This is the circuit diagram of Vox Tone Bender Pedal. The circuit is very similar to Fuzz Face pedal. The Vox ToneBender will have a lot more treble response than the Fuzz Face…maybe to help brighten up those characteristically “dark” sounding British amps some. Using a Vox ToneBender with a Fender Twin, or any other Fender amp, would be nearly ear-piercing with all the treble that’d be blasting through. Another change that will remove more bass is the bypass capacitor on the wiper of the “attack” pot (1k pot). Using a 15uF instead of a 25uF will reduce bass and it will also back off the fuzz some, too. The 50K “level” pot will also pass more treble compared to the 500K pots used in the Fuzz Face.
Another thing makes a noticeable difference is the 1K resistor between the collector resistors of the two transistors. In the Fuzz Face this resistor is 470 ohms in the Germanium versions and 330 ohms in the Silicon versions. Using a 1K resistor will give more output from the circuit, which really helps.
Circuit Notes:
- Transistor Q1 is a SFT 363
- Transistor Q2 is a SFT 337
- The 2n3906 may be used as a replacement for Q1 and Q2, however originals were probably germanium.