s): Loudspeakers

    Matthias was not the person to take decisions lightly. His background in electronic engineering, paired with extensive reading and long-time experience in setting up HiFi equipment, had granted him a sophisticated setup, and his exploration of new devices seemed to be complete for the time being. Instead, he had once again shifted his focus towards the music itself and was happily listening on his Devialet Expert 250 amplifier paired with Duevel Bella Luna loudspeakers. The Devialet was a modern and hybrid device with internal DAC, built-in room correction, versatile connectivity, and a cleverly designed 250 Watts per channel output stage that was fed from a digital power supply, capable of making bursts of 4000 Watts available, all at generally very low noise levels. This amplifier made the Bella Lunas present all kinds of music with great ease. And such was also my very positive verdict following my visit to Matthias’ house back in May 2023.

    In Spring 2024, less than a year after my visit, Matthias informed me that he was contemplating upgrading from his accustomed Bella Luna loudspeakers to Duevel’s flagship of that period, the Jupiter. He explained that these speakers had once been completely unaffordable and that they had over a 25-year period dropped in price and thereby become quite attractive. And although used specimens of these speakers were rarely found, a pair of Jupiters was being offered within comfortable reach. Matthias was facing a dilemma because, on the one hand, he really was satisfied with his Bella Lunas, while the larger and more elaborate Jupiter, on the other hand, held the promise of being even more capable in every conceivable way. As I was listening to Matthias contemplating if he was to take this leap of faith, I could feel the tingling sensation that captivates me before each new exploration and has led to the birth of this blog. And so I simply told him that, if he took the plunge, I would come and write about it.

    Matthias auditioned the Jupiter at their seller’s house twice before making his decision. On the second occasion, he even brought his Devialet amplifier and his preferred loudspeaker cables along, to see if this would bring the Jupiters to life. Happy with the result, he wrapped them in blankets and drove them back to his house with anticipation. Positioned side by side, the Jupiters dwarfed the already quite impressive Bella Lunas to an unanticipated extent. Being 22cm taller and 10cm wider appeared to be less significant on paper than it was in real life. The one aspect that might have given this considerable difference away was the increase in weight: from the still moderate 30kg on each Bella Luna to the impressive 70kg on each of the Jupiters. One benefit of the larger cabinet was a 10 Hertz drop in the lower cut-off frequency, down to 30 Hz. While Matthias was getting used to the Jupiters’ dimensions in his living room, he critically listened to them, until his final doubts subsided and he finally put his Bella Lunas on sale.

    Duevel loudspeakers are niche products and therefore not necessarily easy to sell. However, we decided to put the terms “omnidirectional” and “high end” in the advertisement header and soon managed to find a new home for them. There are fan communities for omnidirectional speakers, because some audiophiles believe that dipoles and omnidirectional speakers are the only means by which the authentic sound stage can be recreated in the listening room. Both the Bella Lunas and the Jupiters are omnidirectional 2-way speakers that have their drivers placed in horizontal position and employ wooden horn diffusers to disperse the sound in a 365-degree radius. While both speakers use an up-firing dynamic bass driver with die-cast chassis and M-roll surrounds, the Jupiters employ a high-output PA driver with paper cone that is 10cm larger in diameter than that of the Bella Lunas.

    To match the performance of the larger bass driver, the tweeter section of the Jupiter needs to be much larger (10cm instead of 4.4cm) and must reach much lower as well. As a consequence, the Jupiter’s treble drops off 3,000 Hz earlier, at 20,000 Hz. And although this is already well outside most people’s hearing, the Jupiter’s treble shows greater sensitivity to subtle changes in the front end, the interconnects, and the choice of speaker cables. Both cabinets are designed to operate on the principle of a Helmholtz resonator, using one bass-reflex port calculated to the lowest cut-off frequency in each of the four cabinet corners. Strong internal bracing assures that the bass is dry and without much internal reverberation, even when the speakers are driven at high volume. The high and low frequency drivers of the Jupiter taken together contribute almost 20kg in weight to each speaker.

    Matthias and I arranged arranged a listening session for mid May, right about the time I had first listened to the Bella Lunas one year earlier. We also invited Michael and Alexi who had been with us on the first occasion, however, only Michael managed to free himself for the event. Instead of two studio mics for the creation of a YouTube clip, this time, I brought along a calibrated UMIK-1 microphone and R.E.W. room analysis software on my MacBook to assist Matthias with the setup and positioning of the speakers. When I arrived in the early evening, I found the Jupiters standing at equal distance near the left and right walls of a relatively narrow but very deep living room. In this position, there was about 1/5 of space behind the speakers and about 4/5 towards the front. Their approximate position had been determined based on my calculation sheets on room modes that had been given to me by Peter English.

