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Accuphase C-2450 and A-47

Golden Times
Whether you have the sum to spare or would need to save it up little by little:
you can hardly make a more high-end oriented investment than in the newAccuphase C-2450 preamp and the A-47 power amp – a whopping soundyield is included.

For prospective Accuphase owners that much is true: once it hurts, but then golden
times will be dawning, namely years of joy in perfect workmanship, luxurious comfort
and exhilarating sound time and again. The painful moment is at the dealer’s cash
desk. I know what I’m talking about since I forked out exactly 2998 Deutschmarks for
the E-303 integrated amplifier back in 1981. Certainly the amp was also so dear –and precious – to me in the sequel because it involved an enormous, mostpainstakingly saved up sum for me, a 19-year old draftee. But as soon as theAccuphase was driving my Celestion speakers to undreamt heights, all the pains anddoubts were completely gone and replaced by sheer euphoria.
Those memories came back to my mind when the new C-2450 preamp from theYokohama based prestige maker, joined by the A-47 class-A power amp, weredelivering a superb performance in the listening room at a hefty package price of
22,700 euros. Well, everybody should know for themselves on what to spend theirmore or less hard-earned money. But considering the fact that in Germany theaverage price for a new car is currently about 30,000 euros, the Japanese teamsuddenly doesn’t appear to be so horrifically priced, the more so as in 15 years’ time
the tin box will stand rusting on the junkyard, whereas the Accuphase duo, asexperience teaches, should probably be almost as fresh as today by then.
Anyway: with such an investment it’s all about happiness in the here and now, ofcourse, including the readiness to treat yourself to something good. The financial cut
will probably not be as huge as it was for me back then. However, the enthusiam willbe. For with the Japanese amps you can feel the lavish opulence in effort and soundjust as much as the commitment to an almost philistine accuracy.
AAVA, the extremely sophisticated ”Accuphase analog vari-gain“ volume control
which is to ensure ultimate, long-term constant precision with finest increments, may
serve as an example of this. Where other manufacturers make do with utilizing a very
precise classic potentiometer or else a level control via resistor banks, theAccuphase designers – who, by the way, keep rotating within the product groups togive new ideas a chance – were hitting the limits both ways. So they devised this fully
analog technology, individually implemented for each channel, to convert the signal
into 16 differently weighted currents, their combinations being able to create morethan 65,500 intermediate values which allows steps of one-tenth of a decibel over awide range. Not that anyone would need this mega resolution. But it’s definitely cool
to watch the display digits run up and down after the decimal point.
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Opulence – precision – soundOf all that the listener will not notice a thing because the level control, hence thevolume knob, which is suspended floating on isolators in a solid aluminum block,turns so softly and smoothly as if its axle were moving a top-level sliding contact
potentiometer instead of a sensor mechanism for angle detection.
Not only the AAVA works in a channel-discrete manner. Likewise the strong power
supply of the preamp not only features separate banks with smoothing caps, but haseven two transformers. That way a mutual interference between the two channels,
which might do harm to the spatial imaging, can largely be ruled out.
Soundwise, as was almost to be expected, the C-2450 also meets the highest
demands, for instance by combining utmost differenciation with homogeneoussuppleness. So despite an exemplary obsession for details and joy in meticulously
unraveling complex structures, it therefore doesn’t sound a bit analytical or ostensible.
It rather builds up its dynamically refined, vibrantly breathing soundstage consistenly
from the room depth, embezzling neither the most subtle proportions of reverberation
nor articulation noises which have actually died away already in the moment of theirformation. The listener’s ear quasi lies on the voices and instruments, but at thesame time gets the panorama view of an, where necessary, exceedingly far spanned,
perfectly organized stage.
But watch out: behind the flap of the preamp, which is fully equipped in the typicalAccuphase way, lurks a little sonic trap in the shape of the ”gain“ switch used to set
the basic gain. Only in the lowest ”12 dB“ setting you’ll get the highest possible
easiness and airiness. At six decibels more the performance appears to be slightly
more consolidated, but not quite as casual as before; and 24 dB of gain is only
recommended for very soft sources, as the super pre will then produce slightly glassy
mids and a marginal narrowness. Check it out!
As a matching game partner for the C-2450, which can optionally be upgraded withthe widely adaptable ultra-quality AD-2850 phono module for 3885 euros, we chosethe class-A A-47 power amp. This is certainly an amazing amplifier already becauseof the fact that, for design reasons, it would be limited to the 45 watts of continuous
output power into eight ohms per channel, as specified by the Japanese. Strictly
speaking, class-A implies that the power transistors, which are permanently fully
open to avoid crossover distortions at the change from the signal’s positive to thenegative half cycle, always give off fifty per cent of their maximum power as heat into
the heatsinks. And in idle mode the A-47 takes up about 180 watts from the grid. So
it fits!
Massive power despite class-A
However, we measured more than twice the output power into eight ohms at ourdistortion limit of one per cent (see measurements), which proves that above theindicated value the A-47 leaves the class-A mode and its total of 24 MOS-FET
semiconductors changes over into switching mode. Up to 2 x 228 watts could then bemeasured with bursts into four ohms. Yet one shouldn’t accuse the manufacturer ofany fraudulent intent, for the promise of the pure class-A mode is indeed kept up to
the apparently moderate ”guaranteed power“. And with 45 watts into eight or 90 watts
into four ohms resepectively it’s of course so loud already that you will probably
hardly ever exceed the class-A limit with music listening, even with speakers of only
average sensitivity.
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Apart from the avoided switching distortions, the A-47’s entire technical concept islaid out for ultimate attention to detail, as is shown by the extremely low distortion orintermodulation figures. Just like the high S/N ratios, these are presumably due to thesophisticated, fully balanced input stage of measuring device grade and also to thecurrent feedback which, according to Accuphase, works without phase errors, i. e.
shifts in the time domain.
In their efforts to eliminate even the smallest of losses, the designers used metalbolts to connect the generously sized, firmly gripping speaker terminals directly to thecircuit board which contains e. g. the smart protection circuit. In former times this waslinked to the connection panel via cables.
The amplifier which is powered from a fat power supply and may also be switched tomono bridge or bi-amping mode – in the latter case both channels are fed the signalof the same input – displays its output on lavishly sized, sensitively twitching andoptionally defeatable level meters. No ”guess gauges“, as our measurement engineer
noted, but precision instruments. In spite of the relatively high dissipation the A-47,
which is loaded with two broad heatsinks, only gets lukewarm even in continuous
operation and will therefore not sit silently glowing in a breeding heat like other classA power amps.
In terms of sound the A-47 is a true class-A Accuphase. What this means? That its
delicately woven, utterly transparent performance, which sometimes appears to be
playfully dabbed in its finesses, creates an almost floating lightness. Down to thedeepest registers the reproduction was fanned out airily, with great love for detail andan elegant attitude. Of course, the bass was clear and contoured. However, it neverseemed to be chiseled from stone, but came along equally graceful, nimble-footed
and agile like the entire sound image.
With vocals the A-47 indulged the senses with an almost intimate nearness andsensitivity, thereby definitely promoting its immediacy and emotional impact. In
Radka Toneff’s excitingly intense song ”The Moon is a Harsh Mistress“ the amp was
worth a mint, because it sent us audiophile chills up and down our spines. True, theA-47 didn’t shy away from harder stuff – it has enough power anyway –, but evenwith earthy rock and blues things don’t get really ”dirty“. It’s the tip for esthetes, thepower amp praliné, perfectly seasoned down to the nuances. In this capacity the amp
stands for the whole Accuphase set: certainly not cheap, but an exquisite enjoyment!
Matthias Böde3