Accuphase A-200 User Manual

Complete review in hifi & records magazine (Germany), Issue 02/2013

Monophonic Amplifier Accuphase A-200

Monuments

By Wilfried Kress

With the new monophonic Class-A amplifier A-200 Accuphase is to
complement its range of reference audio components, whereby the Japanese
have once again set a new benchmark.

Confidence is indeed the beginning of all, i.e. the basis for our social existence
and relationships. Principally, people want and must initially give their leap of faith to
others while imploringly hoping that one’s trust in someone will eventually not be
disappointed. Still, sometimes we are to err and sometimes we are lucky. C’est la vie.
In today’s crazy times however, even most reputable institutions, which to this date
would have been considered respectable ones, are prone to falter. In view of this
aren’t we even more so in the need of a specific feeling of confidence? In such a
point of time we become aware how important it is that one can rely on a partner who
does what he says and is not merely paying lip service to one’s ideals. Who is not to
change the horses every now and then or jumps on the bandwagon. Well, this
applies to enterprises as it would apply to human beings: if a company or (audio)
manufacturer is able to convey a straightforward and reliable attitude something very
precious will emerge from this, generally known as “brand loyalty”.

In 1972 “Accuphase Laboratory Inc.” has devoted itself to high-quality music
reproduction and has since followed up this objective with stunning persistence. Like
for example SACD: after a quite early participation the Japanese have – even to this
date – constantly been supporting this digital format, whereby in this context they
never really cared to also consider the issue of “home cinema”. When others began
turning their back towards CD, Accuphase started to build its own, proprietary CD
transports. And from a technological point of view, the engineers in Yokohama never
rested on their laurels of the past but have rather devoted themselves to the
refinement of the circuitries employed in their audio components. What I want to say
is that those who are consequently putting the focus onto the essential will in the long
run be rewarded by the consumer’s faith.

I personally would never assume that a new CD player or amplifier from
Accuphase could be inferior to its predecessor. Or that perhaps just the front panel
has received some cosmetic upgrading whereas the inside was more or less subject
to cost cutting. As long as Accuphase is not to be sold to some big global players of
the audio trade, I simply cannot imagine such things to happen. In fact, the opposite
is true because to this date the quality of the new line of reference components the
Japanese launched in the past couple of years was clearly surprising as well as
exciting us: the preamplifier C-3800 (issue 04/2012), transport DP-900 and DAC
DC-901 (issue 01/2012). Add to this the new A-200, Accuphase’s definite statement
with respect to power amplifiers.

On the first sight, the A-200 seemed quite familiar to us, owing to the fact that it has
exactly the same dimensions as its lesser powered brother A-65 stereo amplifier
(issue 04/2010). Each chassis puts a hefty weight of 46 kg onto the scales, which
may still be considered “moveable” in one or the other way. Well, thanks to the large
handles and bars alongside the external heatsinks this is indeed the case. A
substantial part of the weight can be attributed the huge encapsulated toroidal
transformer in the centre of the case, which is accompanied by two big electrolytic
“beaker” capacitors with 100,000 µF each. This is quite typical for Accuphase
amplifiers and apparently the engineers there do not favour the parallel array of lower
capacities in the power supply.

Twenty power MOSFETs in push-pull mode are forming one amplifier
assembly including its own heatsink whereby in each A-200 unit there are two of
these combined in parallel configuration. So, the 40 output transistors per mono block
are to provide plenty of power: Accuphase specifies the A-200 to deliver 100 Watt
Class-A at 8 Ohm whereupon we measured a rated output power of 166 Watt into 8
Ohm, respectively 322 Watt into 4 Ohm. Do we really need more? Well, I personally
don’t but those who prefer to listen to punchy Heavy Metal, etc. all the time can never
have too much power anyway. The employment of two A-200 monos in bridged
operation may perhaps be a bit over the top for this purpose but Accuphase has also
got some nice, big and more powerful A/B amps in its product line. Fortunately, there
are absolutely no doubts coming up with respect to the “question of power” delivered
by the A-200 because it features a very precise peak power meter to rely on. When
classical music is playing most listeners will be happy with a mere 25 Watt and with
50 Watt one is definitely on the safe side. And who would really want to do without
the magic of Class-A for something else? Power alone is in no way a warrantor for
good sound. Even at low volume levels the A-200 is sounding superior to the A-65,
whereby both amps have virtually nothing to do when rendering Paul Simon just
playing his guitar.

The A-200 is said to be not only powerful but above all very “quiet” also. A
statement of Accuphase declares the A-200 to be the amplifier with the lowest
inherent noise in the 40-year history of the enterprise. Indeed, the signal-to-noise
ratio is a stunning 6 dB better when compared to the A-65 and thus has set a new
benchmark in our laboratory. This outstanding quietness can be attributed to the
output stages working in parallel configuration as well as to the discrete design of the
input stages and some modifications of the “gain management”. In preceding
Accuphase amplifiers the input and power stages were made with a rather high gain
factors, i.e. 12 and 16 dB. In the A-200 however the input stage takes the lion’s share
of voltage amplification in the amount of 22 dB whereby the output section is to
contribute merely 6 dB. By means of this reallocation Accuphase can proudly assure
the attenuation of noise by 33 per cent.

