February 2014

World Premiere!
AbysSound ASX-1000 Power Amplifier
Powerful, warm and fast Class A amplification from Poland.
Review By Wojciech Pacuła
Photos By Wojciech Pacuła, Bartosz Łuczak / Piksel Studio

  From a philosophical point of view, the argument for or against the existence of coincidence seems to be a "boundary" decision, conditioning our entire worldview. It is a fundamental experience, one that is used as a basis for the whole superstructure: faith or unbelief, religion or irreligion, optimistic or pessimistic approach to the problem of free will. Without that, we will live in suspension. And it probably doesn't really matter which decision we make, whether we follow, say, Michael Heller, the author of "Filozofiaprzypadku" ("The Philosophy of Coincidence", 2012), who sees God in chaos and probability calculus, or we rather side with Richard Dawkins, the author of "The Blind Watchmaker" (1986). What matters is that this is our choice.

My own approach to this question is pragmatic: sometimes events really look to happen by coincidence. I am aware, however, that I'm saying this from the microcosm point of view, while the regularities described, for example, by Heller are visible at the macro level. On the other hand, how can you not talk about the lack of coincidence in situations such as that involving AbysSound.

I have known for several years that such a manufacturer exists. It was promoted at the Audio Show by people from Chillout Studio who presented its beast of an amplifier, the ASX-2000, operating in Class A, boasting two 50 Watt each power output and weighing 115 lbs. I had a chance to look at it at the show. Everything about it was puzzling. The assembly and finish quality resembled that of Krell from its best years, and the interior looked like current Krell. The sheer number capacitors and transistors could give any ecologist a heart attack. And last but not least, those 80 Watts in Class A!

However, I have never had the chance to talk to AbysSound head, Mr. Marek Stoliński, much less to its chief designer, Mr. Julian Studnicki. Or so it seemed to me. When we finally arranged a meeting, and Mr. Stoliński arrived at my house together with Mr. Jacek Biskupski, responsible for logistics, the former looked at me and said that he knew me. I was dumbfounded. I could swear I never saw the man before! He seemed to read it in my eyes for he quickly explained what's what.

As it turned out, we met once, 12 years ago (what a memory!), at the Audioholic audio salon. Audioholic was a Polish distributor of American high-end gear from the likes of McIntosh, VTL, Aerial, Enlightened Audio Design and Runco, as well as PSB and Nakamichi. I used to work there over a year, curing myself of former professional influences (I had spent previous eight years as a sound engineer, in the studio and on stage) and getting ready, in retrospect, to work as an audio journalist. The audio salon was actually a villa on the outskirts of Krakow, wholly dedicated to audio presentations. They could be arranged in several listening rooms furnished to resemble a normal apartment, and a home cinema room. Lots of very interesting people visited the salon, including - for example – Zbigniew Preisner, a Polish film score composer, and Dr. Studnicki, a lecturer at the best Polish (in my opinion) institute of technology, AGH University of Science and Technology in Krakow.

Once I knew what to look for, I immediately retrieved this event from my memory, with all details. I vividly remembered the effort with which Marek helped by another person had lugged up to the second floor a true monster – the work of AGH lecturer. The thing looked hideous but sounded wonderful. It was the prototype of a 50-Watt Class A amplifier, whose further, more powerful (80 Watt @ 8 Ohm and 160 Watt @ 4 Ohm) development is the ASX-2000. I compared it then with a McIntosh power amp, the MC500 predecessor, and the results were at least promising. The tonality and dynamics of the Polish unit were clearly better. The one thing where the American amp seemed to come up on top, at least in such a short audition, was its better resolution. It was clear, however, that the Polish amplifier was not a finished "product" in the full sense of the word. It was not suitable for sale, primarily due to its finish and looks. I did not see it for the next ten years.

A few simple words about... Julian Studnicki, Ph.D. Eng.
The history of AbysSound has been linked for years with the famous Krakow-based designer of acoustic amplifiers, Mr. Julian Studnicki, Ph.D. Eng. A few decades ago, when power transistors were scarce in Poland, Doctor's amplifiers were well-known in Krakow and beyond, and recognized by many music lovers as a reference. The first designs from Dr. Studnicki were based on vacuum tube technology. It was in those years that he designed various electroacoustic devices for musicians. Mr. Julian Studnicki has always been associated with the scientific community, as he holds a Ph.D. in Physics, and was for many years an assistant professor at the Electronics Department of the AGH University of Science and Technology in Krakow, teaching courses on analog circuits. He is the designer, among other things, of a tube-based pulse neutron generator that was used to test the nuclear reactor at the Institute of Atomic Energy in Swierk near Warsaw. This invention can be now seen in the AGH-UST Museum of History and Technology. He also designed an amplifier to power a CT scanner for the Nuclear Research Institute in Krakow. However, chief AbysSound designer's heart was always in electroacoustics. Working at the university, he was the supervisor of several master's theses in that field. He is the author of dozens of scientific articles on analog circuits.

