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.
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.
Author: Karsten Hein
Category: Gear & Review
Is it generally a good idea to buy audio cables for our HiFi system from cut-price vendors in China? The answer is: no.—Is it a good idea to buy this particular audio cable from China? The answer is: you bet! There are exceptions to every rule, as we shall see. The problem is that we can never be certain, whether the item we are looking at is the rare and exciting exception, or just another recapitulation of the boring old rule.
From the very first paragraph of writing about this interconnect, I can already feel the sad downside to cheap Chinese imports: The ever-present lack of credibility, certainty, and responsibility towards the customer. As some market observers will know, the cable shown here is sold on eBay. This particular variant is from a Chinese vendor by the name of ’audiophileseller’. But is this even a proper shop, or just a makeshift eBay address, hastily set up to sell off products that have fallen off the back of a truck? And who—or what—does the term ‘audiophile’ in the seller’s name refer to? The shop? The products sold? Or does it merely describe the ambition of the seller, as the name suggests? These are important questions, for those wanting to estimate the risk involved in purchasing from an unknown vendor in far-away China. The few ratings from international buyers rarely help in obtaining a clear picture.
To make matters worse, similar-looking cables can almost always be found from other Internet vendors, often for even lower prices. And, consequently, down the rabbit hole we go: Are these the same products? Are they better or worse? And—finally—are any of these items actually made out of the materials that they are claimed to be? In other words, how many buyers are going to have them delivered, take them apart, run a materials test, and publicly report on them, if their incentive was nothing more than the petty impulse of wanting to save a few bucks? By nature, tests of this kind are rare. And when they do occur, there is still the worry about consistency in the quality of manufacturing. Can we trust the craftsmanship to always be on the same level? Or do products made of similar components differ, simply due to changes in the quality of manufacturing?
In our western mode of doing business, branding helps us to give a product a finished form and character, and—paired with a contact address in case of trouble—a sense of legitimacy. The Chinese brand-free culture sees no other obligation, than to present the most attractive bling at the most approachable price, right at the point of sale. Much like a street vendor. After all, the “30-day test-and-return policy” is little more than a joke. If we consider that many cables have run-in times of more than 30 days, the only thing we can say for sure within this period, is that the product has arrived. And at times, I have even found that the sellers have meanwhile closed shop and are no longer able or willing to accept returns. For these very reasons, I have spent quite a sum of money in hunting for cables that fall short of the term ‘audiophile’ over the years.
Ultimately, this leads us back to the initial question. Is it a good idea to pruchase cables directly from China? Well, I am surprisingly relieved to find that the particular cinch/RCA interconnect that is presented here is a welcome exception to the norm. The plugs really are from the Chinese HiFi-brand Audiocrast, and, from what I could hear in my listening tests, I am also willing to believe that they are of solid copper and plated with 24k gold, just as described. In fact, the plugs are so heavy and slide on so well that they are a genuine highlight in themselves. The cables are described to be of OCC copper with an 8N silver coating. This, too, I can believe.
After all, there is something incredibly satisfying about stumbling upon a great cable. It is usually not any one particular thing that it does well, but rather the sum of its characteristics that comes together in what can only be described as—music. Now, this appears to be an easy enough conclusion to reach, you might think, because all cables connecting audio components cannot help but play the music that is fed through them. Sadly, this is only partially true, because, more often than not, a significant amount of the content of the original music is lost in terms of speed, dimension, dynamics, and tonality. The accumulated loss accounts for the phenomenon that people listening to your system play from another room will not think you have invited the musicians to play for you. The better our system is, the harder this distinction becomes.
The Audiocrast OCC and silver cable, sold by a Chinese eBay vendor, with its golden cinch/RCA plugs, braided design with Teflon dielectric, silver-plated OOC copper wires, and its non-branded manufacturer in who-knows-where, pulls of a magic act to rival well-known manufacturers, such as Kimber, Fadel Art, etc. Perhaps it is just a lucky shot, but the combination of materials works great, with the OCC copper-core providing tonal harmony and the silver-coating maintaining speed. If your system has music inside it, this interconnect will help you bring it to the surface. Never mind that of the three cables I ordered over a period of 4 months, not two actually look the same: two cables have direction indicators that are missing on the third. And one of the two cables with indicators sets itself apart from the rest by having the red and black colour-coating of the plugs confused.
Note: I did ask the ‘audiophileseller’ eBay shop for specifications on the cable (with plugs or without). The response was that they only knew it was made of OCC copper and silver, terminated with gold plated Audiocrast plugs. Well, I expected no less.
Author: Karsten Hein
Category: Gear & Review
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 TDA1550 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 TDA1550 DACs 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.
Author: Karsten Hein
Category: High Fidelity
Differences in ground potentials on interconnected HiFi units are arguably the most significant cause of signal infidelity in sound reproduction and constitute one reason for the manufacturer’s THD levels not to be met. Ground potentials may vary due to small amounts of voltage leakage from the transformer within a unit, or similar issues, but they are even more likely to differ between units, due to internal design choices and—most importantly—due to differences in the grounding that is provided by the AC power source. Furthermore, external antennas and installations from cable network providers constitute additional noise sources.
