BMP Green Russian (tagboard build)

[HunkFunkPedals]

The pass through/led work. Not getting any effect.

I set up my audio probe. While tracing the input I discovered a weird squeal/oscillation. I can actually change the pitch with the tone knob.

I've swapped out the transistors, thinking maybe one shit the bed. But that wasn't it.

Has anyone ever experienced this?

https://tagboardeffects.blogspot.com/2012/06/ehx-green-russian-big-muff.html?m=1

That's the build docs.

[idy]

Give the folks a picture of your board, both sides. It is amazing what people can spot.
You traced the signal? where did the Squeal start? Q1?

[HunkFunkPedals]

[HunkFunkPedals]

Give the folks a picture of your board, both sides. It is amazing what people can spot.
You traced the signal? where did the Squeal start? Q1?

Yes, around Q1. After Q1 all nonsense breaks out.

[Locrian99]

Component side would be helpful.    You mentioned no effect, but are you getting no audio at all when engaged and it is fine in bypass?   

I've built this layout so the layout is fine albeit he used some weird values that are in no way the green Russian values.   

Every problem with a vero build I have built I could have solved by just printing the layout and going through each component one by one and making sure it is in the right spot.    And assume you did it wrong otherwise it would be working.     Print it and just verify comping by component you'll find your problem.  Thankfully muffs don't have that many parts.   

[Mark Hammer]

Without wishing to be disruptive, I'll just say that building a BMP on perfboard is actually pretty straightforward.  The circuit itself is easy to follow and lay out, since each transistor stage is nicely self-contained.  It's also MUCH easier to troubleshoot because you can know how each segment of the circuit connects to every other, without the snakes-and-ladders nonsense that stripboard entails.

[HunkFunkPedals]

I've built multiple BMP on vero and this is the first giving me this issue.

I guess breaking it down and building from scratch is the answer?

I'm going to go through and re- verify the components first.

[idy]

Going through and verifying is a good idea.

My eyes don't spot anything. But the solder side, very hard to see if there is a tiny short somewhere or not... You will go over this (probably already have.) Testing for continuity between neighboring strips, cleaning in between...

Generally:
1) Always test before attaching jacks and footswitch. Sometimes with high gain circuits foot switch wiring is enough to set things oscillating.

2) Don't remove components randomly assuming they are bad. It's tempting, I know. This is more likely to damage PCBs than strip board. That little voice telling you to pull things out is not the one with the wings and halo...

3) I often do strip-board one stage at time. Set up the voltages, then the first transistor, and listen to the boost. Second Q, listen to the fuzz. Third Q, listen to smooth fuzz. Tone stack, hear that working. Recovery stage. That way there are no doubts and I can be sure that any issue can be pinpointed to a handful of components.

[stallik]

If I build with strip board, I take it as a given that there is a short between the tracks. When everything is soldered in, I run a sharp jewellers screwdriver down each gap, clearing shorts, flux, stray solder blobs etc. My soldering may have improved over the years but I never miss this step.

Just sayin'

[HunkFunkPedals]

Going through and verifying is a good idea.

My eyes don't spot anything. But the solder side, very hard to see if there is a tiny short somewhere or not... You will go over this (probably already have.) Testing for continuity between neighboring strips, cleaning in between...

Generally:
1) Always test before attaching jacks and footswitch. Sometimes with high gain circuits foot switch wiring is enough to set things oscillating.

2) Don't remove components randomly assuming they are bad. It's tempting, I know. This is more likely to damage PCBs than strip board. That little voice telling you to pull things out is not the one with the wings and halo...

3) I often do strip-board one stage at time. Set up the voltages, then the first transistor, and listen to the boost. Second Q, listen to the fuzz. Third Q, listen to smooth fuzz. Tone stack, hear that working. Recovery stage. That way there are no doubts and I can be sure that any issue can be pinpointed to a handful of components.

I am paying for my hubris....