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MOSFET Clippers/Shaka 1/III circuit

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5/2/1999 12:46 AM

MOSFET Clippers/Shaka 1/III circuit

I have been working on a circuit which has the drive part of the Shaka III with a different feedback cap going to ground and MOSFET diodes+Ge (ala John Greene) to ground -> Shaka 1 Booster section - but modified to tame the sound.

I've got a good sound going. Not as smooth as the Shaka III, but an agressive sounding pedal that sounds like it would be good for boosting the front end of an amp and for blues playing.

The key is slamming the MOSFET diodes because they don't compress that much for higher gains, then controlling the level going into the FET booster. Control of the amount of FET overdrive ala a trim pot allows the circuit to get the precise amount of overdrive from the FET to round off the distortion.

A lowpass filter after the FET Booster rounds everything out.

For low overdrive settings, the MOSFET diodes are great - very touch sensitive. The trim pot allows you to adjust the interactive of the FET overdrive here as well.

I really think that using MOSFET diodes for clipping are the key to the best sound for _me_ right now. (Thanks John - and R.G.!)

Either way works well, source as anode or cathode, good clipping occurs.

I've had good results with the BS170, VN3000L and the 2N7000.

The FET at the end of the whole thing is a big plus - either a single FET or the great Minibooster circuit just makes the pedal kick!
(Thank you Jack Orman!)

The Shaka circuit is certainly an example of how well this forum works and how much the contributors (you know who you are) have helped me.

Thanks!

Aron

5/2/1999 8:43 AM
jason	Can these mosfet clippers be used in other circuits...say a tube screamer clone? Jason

5/2/1999 12:19 PM
R.G.	Yes.

5/2/1999 12:38 PM
aron	That's where John Greene originally had them. Aron

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