Expression pedal controlling the blend pot of Green Ringer

[nonost]

Hi. I'm building a Green Ringer + RAT + SHO and I would like to use an expression pedal to beheave as the blend octave pot. Here the schematic:



At least a stereo jack is needed. But even though I don't really know how to do it. I guess it could be done using the three wires of the stereo jack(assuming the ground lug is not grounded to the expression pedal chassis). Then I have the problem of the pot itself. How I disconnect it?

Cheers!

[ElectricDruid]

If you use this type of stereo jack socket, you can connect the pot to the "normalled" connections (the ones on the side we can't see) and connect the circuit to the other side (the side we're looking at), and then when you plug the pedal in, the pot in pedal takes over.

[nonost]

Really? That's some good magic!

Thanks a lot

[Mark Hammer]

If you use this type of stereo jack socket, you can connect the pot to the "normalled" connections (the ones on the side we can't see) and connect the circuit to the other side (the side we're looking at), and then when you plug the pedal in, the pot in pedal takes over.

Which is precisely what they're for.

Realistically, one doesn't really use or need an "expression pedal" for this task, since they will expect at least one contact to serve as ground.  What's required here, in the simplest instance, is just a 50k linear pot, in a volume pedal, connected to the three contact points of the on-board pot, none of which are ground.