When semiconductor components became widely available in Poland, Mr. Studnicki fully devoted himself to electroacoustic designs. He designed studio equipment, including compressors, peak limiters and de-essers. He also developed unique microphone amplifiers and studio monitors. Dr. Studnicki actively participated in recording studio work, using his proprietary designs in the signal path. He collaborated with the Polish Radio in Warsaw. During that time he designed the B-500 bridge amplifier. It was a fully proprietary design that resulted in filing a patent application.

For the last ten years, Dr. Studnicki has been associated with AbysSound. He has been responsible for developing analog circuits in our products. A common feature of all his circuit designs is the lack of operational amplifiers in the signal path. Over the years, he and other AbysSound engineers created dozens of prototypes and carried out numerous tests, comparisons and auditions. They analyzed a lot of circuit design solutions to select and refine the one and only circuit for each of the devices they created. Their current work includes, among others, audio preamplifiers, phono stages and headphone amplifiers, DAC output stages and input stages for analog-to-digital converters. Based on Mr. Studnicki's experience in the field of vacuum tube technology, a number of prototype tube-based circuits have been tested and developed. Ultimately, they will become the basis of our future products. The main work, however, has been focused on acoustic amplifiers. This resulted in our two amplifiers that have been launched to the market.

As you can see, Mr. Studnicki was always full of bright ideas backed by his theoretical background and experience. What he did lack was something every ambitious designer dreams of: the funds. This is where Mr. Marek Stoliński came to help. His company, ARTMAN Electronic, specializes in industrial automation systems designed to work in the most demanding conditions. The systems are resistant to high and low temperatures, high humidity, electromagnetic interference and supply voltage changes. It is his devices that are used to measure and evaluate the technical condition of all four football stadiums prepared for UEFA Euro 2012 in Poland, and of the largest new bridges in our country.

Theoretical Background
The basic design principle of AbysSound power amplifiers is the lack of negative feedback loop. The advantages of this solution are commonly known. However, it proves very difficult to achieve very good and stable amplifier characteristics. In the case of Mr. Studnicki's amplifiers it required investing in new technologies and a careful selection of components employed, as well as developing completely new design solutions, not used by other manufacturers. The result of years of research was the development of fully proprietary voltage amplifier and power output stage circuits.

A high-end voltage amplifier must have an extremely good linearity, while a good output stage needs a very low output impedance. Both characteristics must be achieved without any local negative feedback loop in either of these circuits, and with zero global negative feedback (involving the whole amplifier). The following paragraphs include a brief description of the solutions allowing to achieve the above objectives.

BQVA – Bi-Quartet Voltage Amplifier
The amplification gain of the BQVA circuit depends on the value of its characteristic parameter, the number of external transistors that provide voltage gain and are controlled from the BQVA outputs, and the value of two resistors (not included, as usual, in the negative feedback loop). One of them is the load resistor of the voltage amplifier. The input voltage is transmitted (with virtually no loss) to the other resistor. Thanks to the ultra-linear voltage amplifier, the power amplifier is characterized by a very flat frequency response.

ULHD – Ultra Linear High Damping Circuit
The ULHD circuit is used at the amplifier output stage. Its operation is based on compensating the voltage drop on emitter resistors at output power transistors and on the base-emitter junction of these transistors. The compensating signal from the ULHD interacts with the output stage of voltage amplifier. Theoretically, it is possible to achieve an infinitely large damping factor. In practice, with a properly tuned entire circuit, damping factor reaches the value of several thousand. The ULHD circuit allows for an excellent control of the speaker driver cone. Even at very high levels of acoustic signal dynamics, the cone excursion is properly controlled. Another original solution was used in the DC servo circuit. It employs a high-voltage differential integrator. Since the integrator does not feed a DC offset control signal to the amplifier input (as happens in a commonly used solution), it results in no degradation of the audio signal.

