firstly met Mr Andrzej W. Matusiak in 2006 not long after I started „High Fidelity” (‘W’ in the name is ‘Wincenty’). We „met” via email to organize a test of Audiomatus AM250 ver. R amplifier. It surely required a lot of guts from Mr Matusiak to deliver his creation to me, a guy who wasn't really well known at the time and who's magazine also had only just started. Surely a confidence that a product, an effect of several years of hard work, was good enough, must have helped. It turned out it was not just „good enough”, it was actually a very good product that received a 2006 „High Fidelity” Annual Award.

Since that time we have reviewed (I think) all Audiomatus products helping, I would hope, to spread the word about this company and its achievements. Each new product seemed to be a step forward – better performance accompanied with better looks. They all shared one thing in common – a decision that their designer made at the beginning about the way they amplified an audio signal. Namely each power amplifier and integrated amplifier worked in Class D. Today there is nothing special about it – many companies do that – but 8 years ago Class D was something not widely recognized nor appreciated by Audiophile community.

Listening test of Audiomatus products indicated a large potential of this solution, and a high quality of Danish Bang&Olufsen's ICEpower modules used by Audiomatus. This impression seemed correct as also other famous brands like Jeff Rowland (Model 201 for example) and BelCanto decided to use the same modules. Today many large manufacturers including such a big names as MBL and Mark Levinson also offer class D amplifiers. But at the time when Audiomatus started, it was based on a conviction of the potential of this, unpopular at the time, solution based rather on listening experience than anything else.

It is worth mentioning that Mr Andrzej started experimenting with this technology already in a year 2000, when Audiomatus was founded. In the interview published with my first review of his product he gave me three reasons of his interest in B&O modules:

The first reason, that I already mentioned before, was a very interesting result of listening tests of TacT's amplifier, and later also BelCanto's. EVO200.2 was the first digital power amplifier on the market that proved that using simple solution at a reasonable cost, one can build a high quality amplifier.
The second reason was market analysis that we'd done that told us that market for such devices should be growing in coming years and that it was a perfect moment to get on board with this new trend and start our own production. Last but not least we knew we could use our knowledge and experience in designing and building switched mode power supplies which used very similar technology, similar elements, and that required almost the same measuring equipment that we already had at our disposal.

Well, the man was right! And since he got on board quite early, today he is one of the most experienced designers of „switching” amplifiers.

For years Audiomatus manufactured mostly power amplifiers. There were only very few preamplifiers ever offered by them. The first one (or maybe the second, I'm not sure) was PP03. It was a passive preamplifier. Many manufacturers encountered serious problems when trying to create a high quality preamplifier for their class D amps. Mr Andrzej was obviously aware of that as in the already mentioned interview he said:

Wed don't plan releasing a preamplifier in the nearest future. We studied this issue, we even built a prototype. But we concluded that designing a preamplifier performing well enough not to limit the potential of our amplifiers would require a lot of time, effort and money […]
We have not abandoned the idea though. It is possible that by the end of this year we will present a high quality preamplifier matching our amps with both: looks and performance.

The first active preamplifier released was, if I'm correct, the TP 01, that we reviewed in March 2013. So it would seem that development of this project took almost 13 years. When the first one was released next was obviously much easier to develop…
A year later Audiomatus released another active preamplifier, called TP 02. The main difference is a different choice of tubes: TP 01 used two 6H30Pi triodes working in parallel (similar solution to that used in Lamm LL1 and Conrad-Johnson CT5), while TP 02 is a classic design based on ECC82 (12AU7A) double triodes with one triode working as as voltage amplifier and the other as cathode follower. This particular model is an subject of this review.

ANDRZEJ MATUSIAK
Audiomatus | Owner, designer

Measurement system
During our listening test to chose proper elements for our preamplifier we use Beyerdynamic DT 880 headphones driven by LME49600 audio buffers. Output splitters sport carbon Takman resistors. Our source of signal is a PC with Asus Xonar Essence STX soundcard. For measurements purposes we use another PC with exactly the same soundcard. To avoid problems with ground loops we use a separating transformer for PC. Such a measurement system offers parameters that few years ago were obtainable only with a very expensive AP equipment. Our system is surely less convenient to use – no automatic measurements and it's surely less user-friendly but the several times lower cost of it (compared to professional one by AP) is good enough reason not to complain about convenience.

