Full review in image hifi magazine (Germany), Issue 2/2009

Accuphase Stereo Phono Amplifier C-27
by Dirk Sommer [Editor in Chief]

Which dedicated follower of analogue music reproduction would have ever
dreamed of this 20 years ago? The Japanese noble maker Accuphase is for thefirst time presenting a separate, extremely elaborate phono/equalizerpreamplifier.
It was in the end of the year 2001, during the celebrations for the 25thanniversary of P.I.A. [the Accuphase distributor in Germany], in a time when many, inparticular U.S. high-end manufacturers have put an emphasis on home cinema - nolonger a big issue today, eh? - when also Saito-San, in his capacity as Vice-Presidentof Accuphase, unreservedly stood up for the two-channel stereo rendition of music.
How serious this commitment was meant is, amongst other things, documented by
the analogue tuner T-1000, which was to receive an image hifi award, and thestunning CD player DP-500. Accuphase actually never bothered about alleged future
trends but rather had faith in those audiophiles who would like to acquire the verybest component for the playback of the currently widespread formats and media and, yes, Accuphase succeeded.
To this date analogue aficionados had a choice among various phono boards
to suit their preamplifiers or integrated amps from Accuphase. Now this maker istrying to meet the ever so growing demands of vinyl lovers with sophisticated audio
components at home by launching a phono/equalizer-preamplifier which is capable ofprocessing the signals of up to three pickup cartridges, whereby it doesn't matter if
the cartridge is of the moving-magnet or moving-coil variety. Each input can beconfigured accordingly. Yet this is not carried out by simply switching an additional
amplification stage in the signal path on or off, like is the case with nearly any othercompetitive phono preamplifier. No way, in the C-27 Accuphase allows itself theluxury of providing two independent amplification stages, one completely optimised
for MM, the other one for MC.
Moving-magnet pickups generate an output voltage which is about ten times
higher than the output voltage of a "normal" moving-coil pickup and they are usuallydesigned for a load impedance of 47 kOhm. Therefore, three FET buffer amplifiers(x2) with high input impedance, arranged in parallel configuration, are taking care of
the incoming signal before it is handed over to six likewise parallel-configured
differential amplifiers in a push-pull circuitry. In addition to the standard 47 kOhm, thisamplifier stage also offers a load impedance of 1 kOhm and 100 kOhm, which isactivated by relays and accordingly selected by means of a rotary knob on the frontpanel.
The substantially weaker MC-signals are boosted via eight parallel differential
amplifiers in order to ensure a low load impedance as well as an extremely highsignal-to-noise ratio which is oh so important for the operation of pickups with moving
coil technology. Load impedance can conveniently be selected, again by means of arotary knob, whereby 3, 10, 30, 100, 300 and lastly 1000 Ohm are provided forexperimentation. For each amplifier section, the gain can be augmented by 10 dB
and then a subsonic filter can be activated by simply pressing a button. It goes
without saying that the C-27 also features a memory facility for load impedance,
overall gain, subsonic filter and, last but not least, MC- respectively MM-mode ofoperation. All this can be programmed for each input.
The MM- and MC-amplifier of each channel share one circuit board made ofTeflon which is said to have a low dielectric constant as well as low loss. The twoboards for left and right channel are mounted above each other and supplied withenergy by separate encapsulated toroidal power transformers with downstream
stabilisation. The output signal is available at both RCA and balanced XLR
connectors for each channel. Fortunately, you need no longer worry about the correct
polarity of the balanced output signal and, if necessary, to have the phase eventually
inverted at the preamplifier. It's because by means of a slide switch on the rear panel
one can select if pin 2 or pin 3 of the XLR socket is to conduct the "hot" signal. The
fine electronic circuitry is embedded in an elegant cabinet with a champagnecoloured front and the side panels made from precious wood, whereby the entireartwork stands on special resonance-absorbing feet. Something one can actuallytake for granted if made by Accuphase.
Upon my first encounter with the C-27 I considered the possibility of testing its
MM stage utterly fascinating. Though not with an MM pickup but with Ortofon's SPU
in combination with the silver-wired step-up transformer Ortofon T-100. This was dueto the fact that my own phono/equalizer-preamp from Einstein would only accept thetiny signals from moving-coils and thus excluding whichever experiment with step-up
transformers anyway. The suitable settings in the C-27 are quickly engaged: input 1
is switched to MM, subsonic filter switched off and the additional gain activated. As tothe load impedance, I switched between 47 kOhm and 100 kOhm during the listening
session.
With the old Contemporary-Mono-LP Shelly Manne & His Men Play "PeterGunn" (C 3560) the higher load impedance yielded a tad more openness and sheenin the sound picture. However the irresistible swing of this old but still fascinatingrecord was conveyed by SPU, T-100 and C-27 independent from the load setting inthe latter. Although I had to turn up the volume knob of my Brinkmann Marconi[preamplifier] more than I usually do in order to get to a more exciting playback level,
there was absolutely no noise from the speakers spoiling the calmness in mylistening room when I lifted the tone arm for changing records. Owing to the
exemplary signal-to-noise ratio of the C-27 as well as to its unconstrained andemotionally appealing way of playing you get bewitched by the charm of the SPU
Royal after only a few beats.
A small portion of more intensity can still be wormed out of this classic pickup
when the Accuphase takes its signals directly in MC mode, i.e. without the detour
through the T-100: now the musicians seem to groove along with stronger devotion,
the instruments sound more sophisticated and pulses have more impact. After ashort time of listening you have simply forgotten how old this recording actually is,while you are carried away by enthralling rhythms and pleasing melodies. In the end I
thought to myself that I should more often search my vinyl archive for old treasuresand also have the SPU wakened up for doing the tracking from time to time.