Design
The amplifier under review is a smaller version of the flagship design. It operates in pure Class A up to 25% of its rated output. That allowed to increase its maximum rated power to 180 Watts at 8 Ohms and 360 Watts at 4 ohms. The massive heat sinks get mercilessly hot, however, and you need to make sure there is a lot of space around the unit. The input stage is very complex, yet the amplifier has an unbalanced topology – hence the RCA-only input connectors. In my case it did not really matter as my Polaris III preamplifier also has an unbalanced design.

A single glance at the ASX-1000 is enough to realize that this is a "macho-man" type of an amplifier. Black, huge and heavy. Its overall build and finish quality is perfect and shows a significant money that went into it. The enclosure design is not particularly original, and includes elements found in other well-known amplifiers. Thick aluminum panels are reminiscent of Pass amplifiers and the rear resembles designs from BAT. The top panel has cutouts that, for the life of me, look exactly like those in the flagship 850A from Cambridge Audio. It is apparently difficult to come up with something new, though. The enclosure features massive heat sinks with cooling fins on both sides.

The only items on the faceplate are a blue-rimmed on/off switch and a deeply milled company logo. The rear panel sports more elements, but also without exaggeration. They include a pair of stereo gold-plated 0201 RCA input connectors from WBT and two pairs of 0765 speaker terminals from the same manufacturer. An IEC socket with an integrated switch is placed in the center, between the speaker terminals. It might be worth replacing the accompanying fuse with something better. The rear panel also features two large handles on both sides. They are not a mere decoration – they are used to slide the amplifier, vertically, into a dedicated case, similar to those used as traveling cases for musical instruments and professional equipment. Each amplifier should be packaged this way.

The interior looks to be designed and made with equal precision. And it is just as predictable, at least when it comes to the component placement. Input buffers are mounted at the rear panel on small circuit boards potted in blue masking epoxy, additionally damping the vibration. From there, the signal is fed to power amplifiers mounted directly to heat sinks and housed in perforated metal screens. Speaker terminals are connected with very thick copper and silver plated copper braid. The same type of wire is used to supply power to the output stage. The latter use eight Sanken transistors per channel. Passive components are all very good quality, including Wima and Evox polypropylene capacitors. The amplifier circuit is Dr. Studnicki's proprietary design and employs his Bi-Quartet Voltage Amplifier in the input and the ULHD in the output stage to increase the damping factor. The amplifier is designed to work with zero global feedback.

Most of the interior is occupied by the power supply. Its basis is a huge, low-noise 1600 Watt toroidal transformer. It works with large ON rectifying diodes mounted to heat sinks and ten Nippon Chemi-Con filtering capacitors for the massive total of 220,000 μF. The currents involved are so high that the capacitors are parallel coupled with thick silver plated copper flat bars instead of usual wire. The input and control sections have voltage control power supplies. The operation of the amplifier is controlled by a microprocessor that has a separate power supply. The microprocessor ensures amplifier's safety and long operation life.

Sound
The first thing I heard from people from AbysSound who brought the amplifier to me was that it's damn heavy and they're willing to help me set it up, followed by a suggestion that in case of any impedance matching problems with my preamplifier they would change the amplifier input impedance from the default 10 kOhm to 100 kOhm. The lower value of amplifier input impedance it comes with as default results from their experience in pairing it with AbysSound own preamplifier, which will go into production in about a month. It offered a lower level of noise and distortion to which they could not remain indifferent, given that at least half of them have an engineering background. They knew what kind of preamp I used and were a bit worried about its tube design, generally resulting in a higher output impedance than that of solid state preamps. Unless we're talking about a tube preamp with an output buffer to lower this parameter. The Ayon Audio Polaris III is, however, an ultra-minimalist design that employs a single tube, capacitor and transformer based gain control. No buffers. In spite of that, its output impedance is a very low 30 Ω, which should not be a problem for the 10 kΩ amplifier input. And it wasn't. To make sure, I also tried a more classic combination with a solid state preamp – the Accuphase C-3800. I didn't notice any major differences in the frequency response and its shaping or in dynamics. The differences concerned the character of sound. Since the sound with the Ayon suited me more, that was how I carried out the whole review. It should be borne in mind, however, that in other systems and with different accompanying components the Accuphase may be a better choice.

What I heard while swapping the preamps was so significant that in a way it "set up" the whole audition. The difference between the two units was large, but it was based on the change of sonic priorities and not of the sound quality. While I preferred the "package" I got with the Ayon, I was not indifferent to what was offered by the Accuphase. The AbysSound showed these differences with grace. "Easy" and "unproblematic" is the starting point in the high-end and I will not even invoke these terms in any different context than to use them as an explanation. The pleasure with which I was watching the differences was caused by the tonality of the Polish power amp way and its approach to the question of timing.

