Complete review in hifi & records magazine (Germany), Issue 04/2010

Accuphase Pre-amplifier C-3800 & Power Amplifier A-65

Maestoso
by Wilfried Kress
Indeed a magic moment of amplifier making: the brand-new, ultimate Accuphasepre-amplifier C-3800 and Class-A power amplifier A-65.
Respect usually isn't heaven-sent, respect must be acquired through hard work.
This has always been the case, even though I venture to say that it is much more difficult
in our modern age than ever before. Too often these days, even the most extraordinary is
reduced to its mere value-for-money in Euro, Dollars or Yen, to be acquired like a ducktakes to water, so to speak.
We all see the ambitious efforts and expenses standing behind a technical product or an
artwork, yet often not more than that. The callousness in us allows hardly any freedom forgenuine respect, for instance, those who have heard the “Appassionata” for the umteenth
time may no longer be easily taken by surprise. And have you never heard among youraudiophile friends some notorious snappy and cool statements about high-end
components, which could go like this: “I know it, heard it, forget about it” - i.e. without theslightest vibration of esteem for the achievement of others.
But there is still another way to go. In the past weeks we've become aware of theacknowledgement and respect amplifiers from “Accuphase Laboratory Inc.” have received
from other people of the trade. The fact that Class-A amplifiers from Accuphase have often
been warmly recommended to us is merely a note in the margin here. Yet if an old handfrom the guild of amplifier makers starts raving after having spotted the Accuphasecomponents in our listening room, that says it all (to quote him: “If wouldn't build amplifiers
myself, I'd certainly buy those from Accuphase”). Another developer marvelled at thepower meters of the A-65 and said “You could actually calibrate your own measuring
equipment with them”. If one is aware that the indicators of most power amplifiers areusually nothing but “guesswork”, then one can perceive a large amount of respect in thisstatement. Hence, I'm quite sure that this respect will in no way diminish when the brandnew Japanese super preamp is going to enter the stage. It's because this C-3800 has not
only messed up our testing procedure a bit (which was easily accepted, mind you), theC-3800 is also a first-rate technical masterpiece. But first things first.
Actually, for the “special amplifier” issue you are holding in your hand now we werecounting on the Class-A amplifier A-65 alone. It was already here together with the preamp
C-2810 and the CD/SACD player DP-700 (tested in issue 04/2008) in order to get a sonic
impression of the entire Accuphase chain. Then we got wind of the C-3800: supercomplex, super-expensive and a big temptation. We couldn't say no, of course, and hence
this review was to become a double test for several weeks.
As far as the visual appearance is concerned, there is hardly any difference
between C-3800 and C-2810. Again, the new one features ventilation slots in the housing
cover yet it lacks the operational controls for the phono section (sorry, lovers of vinyl will1

have to resort to Accuphase's external C-27 we tested in issue 03/2009).
But this became obvious only after having opened the sub panel. In brief, less features fora considerably higher price and the quest for meaning that comes along goes like this: canAccuphase significantly improve such an elaborate pre-amplifier like the C-2810? After all,if closely looked at, a high-level pre-amplifier is nothing but an attenuator which has to fulfil
merely three functions: input selection, volume control and output stage for driving theinterconnects to the power amplifier. So, what's the difficulty here? Where is thetechnological challenge?
Well, in the details, as always in high-end. Simple tasks at first sight can turn out tobecome a real challenge on closer examination. Nearly all makers agree that the ultimate
volume control is demanding the highest attention. In this respect, some interesting
concepts could be realised in the past couple of years. In a presentation, Accuphase
documented the progress of potentiometers implemented in its own pre-amplifiers of thepast decades. They are shown on the next page above right (whereby once again apicture says a thousand words): from the C-200 of 1973 to the C-240 (1978) in Class-A
operation, DC servo control and conductive plastic potentiometer. Then the balanced
C-280L (1987) was launched, of which the V-version of 1990 had been equipped with thefinest potentiometer from Matsushita and thus having set a benchmark of developments
towards the most precise control of signal voltages.
