Making a guitar fuzz pedal circuitboard

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NOTE: I accidentally reversed the electrolytic capacitor (C2) in this drawing.

I’m making a guitar effect pedal for my son, who’s been learning to play guitar and recently borrowed a beautiful Danelectro from my friend Adam Iscove. I found a simple fuzz circuit online called a Bazz Fuss  and decided to replicate it.

I started off on a breadboard and got a good sound out of it, so now I’m making a circuitboard for it.

I re-created the circuit schematic in Eagle CAD, as seen here. I’m not an electrical engineer, and I’m certain I’ve done many things incorrectly and look forward to hearing suggestions on improving things. Heck, I haven’t even soldered it together and tested it yet, so I probably won’t work until iteration #7…

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Next, I manually placed and routed the components, also in Eagle.

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I milled the circuitboard on the Othermill. Here you can see the board in Otherplan CNC control software.

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The airline isn’t running, normally this would be a cleaner looking board at this point

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I realized that I forgot to place all the traces and pads to the bottom of the board, so rather than confuse myself by mirroring everything when I placed and soldered everything later, I pushed everything to the bottom of the board in Eagle and milled another board, this time with more sensible offsets between the pour and the traces so I could use a 1/32″ endmill instead of 1/100″. This sped up milling a lot. I also pulled the board off and saw that none of the small holes had been drilled, so I placed the board back on the mill bed, switched to a 1/64″ endmill and ran just that portion of the job. This is why all my holes are slightly misaligned.

This one had some issues with connected traces, and other problems, so I revised the design, moved some parts, increased the size of the solder pads, and added mounting holes.

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Here’s the improved version.

Next up, I’ll populate and solder it to see if it produces some dirty, nasty fuzz as hoped.

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