Backfeeder background static noise

[thesoundofjusticefx]

I am working on my second backfeeder. The first one no longer produces feedback (I had to replace a component and I think that damaged the pcb.) Now my current build, there is some static in the background and is mostly heard as the note decays and the guitar volume is quieter. It does this whether it's in the enclosure or not. I've already replaced all transistors, op amps and IC's. I also replaced the potentiometers and bypassed the footswitch. I feel like I've eliminated possible hardware issues. I checked all my values and soldering. Happens at low or high gain sounds. I've built the defouler (just the distortion side) with no problems. The other board I was working with, the distortion is fine. It sounds very similar to the occasional static with silicon fuzz faces, but adding a capacitor across the transistor collector-base removes the sound. It doesn't sound like radio signals either. I truly don't understand what the problem is. Has anyone come across this? Thanks.

 

[Chuck D. Bones]

Unfortunately, that buzzing is normal. Mine does it too. It's not very loud, but once you hear it, you can't un-hear it. There's a comparator circuit on the board that's used to process the guitar signal before passing it to the PLL. Some of that comparator noise bleeds into the distortion channel.

Three things you should know about troubleshooting:
1. Swapping parts out at random is not a good way to do troubleshooting. It is a good way to do collateral damage.
2. It is customary to post detailed photos of your board so we can see what's going on.
3. If there is something wrong, the most likely root cause is workmanship. Not casting aspersions, it's just reality.

You might want to read some of the posts in this forum to see how we do troubleshooting.

 

[Bio77]

I've built two of these and also had a noise issue. I built the second one thinking I goofed something, but ended up with a second noisy pedal

This would be a great one for the Boneyard!! It's a really cool idea to use a PLL to emulate feedback, it just needs some fine tuning.

 

[Chuck D. Bones]

I think the DF-2 is way too complicated. Too many parts. I'll bet it could be done with an FV-1.