    Quite a few things had changed since my last visit to the house: Matthias had covered the large terrace windows behind the Jupiters with drapes. The hardwood floor from the speakers towards the listening position was now covered with two rugs. The Devialet amplifier had been moved to a central position between the loudspeakers, and Matthias’ MacBook M1 (running Audirvana and Qobuz) was the only source for music. Two sets of speaker cables were running along the walls right up to the amplifier: The first cable was a DIY design braiding three solid-core CAT7 network cables AWG23 with two CAT7 multi-strands AWG26. And the second was a ready-made “White Bird - Reference” cable by Colours of Sound that was on loan from the manufacturer himself. To enhance the scope of our test, we also had an MIT “Terminator” (previously used on the Bella Lunas) and a Sommer Cable “Elephant” at our disposal.

    Three chairs were positioned side by side, with the preferred listening position being the chair at the center, and we took turns listening from all three positions and also tried kneeling in front or standing behind the central chair to get a better feel for the acoustics of the room. My personal preference would have been for the central chair to be moved a few centimetres forward, which produced greater speed and more detail, whereas Matthias preferred to keep the chairs in their current position for greater musical coherence. We started our listening session with the CAT7 network cables in place, playing Halie Loren’s title “Whiter Shade of Pale” which was performed Live at the Cotton Club, and it quickly became clear that the Jupiters really could and were eager to move some air.

    After all, these speakers were built to handle up to 200 Watts of power coming from the amplifier, and their drivers, although quite sensitive even at one watt, were of sturdy build quality by nature. To be able to present their most linear performance, especially the dynamic bass driver required some momentum. The closer we got to realistic-to-live listening volumes, the more the speakers started to carry the sensation of live music. Their ability to faithfully play back frequencies all the way down to 30 Hz certainly enhanced this acoustic effect. The Jupiters’ omnidirectional horns created a deep soundstage that extended well beyond the speakers, right up to the front wall of the room. In our setup, the Jupiters had to be positioned quite close to the side walls which led to a mild blurriness of the phantom center. The amount of musical detail presented was sufficient but not staggering. It was just enough for the music to sound natural.

    From the Planets to the Bella Luna, I have found a full and natural tonal balance to be the typical character trait of Duevel loudspeakers, and the Jupiters were no different in this respect. Due to this, it was possible to listen at higher volumes without fatigue. Further tracks included “Another Night” by Cody High and “Smoke on the water” Live in Osaka, 1972, by Deep Purple. I found that the Jupiters presented the quality of each recording well and also pointed out the limits. However, they equally served to highlight some unresolved issues in the setup and room. For one thing, the vertical motion of the woofer set the floor boards underneath the speakers in motion despite their colossal weight. This led to an unpleasant resonance in some songs. Matthias had used stone bases as a counter measure underneath the Bella Lunas. However, these proved to be too small in diameter for the Jupiters.

    We also discovered that the Jupiters had not yet been set up to perform in a highly linear fashion. Measurements conducted with the UMIK-1 microphone in proximity to the listening position soon confirmed a 6dB drop in sound pressure levels between 80 and 180 Hz. While this effect might have served to enhance acoustic clarity, it also made these large speakers sound slower and less dynamic than would otherwise have been the case. I have sometimes found that larger drivers serve to accentuate room modes and resonances and demand more attention from their owners in terms of proper placement. Matthias was still getting to know his speakers, of course, and was learning how to best handle them from each new listening session.

    Changing from the braided DIY CAT7 network cables over to the White Bird - Reference produced a more homogenous listening experience with a fuller bass at the cost of musical detail. Although our UMIK-1 frequency sweep measurements still showed the dip between 80 and 180 Hz, music is a complex occurrence that is difficult analyse when recording the response to a single frequency at a time. I enjoyed the increase in coherence, but I could see that Matthias remained reluctant to sacrifice the more revealing treble. Micheal agreed that the difference between these cables was so enormous that each of them presented a compromise, and so we decided to open up our test to include further cables.