In the year 2002 however Accuphase paved the way for a completely different
approach in its own right, whereupon they presented the proprietary AAVA concept with the
C-2800. This abbreviation stands for “Accuphase Analog Vari-gain Amplifier” which
conceals nothing but a farewell to potentiometers of conventional make and all theirproblems like channel imbalance, changes in output impedance and last but not least, alack of long-term reliability. A potentiometer is a variable resistor for the attenuation of
signal voltage. In order to get rid of this, Accuphase converts the signal voltage into acurrent gradation. 16 voltage-to-current converters per channel allow a resolution of
65.536 combinations, which can be considered more than fine enough. After summing up
the current is transformed into a voltage again, whereby the provided output voltage, which
is determined by the current switches, is then equivalent to the desired volume level. In the
C-3800 the AAVA circuitry has for the first time been realised in fully balanced configuration.
According to Accuphase, altogether 36 converter amplifiers are to yield a virtuallynoiseless current source. Well, the measurements in our lab are going to reveal if this istrue.
In the good tradition of Accuphase, the sub panel of the C-3800 has much more tooffer. Gain can be selected in three gradations. A volume correction dubbed“Compensation” is augmenting the lower frequencies in music when listening at low
volume levels. Here again three different positions can be selected (however, as opposed
to a conventional “loudness compensation”, the high frequencies are not augmented). And
the C-3800 is equipped with a dedicated amplifier module for dynamic headphones as wellas with switches for absolute phase and monophonic rendition. Lastly, the display can beswitched off, too.
Owing to the arrival of the new super preamp, the “Class-A-darling” A-65 has fallen
behind a bit. I was really looking forward to this top component in the Class-A range of
amplifiers in Accuphase's portfolio, which have already gained an excellent reputation
through the predecessors A-50 and A-60. With a weight of 43 kg the new A-65 is a real“high-end calibre” and therefore the solid handles at the front and rear do make sense2indeed. And, yes, during operation this amp is getting warm through and through.
In the technical specifications of the A-65, Accuphase guarantees an ultraconservative
average output power of 120 watts into 4 ohms, whereby we measured 208 watts and thisat a mains voltage of merely 221V. By the way, the power meters, which, if desired, can beswitched to store and indicate the peak values for each channel, are very reliable.
In the centre inside the A-65 is a cased 1,000 V/A toroidal transformer accompaniedby two really “beaker-sized” electrolytic capacitors with 82,000 µF each. Accuphasefavours power MOS-FETs and current feedback for stable phase characteristics.
Altogether 20 transistors from Toshiba (type K3497 and J618) per channel arranged inparallel push-pull configuration are taking care of substantial “steam” at the output. And
those who are perhaps longing for double the power can switch the A-65 to bridged
operation, whereby – it actually goes without saying – a second A-65 is needed for theother channel.
In the A-65 the signal path is also fully balanced and the amplification factor (gain)
can be selected by four gradations. In teamwork with preamps from Accuphase, it isrecommended to have the gain set to “Max” in the A-65 and to “18 dB” in the C-3800 or
C-2810. Compared with the A-60 the output stage was left unaltered, yet according to
Accuphase the damping factor of the A-65 had been augmented from 100 to 400. As the
A-50 and A-60 seemed to tend towards a rather round and soft rendition, some more rulingover the speakers can certainly not be a bad thing. And yes, indeed, the A-65 sounds a tadmore open and controlled when I think back to the sonic performance of the A-50, forexample.
However before we proceed to the listening test, we should briefly reflect on thiscrucial question: do we need a pre-amplifier at all? Well, we may have to resort to a tiebreaking verdict here, namely “in principle yes, but....”. Ultimately, this is greatly dependingon the quality of the output stage in the driving source and sure enough on the quality ofthe pre-amplifier employed. Klaus Renner, the co-founder of the High-End Society [inGermany] made this statement already in 1988 [Das Ohr (The Ear), No. 24]. Not much haschanged since. Generally, passive volume controls are giving away some dynamics andcontrol, whereas digital adaptations at 16 Bit are usually sacrificing resolution. It can beassumed that high-end-made pre-amplifiers are much more elaborate and hence lesscompromised than the variable output stage of a CD player. And this is why in nine out often cases music sounds simply better when heard through a pre-amplifier. All in all, thefundamental tones are more pronounced, resolution appears more detailed whilst thesoundstage has more three-dimensionality and depth.
Certainly, this does not apply to every run-of-the-mill preamp, yet the C-3800 has
once again convinced my ears as to how important this component is in a high-end chain.
