During this years Audio Show I had a chance to talk to the owner of Art Audio, Mr. Tom Willis, who also has the function of the companies technical director. Quiet and reserved, with a clear vision of what he wants, and what he strives to. But without superimposing his ideas on everybody. The full interview will appear in “Audio”, but I want to call upon the piece regarding technology – this shows the ides behind the constructions.
Wojciech Pacuła: Do you think, that there are any new technologies…?
And now everything is clear. We have already tested the amplifier Quintet, but for the first time I had the opportunity to listen to an amplifier from this company with a 300B tube in the output stage, the model Diavolo, being the final product of the ideas of Tom Willis. This is a power amplifier, so I got the preamplifier Conductor to accompany it. The latter is a device with an integrated headphone amplifier. And the DIavolo is a SET amplifier, with 300B output tubes and ECC88 and 12BH7A in the input and driver stage. Interestingly, it can be ordered with many different tubes fitted. As standard we can get the low-power tubes coming from the Electro-Harmonix factories, with the 300B from a renowned (Chinese) brand TJ, ‘mesh plate’ and 274B power tubes. The latter are so big, that they resemble the 300B from outside. The distributor made sure the test would be versatile, so he sent additional tubes: power tubes GZ34 from Mullard, driver tubes E88CC SQ from Philips and 12BH7A from RCA. He also arranged the loan of Western Electric 300B (from current production Westrex Corp) and the Telefunken GZ34. After some testing with the various tubes I finally listened to the amplifier in the following configuration: · 300B: Western Electric · ECC88: E88CC SQ Philips · 12BH7A: RCA · power: GZ34 Mullard
The exchange of my power amplifier Luxman M-800A to the Diavolo brought a change in the concept of the sound. I will tell now what was worse, as this might be important for some readers. Worse from the Diavolo, and that by much, was the bass. Because in this construction it reaches far more down, than in, for example, the amplifier JAG 300B, so the shortcomings of small power were more visible. There were no talking about definition or coherence offered by the solid state amp. You have to be careful in picking the loudspeakers and placing them in a room, as higher bass, with a unfortunate choice, may have a too long reverb. This will not be a big error, but taking into account other, set at a very high level, elements of the sound, it would be a pity not to provide the amplifier with best possible conditions. Also the instruments are bit worse defined in space. In this area my Luxman is an exceptional device, regardless of technology, and Diavolo is half a step behind, in terms of defining the shapes of the instruments and the point from where the sound comes.
And although the bass leaves no room for interpretation – it is how it is and not different – because the Diavolo is a tube amplifier with 10W output power, the case of defining and precision of showing the stage is something you can interpret differently. It is so, that this amplifier is ways ahead of any solid state amplifiers in terms of timbre and the ability of showing the interactions between the instruments. This is a step in the direction set for me by the PAT-777 Reimyo. Naturalness, ease and some kind of spontaneous joy, with what the Diavolo presents instruments is overwhelming. Quite transparent, a tad bright, but incredibly clean loudspeakers Harpia Acoustics Dobermann sounded as if I would be listening to a planar loudspeaker – with coherence from the mid-bass up to the upper treble, with silky precision (I cannot name it differently, this coincidentia oppositorum) showing the natural timbre, reverb and harmony. Incredibly – it was better only with Reimyo – sounded the vibraphone from the disc Pyramid The Modern Jazz Quartet. It had a vibrant attack and full, full saturation – this is repeating, but it describes the situation well. Similarly surprising was the dynamics, with which the amplifier showed the drums and percussion, contrabass and piano from that disc. Shading of the dynamics, showing its every detail, was besides the timbre, the forté of this power amplifier. And with all that it was not “merciless” for compressed fragments, or whole discs, as for example the Luxman is. It does not hide anything, I wrote that the dynamics is shown phenomenally, but it does not expose the errors. It is similar with the timbre – slight brightening of the upper midrange, typical for many contemporary recordings, that is usually underlined by solid state amplifiers (with a few notable exceptions like the Accuphase P-7100, Accuphase E-550 or Trigon Energy), here is somewhat “forgiven”. In absolute terms this is a slight deviation from linearity, but one, that we can only applaud! In an ideal world, I would probably not like to have it, but here and now, having the choice between the 1% of well made LPs and 99% of lesser quality, with digital recordings, I do appreciate what was achieved in the Diavolo. This gives a slightly, really very slightly, softened attack in part of the upper midrange, but it guarantees the transmission of the music communication without signs of boredom or impatience.
