Switch for external expression knob?

[mulletmaster]

Hello! I've modded many pedals before, but I'm getting into my first pedal build. The external expression pedal will be accessed via a 1/4" stereo jack, but I'm not sure what kind of switch it would require, and how it would be wired. Any help would be appreciated, thanks in advance
Dan

[pickdropper]

Hello! I've modded many pedals before, but I'm getting into my first pedal build. The external expression pedal will be accessed via a 1/4" stereo jack, but I'm not sure what kind of switch it would require, and how it would be wired. Any help would be appreciated, thanks in advance
Dan

Are you going to have a potentiometer on the pedal that will be used when the ext. expression pedal is unplugged?  If so, you would want a normally closed stereo switched Jack (probably one of the Neutrik that are most common).

Since you say you are using a stereo hack, the wiring would be:

Potentiometer Out on PCB (3 wires) --> Switched Jack --> Potentiometer.

When there is nothing plugged into the jack, the pot will function as normal.  When you plug in your stereo TRS cable, it will disconnect the pot and the ext. expression pedal will take over.  There are two things to check when doing this:

1.)  Use the continuity tester on a DMM to determine which side is disconnected when the cable is plugged in.  The disconnected side should go to the potentiometer.

2.)  Check how the potentiometer is wired on your expression pedal.  The wiring on the jack should match that.  You will then need to make sure the wires on the internal potentiometer and PCB are correct. If you are making the ext. expression pedal yourself it is even easier as you can just wire everything the same.

[mulletmaster]

Thanks so much!