Xotic EP Booster...gain control does nothing

[soma89]

Hey there,
This one is a headscratcher for me. EP Boost has a gain control that does nothing. The pedal itself does turn on and light up (adding the "warmth" that these are known for) but stays at around unity gain even while turning the pot. I can confirm that this pedal had once worked well and now it doesnt.

Things i've tried:
DC Power and Battery power
tested the pot in circuit and verified that it starts at zero and ends at 10k pot value (its a reverse pot)
touched up some questionable junctions.
visually inspected board and caps


I thought this would be an easy one as its a very simple pedal. Any ideasof how to go about this would be much appreciated.

Schematic and pics of board *mine is the same)

Tracing Journal: Xotic EP Booster V2

The second Xotic trace releasing today (alongside the SL Drive) is the EP Booster. It’s a fairly simple JFET booster modeled after the preamp of the Echoplex tape delay pedal. Here’s a demo video from…

aionfx.com

Thanks!

 

[phi1]

Maybe try connecting the - side of the 10uF cap to gnd, to see if you get a lot of gain that way. (It would simulate max gain knob).

Then you can start to pinpoint if it’s a problem with the pot or wiring, or something in the circuit

 

[z2amiller]

Agree with @phi1, you could do some troubleshooting by trying to take the cap and/or pot out of the equation.
There's not a lot going on here, so either the cap is bad or the gain pot is bad, and you've measured the pot.
I'd try to replace C6 and see what happens.