Κώστας Φ.
Truth hurts. Here's a teddy bear.
- Μηνύματα
- 8.978
- Reaction score
- 895

--- Alan SircomThe designers – Pierre-Emannuel Calmel and Matthias Moronvalle, both from the R&D department from telecoms giant Nortel – set about designing an amplifier circuit that is both incredibly linear and highly efficient, utilising the advantages of both Class A and Class D amplifier designs. What they came up with was ‘Class ADH’ – a hybrid of analogue Class A amplifiers and a digital Class D design.
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It’s important to stress that the ‘D’ in Class D does not stand for ‘digital’. In fact, Class D is a highly efficient high-frequency switching amplifier. However, in the case of the Devialet, the Class D stage is fed by digital processors, so that it receives a digital 300kHz PWM (pulse width modulation) signal. So, it really is a Digital Class D design.
That in and of itself would be enough to impress people, but the rest of the story is just as impressive. The power output (nominally 165W per channel into eight ohms) can be remapped (akin to ‘chipping’ a sports car’s engine management system) to deliver anything from 160-240W, special loads on the phono input and more will be addressable though downloading onto an SD card (supplied). The amplifier treats all sources identically, immediately digitising analogue sources through a high-quality 48kHz ADC, with the Class D amp remaining in PWM mode up to the output devices and the Class A stage only receiving the output of two Burr Brown chips at the last possible moment. Yet again, this isn’t handled in the normal manner, Devialet using what is called a ‘current reflector’ layout.
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At the back are three pairs of phono terminals that share tasks; one set are either the phono stage or the second line input, the next set are either a stereo analogue line input or two of the coaxial S/PDIF inputs and the third pair are either subwoofer and digital output or two digital inputs. These are selected by small, high-quality silent relays just after the phono terminals. The single AES/EBU input, the two Toslinks, SD card slot and HDMI input and outputs remain constant. These last are at first glimpse an odd addition – but they take the high-res stereo output from a Blu-ray and there’s lots of good Blu-ray music out there. Strangely, network and USB connectors are missing, because Devialet is not convinced either is a good pathway for music. There is future provision for a high quality WiFi option, though – the black strip on the top plate is the antenna.
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Full Review: avguide.com (HiFi+)