Primary criteria of the project
1. Preamplifier should offer a tube-like sonic performance (but not too much tube-like).
2. Output impedance no higher than 800 Ω.
3. No cathode capacitors. An experience I gained when working on TP 01 preamplifier tells me that cathode capacitors have a strong sonic influence and not a very good one, I have to add. To lower that negative influence one has to use very expensive capacitors which does not seem to be a reasonable thing to do.

How we chose tubes for the project
When looking for tubes for TP 02 project I assumed that:
1. It would have to be a double triode.
2. It should offer several to 20 times amplification ratio.
3. We needed an acceptable heater negative with respect to cathode of minimum 180 V.
4. A high availability (so current production).
5. Noval tube socket.

We knew that since we wanted to use one of triodes as voltage amplifier and the other as cathode follower the difference of potential on both cathodes would be of half of anode voltage – that's why we created a requirement no. 3.
This problem can be solved in one of two ways:

• we could set heater to a ¼ of anode voltage by connecting it to anode voltage splitter. This solution has been known and used for many years. There is one problem with it though. Today there are many devices of dynamic range bigger than 100 dB and using this solution means increasing distortion and reducing dynamics on both: macro and micro level,
• since we wanted to use full dynamic and microdynamic potential of tubes we had to connect heater with ground and use a tube that fulfills requirement no. 3.

All of the above mentioned requirements are fulfilled by two types of tubes:
- ECC82 (12AU7A) and all types fulfilling requirement no. 3,
- 6CG7 and all types fulfilling requirement no. 3.

We started our selection of tubes with finding optimal operating points, based on measurements on listening sessions, for triode with cathode follower, because I assumed that it would be a sonic characteristic of cathode follower that would determine a sonic character of the whole circuit. My expectation of a bit of “tube element” was fulfilled in a better way by cathode follower in ECC82..

I chose capacitors and resistors basing (mostly) on everything I learned when creating TP 01 preamplifier. Than I'd used an experimental circuit based on a single triode of 6H30Pi tube, with grid polarized with voltage from a battery. The anode power amplifier used for TP 01 offered a very low level of noise and a very low output impedance (below 2 mΩ within 10 Hz - 20 kHz range). Such a circuit with a single, very linear amplifying element working with no negative feedback is very “transparent” which makes it a very good tool to assess even smallest modifications of sound introduced by elements.

When working on TP 01 I primarily focused on input and output capacitors since I assumed these would have a greatest influence on the sound. For my trials I chose only metallised and foil polypropylene capacitors. I found out soon enough that a price itself of a particular capacitor did not relate directly with offered sound quality. What was more important was rather how particular manufacturer positioned particular model in his offer. This did not concern truly costly capacitors (with prices above 80$ a piece) as we did not even test those.
Listening trials were time-consuming since first we had to eliminate obvious problems with the circuit and after we did that it was not easy to tell difference between capacitors. These trials were conducted by two people and we tried to keep them as “blind” as possible. The prime factor we used in our assessment was sound and price was a secondary one. If we couldn't tell two capacitors apart we chose the less expensive one.

After we finalized these trials and chose AMPOHM (later this company was overtaken by LCR) FP-CA-AU caps for output and ESA ClarityCap for input, we started out trials with anode resistors. After few rounds of soldering in and out different elements we draw the first conclusion – the biggest influence on sound had NOS carbon resistors that also added a lot of noise to the sound. This noise, low stability and reliability were the reasons why we decided to exclude these resistors from further trials.

A side note: I am pretty sure that if in the 1950ties designer had had metallised and carbon film resistors at their disposal they would have never used these “mass' carbon ones :-) Significant noise level was also a reason why we excluded MOX resistors from out tests.