Another issue the Japanese had worked on was the reduction of the internal
resistance in favour of a high damping factor, which actually was never a real
highlight in power amps from this maker. For instance, the A-50 from the year 1993
had a damping factor of just about 160 whilst the U.S. and European competition
were already claiming a factor in the region of one thousand and beyond. Still, we are
all aware of the fact that with respect to passive cross-over networks in speakers
there are – in 99 per cent of the cases – resistors in the tweeter’s signal path for level
adjustment. This means any (high) damping factor is rather useless at this spot. If on

the other hand speaker designers are employing extremely low-impedance inductor
coils for the bass region then any amplifier output with snubber (aka Boucherot link)
for the suppression of parasitic oscillations or a protection circuit with relay may tend
to become a bottleneck. Well, no such relays can be found in the output circuitry of
the A-200 but a heavy-gauche flat wire coil (see figure on next page) which is to
achieve a damping factor of 1,000, whereby Accuphase specifies a factor of 400 for
the A-65.

For the listening tests we had – for one month, that is – a complete set of
Accuphase reference components at our disposal, including the clean power supply
PS-1220. We used the XLR interconnects, which were supplied with the devices, as
well as some power cords from HMS, whereby the professional set up of the chain
was carried out by Winfried Andres from P.I.A. [the Accuphase distributor in
Germany]. Once again it became very clear that the Magico V2 and Accuphase is a
fine match which plays together very well. After some days of warming up (please
see “Surrounding Conditions” elsewhere in these pages) the entire system sounded
simply gorgeous. As far as power amplifiers are concerned I’m always trying to be
prudent with respect to an absolute judgement, owing to the amplifier-speaker
interface in which the impedance plays a role that should not be ignored. Therefore,
either bi-amping or bridged operation with two inexpensive power amps may be
beneficial in some configurations. But after having gone through a direct comparison
between the A-200 and the Soulution 710 I came to the conclusion that with
amplifiers of this calibre one has reached the absolute summit of high-end. The
Soulution played a tad more prominent whereby the Accuphase excelled at its more
colourful and refined rendition.

The keywords describing this experience are “absolute control” and
“unshakeable aplomb”. The A-65, too, is brilliant in this respect but doesn’t get as
close to the performance of the A-200. For some speakers it’s a big compliment to
say “They are in the room but they have actually nothing to do with the sound”. The
same applies to the A-200 which likewise “doesn’t make an appearance”. Everything
on the virtual stage in front of the listener is simply “there” and comes along
absolutely effortless and like a duck takes to water. This amp can flex its muscles if
music is to demand it, but not like a poser who elbows his way to the foreground.
With the A-200 impulses don’t “bang”. They just happen, if you know what I mean.

With an amplifier of this class there is really no need to worry about neither
“bass-midrange-treble” nor “auditory spaciousness” or “soundstage”, to be honest.
Furthermore, the A-200 is never going to play music like one or the other notorious
“big amp” from North America, which although being oh so powerful rather tends to
be far away from “swinging”. This Accuphase amplifier is definitely committed to the
classic ideal of high fidelity: nothing added on, nothing left out – in this respect it is
better than the rest of the world.

Conclusion

With the A-200 Accuphase has completed its reference line of audio components.
The unique Class-A mono amplifiers are definitely on par with the preamplifier
C-3800 and the digital combination DP-900/DC-901. Together with the outstanding
measured values it can without any doubt be considered “State-of-the-Art”; whereby
it sounds in no way technical but highly elegant: “Class-A” can simply not be replaced
by anything else.

Surrounding Conditions

It should be common knowledge by now that even the most sophisticated high-end
components do not deliver highest performance right from the start by simply
pressing the “On” button. They often have to be treated rather sensibly and
thoughtful. It’s like with good wine which we would fetch from the cellar in due time,
have it slowly reaching its optimum temperature and then, depending on the vintage,
have it decanted or not and eventually served in a suitable glass. Then we hope the
wine to have “blossomed” in the meantime and in the end is worth the money spent.
The noble Accuphase chain also is rewarding a few days of warm-up with
considerably finer and more colourful playback. It takes some time until technology
has put itself into the background and the magic comes on instead. Visitors of high­end trade fairs may perhaps remember that music sounded best on the last day,
short before the equipment was to be disassembled and packed again. Therefore,
except for the power amps, all components were constantly hooked up to the mains
during the period of our listening tests.
On the last day we carried out several experiments in order to find out what may
possibly damage this wonderful sound picture. If the C-3800 – certainly not a mimosa
– is switched off and on again, then the sonic results were rather “technical” and not
as controlled as before. The same procedure was less dramatic with the DAC, yet
more pronounced with the transport. After having all three components switched off
from the mains the fascination was in some way damaged, while furthermore
disconnected from the PS-1220 the entire magic was gone. Back on the PS-1220
again it immediately sounded less technical. Also, switching interconnects back and
forth was sonically noticeable, even with the unsuspicious speaker leads. These
experiments have clearly demonstrated how essential a good and constant power
supply is and that absolutely stable operating conditions are indispensable for any
electronic audio component.

Lab Report A-200

Irrespective the higher output power, it’s the by 6 dB better signal-to-noise ratio as
well as the perfect spectrum of harmonic distortion where the A-200 can set itself
apart from the A-65. The intermodulation distortions are the same with both amps
and the bandwidth has been well realised from our point of view. In particular with
respect to the signal-to-noise ratio and the harmonic distortions of the A-200
Accuphase has achieved a new record in our laboratory – congratulations to
Yokohama!