Silicon Fuzz Face with Tone Control and lowered Q1 collector voltage

[mac]

This is my Fuzz Face.
I've been using it for many years and I'm very happy with it.
As you can see there are two major mods, a tone control or treble cut, and a mystery resistor R2 at Q1 base.

The tone control works by shunting highs to Vcc through the 0.1uf cap. As the cap gets closer to the output capacitor more highs are sent to Vcc (or Gnd for AC purposes).

And R2?
In a Ge FF Q1 works near 0.4v to 0.6v, but in a silicon version Q1 is about 1.5v to 1.7v, a volt or more above the base.
I was trying to lower the C to B difference to Ge levels, and I thought leakage.
Leakage helps lowering Q1 voltage in the real thing.
Therefore by feeding a few micro amperes to the B using resistor R2 in the schematic, there is more current at the C side lowering the voltage to 1.0v or so,  the C to B voltage is now about half a volt, and at the same time a 8k2 resistor can be used at Q2.
In other words, it is virtual leakage.



The transistors I used are BD237 (or BD175). These are low freq, low gain devices, a bit more trebly than say a Toshiba 2SB56 or Matsushita 2SB175. For this reason I did not put roll off caps in mine. Salt and pepper to taste

Enjoy!

mac

[Arcane Analog]

I experimented with the same idea a while back - induced leakage to Q1 - and I definitely like the results. I am also a fan of a tone control on the FF but I usually go with an input cap blend.

Thanks for sharing Mac.