    The “Elephant” by Sommer Cable proved to be a step back in many ways. It was less informative than both the CAT7 and the White Bird; it did not express tonal colours in a sufficiently vivid way, and transients were sorely lacking, although it did present low bass lines in a manner comparable to the White Bird. Given the sum of its character traits, Sommer’s Elephant cable could perhaps be a match for HiFi systems with an aggressive treble, however, it did feel out of place with the Jupiters. The MIT “Terminator” sounded more solid than any of the other cables. It presented the music in warm tonal colours and always with a bit of aristocratic restraint. There was a prevalent sense of order that would go well with a relaxing gala dinner or an evening in a cigar lounge. In comparison to the White Bird, it lacked some of the initial excitement, and, in comparison with the CAT7, the music seemed less forward and insightful with a reduction in stage depth and width.

    Further song titles we listened to in our session included “Nite Mist Blues” recorded Live at the Montreux Festival and performed by The Monty Alexander Trio; a further live recording “Empire State Express” by Richard Bargel; “Friday Smile” by Yello; “King of a Land” by Cat Stevens; and “Acoustic” by Billy Raffoul. Each song served to highlight different strengths and weaknesses of the current setup, and, in our minds, we compared the sound of the songs to the various HiFi systems we had heard before. For instance, I had listened to “Empire State Express” played on a Symphonic Line system with Görlich chassis just a few days earlier and vividly remembered the many layers of bass dynamics in this song. This effect did not show as much with the Jupiters while placed in their current position. I also remembered listening to “King of a Land” via our Martin Logan SL3 electrostatic speakers, with Cat Stevens coming alive almost “visually” right at the center of the stage, his voice felt so intimate one might think the artist was physically present in the room. Clearly, each loudspeaker has its own special field of expertise, but with the Jupiters I could sense that there was still a lot of potential waiting to be unleashed.

    We all agreed that putting the speakers on stone slabs would enhance their imaging and help to reduce sub floor vibrations. These slabs would need to be of considerable size to accommodate the immense weight of the Duevels. Felt cushions underneath the stone slabs might be beneficial in further reducing the existing coupling to the ground. The speakers still needed to find their preferred position in the room, and Matthias and I agreed that it would be best to recalculate the exact distances, this time also taking into account some of the furniture in the room. Matthias also wanted to see if he could improve his DIY cable design by optimising the number of solid-core and multi-stand wires. We all liked the CAT7 cables and were eager to see how they would improve. By designing the cables himself, Matthias could learn more about the amplifier, his new speakers and the room.

    The Devialet amp also offered built in SAM room compensation, however we had learned from past experience that the best sound was to be achieved if the speakers were positioned correctly in the first place. Like all great speakers, the Jupiters will force their owners to learn more about room acoustics and electronics in an effort to reach perfection. And it takes the heart of a true explorer to appreciate this challenge.

    — Thank you for giving me the change to write about it.


    • Type: floor-standing 2-way loudspeaker
    • Design: omnidirectional, vented cabinet
    • Frequency response (±3dB): 30 Hz - 20,000 Hz
    • Power handling (RMS): 200 Watts (300 Watts, Series-2)
    • High-frequency driver: 10cm titanium dome tweeter, horn-loaded
    • Low-frequency driver: 32cm dynamic, paper diaphragm
    • Woofer specifics: die-cast chassis, M-roll surround
    • Diameter of horn diffusors: 385mm
    • Gap between diffusors: 85mm
    • Crossover frequency: 700 Hz
    • Crossover design: phase-linear
    • Power sensitivity (SPL): 92 dB (93 dB, Series-2)
    • Nominal impedance: 6 Ohms
    • Cabinet Dimensions: (H) 1270mm x (W) 380mm x (D) 380mm
    • Base Dimensions: (W) 420mm x (D) 420mm
    • Weight: 70 kg
    • Country of manufacture: Germany
    • Year(s): 1998 - 2008

    < Duevel Planets | Duevel Bella Lunas >

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  • 80s night
  • Symphonic Line RG9 MK3

    Symphonic Line RG9 MK3


    Author: Karsten Hein

    Category: Gear & Review

    Tag(s): Integrated Amplifiers

    Introduction to High End

    I would like to begin this journey of discovery with a simple question: “What is High End?” In recent years, the term has become quite inflationary in the context of audio equipment, with private sellers and shops offering ‘High End’ products both at the budget and at the luxury end of the audio market. Perhaps such claims are valid, and perhaps they are not. But who is to decide this if we are still unsure of the definition? Perhaps one way of answering the initial question is to look at the origin of the term in HiFi and at what it meant to the people who coined it and first used it for their products.

