This is a re-creation of the original Dallas Arbiter Fuzz Face effect circuit, continuing my attempts to design guitar effects using KiCAD.
The resulting design is a product of breadboarding and experimentation after an initial build of the original circuit. It emphasizes the ability to easily fine-tune the bias of each transistor to obtain a pleasant sound from a variety of NPN transistors (germanium or silicon). Besides this emphasis, it remains true to the original.
The board is built on the "Noise Floor" pedal platform, which provides basic power protection, audio IO, and a footswitch with LED indicator.
Instructions for biasing transistors (using the incorporated trimpots) are provided in the schematic. (This was the approach that worked for me, after a few hours of research. I'm by no means an expert and would welcome feedback.)
The basic schematic I worked from is widely available on the internet. At the same time my research drew on analyses from far-greater experts than myself, as well as published circuit diagrams. Most notably:
Thanks as always to the folks on the freestompboxes.org forum for feedback and suggestions.
Potentiometer 3D model courtesy Vasily Kashirin.
I am not affiliated with any of the brands, sites, or products named in this overview.
My pcb designs utilize the following versioning scheme (I'll add to this as I produce more revisions):
- v0.0XX: A candidate design that has not yet been produced and tested.
- v0.XX: A design that has been produced, tested, and any initial errors addressed.
The name "Random Input" is a reflection of the nature of the effect (a very basic fuzz) and security nerdery (fuzzing software using random input being a primitive technique to surface errors).