While it is true that the power transformers in our HiFi units regulate the AC current supplied from the wall socket and isolate the chassis, transformers will unavoidably leak small amounts of current, resulting in chassis voltage. Measured on our Harman Kardon HK730 receiver, for instance, the current leakage was confirmed as varying between 0.3 and 0.6 volts. Transformers in audiophile units will most likely be of the conventional linear type, with an iron core and wound primary and secondary coils. Since this winding has a direction by definition, the input resistance is likely not the same at both primary ends. Since in AC power supplies only the phase oscillates, e.g. between +230V and -230V in Germany, there will be a different transformer input resistance depending on which end is driven and different levels of leakage voltage, even if the resulting secondary voltage is the same.
On an all-in-one HiFi unit, slight deviations from ground level are normal and will not affect the sound, but when two or more units are interconnected, differences in chassis potential will be harmonised via the RCA/cinch connectors and form a ground loop with the house installation. It is a loop, because the HiFi units are connected with each other on two levels: the power supply and the RCA/cinch connectors. And even in cases where the noise itself is not audible via the speakers, the integrity of the music signal is compromised, because it carries the additional burden of energy leakage. Human ears tend to be unforgiving to technical noise, perhaps, because it is not a natural occurrence to which our species has had millions of years to adapt. To address the issue of varying chassis potentials, the professional audio industry has long since introduced symmetrical and optical connections that do not connect chassis grounds. There are, however, acoustic downsides that result from the addition of couplers which have made most audiophile listeners shy away from this technology.
In audiophile circles, therefore, it is common practice to minimise differences in ground potential between the units by turning the power plug of each unit and comparing the resulting audio output though listening tests. When there is minimal difference in potential between chassis, the music will sound fuller and lusher with better imaging and tonal balance. When there is greater difference between potentials and more leakage current is carried via the RCA/cinch connectors, both lower bass and transients will be compromised with the tonal balance leaning towards brighter and yet somehow duller highs. To identify the lowest amount of difference, it is important to start from a minimum number of devices and then check the polarity of each new unit. Companies such as Oehlbach offer a polarity tester, however, I have found my ears to be the better judge of polarity and have at times disagreed with the unit’s findings. In recent years, I have achieved the most satisfactory results by checking the polarity by ear.
Since polarity makes such an audible difference on grounded units that are connected with RCA/cinch, finding out the preferable polarity has become a common first step in setting up HiFi systems, especially among vintage audiophiles, who do not follow the path of correcting the signal retrospectively, by running it through a digital sound processor (DSP). In fact, when signal integrity is maintained throughout the unit, the sound will be superior to retrospective DSP corrections, simply because a DSP cannot correct what is not there and will in the end be kept busy filtering and flattening the effects of a hum or of HF interference, without being able to differentiate between the signals. Maintaining signal integrity is similar to fly fishing, whereas a DSP is more the practice of throwing dynamite into the stream. Sure, skilled people will catch fish either way, but I doubt that the pleasure of the achievement will be the same.
My initial reason for embarking on the subject of system grounding was of a different nature, however. For many months, I had a humming issue on our Philips turntable that I could not explain. I had already removed the antenna cable, optimised system polarity, and still the humming continued to be present at a level that was highly annoying. The turntable signal was compromised to the point where it was lacking both dynamics and soundstage. Since I could not find the solution, I decided to write about my sorrows in a vintage audio forum, describing our system setup from power sockets to our Martin Logan electrostatic speakers. The response was imminent: Where did you plug in the power cords of the speakers‘ high voltage supply?
The mistake I had made by plugging in the speakers into wall outlets (right where they stood) was instantly clear to me, but only with the little nudge from a forum member. By using separate sockets, I had created a difference in ground potential between our high voltage powered Martin Logan SL3 speakers and our B&K ST140 amplifier that was now trying to harmonise potential through the speaker cables in the form of an audible hum. Since this only occurred when phono was selected as input, I had simply failed to understand the situation. With hindsight, the reason for this is simple: since phono is more sensitive to interferences, this was the most obvious point of the error to become visible. This does not mean, however, that other sources were not affected. Connecting the speakers via the same PowerStar rail as the rest of our system brought phono noise down by an audible 70%, at least.
Author: Karsten Hein
Category: Gear & Review
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.
Tel.: 0151 241 643 55
Author: Karsten Hein
Category: High Fidelity
The term ‘sound stage’ describes the acoustic impression of width and depth that resembles a live-stage setting, observed from the position of the audience. It is mostly used in the context of two-channel stereo setups but can also be found in three-channel stereo and two-channel mono discussions. A solid sound stage is the result of many important and correct decisions when setting up a HiFi system, and it is difficult, if not impossible, to achieve this without observing most of the ground rules laid out in the twenty two points of the ‘High Fidelity’ section. The sound stage is a result more than it is a ‘thing’ to be done, but in order to describe it and identify flaws in it, we need to make sure that we agree on some basics.
