Volume pedal from expression pedal

[DIY Bass]

My son needed a volume pedal in a hurry to do a bunch of volume swell stuff (well, he could have just done the pinky on the volume control thing, but I needed to tinker with a soldering iron).  I have a Roland EV-5 pedal that I don't really want to break, and I had a box that already had holes for jack sockets drilled.  Built this into a box to plug the expression pedal into and bingo - volume pedal.



Anyway, it work.. OK.  The pot inside is 10K linear, and it doesn't go to completely off either.  I may be able to get another expression pedal, which makes me think of actually modding one to be a volume pedal.  I am not sure whether to go with some kind of active circuit that may use the 10K pot already there, or whether I would need to replace the pot with say a 500K log pot.  If I replace the pot, is there a way of removing the gear from the original pot shaft, or would I need to buy a geared pot?  Any ideas about the best way to mod an expression pedal to do guitar volume?

Thanks

[Chris S]

Usually the gear on the pot slides off. Often expression pedals, wahs and even some more expensive volume pedals wont let you completely rotate from 0 to 100% of the turn.

[Mark Hammer]

Funny, usually conversion is going in the opposite direction volume-to-expression.

Attenuating is simple.  The challenge is one of doing so without loading the guitar signal down.  If the pedal is completely passive, then yes, a higher value pot is called for.  But if you build in a suitable buffer, ahead of the pot, then the existing 10k becomes no different than a 10k volume pot on the output of a pedal.

There is no shortage of simple FET buffers posted around.