Let us start with tonality, as that is usually the most pressing problem. I recently corresponded with one of "High Fidelity" readers from the U.S. who was looking for a matching amplifier for his Focal-JMLab Maestro Utopia speakers. Being aware that their impedance can drop as low as 1.6 Ω and that they need a powerful amp, he was at the same time worried about tonality. In the case of these speakers, it is usually sharpened by the accompanying components. I suggested to him either something from the Soulution 700 series or a flagship amp from Vitus. I know both of them and they are both great. What turned out to be the problem, however, was the price. Over $50,000 for a power amp that requires an equally good preamp significantly exceeded his allocated budget. If I had then known about the ASX-1000, it would have been my second choice.

The reason is that the amplifier offers a meaty sound, in which the most important are the first planes, instruments and vocals. The spatial aspect, i.e. the soundstage, is in the background. Its holography is outstanding, but only when it comes to a given instrument, vocals or music event. The body and three-dimensionality of a given sound source are only slightly inferior to those offered by the Soulution 710 and resemble what I heard from the Accuphase A-200 Class A monoblocks. Yet it was its differently set priorities of the sound source versus the accompanying room response (acoustics and reverb) that made the unit from Krakow engineers a particularly interesting proposition to me.

The amplifier creates large phantom images; dense and saturated. One could even call them mature, in the sense that they do not require further clarification by the listener and are "fulfilled" rather than "suggested". The extent to which we are longing for something like that was revealed to me by the very first album I listened to, a collection of old Dean Martin's recordings released as part of the Collector Series. Although I have many of his albums, this one is special. All the recordings were sourced from the original master tapes and remastered in the analog domain, which would be almost impossible today. Only specialized labels like Mobile Fidelity and Analogue Productions still practice this sort of thing; large record companies stopped doing that anymore. The first two tracks go back to 1948 and come directly from the lacquer discs, and are truly outstanding. The Polish amplifier showed these recordings in the manner usually offered by good turntables and the best audio file players with DSD material: warm, yet with outstanding resolution. Selectivity was less important. The warmth came from a full-bodied lower midrange, both in terms of quantity and quality.

The former is simply related to an adequate power of this range. It made Dean Martin's vocals, as well as those of Bing Crosby I auditioned next, sound credible due to their large volume. What's more, the live recordings that usually sound too light and too ethereal, such as Deep Purple on "Now What?! Live Tapes", moved the air in my room with a strong kick drum and great bass guitar work.

The latter, i.e. the quality, is linked with resolution. You will not be able to say that after only a short audition, or a short exposure to this presentation. This is not the case here. In this perspective, the ability to show differences (differentiation) and small details that add up to something bigger (detailness) translates in us into a kind of inner peace during our listening. Nothing distracts or irritates us, but nothing is missing, either. Obviously, this is not a perfect sound, and the flagship power amps from Switzerland and Japan show it even better, but I have yet to hear that in a $10,000 amplifier.

As I said, what's most important here are the first planes and direct sound sources. This gives us the sense of intimacy and the feeling of being "there." Or, actually, "here" as the unit brings the instruments over to our room rather than creates a separate world in front of us. It does it irrespective whether it's a jazz ensemble, such as Art Blakey's "A Night In Tunisia" on the latest XRCD24 AudioWave release, Portishead's debut on the SHM-CD, or the Bösendorfer Imperial grand piano played by Oscar Peterson during his performance. Each time, the sense of performers' presence was of high intensity and the directness of their appearance could sometimes cause heart palpitations, especially at the volume knob turned up higher.

This type of presentation is usually associated with very fast and transparent amplifiers. However, less experienced music lovers often confuse true speed with fake speed, or even an artifact. I am not blaming anybody or pointing any fingers, but the fact is that only a prolonged exposure to the kind of amplifiers like the Accuphase A-200, the Soulution 710, the best 300B designs or the ASX-1000 enables us to rearrange things in our brain. It is a process and we need to work at it for it to be successful.

