Devialet 140 Expert Pro integrated amplifier

Integrated amplifiers
Devialet 140 Expert Pro
Devialet 140 Expert Pro integrated amplifier

As someone who has been watching the whole Devialet thing evolve over the last decade, it’s been one hell of a rush. The French company – started by a couple of ex-Nortel engineers with a clever amplifier circuit – quickly established itself as perhaps the finest example of disruptive technology in the audio business today. First with the D-Premier, and now with both the Phantom and the Expert series, Devialet continues to innovate, develop, and grow.

And now, where once we had Devialet Expert, we now have Expert Pro, which brings a whole swathe of new technologies and innovations to bear. And, as has been the case from the outset, owners of even the first models can upgrade to the latest Expert Pro technology. Few other brands treat their existing customers so well.

The big change in the move to ‘Pro’ is the new Core Infinity main board. However, to move to that new board requires a lot of heavy lifting on the Expert’s part. This is why owners of original D-Premier models needed to periodically put their devices in for upgrades, so they wouldn’t be left out of the loop for future developments.

Core Infinity is, in fact, the largest change to the Devialet platform since that platform first emerged. It redraws the amplifiers basic Class ADH (‘Class A/Class D Hybrid’) technology at a pretty fundamental level by introducing new Class A voltage amplifier, a new 10-bit current-sensor circuit, and a new Class D current amplifier... and redraws the basic Class A/D algorithm. That’s not a stylistic change... that’s a whole new engine.

There’s more, but let’s focus on that a little first. The move from eight- to ten-bit current-sensor improves the precision of the handover from current amp to voltage amp, and that coupled with more efficient and responsive code controlling the whole ADH circuit means a lot lower distortion figures.

The original Magic Wire D/A conversion circuit has also come under scrutiny in Core Infinity, which itself brings a 6dB improvement in THD and a 2.5dB drop in noise floor. This may be gilding the lily, as the distortion and signal-to-noise ratio of the Expert was already at world-class low levels, but this too represents some of the most significant changes to the basic Devialet core since its launch. All of these changes form what Devialet calls ‘ADH Intelligence.’

In fact, many of these developments (especially in the Class D amplifier) were seen in the strictly limited Original d’Atelier model, but the collective changes eclipse even that design. In fact, the Core Infinity board is one of those technologies that would have been impossible to implement at the time of the original launch of the D-Premier, and prohibitively expensive at the launch of the Expert line, but such is the rate of change in electronics technology that it can be introduced here. AXD is the company’s latest acronym, and it requires suitably-equipped Expert Pro amps to realise. As it stands for Active X-over Design, it also requires a loudspeaker that is both known to Devialet and is in fully active form. This would require getting a pair of loudspeakers we don’t currently have, and several additional Expert Pro amps that we also don’t have to hand, but this is the next step in the company’s Speaker Active Matching... and we could do that with the Wilson Duette II.

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