[sdiy] Continuously variable waveshaping (was Behringer Neutron)

[Andre Majorel]

On 2018-04-07 21:39 -0400, Ben Bradley wrote:

> I've been wondering what the details are on these "waveshaper" things,
> whether they're just mixing/panning between different waveshapes (say,
> sawtooth and square), or if something nonlinear is going on or being
> added.
> 
> I tossed together a four-stage wavefolder (talk about nonlinearity!)
> not long ago, and was amazed at how a sine wave input made an output
> that sounded a lot like a filter sweep, simply by varying the
> amplitude of the input.
> 
> It was basically the bottom four stages in this schematic, and I
> didn't even use the two diodes in the feedback path of the last stage:
> [200-character-long Google URL]

This one ?

http://www.cgs.synth.net/modules/pic/r_schem_cgs29_wave_multiplier.gif

If so, it's part of

http://www.cgs.synth.net/modules/cgs29_wave_multiplier_v11.html

Side note about the "grinder" : Ken says the LM358 is more
effective than the TL072 or 4558 for IC1 because slew rate is
critical in this position. So what are those slew rates ?

  TL072  13 V/µs typical (data sheet)
  4558    1 V/µs typical (data sheet)
  LM358 0.3 V/µs typical (http://www.ti.com/product/lm358)

Amusing that the slowest op amp would be the best at creating
high frequency hash.

-- 
André Majorel http://www.teaser.fr/~amajorel/