Angry Charlie noise

mimosa

New member
I made my own angry charlie, including PCB layout. Mostly using SMD components. It works well, however it does generate a fair amount of noise when engaged and was wondering if it's because of my layout or if this pedal does generate lots of noise due to the nature of the circuit. My PCB has 4 layers, all power paths are on the bottom layer, then ground plane, and all signal path on the top 2 layers, with minimal path crossing. All my capacitors are either film (through holes) or C0G class 1 if ceramic SMD to avoid microphonic effects of class 2 ceramic caps. The power filtering is on a separate PCB on the footswitch, also to avoid noise. So I am a bit puzzled in how I can minimize the noise to a more normal level. I was also careful in the integration to avoid ground loops and signal wires near power wires.
 

JamieJ

Well-known member
I only ever design two layer boards but I place a ground pour on both layers which can reduce cross talk between traces. That could be causing your issue.

Have you also ruled out it’s not your power supply? Try it with a battery only if you can.

We’d need to see pictures of the board and schematic to make a more informed decision.
 

JamieJ

Well-known member
Where have you grounded the circuit? You are using insulated jacks which don’t connect to the enclosure. I would run a wire from a ground point and touch it to the enclosure and see if that makes the noise go away.
 

mimosa

New member
I don't have soldered connection for ground on the enclosure, because my potentiometer have their body soldered to ground on the PCB and they are touching the enclosure directly. Continuity test between a ground point and the enclosure shows continuity
 

hamerfan

New member
Just a thought a continuity is tested with 1.5 volts. Shielding should do the job with mV. You should measure the resistance.
I learned it the hard way. My shielding on a strat did beep, but didn't shield good enough.
 
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