The trick I have in mind is to emphasize the sound attack and to slim down its decay. Often part of it is sound brightening that adds an extra dimension, suggesting a large space. It is but a hollow shell; make no doubt about that. The most resolving amplifiers actually have a dark tonality. Or at least so it seems at first. In reality, detailness is not manifested the way it is usually conceived. It is not a "large amount of details." On their own, they are rather annoying and shatter the illusion of participating in a real event. They only make sense when they build up the presentation and are part of more basic assumptions. The amplifier from AbysSound has this difference in its blood and could be used as a basis to teach about it. However, it is not only its strengths that show the success of people from AbysSound in designing this amp, but also its weaknesses. Against much more expensive competitors, it was not fighting a losing battle but did a good job and hardly ever went wrong.

The density of sound and its saturation causes a feeling of its slight slowdown. It is not entirely true nor is it the equivalent of a "tube sound." However, the dominance of saturation and sustain over attack and decay is clearly audible. Hence, when we play a track that requires real impact, say, Chuck Mangione's "Children of Sanchez", the Polish amplifier approaches the matter from the full body rather than impact side. The Soulution 710 was much better in this respect, as it offered the former without losing the latter. Also, the connective tissue that binds together various sounds, in other words the acoustics together with the attributes of the medium on which the sound was recorded (e.g. noise), were withdrawn. This is not an amplifier that "X-rays" the recordings. In all fairness, it also needs to be said that it does not particularly help in creating a "holistic whole." I have mentioned before the first two tracks on Dean Martin's album, which was transferred from a lacquer disk – the background noise is their inherent part. The amplifier nicely showed it behind the main sound, but at the same time reduced it. I was not lacking the treble as such, at least when it comes to cymbals' tonality. What I did lack, however, was some opening up the sound, something between the sounds that makes them more visible. In this respect, it was very much like expensive amplifiers from Vitus Audio. And finally, the lowest bass. I am not sure whether you would pay attention to it without a direct comparison with an expensive top amplifier from the competition, but the Soulution 710 clearly pointed it out: the Polish amplifier slightly rounds off and calms down the lowest bass. We are talking here about the sub 40 Hz range, as the lowest bass string was shown without any problems. However, the hyper-low electronic sounds on the albums by AnjaGarbarek, Depeche Mode and Portishead were not that low.

Conclusion
At nearly $10,000 for an amplifier from an unknown company, from a country that most Americans cannot even point to on a map and often confuse it with the Netherlands (Poland/Holland), is a huge amount of money. Actually, even if we were talking about an amplifier from Pass, BAT, Vitus, Accuphase and other audio "aces," it would still be a lot. The ASX-1000, however, brings along a very interesting combination of resolution, body, warm tonality and absolute inner peace, which are impossible to simply pass by. All the more so as it is backed with authentic engineering knowledge and many years of experience of real people who know what they are doing. This is not another "empty shell," but something solid that will stay with us for many years to come. It is guaranteed by the authority of its designer, Mr. Studnicki, and the enthusiasm and money of the company owner, Mr. Stoliński. The amplifier offering this kind of sound will prove a perfect "generator" for the likes of Bowers & Wilkins, JMLab-Focal, Amphion, Triangle and other demanding speakers that are notoriously difficult to drive. I am sure that many of their owners will hear them for the first time as it was intended by their designers.

The amplifier from AbysSound is powerful, warm and fast, and favors the foreground. It offers an intimate, dense sound that we plunged into and take off. It is not the best, and I will not even pretend to call it "absolute" amplifier. But for the money, you will not find anything even half as satisfying. The A-200 monoblocks from Accuphase are more resolving, the Solution 710 and 700 are both faster and more resolving, and top 300B amplifiers offer a lighter sonic texture, delving even deeper into recordings and music. The expensive monoblocks from Vitus Audio sound very similar and are generally slightly better in everything. However, you will need to pay for something like that. And that will hurt.

Specifications
Type: Solid-state stereo power amplifier
Output Power: 180 Watt @ 8 Ohm, 360 Watt @ 4 Ohm (RMS)
Pure Class A Output Power: 35 Watt @ 8 Ohm
Input Sensitivity: 1.2 V (RMS)
Gain: 29 dB
Frequency Response: 7 Hz to 125 kHz (1 Watt @ -3dB)
THD < 0.017 %
S/N Ratio: 108 dB
Input Impedance: 10 kOhm
Dimensions: 540 x 245 x 540 mm (WxHxD)
Weight: 155 lbs
Price: 29,000 PLN (~$9500 USD)

Company Information
AbysSound
Ul. Lipowa 3
30-702 Kraków
Poland

Voice: + 48 880 802 843
E-mail: office@abyssound.com
Website: www.AbysSound.com