That yielded the least sputtery note decay of any combination I tried. I settled on a Motorola BC109 with hFE of 175 in Q1 and a BC108B with hFE of 330 in Q2. My experience is that Q1 does best when its hFE is 150-250, and Q2 does best in the 250-500 range. People look at the part numbers and assume that Q1 should be the higher-gain part, but in fact the BC108C can have hFE as high as 800, while an older BC109 without a gain designation might easily end up in the 100-200 range. The original circuit specifies a BC109 in Q1 and a BC108C in Q2. The big knob in the center is still volume, but it also has controls for gain, tone, input resistance, and even voltage sag. After building the previous fuzz pedal, I now have my own set of preferences in this regard, implemented here (mainly to do with using small caps to recreate germanium transistor parasitic capacitances around silicon devices).īut I thought it would be nice to get all of the 1-knob variant sounds in one box, all tweakable from the front panel.

When other companies copy it, they sub in their own component value tweaks, so they all sound a little different. The single knob is just a volume control, so it’s just a gnarly booster. It is itself just a Fuzz Face, with tweaks for higher-gain silicon transistors, and gain permanently set to max. The Colorsound 1-knob blue fuzz box is copied a lot.

Hfe silicon fuzz face