Midway Fair | 1 decade ago
This is my build of the Harmonic Percolator, an extremely rare fuzzbox that became popular in the DIY community in recent years. Yes, I spelled Capucino wrong. I was an English major, not an Italian major. (At least, that's what I'm going with as my excuse.)
I'm not a big fuzz user, but I think this is right up my ally, and I'd gig with this. It's definitely my favorite fuzz that I've built so far.
About the circuit: It uses a Darlington pair transistor stage, with a 1N404a germanium transistor feeding into a 2N3565 Silicon transistor. The Ge transistor is PNP, but the pedal itself is negative ground. And because Darlington pairs create multiplicative gain, you don't need a particularly good or high gain transistor to get the circuit to work. In fact, I ended up putting the one I used in backwards because it worked *better* the wrong way in. Following that amplification stage, it has a pair of Germanium diodes (1N695) with a resistor in series with one of them to create asymmetric clipping that enhances even order harmonics. The Madbean version (which is the schematic I used to build this) has a selector switch to change to a different pair of diodes. I chose OA126s, a European Germanium diode that clips at .65v, more than twice that of most other germaniums.
You can get a board from Madbean pedals. I did mine on perfboard (message me for the layout if you want it) because I wasn't sure if the Madbean board would fit in a 1590A.
