Signal clipper (distortion circuit)

[DDD]

Hi men,
Please take a look at the schematic diagram and wave-forms.
The circuit works as a signal clipper. It does not cut tops of the signal, but reverse them "inside".
Hence we can hear the most of the original signal in opposite to diode clippers, e.t.c.

[Quackzed]

won't the blue unflipped peaks just cancel the red flipped peaks? making the sum flat?

[anotherjim]

Interesting.
Transistor are clamps. As input goes positive, Q1 turns on and pulls the output back towards 0v. As signal falls, Q1 turns off and allows signal (while still positive) to recover. Negative going signal has similar action, but via Q2.

[antonis]

According to Fourier analysis, it seems like partially phase reversal full wave rectification.. 

[Passaloutre]

Looks like it would have a cool octave effect, reminds me of merlin's write up for the cathodyne phase inverter (http://www.valvewizard.co.uk/cathodyne.html)

[DDD]

... Transistor are clamps. As input goes positive, Q1 turns on and pulls the output back towards 0v. As signal falls, Q1 turns off and allows signal (while still positive) to recover. Negative going signal has similar action, but via Q2.

That's right! The circuit works just as described.
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It's possible to omit R4 at all thus cancelling negative feedback through it. The effect will be more ''expressive" in that case.
Also, playing with R2 (and R4 ... R8 also) will change the sensitivity.
R1 controls effect depth strongly.

[DDD]

To make clipping levels lower, one can use the circuit below.
The clipping threshold can be controlled with X1 (100kOhm) pot as shown on the waveform screenshot (X1 pot varies from 0k to 100k, step 25k).