The QCD Aztec Superfuzz is a recreation of the Univox Superfuzz, originally developed by the Shin-ei company in Japan in the late 1960's and called the FY-6. Shin-ei rebadged the circuit for over a dozen other brands such as Apollo, Electra, and Hohner. However, the Univox Superfuzz was the most well-known of the brands and today is considered the definitive version of the circuit.
The Superfuzz uses a phase splitter followed by a differential pair to emphasize the upper octave. It's very similar in concept to something like the Foxx Tone Machine, but with the major difference of using active transistors instead of diodes to rectify the signal. While the original unit only had a tone switch to go between two presets, this pedal provides the option of using a potentiometer to blend between them so it's not just full-on one way or the other.
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