Later we eliminated wire resistors, because of how our experimental circuit behaved in upper frequencies. I personally believe that not every circuit that measures well has to sound well, but is is highly unlikely that a good sounding devices does not measure well. Obviously assuming, that one measures what should be measured. Most of us can remember very well a “distortion war” some years ago that resulted in creating some of the worst sounding amplifier ever created.

So finally we were left with metalized and carbon film resistors. Of these we chose carbon Kiwame ones. They seemed to be almost sonically transparent, and if there was any influence it was towards a little warmth in sound. Utilizing results of these trials I finally decided to use Kiwame carbon resistors and LCR FP-CA-AU output capacitors. When finalizing our project we realized that there was a problem with output capacitor – the results of out listening trials were not consistent with what we could hear now. We thought that results were different because in TP 01 output capacitor is polarized with a direct current and in TP 02 it worked without such polarization. It is our guess for now that has to be experimentally confirmed.
So later we continued our tests to finalize them with a new winner - Mundorf Supreme, that seemed to sound even better than ESA ClarityCap. During our trials for capacitors for TP 01 we thought that it was ESA that was slightly superior sonically. This told us we should always test elements in the circuit we want to use them for. I still had to find the best resistor for inputs triode's cathode. I started with my personal favorites Takmans only to realize that metalized PRP in this particular circuit were slightly better.

Choosing a potentiometer was much simpler job, as we could use our experience with TP01 development.

At that time our reference, we compared other solution to, was a multi-position switch based on Takman carbon resistors. I tested a well known and highly acclaimed resistor ladder, but the results were not even good. These were unfortunately not, at least at this stage of development, the elements that could be used for a high quality tube preamplifier. I wrote “unfortunately” because these were inexpensive, reliable and easy to use. But the unwanted sonic influence was bigger that anything introduced by capacitors and resistors.

Since one of the requirements was a remote volume control, I focused my test on a “blue” and smaller “black” ALPS. They both offered similar sound quality although the “blue” one seemed to sound slightly better. Also measurements indicated that larger pot offered better balance between channels.

Sonic character of a device reproducing recorded music is what defines our long term relationship with it. In other words – if we want to use some product for a longer period of time our needs and expectations and its sonic character have to match. Some features of the sound that we recognize at first often create a sort of a “pattern” in our mind that influences our perception throughout the whole listening session. These sonic features are obviously very important but the general character of the sound turns out to be even more important to our perception.

I think there is not other audio device for which this general characteristic of the sound is more important than for preamplifier. This is the real heart of every audio system, even if, in some cases, it seems not to play any sonic role at all. It's basic functions are: volume control and matching source of signal with power amplifier. The secondary functions are: input selection, and sometimes phonostage, DAC and headphone amplifier. Today there is more and more devices that are more difficult to define as they combine preamplifier with music files player, headphone amplifier with preamplifier, and so on.

TP 02's is a preamplifier with a very simply primary function – it is a linestage with five unbalanced inputs. One can easily realize that designers focused all efforts on this single function as TP02 delivers coherent and well organized sound. Listener is offered a participation in a musical spectacle, a sound that enters his room. This impression is based mostly on a very deep, powerful, rich lower end. And I mean not only bass but also a lower midrange – bass and lower midrange should be treated in this case as a whole. Writing on particular parts of the range is, in this case, on one hand a bit “artificial”, on the other it should help Readers to better understand the description of the sound.

Audiomatus seems to offer a very coherent lower part of the range that smoothly gives over to the midrange. This is why concerts of Krautrock bands like Kraftwerk and Guru Guru, both recorded in 1971 sounded so well. The overdriven, rich guitars, synthesizers, even flute played by Florian Schneider Esleben (Kraftwerk) – all these instruments seemed to be big, rich and powerful. This created a large, in all its dimensions, soundstage. It was a really convincing musical spectacle.

I think that such a presentation of lower range will satisfy those who search for richness in music presentation and not only for details. TP 02 does not convey a particularly detailed sound. It focuses more on the music as a whole rather than on details that create it. Not because the presentation lacks details, but the general sonic characteristic of this device suggest perceiving music as a whole rather than going into details, searching for nuances, phantom images' separation and so on. So I wouldn't count on a precise, detailed “picture” of a double bass player. Low sounds are rather warm and bit rounded. Bass is not boomy, not overblown, but it is surely not particularly taut, there is no fast, hard attack.

My perception of treble is similar. These are soft, “golden” and slightly rolled of against upper midrange. The latter is slightly emphasized, but since it's upper midrange sound remain open. It seems that if some music fan is looking for a stereotype “tube” or maybe “analogue” sound of percussion's cymbals this is a preamplifier for him.

I mentioned “music fan” on purpose. I truly enjoyed Guru Guru and Kraftwerk due to TP02's relaxed presentation of this music, the richness and density of the sound, but it was only the recently released Queen Forever, with, for example, Mother Love or The Miracle that proved that this was a choice that designer had made and not just a coincident. It was a powerful presentation of a musical material that was surely not perfect. Queen's songs sound bit bright and there is no depth to the soundstage due to significant compression of the recorded material. Audiomatus was able to gently modify that with its particularly rich midrange, and this slight roll off in the treble took care of a brightness of Mercury's vocal. Long story short – this album definitely benefited from TP02's sonic signature.

Presentation of midrange requires a separate chapter. As I already mentioned its lower part is extremely rich and dense and it smoothly merges with bass. I also said already that emphasis is placed on its upper part, above, say, 800 Hz. So it is hard to call this sound, at least according to stereotype, a “tube-like”. But there are some “tube-like” aspects – wonderful tonality, and musicality. I think that TP 02 was voiced to match best Audiomatus power amplifiers. So most likely it will be a best match for class D amplifiers using Bang&Olufsen ICEpower modules.

The above information is an oversimplification as Audiomatus worked very well with my mighty Soulution 710. Still I think that owners of Audiomatus amplifiers, but also of Jeff Rowland's should be more than happy with TP02. TP 02 “lights up” upper range of human voice, or lower range of cymbals, and this particular part of the range is not the strongest part of class D amps – it is often rolled off and not very dynamic. The same can be said about tube amplifiers. Combining these two technologies, often within one device, seems like a good idea. They complement each other. For quite a long time I have not heard any bright sounding class D amplifier. If you have, I'd assume that there is some problem in a particular system that should not be credited to the amplifier itself.

One could view a matter of resolution in one of two ways. If one considers precision of placement and detail selection as the key factors, one has to consider purchasing a different device. Audiomatus is not a master of these elements. Its designer chose a different path for it – via wonderful tonality and timbre differentiation and fantastic stereophony.

Whatever recording is played Audiomatus will deliver a large scale sound and amazing spacial effects if that's what its producer wanted to achieve, like on Polish group's Abraxas album 99, or Roger Water's Amused to Death. Listener is surrounded with rich, dense sounds, he can hear a lot of details, nuances and so on, that when played by most preamplifiers at this price range are barely audible. In this presentation these are an important part of it.
The soundstage ahead of listener is presented in a slightly different way, It is not very wide, what matters in richness of everything in front of the stage. These wonderful spacial effects I mentioned create an impression of a huge soundstage, but in fact they tell us more about space, acoustics, and not particular placement of instruments.

Summary

TP 02 is a serious product made by serious manufacturer. It offers a “mature” sound, solid casing – it is easy to tell that we deal here with an experienced designer who has a plan and knows how to carry it out. I guess it helps that he can really hear/recognize the sound he creates, and while he does it to fulfill his own need and expectations I bet that many music fans share exactly the same ones with him.

This preamplifier offers a rich, warm sound, and its way of presenting treble allows listener to enjoy even not so perfect recordings. There is a slight emphasis in the upper midrange so when choosing speakers one should avoid those that put emphasis in their presentation in the same area. Bass goes down deep, it is rich, powerful, but not as precisely defined as it is by reference devices. Spacing is one of the greatest attitudes of TP02 – soundstage is impressively huge.

It is an excellent product made by a man who knows how to put knowledge and years of his experience to use. TP 02 is the best device he created so far, at least among those I had a chance to listen to.