    In America, it was the Audio Research Corporation (ARC) who especially referred to their large tube power amplifiers as High End products. And in Germany, the term was taken up by Rolf Gemein’s Symphonic Line, Ulrich Rahe of the famous RABox, and Dieter Burmester who runs the now internationally renowned audio company by that same name. Together, they founded the ‘Deutsche High End Society’ and were among the initiators of the High End trade fair in Munich, which is the largest High End audio fair in the world today. Both Gemein and Burmester set out to create audio devices that were originally not geared for the mass market (a competitive environment in which their products would be scrutinised in terms of shipping and production costs for the sake of profitability) but instead focused on creating the highest quality circuits and combining the best possible components to reach the maximum in terms of sound.

    When you pair long development times with exceptional engineering skills and high quality components, this inevitably becomes costly. And most manufacturers are worried that they will not be able to generate enough demand for their products in this high price range. In consequence, most products are designed to perform at their best within a given price bracket. I was once part of a discussion in which the engineering team of a TV manufacturer had just finished designing the audio section of a new television model. The internal purchase price for the components was quoted at 35 EUR. Upon this, the team was informed that they had a budget of 7.50 EUR and was asked to rework the design and talk to their suppliers. Such choices are in fact very real, and, in the described scenario, the acoustic components were to be designed for a television set in the higher-priced premium segment and not some cheap entry-level product.

    While most successful companies see their development and production departments as part of their costs and are trying hard to keep these as small as possible, both Rolf Gemein and Dieter Burmester gave their product philosophy priority over all other considerations, thus creating a utopia in which the forces of the market—forces that apply to everyone else—appeared to have no effect. In this sense, High End means true devotion to the cause from the side of the manufacturer, until the product is completed. And finally, primarily due to their higher price tag, High End products can only exist where enthusiasts recognise the extra effort and are willing to pay the higher price.

    Having said that, not everything that has a high price tag can also be considered High End. This makes it difficult for customers to determine where exactly High End starts (and is actually worth the investment) and where it is just a term used to pedal HiFi gear for the sake of higher profit margins. Therefore, when a friend (and invaluable supporter during the building phase of our listening room) suggested that I contact Heinz-Peter Völkel and ask him to send me some Symphonic Line products for testing, I was unsure of what to expect. After all, I had set up my HiFi systems with great care using selected industry classics. I had just finished construction on our listening room and had installed new acoustic absorbers. I was indeed very happy with the resulting sound. What more could I possibly say about Symphonic Line products other than simply reiterating the fact that they, too, sounded great?

    Seeing that I was not yet convinced, Heinz-Peter suggested that we should meet at the Norddeutsche HiFi Tage trade fair in Hamburg where Symphonic Line had booked an unpretentiously small room on the third floor. As I walked in, I found Heinz-Peter and Rolf Gemein taking turns at presenting the Symphonic Line products with various music. Having spent some hours at the fair listening to different HiFi setups, I found the choice of music at their booth refreshing and the Symphonic Line setup sober and sophisticated. This was more than many of the other booths had been able to deliver, and, for the first time, I had the very real sensation that this company’s products could indeed be worth exploring. Later that week, Heinz-Peter and I talked about where to best start our journey of exploration. We soon agreed that it could be educational for the blog to get to know the products from the start. And thus, we begin or story with an RG9 MK3 from around 1994.

    An Elusive Beast

    It seems chrome-plated Aranja (or grape fruit) was among the most fashionable colours on High End products back in the day, and the RG9 boasts this shiny surface on a chassis made of a bent brass alloy that is 2mm thick and has a 10mm face plate. In other words, this amplifier feels very solid and is quite heavy. In the household environment, its surface will act as a tinted mirror, giving the RG9 a chameleon-like presence that makes it more visible from some angles and less visible from others. In the studio, however, I attempted to minimise all reflections in order to better show its exact features and dimensions. In doing so, I also revealed some of the stains and wounds that it had collected over its 30-year lifetime. During daily operation, these would hardly be noticeable because you would hardly ever see past the mirror effect. Except for these photos, the body of the RG9 in Aranja is hard to catch.

    The Symphonic Line logo, the RG9 MKIII model name, and the labels of the controls are all engraved on the face plate. As a first-time user, I sometimes found these labels difficult to read, especially when operating the unit in low-light conditions. I also noticed that the position of the rotary knobs is not easy to determine. With three rotary knobs of equal size, colour, and design, it was probably best to memorise the functions of each control until one could use them intuitively. Moving from left to right, the first knob is actually a rotary switch that turns the RG9 on and off without any audible switching noise on the speakers. The next button to the right is the input selector that changes between sources, again without audible noise. The third knob switches between the Tape Monitor and the Line signal.

