"Heartbeat" Noise Issue with Fuzzface

[Sabzor]

Hi all,

I had a fuzz pedal built and we keep having issues with a popping/heartbeat noise. When I originally got the pedal it was fine but after a while it started making the noise seen in the video below. It was sent back and to our surprise it work normally on the other end. The transistors got replaced for safe measure and it got sent back. When I received it on my end I plugged it in stand alone (battery) and the same issue persisted. I've tried all varieties of different gear - posting here as a last measure to see if someone has any idea?

The noise happens with the guitar volume pot off so that isolates the pedal. When the fuzz knob is turned it changes the rate of the "heartbeat". Changing the bias pot doesn't help either.

https://www.youtube.com/watch?v=rFXafb0uNCA

[duck_arse]

do you have a multimeter? you'll need one anyway, cause you need to take voltage measures around the transistors. also, transistor type numbers, show the actual circuit the pedal was built to, and some close up photos of the board, please.

[garcho]

I had a fuzz pedal built

by someone who has built a lot of 100% working quality pedals?

When I originally got the pedal it was fine but after a while it started making the noise seen in the video below.

electronics very rarely ruin themselves. it might be coincidence. how much time between "originally got it" and "started making the noise"?

it work normally on the other end.

that happens more often than you might think. it might mean that there is a short somewhere in that enclosure; shorts can be tricky because if they're caused by something physical, it's not always obvious why/when/how. There's also something of the "observer effect" in building electronic devices. The most important test is the one that happens when it's all closed up in the enclosure and finished. Unfortunately, that means you can't probe/see inside the enclosure while you test it.

I see a mess of wires by the in/out jacks, and the lugs of those pots are only a mm or two away from the enclosure. If you (gently) wiggle the knobs/switches anything physically attached to the enclosure, do you get any snap crackle or pop?

It could be a bad cap, or something is messed up with the transistor bias. Have you touched that trim pot on the circuit board?