YA CMOS TSF variant and new fuzz circuit

[Tim Escobedo]

I've posted the Calavera, a new Tube Sound Fuzz variation which, unlike typical linear CMOS schemes, utilizes voltage dividers rather than negative DC feedback to bias each stage into linear mode. The result is a very hot sounding distortion, each stage running full gain, with attenuation between stages, similar to the way some tube amps are set up.

Also posted is the Cinnabar, a unusual fuzz circuit that changes timbre from a smoother fuzz to a very unusual spunky fuzz. This one again uses the source follower/current source idea for both very odd waveforming, gain, and battery savings.

[gez]

Interesting!  I've tried this approach but had problems with the outputs biasing way off centre (probably just me).  Trim pots helped but in the end I did the following:

With two stages you can decouple the AC feedback of the first one, so you can run it at more or less full pelt, and then simply connect the second inverter's input directly to the output of the first - no feedback resistors (output of first stage acts as a divider).  Because the inverters are on the same chip the output of the second stage should be at a similar voltage to the first stage's output.

So long as the output is heavily loaded (10 - 50k pot) there shouldn't be a problem with oscillation.  

To get variable gain I used a IM pot at the input of the first stage.  The input cap attaches to one of the outer lugs, the wiper attaches to the input of the inverter and the remaining lug connects in series to a large value resistor which in turn hooks up to the inverter's output.  The junction of the resistor and the outer lug of the pot is decoupled with a cap.

gez