TP 02 surprised me with its size and weight. I was used to Audiomatus power amplifiers (Marek Dyba had reviewed TP 01 for HF) so I wasn't prepared for such a heavy weight and dimensions. The front panel is a thick aluminum slab and the rest of the casing is made of steel sheets. Front sports four knobs that reminded me of the 1970ties and a Mark Levinson LNP-02 preamplifier (more HERE).

The on/off knob is placed bit atypically, as it is not the first from the left or right, but one in the middle. Next to it there is another, bigger one that allows user to select inputs – there are 5 of these marked with letters (from A to E). On the other side of the front panel there are two more knobs: a smaller one for adjusting balance between channels and larger one for volume control. The latter can be adjusted also using a remote control. Mr Andrzej decided to use not a very handy, programmable one, but it does it job fine.

The back back panel reminded me the one of the Audio Research devices, like SP20 for example, or one of Ayon Audio's, like Spheris III, due to installing high quality RCA sockets and placing them far enough from each other to accommodate even largest RCA plugs – one can use any RCA cable with any plugs and there will always be enough space. There are two parallel outputs. Since this is an unbalanced design there are only RCA inputs and outputs.

Not only the external design seem very orderly, the internal one also looks this way. Electronic circuits are placed on few circuit boards. Input and output sockets are soldered directly to small board bolted to the back panel. When one looks from the inside, it easier to tell that manufacturer used high quality RCA sockets. Inputs are switched with a small, hermetic relays. Signal from a selected input goes with quite long cable to the front of the device, to a blue Alps pot. Next to it, on the same board, there is quite a large bank of relays that switch resistors used to adjust balance between channels. Attenuated signal goes again with quite a long cables to another circuit board where it is amplified.

As most tube based designs also this one is quite a simple one sporting high quality passive elements. One ECC82 for each channel is used to amplify signal. The unit under review used NOS tubes. These sat in solid ceramic sockets with gold plated pins. Tubes are coupled with pot section with Mundorf M-Cap Supreme capacitors, and on the output side with large LCR FP-CA-AU ones. T he resistors were chosen in course of listening tests – these are carbon ones from Kiwame. Manufacturer used also large, high quality Wima caps.

Power supply is mounted on two separate circuit boards. They are powered with a solid toroidal transformer made by Polish company Toroidy. It sports two secondary windings: a high voltage one for tubes anode, and a low voltage one for a heater and auxiliary circuits. Both voltages are rectified and regulated. There are four large BC smoothing capacitors. Transformer is bolted to sort of a “platform” as far from tubes as it was possible in a common casing. These two elements should be kept as far from each other as possible.

The whole design look really solid, well made and meant to last for a long time – that reminded me a solid job of another brilliant Polish designer, Mr Eugeniusz Czyżewski of Linear Audio Research, a his creations are in this aspect an absolute point of reference for me.
The only thing that caught my eye were these long cables form input to pot and back. It is just my guess, but it is possible that getting rid of them by moving pot to the back of the device and using a long ax from the know in the front to the pot in the back could even improve the sound. But first of all I am not a designer, a secondly I don't know the story behind TO02 prototype – maybe Mr Andrzej tried that and found his solution to sound better.

Specifications (according to manufacturer)

Tubes: a single ECC82 (12AU7) per channel
Gain (typical): 7 dB
Input impedance: 22 kΩ
Frequency range: 5 Hz – 200 kHz (+ 0/-1 dB; @ R load > 20 kΩ)
Dynamics (typical): > 106 dB (A-weighted @ 2 V output)
THD+N (typical): < 0,1 % (f=1kHz, U output =1 V, R load > 20 kΩ; only second harmonic)
THD+N (typical): < 0,003 % (f=1kHz , U output =1 V, R load > 20 kΩ; harmonics above second)
Output impedance (typical): 600 Ω (@ f > 1kHz)
Balance adjustment: in -1, -2, -3 dB steps
Inputs: 5 x stereo RCA
Outputs: 2 x stereo RCA
Voltage: 220-240 V AC/50-60 Hz
Power consumption: 30 W
Weight: 10 kg
Dimensions: 440 x 126 x 400 mm (W x H x D with feet and sockets)