Sola Sound ToneBender

This is probably one of the most legendary fuzz pedals that has ever existed, and for good reason too! This thing can produce some completely saturated fuzz that is capable of slipping into feedback easily if you crank it up loud enough. I just can't say enough about this pedal. This is, without a doubt, my all-time favorite fuzzer. It's a genuine kick in the teeth that will have a permanent spot in my setup. Supposedely, this is the fuzz pedal that Jimmy Page used on the first couple of Led Zeppelin albums, which makes it even more famous. Below is a picture of the circuit board in a ToneBender MKII. Note the silver Mullard OC81D transistors
Sola Sound ToneBender - schematic

There are a lot of schematics on the internet that don't have the 0.01µF capacitor on the input jack side of the input capacitor, but in the original ToneBender MKIIs, there was one there. This capacitor helps to get rid of some of the intense treble that this circuit has without it. I would recommend that you replace the 8K2 resistor on the collector of Q3 with a 20K trimpot which will allow you to adjust Q3s collector voltage to -4.5VDC. I would also add a pulldown resistor to the input of the circuit and a reverse polarity protection diode to help protect those expensive Germanium transistors. Another nice tweak is to replace the 470-ohm resistor in the original circuit with a 1K or 1K2, which will boost the available output quite a bit. The original OC81D transistors will be very hard to find...and very expensive if you do find them. The Marshall Supa Fuzz is an "almost twin" of the ToneBender MKII. The only differences between the two: the input capacitor is 10µF instead of 5µF, the bypass capacitor on the "attack" pot is 10µF instead of 5µF, Q2's collector resistor is 47K instead of 100K, the resistor from the base of Q1 to ground is 10K instead of 100K, and the transistors are OC75 instead of OC81D. The sound of the pedals should be nearly the same, although the Supa Fuzz will probably be bassier since the input capacitor is quite a bit larger, especially with that 0.01µF from input to ground still in place, which...

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