Crybaby to Expression, is a 100k pot ok?

[nero1985]

Hey guys, i got an old crybaby that doesn't work, i wanted to turn it into an expression pedal, is there any reason NOT to use the 100k pot that came with it? most schematics for expression pedals list a 10K pot, should i use a parallel resistor or just use teh 100K wah pot?

[Transmogrifox]

The answer is "it depends".  There are certainly reasons NOT to use the 100k pot if a piece of equipment uses it like a rheostat, or if the equipment's wiper connection goes to a low impedance input.  It depends what is using it and how.

>>You need to know something about the equipment that is using the expression pedal.<<

The best way to find out is to try it.  If it doesn't work with a certain piece of gear then start fooling with it.  One thing for certain is if you start adding resistors it will mess with the equivalent pot taper and you might never get it right.  Better would be to get a 10k pot to replace it, but then that isn't necessarily free nor cheap.

The best thing about "cheap as free" is it MIGHT work.  If it does, job finished on time and under budget

[ubersam]

I think the taper will mess with the control. When I was using a midi controlled rack system, I tried to use an Ernie Ball volume pedal as an expression pedal with the midi controller. The pot was 250K audio taper. It worked but the bulk of the change happened towards the toe-down position. So, I swapped the pot out for a linear taper of the same value. That worked much better. The changes were more evenly spread through the sweep of the pedal.