[sdiy] more sh-101 mods?

[WeAreAs1 at aol.com]

In a message dated 12/3/05 7:49:37 PM, harrybissell at prodigy.net writes:


> 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 ???)
> 

This is true.   They often use one in series with the signal and another as a 
shunt to ground, with opposite polarity control signals for each.   
Presumably, this configuration enables them to completely attenuate the signal, with 
nothing bleeding past the two LDR's.

It seems to me that it should be possible to rig two LDR's into 
three-terminal variable resistor configuration, but probably with rapidly diminishing 
returns in terms of cost effectiveness and performance.   It sure would be nice to 
figure out a kind of universal (and cheap) voltage control circuit for filter 
resonance/feedback that doesn't eat up an OTA, though.

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