HELP! expression pedal wired to work either in series or bypass exisiting pot

[big bustle]

i am having a hell of a time trying to figure this one out

i have a 100k pot in my box. i'm only using two terminals for all my pots.

i have a switched jack wired to bypass the 100k pot jack when an expression pedal is connected.



that part is simple.

what i can not figure out is how to wire a switch so that expression pedal can be switched to run in 2 states:
1) as a normal expression pedal with the 100k internal bypassed when plugged in
2) in series with the internal 100k pot

and... when the exp is not plugged in i want the 100k pot to function normally with out the switch having any affect on the behavior of the 100k pot.

i have spent all morning diagramming and soldering. this one is just a little too confusing.

any help at all will be very very very very appreciated

[trixdropd]

The only thing that i can think is using a relay to bring the pot back into the fray...

[slacker]

There's probably a way to do it, but I would just wire it so the expression pedal is in series with the pot. Turn the pot all the down and that's the same as having the pot bypassed. Or you could add the switch in parallel with the pot, so that it shorts it out, that would nearly do what you want except the switch would still  work with the expression pedal unplugged.

A couple of questions that might help figure out how to make it work like you want.
Does one end of the pot connect to ground?
Are you using a stereo or mono cable to connect it to the expression pedal?

[big bustle]

There's probably a way to do it, but I would just wire it so the expression pedal is in series with the pot. Turn the pot all the down and that's the same as having the pot bypassed. Or you could add the switch in parallel with the pot, so that it shorts it out, that would nearly do what you want except the switch would still  work with the expression pedal unplugged.

i tried this but when the exp is unplugged the pot won't function.

A couple of questions that might help figure out how to make it work like you want.
Does one end of the pot connect to ground?

nope

Are you using a stereo or mono cable to connect it to the expression pedal?

mono. im only using 2 lugs.

[jacobyjd]

i tried this but when the exp is unplugged the pot won't function.

Are you using a switching jack? you should be able to wire one so that the connection is closed when the exp. pedal is unplugged from the effect. However....

mono. im only using 2 lugs.

If you're using a mono jack and neither connection should go to ground, is your jack isolated from the enclosure?

If I was going to do this, I'd do what Slacker said, but I would also use a stereo cable and stereo switching jacks. This way, you wouldn't have to isolate the jack from the enclosure, plus the shield of the cable going to the exp pedal would be grounded. When you unplug, the signal would continue uninterrupted then, and you would have reduced noise...and no problematic grounding issues