Built this to see if it delivers. It does. Sounds sort of like an inverted, bastard brother of the Green Ringer. Just a bit sleeker in its overall feel. All the information needed on this design (and more) is available at JC’s site.
A snippet from the page: Ever wonder what F(x) = |x| sounds like ? Of course
I’m speaking in terms of the DC-Transfer function of a non-linear
wave-shaper circuit … for those who don’t know Spice or network theory
very well – this transfer maps out the quasi-static change in DC
conditions everywhere in the circuit (currents and voltages) as the
input source (current or voltage) changes in same manner … this
mapping, I should add, totally ignores the frequency dependent behavior
of the circuit – it’s doing the test at DC (0hz) … this stuff is
routinely used to uncover the harmonics generating capability of
non-linear analogue gain stages …
To build yours with only one pot, you’ll need to swap the lower left hand side 15K resistor with a 100K and replace the “Control” pot with another 100K resistor. I’m calling the pot “control” as it doesn’t have a designated name on the schematic or in the description. There also added 1M pulldown resistor at the input, as well as added polarity protection diode. I used LM358 opamp, but i do believe you should be fine with JRC4558, TL072 or any other dual opamp with the same pinout. Oh. I also recommend to use 10K lin pot for the level. That’s why it is listed as linear on the layout.