    The volume control is the fourth and final knob in this row and sets itself apart due to its superior size. Upon first turning it, I was a little disappointed that this was not a stepped attenuator and that it was instead smooth and easy to move. I have since read that it is a double-mono design and of high quality, however, I personally prefer stepped attenuators, because they help me remember listening volumes in increments. For instance, I usually turn the volume down by two steps when changing from Phono to CD on my Restek V1 preamplifier. Such helpful points of reference are missing on the RG9 dial. On the positive side, the rear panel of the RG9 is far easier to access than on the Restek. All Chinch/RCA sockets are easy to reach and have sufficient space between them to accommodate most HiFi and High End cables.

    There are two pairs of Chinch/RCA sockets available for phono, of which one pair can be used to increase the input capacitance by means of adaptor plugs. There is also a switch on the back panel to accommodate for MM and MC cartridges. This switch had me worried for a moment, as, upon first trying, it did not want to activate the setting for MM. It seems the RG9 had been used exclusively with MC cartridges for many years and the circuit had become stuck in this position. This is a common issue with relays that are left unused over longer periods of time, no matter how well they are built. However, I was not about to give up easily. After some further attempts of toggling the switch, the internal relay audibly clicked into position with MM engaged.

    The rotary clamp to connect the ground wire is sufficiently large and near the phono input. That is indeed practical when pairing the RG9 with vintage turntables that have a fixed phono cable and ground wire. There is one stereo set of WBT terminals available for connecting the amplifier with the loudspeakers. They take banana plugs as well as bare wire or spades. All inputs and outputs, including the rotary clamp for the ground wire, are 24K gold-plated. As on our Restek, the back wall of the RG9 bends inward ever so slightly in combination with very tight-sitting plugs. I do not really like this impression on either occasion and would have preferred the otherwise sturdy rear panel to find some support on the amplifier’s top lid.

    Although it might not look as monumental when perched on a HiFi rack, moving the amplifier around is a reminder of the high quality materials that went into its production. At a round 18kg, the task of simply setting it down on a table or in a rack proves to be a small challenge. As can be seen on the photos, the original feet are not very tall. This makes it difficult to squeeze the fingers underneath the amplifier for lifting and again a challenge when setting it back down. I would have wished for the feet to be at least high enough in order not to get my fingers pinched while rearranging the system. I have sometimes heard it said that High End audio products and the concept of convenience tend to be mutually exclusive, and I think I have by now gathered sufficient evidence in this report to prove that this is not an unfounded observation. But then sports cars are not really convenient either, but very, very sexy.

    Down to Earth Listening

    For the start of my listening explorations, I had four HiFi setups to choose from. I weighed the pros and cons of each of them and ultimately decided to get to know the RG9 on the least complex system of them all. On this, the music sources were a Philips GA 212 turntable fitted with an entry level AT VM95 E cartridge, as well as a Pioneer PD-S604 CD player that recently had been upgraded with an anti-resonant coating on the inside of its enclosure as to further stabilise the already quite remarkable drive unit. Both devices were rather musical for their class but they were by no means High End. They were connected to the RG9 by means of Silver Solid-Core chinch/RCA interconnects of the HBS4-Type shown in this forum.

    The loudspeakers were American built Epicure EPI 500 with 10-inch woofers and two 12-inch passive radiators per speaker. They, too, were rather musical despite showing a measurable dip between the woofer and the passive diaphragms. Ground potential between the devices had been harmonised and the speakers had been positioned in the large studio as to present the most possible linear performance. As usual, I used the acoustic calculation sheets handed to me by Peter Englisch to determine their basic positions and then proceeded to set up the remaining centimetres by hand, or rather, by ear. Finally, the exact matching of the stereo channels had been conducted using a laser distance gauge. No signal wires or power cables were crossing or even touching behind the rack. The electric mains was fed from the fuse box straight to the system for extra low interference.

    Based on my standard components, a small Rotel preamp with improved Faraday cage (not a difficult upgrade, if you take into account that the original floor plate was made of plastic) and Becker MOSFET amp, I already had spot-on centre stage imaging, seamless panning from left to right, tonal accuracy and believability. In short, there was little on my original setup that troubled my ears, stuck out to me or was obviously missing. The Becker amp’s strengths were its enormous capacitors of 64,000 mF each and its four Hitachi MOSFET J49 output transistors. Its weaknesses were pretty much everywhere else, from its flimsy transformer to its haphazard wiring, and it sometimes amazed me that I could find such deep affection for this little hand-made amplifier at all.

