I have this bag of NPN Germanium transistors. These are rare and you don’t see them much in pedals. They offer a huge advantage over the typical PNP types found in Fuzz Face’s, you can use a regular power supply!
PNP Fuzz Face must use a reverse power supply, the + and – are switched. This means these pedals either need to run off a battery, or they need a charge pump. I stopped using batteries years ago, and adding a charge pump requires a lot more parts and expense.
NPN to rescue! Using NPN transistors we can make a Fuzz Face that uses a standard power scheme. Here is the schematic I used. I can’t remember the original source for this, but I’m borrowing from the wisdom of the interwebs. The two trim pots allow the bias to be adjusted for a wider range of transistors.
My notes say “20k might be best”. This might not be correct. I started with 100k trim pots originally, these seemed too touchy. I used 20k in the last build and they might not provide enough range, 50k might be a better choice.
Here are a few pictures from a recent build.
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