The picture shows the current 2-channel setup of our Hafler XL280 and Tannoy XT8F system. The loudspeakers are positioned 90cm from the front wall, measured from the front of the driver and the center axis of the speaker. When discussing the distance to the front wall, we refer to the distance between driver and front wall, rather than the back of the cabinet, as this changes with the dimensions of each new speaker. The reason for this method is simple: It is the driver that reacts with the room, not so much the speaker’s cabinet. Based on the circumstances found in our specific room, the distance between the speakers results in only two meters, again measured from the driver’s centre axis.
We have positioned our listening chair to assure that the listener’s ears are at level with the tweeters, which is usually the manufacturer’s advised position. Since the Tannoy speakers are of coaxial (or dual-concentric) design, tweeter and midrange share the same axis, making the correct level of the ears even more attractive. Furthermore, to assure ideal listening conditions, the distance between the ears and the drivers should form an isosceles triangle with the distance between the speakers. As in many domestic environments the distance to the listening position needs to span the full depth of the room, it is advisable to place speakers and listening position on opposite sides along the wider walls of the room. This setup offers the additional benefit of minimising first-order reflections from the room’s side walls.
In our setup, we have turned the speakers towards the listening position by 5 degrees. The resulting angle is called ‘toe-in’. Depending on room conditions, speaker distance, and speaker design, more or less toe-in will be preferable. It is therefore advisable to begin on a slight toe angle and to increase and decrease the angle while repeating the same song. This is most quickly achieved with a friend, or even better two friends, one at each speaker. While changing the angle, it is important to maintain the exact distance to the front wall. Even one centimetre of forward or backward movement will have a strong impact on sound.
There should be three discernible positions from which the music emanates. The left speaker, the right speaker, and the centre between the two speakers. The centre image results from mono signals in the recording, and since there is no visible speaker in this position, it is often called the ‘phantom’ centre. Speaker toe-in and listening position should be such that the music creates one seamless stage, panning from left to right. If there are holes in the stage, the speakers probably need more toe-in. If the stage is too narrow or compressed, the toe angle should be decreased. When positioning speakers in this way, you are looking for believability, i.e. a position in which the stage appears to be most natural.
In most forums, the vast majority of people discussing the merits of equipment have not even taken this basic step to assure fidelity. What they are discussing, therefore, is a random overlapping of frequencies. This becomes clear when they post images of their rooms and their setup. Based on their observations, they proclaim that speakers matter or that amps matter more. Little do they know that moving the speakers a few inches will transform their systems more profoundly than any new speaker or amp could ever do for them. No wonder, they cannot hear the difference between HiFi racks (in their ability to absorb micro-vibrations), or the merits of different cables (in their ability to protect and time-align signals), for as long as simple acoustic laws are not being observed.
If the speakers are set up correctly, listeners will be able to discern the three positions, but they may find that the music does not free itself from the speakers, so that the width of the channels, or that of the centre, or both, is very narrow still. The channel width can be fixed by making sure that ground potentials between the HiFi units are minimised. This is usually done by checking the polarity of the AC plugs. This is however not applicable in countries with fixed polarity plugs, unless you have a faulty AC outlet, power cord, or your unit has been meddled with internally. The centre image becomes narrow, for instance, if electrical interference affects the audio signal, either through HF interference, or through touching or crossing RCA/cinch interconnects. When the signal is received in a pure and clean fashion, the centre will be wide and pleasant.
When music is recorded, natural instruments such as piano, guitar, and drums are picked up indirectly with the use of microphones, rather than being directly connected via the use of cables. This means, music is captured in two ways: Directly from the source of the signal, and indirectly, when reflected from walls, floor, ceiling, and objects in the room of the recording. When sound waves are reflected, they are delayed and/or inverted. Our brain calculates the amount of delay and inversion and from this derives a sense of room dimension, material property, signal location, and distance. In a two-channel setup, it is therefore possible to hear music coming from positions to the far left and far right of the actual speaker positions. This is called stage extension.
On a proper setup, we can also sense elements of music that seem located nearer to us and elements that seem to be further away. The impression of stage depth is the result of recording choices, but the recreation of this stage in our listening environment is just as much dependant on our choices in setting up the system. Speakers that are pressed into the corners of rooms or standing too close to the front wall will not be able to deliver the same intact quality of imaging as speakers that are placed properly. And as timing has an electrical as well as acoustic dimension, proper speaker placement will enable you to identify HiFi units and cables that have frequency dependent timing issues.
I hope to have explained my findings well. Although I have read extensively about the subject of soundstage in recent years, the image and explanation I have shown here is based on my own findings as audiophile listener. If you feel that an important aspect of sound stage is missing from this description, I would welcome your input. Feel free to leave your comment below or contact me directly.
Enjoy your music.