PedalBuilder
Well-known member
I've build several Tone Bender Mk. III x Big Muff circuits, and this one might be my favorite. You should build one if you haven't already—grab a Scythe and get started. Compared with the Yellow Hybrid Tone Bender and the Colorsound Supa Tone Bender, the Tone Reaper has more Tone Bender Mk. III DNA, both sonically and electronically.
One thing that makes this circuit stand out to me is that it's a great way to use those otherwise useless super high gain, super high leakage NPN germaniums that one inevitably acquires. I'm not sure if it's still the case, but one point it was a rite of passage to buy some AC176/AC187 (or GC521, in my case) NPN germanium transistors from some European eBay seller, with visions of Fuzz Faces dancing in one's head, only to discover when they arrived that the transistors had obscenely high leakage and weren't useable in the classic vintage germanium fuzz circuits. I'm happy to report that they work perfectly here. I used a relatively low leakage D18 germanium diode because it looked and sounded cool, but a silicon diode works just as well. Q2 is a Tesla GC521 with hFE ~160 with 1.2mA leakage. It's very loud, with no noticeable hiss. Q2 collector voltage was 1.78v with VCC=9.25v. Q1 is a BC108C with hFE ~600.
The tone stack follows the Big Muff topography, but with unusual values. I had a spare 470pF StyroFlex capacitor that I accidentlyy ordered from Small Bear about a decade ago, so I created a footprint and used it here.
I made one other mod that people should consider if you're building a Scythe—solder a 560pF capacitor between lugs 2 and 3 of the Fuzz control. Without the capacitor, the fuzz gets muddy and lifeless when the Fuzz control is below noon. Adding the capacitor brings back the highs and makes the fuzz control useable across the entire sweep of the control.
Enclosure
Inside
Glamor Shot
One thing that makes this circuit stand out to me is that it's a great way to use those otherwise useless super high gain, super high leakage NPN germaniums that one inevitably acquires. I'm not sure if it's still the case, but one point it was a rite of passage to buy some AC176/AC187 (or GC521, in my case) NPN germanium transistors from some European eBay seller, with visions of Fuzz Faces dancing in one's head, only to discover when they arrived that the transistors had obscenely high leakage and weren't useable in the classic vintage germanium fuzz circuits. I'm happy to report that they work perfectly here. I used a relatively low leakage D18 germanium diode because it looked and sounded cool, but a silicon diode works just as well. Q2 is a Tesla GC521 with hFE ~160 with 1.2mA leakage. It's very loud, with no noticeable hiss. Q2 collector voltage was 1.78v with VCC=9.25v. Q1 is a BC108C with hFE ~600.
The tone stack follows the Big Muff topography, but with unusual values. I had a spare 470pF StyroFlex capacitor that I accidentlyy ordered from Small Bear about a decade ago, so I created a footprint and used it here.
I made one other mod that people should consider if you're building a Scythe—solder a 560pF capacitor between lugs 2 and 3 of the Fuzz control. Without the capacitor, the fuzz gets muddy and lifeless when the Fuzz control is below noon. Adding the capacitor brings back the highs and makes the fuzz control useable across the entire sweep of the control.
Enclosure
Inside
Glamor Shot
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