I talked about bass – this is not that the amplifier plays it badly. When I listened to the disc Sleepers of the prog-rock group Galahad, and then to masterpiece Radiohead, album Kid A, it turned out that the bass guitars are big, have proper weight and body. They just do not reach that far down like with the Luxman and do not have such a tight lower part. But it did not prevent the amplifier to sound with a really nice, full sound. Because the Diavolo has a big, saturated sound. I characterized the space already, I would only like to add, that this amplifier rather brings the instruments to our room than placing us in another space. The relationships between the performers are kept true, the distances – in depth and in breadth are precise. But the acoustics of the recording place, the true one, or the artificial one, is of second interest, allowing to keep the connections and tension between the elements on the stage. This is important to listen to that during the listening session – there are people that like another space being opened between the speakers, other want the instruments to be placed in the listening room. And the Diavolo with the preamplifier Leben RS-28CX offered the second solution.
Coming from the Leben to the Conductor showed, that the Japanese player is much more resolving. It cannot be denied, as well as the fact, that the Conductor with the Diavolo has much more credible timbres. This is another time, when we hear that certain devices were constructed thinking about them being together, when they were listened to as a whole during the construction process and make a “whole”. The easiest comparison is to the C-1000f Luxman, only with better timbres and more natural shading of the dynamics. The Art system gives an incredibly credible testimony for what was happening in front of the microphones. In absolute categories the attack, especially in the midrange and treble, is a bit softened in the preamplifier, but this does not translate to softening of the sound, but more to deepening and modeling it. The cymbals are more “gold” than brass, but we cannot say, that anything is distorted. It is just closer to what we can hear with the C-2810 and C-2410 from Accuphase than to the Krell EVO222. This is a proposition that is inscribed in the general character of this system. This is also a step in the right direction, if we place the preamplifier CAT-777 from Reimyo as the ultimate reference point. This is a similar striving towards reproducing a maximally credible event, without the urge to present as much information as possible – but within the taken compromises – to communicate that, what a give musical piece is about. Of course we do not have the ultimate resolution, that gives both elements – analysis and synthesis – but this is just the compromise.
The timbre of the British system is set a bit lower, that that of my system, lower than Reimyo, but higher than (I am sorry for the “height” thing, but it is necessary) the Accuphase system P-7100 + C-2810 and Luxman C-1000f + M-800A. The Art does not have any tendency towards enlarging the virtual sources, because even the beginning of the piece Lamento I from the disc Lontano Tomasz Stanko Quartet, with the characteristic trumpet playing, where we can hear much, much air from the mouthpiece and the basic sound “below”, the image had natural size and was not brought closer. The same situation was with the phenomenal piece Premonition from the disc Leucocyte of the e.s.t. trio, where the contrabass, made bigger and warmer by the sound engineer, was not “boosted” by the Art. And this while the treble was softer than with the Luxman. In this case this is not fully about softening the sound of discs (but well, until some extent it does), but showing it in a way it should be shown (I rely on comparison and the knowledge of the sound of particular instruments). It is mostly about playing without a trace of internal tension, present in my Luxman and my Leben, and that does not come from the tension in music. This is something my gear adds to music. We cannot hear this, while we compare those with 99% of other devices, but after listening to Reimyo and Accu P-7100 I know what it is. Also the Art system shows this, and although it has worse bass (this is the power amplifiers fault), is not that resolving (this can be attributed to the preamplifier), still it generates incredibly, really incredibly natural and credible reproduction. This is only the third time I heard, after my system and Reimyo, what the disc Sleepers from Galahad is about. For years I thought it was defective – flat, sloppy and with clear phase anomalies. When I exchanged the subsequent devices (the discs comes from 1995 and I have it from the premiere) nothing changed in that matter, and while I admired its musical contents, the sound bugged me. And then, not so long ago – a year or two – I heard, that in terms of space this is an incredible production. The created acoustics surrounds the listener and creates new dimensions, like the claustrophobic voice in Exorcising Demons. And everything is based on phase manipulations. Although the key album for such recordings is Amused To Death Roger Waters, recorded with the usage of the QSound system, but Galahad surpassed it without a trace of a problem. The case is, that when Waters sounds splendid on every stage of the battle for the “absolute sound”, then the disc Sleepers shows their possibilities only with the best systems. And Art Audio is one of them.
