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So guys, I have just built this:



And replaced the pot with an input TRS jack to control it with an expression pedal and it works nicely (exp. ped. As same pot value).

Now I'm wondering what the approach would be to build something similar that would accept a voltage source as the controlling signal... How would you tackle it?

I might give this a go. I'd like to put the circuit on a push-to-break momentary after a latching footswitch. What value pot are you using?

100k

Edit: Might have found a potential answer, I should explore the vactrol route...

actually no you should not use a optocoupler or vactrol etc.. the on and off resistances are all wrong for a 100k pot. the second reason is that you would need two optocouplers with one of them on while the other is off. you can buy these for $9 each but I think the linearity is shit for the amount of money spent. you can get better linearity or at least you can get the results you want from the blender if you tweak the optocoupler driver circuit just so however, it will bleed on both sides just a bit. 125 Ohms is as good as it gets. on the other end they go like 5M. you would do better to look into a small transistor vca circuit, an LM13700 VCA, a THAT 2180/2181, or a cool audio 2162/2164. google VCA. most of them will be for bipolar supplies +/-9v, 12v, 15v etc.. if you troll the commonsound (4ms pedals) wiki, and look closely at the trem/panner, you will see that he uses these optocouplers. he calls them cds cells. he might actually have a design that does not bleed.