    Switching over to the RG9 MK3, I kept our Audioplan PowerCord S and the Belden 9497 speaker wires in place. I knew the PowerCord S to be a well-engineered cord of symmetrical anti-resonant design, and the Belden cables had repeatedly proven themselves to be an excellent match for vintage speakers. My reason for doing so was not to introduce more than one new component at the time. I powered up the system, put on a CD and left the room for the next 30 minutes. When I walked back in later, I was greeted by a calm and sophisticated sound. I sat down in my armchair to listen and was deeply impressed with this system’s tonally warm storytelling. I especially enjoyed the breadth and width of tonal colours that are capable of connecting music with memories.

    Gone were the few ramaining traces of static flicker, sibilance, and haze of the Rotel Becker combo. In their place, there was ample room for the nuances of piano, strings, and wind instruments. In addition to a more distinct separation of tonal events, the RG9’s superior power per channel held a tighter grip on the EPI 500’s bass lines. In this combo, there were simply more bass nuances and more texture. The presentation was brought forth with great assurance. Like an artist painting with a big brush, it was at once insightful and bold. This is not to say that the RG9 would show its audiophile qualities on every single record. Where the recordings had their limits, the system still showed this quite clearly. In this sense, the music did not seem ‘sounded’ in any way. Instead, each music event was presented with good measure and in a down-to-earth manner.

    Real-World Impressions

    Till Brönner’s song “A distant Episode” highlighted the impressively precise 3D imaging of the Pioneer CD player’s platter drive mechanism in combination with Legato Link. Patrick Kelly’s live concert performance of “A Litte Faith” revealed formidable lower bass extension and quick rise times of the amplifier. The same cannot be said of his song “Land of Bliss” that did not undergo the same positive transformation. Peggy Lee’s “Fever” showed splendid attack and decay paired with a formidable differentiation between drum materials, tensions, techniques, and dynamics. Cristin Claas’s song “In the Shadow Of Your Words” served to reveal the multiple tonal colours of vocals, nylon and steel strings, and of the synthesiser. Although the music events often coincided, the RG9 managed to keep them separate and in good order and proportion throughout the performance.

    Sean Heel’s album “A Dry Scary Blue” can be superbly insightful with occasional moments of unpleasant clipping. However, on the RG9, it sounded a bit more compact and less airy than I was used to. Then again, Jörg Hegemann’s much praised album “High End Boogie Woogie” sounded full and engaging. On Jörg’s album, Paul G. Ulrich’s double bass was rendered razor sharp and wonderfully separate from the piano. Gurgling low bass notes maintained more refinement than usual with a discernible metallic ringing and rasping to them. I had never before experienced the Steinway grandpiano’s nuances so separately, for instance on the song “When you and I were young, Maggie”. And I do remember it well from standing next to it during parts of the recording.

    Switching to phono, the Helge Lien Trio’s album “Badgers and Other Beings” sounded spacious and open and at the same time intimate and warm. In addition to the usual panning from left to right, the stage felt more seamless and deeper. In my setup the phono section was of very low noise and tonally insightful. Instrument separation was maintained during fast, loud, and crowded passages. Having spent some time listening, I could sense that the only limiting factors were the speakers and the entry-level Audio-Technika cartridge. I was eager to find out how the RG9 would perform in combination more translucent gear that was positioned higher up in the food chain.

    Higher Up the Food Chain

    Our second test environment consisted of a Marantz CD-17 CD player, a Thorens TD 320 turntable paired with Audio-Technica VM95 ML cartridge, both connected via Silver-Solid Core to the RG9-MK3, and Martin Logan SL3 electrostatic speakers that were connected to the amplifier in the from of Y-wiring. On hybrid speakers, this way of wiring had the advantage that both the electrostatic panel and the dynamic bass driver of the SL3 could be addressed separately for improved back-current handling but found a uniform point of contact on the side of the amplifier to preserve homogeneity.

    In this new position, the RG9 MK3 was to replace an RGR Model 4 preamplifier that was paired with a B&K ST140 solid state amplifier. This was a decent-sounding combo capable of delicate tunes and insightful presentations. With its still rather modest 105 Watts per channel, the ST140 was at times a little weak in the chest for the SL3 despite its high current-handling capabilities.