Yet in the first place, we are talking about the C-27 here, which is currently working in"high gain" mode of operation and loading the SPU with 100 Ohm. When I switched
to 30 Ohm the playback level was significantly lower so I went back to 100 Ohm
again. In this configuration I did not need to turn up the volume knob on the Marconi
as far as with the C-27 being in MM mode and the T-100 loading the SPU. Although
the Accuphase without step-up transformer had to accomplish an additional gain of30 dB, some low noise was audible only during playback intervals and my ears inclose proximity to the tweeters. Evidently, the engineers at Accuphase have once
again done an excellent job here!
Ultimately, it's the sound that counts, and which ought to be ideally assessedby comparison, for instance with my fully balanced phono/equalizer from Einstein.
Once again after a long time Chuck Maggione's Children of Sanchez came to rest on
the platter of the Brinkmann LaGrange. The dynamic overture with its opulent
instrumentation was really thrilling, no matter which of the two phono stages took
over the amplification. Through the Einstein and balanced tone arm leads fromPrecision Interface Technology it altogether sounded a bit more analytical and a tad
too chilly than through the Accuphase and leads from Ortofon. I have usually a large
selection of tone arm leads from various makers at hand, but unfortunately not thebalanced and unbalanced variety of the same maker. Therefore I cannot say for sure
as to whether the audibly perceived differences are on the respective phono stages
or rather the leads. It's however safe to say that the purist Einstein and the opulently
equipped Accuphase are both playing at the same extremely high level, even if there
are marginal differences audible, which eventually may be a matter of personal taste
and preferences also.
What has been said above can be applied on the condition that - like with theEinstein phono stage - the output signal of the C-27 is sent to the preamplifier inbalanced mode. Now, unlike the Einstein, the Accuphase also offers the possibility ofsignal transfer via unbalanced output jacks and interconnects. Well, in this respect I
can make some definite statements because I happen to own balanced as well as
unbalanced interconnects from the same type and maker. For this specificcomparison I allowed myself a different tone arm/cartridge combination: thededicated position on the LaGrange for 12-inch tone arms was taken over by theBrinkmann 12.1. arm to which I mounted the quite expensive (from an absolute pointof view) Air Tight PC-3 cartridge, yet which nevertheless offers excellent value formoney and is ideally loaded with 100 Ohm. To wit: luminous sound colours, thewonderful transparency and effortless rendition of pulses made the Discovery reissueof Oregon's Out of the Woods a joy to listen to all the way across Side A, during
which the PC-3 could also flourish again after a long time of rest.
With "Waterwheel", my favourite piece on Side B, the audible differences
between balanced and unbalanced connection from C-27 to the Marconi preamp
were very small indeed: through the RCA interconnects the sonic picture was a wee
bit more crisp and vivid and in the high frequencies a trace more gleaming still. Yet Ishould rather verify this first impression by playing one of the "test records" I'm mostfamiliar with. So, Dick Schory's Percussion Spectacle makes soon clear that bymeans of XLR interconnects there are simply more of the minute soundstage
information transferred to the preamplifier than via the RCA jacks. I assume that thehint more sheen I heard in unbalanced mode might well be attributed to the valves inthe phase inverter stage of the Marconi. So I kept the balanced leads connected forthe next records I was going to listen to.
After two pickup cartridges with rather low internal resistance I went to confront
the input of the C-27 with the Da Vinci [by Clearaudio] of which the gold-wired coils
have an impedance above 30 Ohm. For this cartridge I preferred a load impedance of300 Ohm rather than 1000 Ohm, because the first setting created the illusion of adeeper, more 3-dimensional soundstage whereas with the latter load the sonicportrait took more centre stage. Differentiation, the love for details and utter dynamics
were exactly as one would have expected from the Da Vinci in combination with highclass phono stages.
Summing up, the Accuphase C-27 was made to drive any pickup cartridge to its
maximum performance. From this point of view it's actually a great pity that we all
had to wait for this world-class phono amplifier until the end of 2008.