After its arrival we compared it “cold”, i.e. right out of the shipping box, with the C-2810 thathas already been sucking on the mains for several days. It was immediately audible thatthe new one had some tangible virtues. Nevertheless, experience told us to calm down
and rather have the C-3800 sent first to the friendly photographer and then to our lab formeasurements, whereupon we would have it back in our listening room in order to stayunder continuous operation.
Therefore, under these circumstances it was not really difficult to clearly answer the“quest for meaning” mentioned above: those who are going to compare the C-3800 with
the C-2810 in an Accuphase chain are going to take a great risk – they will likely be lost3and unable to turn back (provided they've also got the necessary small change).
The C-3800 has simply more tonal authority and resolution to offer, whereas the C-2810
still sounded with a sort of “electronic flavour”, no matter which power amp was to receive
the signals. In fact, the C-3800 works wonders: if one of the high-definition pre-amplifiers
conveys a sound without any “technical artefacts” then it's the new big Accuphase. Thispreamp lacks any nervousness. It plays with wonderfully deep sound colours andexceedingly cultivated.
“Poetry clad in silk”. I remember this from a song by Paul Simon and I think this iswhat describes the essence of the C-3800 to the point. The very high level of authenticity
rendered by the C-3800 is deriving over and over again from its astonishing richness intone, the precision of its transistors notwithstanding. In comparison, the Soulution 720
seemed slightly more controlled and present, whereas the likewise extremely neutral
Mark-Levinson 326S sounded just a tiny bit leaner and thus has put itself in between the
C-3800 and C-2810.
However the closest approach to the “expressiveness” of a valve preamp is without doubt
achieved only by the Accuphase C-3800, and you can be sure it's doing that without
hidden tricks: at least in the “in-house” environment of DP-700 and A-65 this preamp is up
front with respect to sound colours, atmosphere and three-dimensionality.
The euphonious share of the A-65 within this splendid rendition should not be
underestimated, though. It contributes a dash of warmth and richness, offside all transistor
chilliness, whereby it plays slightly more succinct and perhaps a wee bit more transparent
than its predecessor. The A-65 should in any case be driven in balance mode, butotherwise and quite honestly, there isn't much to do wrong with this dream amplifier. ClassA has simply got a magic of its own. Thus, Accuphase is far ahead also in this league.
Please excuse me if I'm right away going back to the C-3800, but I still would like toreveal that this preamp has practically no weak spot, just as much there is hardly anything
to nag about with respect to the entire Accuphase chain. One evening during the testingseason, Stefan Gawlick and I were in our listening room whereby he reasoned that it's
pretty disillusioning if he recalls his own efforts to compile a decent audio system and oneis then going to hear something like that. Admittedly, the Accuphase chain in teamwork
with Magico V2 speakers and completely wired by HMS Gran Finale Jubilee interconnects
has indeed got something “incontestable”: the sound is gorgeous, palpable, musicallymeaningful and marvellously fluent. Put in a nutshell: it simply sounded like real music!
“Money is scoring goals, after all”, I said, whereupon Stefan Gawlick remarked that thiscan without doubt be applied to Accuphase and Magico. It was a very nice evening – andan instructive one, too.
Conclusion
With the C-3800, Accuphase has launched an absolutely world-class pre-amplifier, whicheven among the best of the best excels in terms of sound quality and technologicalachievement. And - oh so sorry - it leaves the hitherto in-house top preamp C-2180 behindby quite a clear margin. In view of the outstanding craftsmanship and perfection in details
the high price is certainly justified. And the A-65 is a recommendation par excellence
among the power amps from Accuphase. Class-A, well, that's just the way it is.
Lab Report
Together with the Soulution 720 and Mark-Levinson 326S, the Accuphase C-3800, too,has set an absolute benchmark for pre-amplifiers when it comes to measured
4specifications. Among this selected trio the Accuphase is slightly ahead of the others
regarding the sum of technical properties. Compared with the C-2810 however, the mostdistinguishing difference is not to be found in the distortions, which are fractional, butrather in the signal-to-noise ratios: on average, the C-3800 betters its older brother by
5 dB. Yes, one must have a look at the noise spectrum of the C-3800 in order tounderstand what perfection really means. The A-65 is likewise an excellent sample ofhaving mastered technical specifications, as we couldn't detect the slightest shortcomings
and, once again, the signal-to-noise ratio is simply outstanding. It will become very difficultfor others to compete with this brilliant amplifier combination. From the perspective of ourlab, Accuphase deserves the highest respect and appreciation – hats off!

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