Re: Digital volume control question....

In article <yfidnf92BeJdSfDZRVnygA@xxxxxxxxx>, Keith G
<keith_g@xxxxxxxxxxxxx> wrote:




As Don Pearce mentioned, the provision of a "digital" volume control
is often done for reasons of cost. Digital volume controls track left
and right channels virtually perfectly (comfortably within 0.1dB)
from full output to extremely quiet, and don't generate any
significant noise when changing levels. Normal carbon pots can be
relatively quite noisy, and even conductive plastic pots will find it
difficult to track both channels to better than 2dB at high
attenuations.


Interesting.

FWIW some of the larger and more expensive 'pots' are stepped attenuators
with laser-trimmed resistances. One of the benefits of these can be much
closer tracking of the balance as you wind down the level. They may also
use 'landings' between the settings that are particularly good at not
deteriorating with age/use. However they have tended to cost far more than
simple pots...


Excellent answer Serge - thanks. Makes me think there's even less of a
good reason for manufacturers to avoid them if, as Don says, they are
'properly implemented...???

The problem is that the 'proper implimentation' involves processes which
the user can't directly check, and the makers may be lazy or trying to cut
corners...

I would have thought a standalone 'digital attenuator' (with remote?)
would be a good thing for some valve amp owners - I wonder if such a
thing is available??

The concerns may be:

1: such a unit would require its own power and ADC/DAC, buffers, etc.

2: Would valve/analog enthusiasts wish to have this digital/solidstate
device always in their signal chain? I'd have thought they'd fear it would
corrupt the 'purity' of their system. :-)

3: Good quality stepped attenuators and detented pots exist and can work
fine.

FWIW I have always used the ALP 40mm stepped detent volume controls. When
I bought them commercially in the past I got them with tight levels of
balance, etc, spec. If you can find a source for these, I'd recommend you
try them. You may find they give an active attenuator a run for its money.
:-)

Slainte,

Jim

--
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