Moog Music Forum

Hi,
I opened up my old EP-1 and found that the pot inside is 20K, not sure of the taper.
The MF manuals specify a 50k or 100k W taper pot. I wonder how come my EP-1 came with a 20k pot? I bought it
new from the store many years ago... I will try other pots to hear the difference anyway...

You shouldn't use a W-taper, rather a linear one. The "W" in the manual is a substitute for omega/Ω/ohm.

Pots in these usecases act as voltage dividers, so the value isn't critical. It's the ratio of resistances between the wiper and one of the two ends that counts. You get more apparent "resolution" with a lower value (5/10/20k) at the expense of drawing more current. But this is more apparent for AD converters e.g. a pot connected to a microcontroller.

I'd recommend a linear pot of 10-50k, but 100k is likely to be fine as well.

Thanks, I tried several pots and indeed settled on a B20K which had the best sweep to my ears.
I found this posted somewhere: maybe it can come handy to someone who wants to build or modify an exp pedal: