Modified Foxx "Tone Machine" PUBLIC

Modified Foxx "Tone Machine" Octave Distortion Circuit

Highly-modified Foxx "Tone Machine" octave distortion circuit. Originally from the early 1970s, later used by the Danelectro company in their DJ13 "Frenchtoast" pedal. Both pedals only available used today. The original circuit in this mod is represented by the discrete BJTs while the modifications involve minor changes to the original circuit plus the addition of the op-amps. Controls Include: Direct Send, OD Drive, OD Tone, and OD Send (OD = octave distortion, not overdrive). The original switch that added octave to the distortion has been eliminated, so the distortion here always includes an octave component, although the distortion and direct signal levels can be adjusted separately. Not high gain. Maximum gain at 1 kHz is +14.7 dBV with Volume at 100% but all other controls at 50%. Yet, due to interaction between filters and active subcircuits, it falls to +11 dBV with all controls at 100%. Intended for 6-string guitar. This circuit is suitable for stomp-box applications but the battery can be replaced by a regulated single-polarity DC supply providing +9VDC at >= 40 mA of current. The original pedal was part of Peter Frampton's signature sound and has also been used by a number of other guitar legends, such as Billy Gibbons of ZZ-Top. And while simulator verified, treat this mod as experimental. Breadboard test it before committing to a soldered build.