Hi,

I have a guitar circuit I've been working on. Newest iteration has switch pop that I didn't have before - this is usually considered DC offset across the switch hitting the audio path. I've simplified the circuit to just the below, a JFET and buffer. The switch is simply wired as a test case, to pass signal or mute. I've tried different values of R11. Initially had nothing, then 1M, lastly 10k. The 10k worked for a few seconds but eventually the charge built up and wouldn't go away.

In a previous iteration, JK1 went directly to the switch, and then the JFET, buffer and rest of circuit. But to cut down on noise pickup I wanted the JFET as close to the jack as possible so I rearranged the routing as such. I'm not sure if that's related to the switch pop or not. But the previous version doesn't have switch pop.

I'm not sure what to do next. (Disclaimer, I'm a mechanical engineer, not EE)
Any ideas?

 

It may ne that charge: " eventually the charge built up "??? The charge ON WHAT???
Aside from that, you are switching the relay coil current inside the same relay that is switching the AUDIO SIGNAL. ALSO, you are switching an audio line between a coupling capacitor and a solid ground. Two probable sources of a dc offset.
In addition, the relay coilcurrent is flowing thru the signal output ground. That is always a source of a DC voltage. AND, besides that, the relay connection thru the NC contact will assure that it acts like a buzzer when the relay coil is operated.

 

Turns out it was leakage through the electrolytic c10. Changed it to a 2.2u film, problem solved.

I don’t have a relay. The switch is a mechanical 3PDT.

But c10 is a coupling cap as you say, is that the right configuration for it?

 

Turns out it was leakage through the electrolytic c10. Changed it to a 2.2u film, problem solved.

I don’t have a relay. The switch is a mechanical 3PDT.

But c10 is a coupling cap as you say, is that the right configuration for it?

The symbol for the switch looks like a relay to me. So thatis the reason for my comment.
Experimenting wiith the value of resistor R11 may help, and a smaller value of capacitor C10 might still allow adequate frequency response.