Andy40's Madbean Greenbean (tubescreamer)

[Andy40]

Arrrrggg. Nothing but static and squeal. I gotta put it down as I'm outta time. See if you can spot the problem.

[Simon Barden]

I can see two capacitors that I think are the wrong value, C1 and C4. 4n7 (4.7nF) installed instead of 47nF.

[WeirdBits]

According to the values written on the mag board, yep.

[Simon Barden]

Apart from that, testing a gain pedal out of its grounded case might let a lot of noise pick-up in.

Also, if you've bought the parts yourself, double check that all the capacitor voltage ratings are 25v or higher. I checked over half of the resistor ratings and they looked OK, but you might as well double-check those.

However... looking further at the greenbean website diagram, I think I know what the problem is. The input jack has no direct ground connection and is reliant on the casing connecting the ground through from the output jack. Not surprising you just get noise as there's no complete circuit and the guitar is just acting like a noise aerial! Try linking the jack socket grounds together when testing without a case. You'll probably need to replace C1 and C4 to get the sound right but they probably won't stop it working.

[Maddogm]

are some of those resistor solders (towards the bottom right) a bit dry? hard to be sure without seeing the other side of the pcb though

[Andy40]

Thanks guys, I pulled those caps and replaced them. There was something wrong with how i wired that switch, it was a bit more than just the earthing issue.
Tested on the breadboard today with the new caps and bypassed the switch and she worked a charm!

This circuit really rocks!

[Andy40]

Sufficiently rocked and boxed

Time to decorate

[Dedman]

congrats! No idea what any of the afore mentioned posts were about but I take it you got it working!