This Week on the Breadboard: The Spunk-O-Matic

[Chuck D. Bones]

This circuit was inspired by T1redHands' contest entry. Loosely based on the Karma Suture, which in turn is based on the Harmonic Percolator. The main thing I did to be different was use a MOSFET for Q2. This could be built on a PedalPCB Antithesis board (omit R7). Mind the pinouts on the transistors.




Knobs (L-R): OUTPUT - DIODES - DENSITY - INPUT



HAPPY 420 Day!

 

[cooder]

Ooooh Spunky!

 

[t1redhands]

In all of my experimentation with the HP circuit I have never thought to try a MOSFET for Q2. BRB gonna breadboard this...

 

[Chuck D. Bones]

It was just a crazy thing I tried and it worked!
The DC voltage on the 47uF cap is much more stable with a MOSFET for Q2.

 

[cooder]

 

[szukalski]

Giving this one a whirl (with opinionated knob placement).
Dave - I put a 500k trim pot in series with R2 for adjusting Q1. I'm thinking 750k resistor with a 500k, thoughts?

 

[Chuck D. Bones]

I have no clue how big R2 might need to be. That trimpot should be at least 1Meg.

Note to Cooder & Szukalski: The tranny I used for Q1 (1T308) has the collector pin in the middle. A dual footprint is highly recommended.