[sdiy] VC distortion?

[Tom Wiltshire]

On 29 Nov 2006, at 05:20, gerald stevens wrote:

> Hello,
>
> I have been thinking about using vactrols to add voltage control to a
> distortion pedal.  Looks like my grunge pedal requires pots and not
> variable resistors.  I imagine you could build a voltage controlled pot
> using two vactrols, one with an inverted level sent to an LED - has 
> anyone
> done this?  I have also seen tech notes on using digital pots in pairs 
> to
> create voltage controlled pots, but most digital pots are surface mount
> these days, and too much caffeine precludes the use of such tiny 
> components.
>
> Has anyone taken the PAIA quadrafuzz and modified it for modular synth 
> use?
> Know of any other voltage controlled distortion circuits online?
>

I don't know of any existing circuits, but this is something I've 
wondered about doing too. My thought had been to use a variable gain 
stage based on a transconductance op-amp (Say a LM13700) as the 
'op-amp' part of a basic circuit like the Rat Distortion or the Tube 
Screamer.

Perhaps this is an approach you'd be interested in?

Electric Druid ++++
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