Accuphase digital preamplifiers (DC-300, DC-330)

[meltemi]

Originally Posted by Mattia

What is also interesting, is that on the used market a DC-300 is valued 1/3 or max 1/2 the price of a C-290V, even if his price in Japan, at the time, was exactly the same (980'000¥).

This fact alone maybe can partially answer my original question on the first post: the "DC-3xx" line of preamplifiers was probably never updated (also) for lack of clients interest and then sales.

The subsequent 2xxx line, with AAVA, seems in fact to try very hard to push the fact that the AAVA is analogue. It is repeated a thousand times everywhere in the promotional material. Evidently, many Accuphase customers perceived the digital volume of the DC-3xx as something obviously and surely inferior to Good Old Analogue (maybe, as often is sadly the case, without having the possibility to properly test out and compare).

In a review of the C-290V in (german) Audio 5/1999, Accuphase allegedly said, that the C-290V would be the last of it's kind and the future would be digital (i.e. DC-300, DC-330).
One of the reasons for this might have been the fact, that Panasonic was no longer producing the 4x pots Accuphase was using in their top analog pres since the C-280V (December 1990).

Since a pre is essentially a volume control, the methods implemented have a great impact on overall quality:

1) When using pots (or an array of fixed resistors) you change the input and output impedance of the circuits. This has a negative effect on several parameters as distortion, phase and s/n figures. When setting low levels, you lose musical detail.

2) Digital volume controls reduce the number of bits available at the output. Attenuating 24dB on a 16bit system reduces the number of available bits to 12. On a 24bit system you still reduce the number of available bits to 20.
The latter may be more acceptable than the former, but it is still likely to somewhat deteriorate the music signal.
In addition, using a digital volume control in an otherwise analog pre necessitates the use of ADC/DAC conversion, which does not go without some losses either.

3) AAVA is an analog solution, but does not have any of the negative effects of 1) or 2) above. However this method requires considerable effort and know-how and is a pretty costly solution.

Accuphase introduced the C-2800 with the first generation of AAVA in July 2002. The current generation of AAVA is the third for C-2xxx and the fourth for C-3850.

Martin