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Theremin Fuzz help

Started by Shugazer78, January 16, 2023, 05:10:17 PM

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Shugazer78

The fuzz works and sounds GREAT, but the theremin side isn't working. I can hear a low glitchy rumble, the Sens Trim doesn't do anything and when I turn the Blend all the way to the theremin there is no sound. Which components should I be looking into?

mauman

Welcome!

Here is the schematic, and the full build doc for reference.

Are the backs of the Volume and Blend pots insulated, or well distanced from the solder side of the PCB?  A bit of tape will do it if they're close to touching.

I'd suggest an audio probe to trace the missing Theremin signal backwards from the output, to see where you pick it up. 

Shugazer78

I did put some tape on the backs of the pots. I've never used and audio probe before(I'm a noob), but I'll get on the YouTube.

mauman

Audio probe instructions are at https://aronnelson.com/diywiki/index.php?title=Debugging if you're not familiar with the process, it's a lifesaver for this kind of troubleshooting.

Shugazer78

#4
Nice! Always excited to learn something new! Since I have a signal passing through the circuit and the fuzz side is working, what are the components controlling the theremin(still learning how to read schematics)? Just so I can narrow my search.

I'm assuming it's this section...

NorthCoast

Quote from: Shugazer78 on January 16, 2023, 09:28:42 PM
Nice! Always excited to learn something new! Since I have a signal passing through the circuit and the fuzz side is working, what are the components controlling the theremin(still learning how to read schematics)? Just so I can narrow my search.

I'm assuming it's this section...

Yes, that's it.

Also take a look at R12 R13 R15
"People discuss my art and pretend to understand as if it were necessary to understand..." - Claude Monet