Serge Auckland wrote

I would have thought that as soon as the word "digital" is mentioned many
valve amp owners will run a mile.....

There are a number of passive volume controllers available albeit at ludicrous
prices for what is basically a good quality pot in a tin box; and not
forgetting the multi-tapped transformer controller which will have all the
benefits and cons of a digital controller, but again at vastly increased cost
and price.


The DSP solution would appear to be preferable. However, presumably there are
rounding errors. That is, if I divide every word by a constant, each result must
be rounded to the nearest step, and this rounding error is not linear wrt the
audio signal. I assume there is a name for this kind of error? How significant
is it?

A digitally controlled attenuator chip contains not only a resistor ladder, but
also a heap of semiconductors to do the switching. I expect those who object to
them are wary of the SS junctions in, and perhaps also parallel to, the signal
path.

A motorised pot may be an expensive component, but it is easier to program the
control system. The pot remembers where it is, and only needs 2 bits to control.
OTOH, it is not convenient to use if you want a rotary control on your remote.

I have never seen a remote with a rotary volume control. Why not? If the link is
reasonably error free, then it should be possible to put a rotary encoder on the
remote as well as on the system case. I hate push-button volume controls.

As for what valve aficionados might think, look he

http://stiftsbogtrykkeriet.dk/~mcs/index.html

cheers, Ian

S.