A/B switcher for expression pedal

[justallama]

So i was wondering, would i be able to have an expression pedal hooked up to an A/B switcher style box, swapping between volume control and a wah? if so, how would this be done? it imagine it would be cheaper and save more space than buying separate volume and wah pedals. thanks in advance :)

[Jopn]

I had an idea for that, but in full disclosure, I haven't tried it yet.

I was thinking that it would take two toggle switches.  One 3PDT to switch the connections to the 3 legs of the pot, then one 2PDT to switch the connections to the in and out jacks.  Ideally, a 5PDT so you could switch them all at once, but that'd be harder to source.

I personally wouldn't tackle it as an external A/B box because of the number of things that would be switched.  Someone who is more relay inclined might go that route however.

[justallama]

I think I kinda get what you mean, I'm new to all this and am doing the typical planning of a pedal board ages before I even get the time to build these haha :P Thanks for the reply though, I'm sure collectively some people on here more knowledgeable than me would be able to come up with a practical design for something like this...I kinda wanted to do it with an A/B style box because wah enclosures are unnecessarily expensive...

[Jopn]

The trick is that you're wanting to reuse a total of 3 components:
1. The pot attached to the expression pedal
2. The input jack
3. The output jack

The pot has 3 legs that you'll need to swap between connecting to the wah circuit, or connecting to the volume "circuit".  To make that switch, you'll need to connect to something to toggle those 3 legs (or poles) to two different locations (or throws).  Thus, a 3 pole, 2 (dual) throw switch (3P2T or 3PDT).  

*Worth noting that I'm saying this without looking at a wah schematic.  There's a likely possibility that 2 of the legs on a wah pot connect to the same point, in which case you could do this with a 2 pole, 2 throw switch (2P2T or more commonly called DPDT).

For the in and out jacks, you'll just have to switch the tip connection on both to either connecting to the wah circuit or the volume "circuit".  2 poles, 2 locations/positions/throws, so you'll need a DPDT.

To clarify my point about making this external: It would be entirely possible to have these two switches (which you'd always want to switch at the same time) as stomp switches on an external box.  The trick is, how do you connect to that box?  For this mechanical connection, you'd need to be running a 15 wire bundle.  Old skool printer cable perhaps?  ;)  

That's why I think I'm going to either go the route of putting 2 flip toggle switches (one 3pdt, one dpdt) on the side of my wah, or if I wanted to go with an external stomp, I'd start reading up on relay switching (which can take a single pulse from a remote momentary switch to initiate several switching actions).

Hope that helps to clarify a bit!

Cheers,

Jopn

[justallama]

ohhhh right i think i get what you're saying now, all a bit too complicated to bother trying! :L I imagined the circuitry would go along the lines of: input jack -> footswitch (or two if you had one for each setting) of some sort -> split into two circuits -> both go to external expression pedal -> both go to output. I guess my inexperienced made me a bit nieve haha! thanks for explaining this though, means a lot