    I began listening via the Marantz CD-17 and immediately noticed that the music sounded more seamless and the soundstage more consolidated. As electrostatic speakers radiate both towards the front and to the back, perfect timing is essential for the speakers to disappear in the room. In my usual RGR/B&K setup, stage imaging often did not feel quite right in the transition zone between the left speaker and the left section of the stage so that some instruments or notes would jump forward in an unnatural fashion. This effect reduced by a large portion, with the music wrapping around the speakers from the far left to the far right. Woofer integration was also improved and made faster music more fun to listen to.

    Switching over to phono, I was pleasantly surprised not to experience the drop in dynamics that is all too often the case. In this system I was using the original Symphonic Line power chord and was impressed with its contribution to the performance, especially in comparison with our cheaper Lapp Ölflex that I had quickly replaced after just a few minutes of listening. The ability of a power cord to make or break a system still amazes me each time I hear it.

    After listening to the Helge Lien Trio’s album “Guzuguzu” which portrayed lots of musical insights as well as dynamics, I changed over to Manu Katché’s album “Neighbourhood”. On his song Katché’s “Rose”, in particular, I was perplexed by the fact that I had never before been able to identify the two separate saxes performing the chorus side by side as distinctly as with the RG9.

    The Pain of Parting

    I am not sure if you remember moments from your early adulthood when the party at your house was over, and as you were watching your guests leave, it slowly dawned on you that the house would again be empty and that you were left to deal with the emotional and physical aftermath on your own? At such moments, it suddenly became painfully obvious that adjusting back to life as usual would require some time and effort. The head still buzzing from all-new impressions, I had to think of my HiFi friend Luigi’s words: “Once you have heard it, going back won’t feel the same.”

    Changing back to our Rotel & Becker combo, much of the tonal width and fullness that I had since come to accept as normal was gone. The sound became lighter and sharper, displaying slightly compressed mids. What had not troubled me at all and initially seemed to be little more than an upgrade had since become an essential property of the music to me. In my impression, not enough has been said about the weight of tonal width in music. While most HiFi talk still fusses about dynamics, bass performance, or high resolution files, etc., the one element that addresses our emotions and has the power to lead us back in memory is correct tonality. And, according to my short experience, Rolf Gemein understands how to play that card well.


    • Type:  Integrated solid state stereo amplifier
    • Transformer:  430 VA, toroidal with mumetal enclosure
    • Output power (RMS, 8 Ohms):  2x 140 Watts
    • Output power (RMS, 4 Ohms):  2x 250 Watts
    • High current stability:  > 2 Ohms
    • Phono section:  MM/MC with adaptable capacitance
    • Number of line inputs:  3 + Tape loop
    • Country of Manufacture:  Germany
    • Dimensions:  (W) 450mm x (H) 100mm x (D) 380mm
    • Weight:  18kg
    • Year(s):  1994 - 1998

    Digitising Records
  • 31. Understanding Room Acoustics

    31. Understanding Room Acoustics


    Author: Karsten Hein

    Category: High Fidelity

    Often, even before we listen to a classical instrument, we can imagine how it sounds just from looking at it. This might seem like a bold statement, but think about it: A cello, for instance, is a large wooden instrument with long thick strings, whereas a saxophone is a brass instrument on which air is blown past a reed into a tube that culminates in a horn. Is it not true that we would imagine the cello to sound warm and wooden and the saxophone to sound cooler and more tinny? And would we not expect the larger cello to play low frequency tunes and the smaller and horned sax to play higher notes and very loud?

    The sound of classical instruments is mostly determined by their size, shape, and inner dimensions, because these features serve to create rooms and chambers in which the instrument’s sound is shaped and amplified. The source of the sound (strings or reed) is mostly separate from the resonating chamber itself. In the case of the cello, its strings are made to vibrate and resonate over a well-conceived box behind. In the case of the saxophone, pressurised air passing over a reed sets it in motion, with the sound being augmented by valves and tubes and further amplified through the horn's mouth.

    The exact match of the strings with the body of the cello, or of the reed with the size and design of the saxophone, finally determine how each instrument sounds. Great instruments get this balance just right, and no one would imagine that inserting a louder reed or getting more power to the strings would greatly improve the sound. And most of us would not think of changing the position of the reed or strings either. Instead, it is simply understood that the source of the sound and the corresponding chamber need to be perfectly matched for the instrument to deliver the optimal sound. In fact, it is the precise matching that gives each instrument its own distinct tonal colour and character.

