Black carbon fuzz ground issues

[knappster]

So I'm getting ground noise.high pitched..when touching the guitar strings and the footswitch/pots it goes away.

I noticed it happens when the guitar cable is plugged into the output. When plugged into the input it doesn't happen.

Anything I can add to help ground it? I'll try to reflow the grd on the PCB/footswitch later. I already reflowed the grd on the jacks. I'll reply to any comments later today.the PCB is floating from the wires. I did glue them when I was done to maybe help secure the them.

I've never used an enclosure like this before. I used an A500k because the vol was too loud for me. Same issues tho with A100k. Everything else is what the board calls for

 

[Robert]

Changing the pot value isn't going to have much of an impact on volume.

Replace the wire connecting Lug 3 of the pot (the lug on the left) to the PCB with a resistor. (Try 47K or 100K)


As for the high pitched whine, have you tried adjusting the bias trim pot?

Also, try separating the wires connecting the 3PDT to the main PCB so they aren't bunched up laying across each other.

 

[jwin615]

Are your + and - wires at your DC jack shorted? Looks like it. I'd trim the excess bare wire off.
Unplug the guitar and engage the pedal and see if it still makes the noise. If it doesn't make noise without input cable, check your guitar cables. I've had grounds to bad in $$$ cables. Check sleeve to sleeve resistance. Be sure to check all cables.
If it makes noise with no cable, try moving the PCB around and see if it changes the noise. You have a lot of extra wire in that enclosure. With high gain circuits, you can get some coupling where small amount of signal bleeds from wire to wire or wire to PCB(this is why we run IO cable far from the pcb and sometimes use shielded wire.

 

[knappster]

I'll try adding a resistor, adjusting the trim doesn't change the grounding issue. It's happening with the pedal off. I'll fix up those wires connecting to the board

 

[Robert]

It's happening with the pedal off.

What about if you unplug power from the pedal (while bypassed)?

 

[knappster]

Are your + and - wires at your DC jack shorted? Looks like it. I'd trim the excess bare wire off.
Unplug the guitar and engage the pedal and see if it still makes the noise. If it doesn't make noise without input cable, check your guitar cables. I've had grounds to bad in $$$ cables. Check sleeve to sleeve resistance. Be sure to check all cables.
If it makes noise with no cable, try moving the PCB around and see if it changes the noise. You have a lot of extra wire in that enclosure. With high gain circuits, you can get some coupling where small amount of signal bleeds from wire to wire or wire to PCB(this is why we run IO cable far from the pcb and sometimes use shielded wire.

The DC isn't shorted, it just looks like it from the picture. Bad angle. It's also not my cables. Tested them with all my other pedals I've made. I will shorten up those wires. I'm thinking some wire in that mess is probably the issue.

 

[knappster]

What about if you unplug power from the pedal (while bypassed)?

Honestly, I believe it was happening last night when I was messing with it last night. I'm not home right now but I believe it was happening without the power plugged in.

 

[Robert]

If it's happening without power plugged in you can ignore everything on the effect PCB, it'll be some sort of offboard wiring issue.

 

[knappster]

Ok, I'll check that in first thing when I get home. Thanks robert