[sdiy] more sh-101 mods?

[harrybissell]

Most of the Mesa/Boogie designs that use pairs of vactrols are doing
switching, not linear control.  I haven't seen them do a real potentiometer
with a pair of vactrols. (I'd like to... and schematics or links ???)

H^) harry

Paul Higgins wrote:

> > "The 'voltage controlled potentiometer' is one of the Holy Grails of
> > s-diy design. There
> > are so many ways to do it, and none of them is quite perfect."
>
> Mesa/Boogie used pairs of LDRs, driven with opposing control voltages,
> to act as voltage-controlled pots in their TriAxis tube guitar preamp.
> By all accounts it seems to work pretty well.  I think our own JH did
> something similar with his Poly-Korg clone.  Mesa used LDRs for a very
> practical reason: the high signal voltages in tube circuitry make most
> other solutions impossible.
>
> > That reminds me of an idea to use a motorized pot. Electronic Goldmine
> > has them for cheap but I keep forgetting to include it in my orders.
> > Has anybody experimented in this area?
>
> Another example from the tube world: Tim Caswell of Studio Electronics
> used servo-driven pots (six of them, I think) in the Soldano/Caswell
> MIDI-controlled guitar preamp.  A no-compromise--but pricey--solution
> to the problem.
>
> -PRH