    When first entering the realm of High Fidelity we might be led to believe that larger loudspeakers or or more potent amplifiers will solve the issue of lacking musical presence or improve bass performance in a room. However, the instrument analogy shows that proper calculations and correct loudspeaker positioning within a room are just as important. More power, speed, and accuracy will in a first step serve to accentuate flaws in the setup, which is often the reason behind expensive High End systems sounding quite unbalanced in their owner's homes.

    The more classical instruments we have heard and the more materials we have touched and played with, the better we become at predicting an instrument’s sound even before we actually listen to it. Experience, attention, and imagination play an important role when it comes to listening. Children, for instance, are often said to have superior ears, especially when it comes to detecting high frequency sounds. And that is probably true, however, the physical ear mechanics only play a very small role in respect to critical listening skills. This is how children are far more likely involved in traffic accidents than adults. Although they may hear a vehicle approaching, their cognitive skills are not yet fully developed, so that the bending of sound waves from the speed of movement and the increasing volume of an approaching vehicle will mean very little to them. The ability of the brain to filter and pay attention to specific sounds in order to derive meaning from them only evolves with listening experience.

    In that same way, I must confess that room acoustics meant very little to me, until I first owned a room that I could personally build from scratch and thereby experience the steps of transformation first hand that were necessary to make it sound great. It was not until we moved to Marne, a small town at the North Sea coast of Germany, in summer 2023, that I had a dedicated listening room for experimentation. Located under the roof of the building, the wide open space was initially an attic with visible beams and bare insulation that was still dangling from the ceiling ready to fall off. I remember clapping my hands in this room and being thrilled by the fact that there was no echo to be heard. At that stage, I was standing in “silent” room, perfect for listening adventures.

    Original Room Presentation Video

    On the other hand, the attic was also dusty and still poorly insulated. Bugs and spiders had invaded every nook and cranny, and I could hear the wind blowing through small gaps under the shingles. This was no place to set up our Martin Logan electrostatic speakers. High voltage panels are dust magnets, and turntables to not benefit from dust and wind either. To turn this space into a studio for audio auditions would require some effort. We began work by insulating the floor and adding an extra layer of OSB (Oriented Strand Board). And we decided to preserve the original tongue and groove boards on the side walls and only added an extra layer of insulation to the ceiling, which we then covered with one layer of plaster board.

    At this stage of development, clapping my hands in the room led to quite a different result: The OSB floor and the tongue and groove walls still gave off a warm and pleasant air, but they also reflected a lot of sound energy instead of absorbing it. The slightly domed ceiling gave the room an even more confined and boxy impression with an audible reverberation despite its generous height of three meters. The listening room was 7.80 x 9.20 meters in size, and so the first, second, and third order resonance frequencies were relatively low, starting at 18 Hz, however, there was plenty of time for the higher frequencies to bounce off the smooth ceiling and walls and reflect back to the listening position with obvious delay.

    On the positive side, there were lots of open wooden beams to deflect some of the reverberation energy and three of the side walls were sloping from about 95cm height. The tongue and groove wood cladding also provided some natural deflection, especially of the higher frequencies. And the one straight wall in the room had a large recessed portion leading towards a narrow storage space in the back. On the negative side, the room was relatively square, which might serve to further accentuate specific room modes. And, most obviously, there still were no furnishings and fabrics in place to absorb some of the reverberation energy.

    The most pressing first step, therefore, was to lay down a carpet that would cover the complete floor. Carpets are great at absorbing acoustic energy and can be used in combination with rugs to provide an even greater absorption effect. Once the carpet was in place, we brought in the first loudspeakers and set them up as described in the chapter on Room Mode Calculations. In keeping with our instrument analogy, it really does matter where the sound generator is positioned and what building materials are found in the room. After all, the listening spot is to be provided with a relatively linear sound over all frequencies that is similar to the experience of the sound engineer when listening to the recording via a decent pair of stereo headphones in the studio. For this to be the case, both the speakers and the listening position need to be in correct relation to each other and to the room.

    Obviously, our journey of exploration is not finished here. The completed room with carpet still sounded far worse than the unfinished room that I originally fell in love with. Be sure to read the chapter on room mode calculations for loudspeaker positioning and the chapter on acoustic treatments to learn about some of the easy fixes to sound issues.

    As always, let me know how you feel about this chapter of the journey. Reflecting on your own experiences, how have room acoustics affected your enjoyment or perception of sound? Share your stories in the comments below — I'm eager to hear about the unique soundscapes you've encountered!

    First Sound Check Video

    < Room Mode Calculations  |  Acoustic Room Treatment >

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