Much, much too much has been said about the lengendary fuzz face circuit. I will blog down some essential links later on.

Ever since I started wiring boxes, I went out looking for magic germanium transistors that were in the original circuit. The disavantages of these devices over more modern silicon transistors are numerous: very heat-sensitive, very often off-spec, expensive, hard to find, easy to burn during soldering. One feature of the germanium transistor everybody agrees to be essential to a vintage fuzz sound: its low gain.

Modern silicon transistor have a much higher gain that germaniums. Where the latter have hFE 100-150 max, the former are hFE 200 and higher, with some exceptions. Ideal for Fuzz Faces tends to be 70-130hFE. The very good news is that recently a technique has been revealed on how to reduce the gain by taking two identical transistors, tying the BASES together, cut off one COLLECTOR, connect a 3k to 6k resistor to the EMITTER of the collectorless devices, and connect that to the EMITTER of the other transistor. By varying the resistance, you can dial in the gain you want...

On the below graph you can see that two parallel transistors can be varied to any gain by changing the resisiances on the emitters:



I tied the transistors upsidedown together with the resistor and then tightened them together with a strip: