LEPRECHAUN(EQD rainbow machine clone) what Potentiometer value for diy EXP Pedal?

mikef

mikef

New member
Hello! Well I have a ton of wah and vol shells, so I am wanting to DIY an expression pedal.
What value should be the Potentiometer? also, audio taper or log taper? Thanks!
 
mikef said:
Hello! Well I have a ton of wah and vol shells, so I am wanting to DIY an expression pedal.
What value should be the Potentiometer? also, audio taper or log taper? Thanks!
Click to expand...
My Leprechaun PCB arrived today and I was wondering that same question myself after printing out the schematic and build docs. The build doc didn't have the schematic, but I found it here in the forums. Just to the right of IC2 (the FV-1) in the schematic, you'll see 3 connections labeled "T", "R" & "S". The "T" is connected directly to pin 20 of the FV-1. And below those 3 connection points, you'll see the "Pitch" pot wiring. That's also the external expression control.
PedalPCB-Leprechaun.jpg
Based on the schematic, BOM and close examination of the PCB, it appears that the top-center pot (labeled as "Pitch" in the schematic, but labeled "Spectrum" in the BOM is a B50K) as the value used for the external expression control. You could experiment with the different tapers if you want; but I suspect the B50K will do just fine.

Just a head's up, "audio taper" and "log taper" are the same thing- usually annotated as "A".
A "reverse log taper" or "anti-log taper" are the same thing - usually annotated as "C".
But in this build, the "Pitch" control calls for a B50K which is linear.

Good luck with your build.
 
Any value from 10K to 500K should work fine so just use what ever will be the most compatible with your other pedals.
 
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