All listening sessions were made with the input tubes exchanged from stock – I played with the E88CC SQ Philips and 12BH7A RCA. The standard Electro-Harmonix are not bad, you can start with them, but the mentioned two are much better in terms of resolution and timbre. Another case was with the power and output tubes. The distributor and a friendly audiophile allowed me to listen to the standard TJ 300B tubes compared with Western Electric 300B (current Westrex Corporation production), and compare the power supply tubes – the standard 274B of Chinese make, but selected by Art Audio, with the CZ34 from Mullard and Telefunken.
The comparison of the 300B from TJ and Western Electric was fascinating. The latter have much better treble and midrange, at least in terms of timbre. In general the timbre of WE is lower and fuller. After plugging-in those tubes everything gains weight and dignity. Cymbals, reverbs, and most of all space, are phenomenal with the WE. The piece Pyramid The Modern Jazz Quartet is based on a constant snare drum rhythm as basis, in front of which, in the right channel, sometimes a vibraphone hits, and in the left channel we hear a piano. With the American tubes the distances between the instruments were much clearer, the snare drum was further behind the vibraphone. With TJ those elements was more on each other. The same with the instruments on the disc Leucocyte e.s.t. – fleshier, even more credible and created an incredible, intensive communication. The treble in WE is less “metallic” than TJ. I know how this sounds, because TJ is not metallic at all, but the WE creates the treble in a more natural, soft-vivid way. The Chinese tubes stiffened the cymbals and vibraphone a bit, what made those elements less resolved, and thus less natural. Well – resolution. WE have less thorough bass that than TJ. The latter can also reach further down. But if I would choose, I would take the WE. The cymbals from Lontano were electrifying in their “presence”, timbre, weight, etc. There is one “but”. When I listened to Stanko’s trumpet, I had no doubt, that the TJ better showed the relationship between the mouthpiece and the funnel – I know this sound from many recording sessions I attended, and I would say, that this element was shown better by the TJ. The WE are slightly less resolving in the medium midrange. TJ show more there, deeper. But the overall impression is that the American tubes are closer to the goal, but TJ still have something to say.
And while WE were a step forward compared to TJ, then the exchange of power supply tubes from Mullard (I tested the amp with) to Telefunken was just a step to the side. The German tubes give a more to the point and brighter sound. It gave interesting results with the 300B WE, but it did stir-up the ideal balance I hade before. The mentioned snare drum from Pyramid was closer to the vibraphone, and the latter lost some of its “height” – it was still in the same place, but you could not “see” that it had a height. The cymbals were stronger with the Telefunken – but again – I think, that the Mullard were the “golden mean”. The German GZ34 are splendid – much better than the Slovak JJ tubes (too bright) and Polish Telamp ones (too little resolved). But the depth and fullness of the Mullard catch me most. And my opinion did not change even by the mouthpiece of Stanko drawn better. The 274B turn out to be weak. They lack the saturation of the Mullard, or the resolution of the Telefunken. It is incredible, how power supply influences the sound! But if we think about that, then through the loudspeaker’s voice coils flows the current supplied by those tubes, and in this case, the effect brought by a certain element is key.
This was to be a small addition to the main test, even below the tube tests. And although graphically it just located like that, still the listening test to the Conductor as a headphone amplifier prolonged, so that I listened to it, in some spare moments switching to the Conductor + Diavolo set. Since a long time I use the integrated amplifier Leben CS300 for my headphones. This is a brilliant device, incredibly competent as an integrated amp, and even better as a headphone amplifier. I heard only one amplifier better than it with headphones, the expensive Cary CAD-300-SEI. I think that the Conductor is as good, and in some elements even better than the Leben and even the Cary. Compared with the first one, the British preamplifier shows an even more vivid, slightly softer – but in the good meaning of that word – picture. The stage is visibly deeper, the instruments are better separated from each other and better defined by the changes in dynamics, that the Leben does not catch anymore. CS300 is still the hi-end of headphone amplifiers, and probably the best translation of money to quality, but in absolute categories, the Conductor shows more credible sound. It is – like I wrote – at the same time more resolving and devoted from sharpness and brightening. The effect is overwhelming – my AKG K701, being a bit soft and with rather withdrawn treble, just “sung”. And only in one area the Japanese contestant bettered the Brit – in terms of bass. It goes down more, and the sub-range is tighter. In the first week of listening to the Conductor I had the idea, that the bass is a little compressed and sounds in a slightly clipped way, as if the unit could not supply enough current. After some time the effect disappeared, but full tightness and “kick” is not something this amplifier could be proud of. But anyway you need to give him a listen in this role – if you love headphones, then even if this is too expensive, you will know in which direction you should look.
Discs used during listening session::
Inside we see a lot of specialized PCBs. Horizontally mounted are three large ones, with the amplifying circuitry on them, one big with the power supply and a smaller one with a remote controlled volume potentiometer. A vertically mounted input selector PCB is near the front panel and two near the back panel – one with the logic, the other with the relays. The circuit is based on two tubes per channel, 6922 EH Electro-Harmonix on the input and 12BH7 from the not existing anymore Yugoslavian company Ei as output buffers. The coupling capacitors are polypropylenes from Wima. The potentiometer is a blue Alps, connected to the circuit with unshielded cables. There are lots of cables inside – running with audio signals, ground cables running from each PCB to a central point, creating a star ground topology. The power supply uses a medium sized transformer and lots of Vishay/BC capacitors. The headphone socket is not gold plated. The manufacturer states, that there are no capacitors on the output, that would be responsible for high output impedance and limitation of the frequency response. This is a tube circuit, so those could only be replaced by two means – a output transformer or… DC-Servo, like in most CD players and solid state preamplifiers. And DC-Servo is probably on the PCBs above the main ones.
The Diavolo power amplifier is a SET 300B unit – here with TJ 300B, as an option V 32B from KR Audio – on input E88CC SQ from Philips and RCA made 12BH7A. In the power supply we have one 274B tube per channel, that can be exchanged to GZ34 or CV378. Behind the tubes we see big, and very heavy, transformers – power and output ones. On the back we have RCA input sockets, speaker terminals with separate outputs for 4 and 8 Ohm, and two heat sinks, that get very warm during operation. I almost forgot – we have also XLR balanced input.
The circuit is split between two separate PCBs. The whole is truly minimalistic, and most elements are on small PCBs used for output tubes BIAS setting. The power supplied is rectified and stabilized for the input tubes and heating. In the power supply we find many capacitors, including splendid BHC from Denis Morecroft. There is also one choke per channel. The coupling between tubes is made using polypropylene capacitors Hovland Musicap. The balanced input id de-symmetrized in canned transformers. Similar to the preamplifier, earth is lead in star topology to one central point.
CDs FROM JAPAN
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