Accuphase E-370 integrated amplifier

Integrated amplifiers
Accuphase E-370

Even non-jazz-lovers seem to connect with the Tord Gustavsen Trio (or maybe they’re just polite while keeping one eye on the exit) and ‘At Home’ from Being There [ECM] is one of my set-up tracks. I never tire of it but mostly because, in the right circumstances, it can be transcendent. It has a contemplative, luminous stillness, and if I get that, I know the system is working OK. Happily, it took very little time to get to that place with the E-370, but interestingly, I also went to places I’d not been before. In all that stillness, with the trio’s consummate delivery of textures, timbres, and timing, there’s also a real sense of a groove as the track builds and develops. Until now the recording has always been about mood, with a delightful but melancholic bent, so to discover a subtly subversive undercurrent of a groove, in a track that I thought I knew intimately, was slightly surprising. As was another track from the same album, ‘Wide Open’ which turns out to have some quite astonishing subtleties in the phrasing; the trio’s timing has gone from merely superb, to exquisite. I’m not a fan of hyperbole, but when the last track on an album leaves you sat in silence, savouring the musical experience you just had, ‘exquisite’ feels like an entirely appropriate term. It’s all in the tiny, micro-dynamic push, here, or the fleeting holding-back, there, or those fractional pauses, delays, or anticipations of the beat. And through the E-370 they so clearly and not only make sense but could hardly be anything else. If music can move you to tears, you’d better keep a box of tissues handy.

There are transparent amplifiers, and there are powerful amplifiers, and there are amplifiers that give you lots of detail. Still, I’ve not experienced an amplifier which delivers in quite the way that this Accuphase delivers. It’s not just about detail; it’s about the way the information is conveyed ‘just so’ allowing its contribution and relevance to the musical message to be understood immediately. If you boil it down to basics, it’s a combination of accurate micro-dynamics, pitch, and timing; though the reality the listener experiences is much more profound than that, albeit mostly at a subliminal level. You realise that all of a sudden, that album you used to listen to a couple of tracks from, is brilliant from start to finish. Or that you ‘get’ a band or a musician that you knew you ought to get, but somehow you’d never clicked with before.

A truly great artist can imbue a tiny gesture with more impact and significance than a lesser mortal might manage in an entire work, and that’s what makes them great. It’s a mastery of their craft, combined with intuitive artistry, and it’s the nearest thing I can think of to describe what it is that the Accuphase manages, and which few if any other amplifiers I’ve experienced can emulate.

Part of it, I’m sure, is the careful attention to the phase relationships within the music, which the company literally built its name on, but Accuphase’s proprietary AAVA preamp technology is doing something rather special here, too. Most analogue preamplifiers use a potentiometer, or a resistor ladder to attenuate the output received by the power amplifier stage. Accuphase argues that this varies the impedance within the amplifier, so that signal to noise ratio, and distortion figures, can vary depending on the volume level set. Their solution, dubbed Accuphase Analog Vari-gain Amplifier, is to take the input signal and feed it to a voltage-current converting amplifier. This solution consists of 16 discrete, parallel stages, each stage producing exactly half the output of the previous one. The preamplifier output sums these parallel outputs in different combinations, depending on the demands of the volume control. There are thus 216 possible output combinations or 65,536 volume ‘steps’, which is orders of magnitude more than even the best stepped-attenuator can manage. The volume control isn’t a potentiometer but instructs a control unit to select the necessary combination of outputs corresponding to the volume demanded, recombining in a current-voltage converter before being sent to the power amplifier stage.

The advantages of the AAVA implementation are said to be a virtual elimination of crosstalk and left-right tracking differences, and a significant reduction in noise, to the benefit of the signal to noise ratio. The frequency response is also more consistent, thanks to the invariant nature of the impedance seen by the signal. I suspect there’s also some benefit from not having an essentially parasitic component (the potentiometer, or resistor ladder) between preamp and power amp stage. Indeed, the Accuphase sound has a natural vitality and presence that speaks to the purity of the processing. It’s a bit like the difference between a passive and an active preamplifier. Passives tend to be transparent, delicate, and beautiful; actives tend to have more drive and energy, and in my experience, there does seem to be an advantage in having an actively driven power stage. In the case of the AAVA, you seem to get a good dollop of both; the delicacy, coupled with speed, drive, and energy of an active pre-. The circuitry is claimed to be electrically very simple, and hence reliable, and is also used to manage the balance control and attenuator (loudness) functions. (Accuphase remains committed to offering such fripperies as tone, balance, and loudness controls for all its amplifiers).

Perhaps the most obvious advantage is that music retains its energy and vitality, even at low listening levels. That ‘sweet spot’ where the volume level is just right for the music, is now mostly a thing of the past; pick a level that suits your mood. Accuphase provides a handy LED display which shows volume level as the amount of attenuation, in dB. My normal listening levels, depending on the recording, varied from about -27dB (positively antisocial) to -34dB (of course, no problem, officer. Thank you, sir). Abdullah Ibrahim, playing with the NDR Big Band on ‘Black and brown cherries’ from Ekapa Lodumo [Enja], retains its sense of scale and dynamics even at a setting of -42dB. In the process, the E-370 preserves the life and energy of the big band, and the image didn’t collapse down between the speakers as it usually does when played quietly. It kept all of its expansive exuberance and joyful enthusiasm; just did it more quietly.

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