A couple of thoughts:

> Now for the other problem of transients in relay attenuators.  Andrew
> said they sound great, other than when changing the volume.  It seems
> like the simplest solution would be to place an inexpensive but
> smooth-changing parallel "bypass" attenuator in the signal path while
> the
> relays are changing.  The bypass attenuator would maintain smooth
> changes
> in level, though at lower fidelity, while the user is turning the
> volume
> control.  After the volume is adjusted, the relay attenuator would be
> set
> for the corresponding level and switched back in.  This would also
> save
> noise and wear on the relays since they wouldn't need to switch at all
> until the user has decided on the volume setting.  Switching could
> occur
> a few seconds after the last change in the volume.
>
Using a rotary encoder for the input sensor, one could do all sorts of
things. I wondered about only changing the attenuation _after_ the user
has finished turning the knob. You could have some bypass attenuation as
you mention, or even a mute switch to momentarily mute the O/P whilst
the relays are changing. The behaviour would be rather different from
what most people expect from a potentiometer, though. I actually
experience this at the moment with my attenuator switch - it's a fixed
series / switched shunt resistor arrangment, and the make-before-break
switch means you get a 'burbling' change in volume. This is very
liveable with, though.

My other thought - Andy confirms a worry I had about the relays all
changing at once, and with differing switching times. My thoughts start
turning to Grey codes, but don't ask me how (yet...)

        jon N