Help clarify wiring stereo audio jack(expression pedal) and potentiometer in parallel.

Thread Starter


Joined Mar 4, 2018
So i'm working on a mod for a guitar delay pedal.
it has a 10k pot that controls feedback.
I essentially want to wire in a stereo audio jack which will connect to my expression pedal which is just a potentiometer controlled with my foot, to control
the points that normally connect to the 10k pot on the board.
Now thing is i know it will work if i completely disregard the 10k pot.
What I have been pondering is if i wire the points to the audio jack, and then from the audio jack back to the 10k pot on board, when I plug the expression pedal in, will it only read from the expression pedal, or both the 10k pot and expression pedal?

Im sitting here with everything I need to do it and have already tested that it works by attaching some probes from the expression pedals male jack onto where the 10k pot is, and it works but only lets me go as far as the 10k pot is turned.
Im just trying to make sure all of my ducks are in order before i commit and solder it all in.

So will it work or am I missing something?
I mean I know I could just put a switch in to flip between the 10k pot and stereo audio jack, but if it would work as is and read only from the stereo audio jack when the expression pedal is plugged in, and then go back to the 10k when unplugged that would be wonderful.

I dont have a way to like show a schematic or anything so I hope I have written out what I'm trying to accomplish well enough.


Joined Aug 1, 2013
Without a schematic or wiring drawing or ***something***, it really is very difficult to say.

Keep in mind that while you don't know what we know (that's ok; after all, this is a help forum), we don't know what you know. Not all electrical engineers are guitarists. What is an "expression pedal"?

Are you dealing with a stereo audio signal (two isolated but related channels of information), or are you talking about a dual-circuit 1/8" or 1/4" connector called TRS (tip, ring, sleeve)?


Thread Starter


Joined Mar 4, 2018
Im dealing with a 1/4" TRS female audio jack. has three connections, when the expression pedal is plugged in the expression pedal its self is just a potentiometer that can be controlled by foot(rocking it back and forth by foot, all the way forward is the pot at 0% resistance, and all the way back is 100% resistance).
So we have the delay pedal, it has a pot for feed back, im trying to substitute the on board pot with the expression pedal(which is just a pot controlled by foot).

they way im wiring it is board -> audio jack -> onboard 10k pot
(i just discovered a free schematic program so im going to try my best to visually express whats going on)
first pic is me trying my best to show the whole set up, audio jack and all
second is the basics of whats happening, except when the expression pedal isnt plugged in the second pot just doesnt exist, only the 10k pot thats on the board. ignore the things like the battery and me using ground to tie it off, it woudnt let me just drop the wire anywhere for place holding. I apologize ahead of time that I am not the most knowledgeable in terms and stuff.