madbeanpedals::forum

Projects => General Questions => Topic started by: Shugazer78 on January 16, 2023, 05:10:17 PM

Title: Theremin Fuzz help
Post by: Shugazer78 on January 16, 2023, 05:10:17 PM
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?
Title: Re: Theremin Fuzz help
Post by: mauman on January 16, 2023, 07:26:40 PM
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. 
Title: Re: Theremin Fuzz help
Post by: Shugazer78 on January 16, 2023, 07:32:41 PM
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.
Title: Re: Theremin Fuzz help
Post by: mauman on January 16, 2023, 08:11:03 PM
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.
Title: Re: Theremin Fuzz help
Post by: 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...
Title: Re: Theremin Fuzz help
Post by: NorthCoast on January 16, 2023, 11:45:10 PM
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