I'm designing a guitar pedal to boost harmonics in the signal here: Falstad Link

I'm wondering if there are ways to boost harmonics that don't clip the signal, as well as any adjustments I should make to maintain a clean tone, (the point is a clean harmonic boost, I would like to avoid hard-clipping distortion and heavy gain)

Edit: I simulated the circuit in Falstad, and It's a rather nice crunch tone. Sound sample

  • \$\begingroup\$ I think you're describing a multi-band compressor. \$\endgroup\$
    – JYelton
    Apr 28, 2022 at 16:04
  • 1
    \$\begingroup\$ Adding harmonic is distortion, so adding one always gives you the other. \$\endgroup\$ Apr 28, 2022 at 16:10
  • \$\begingroup\$ @user1850479 More specifically, I want to avoid hard clipping, I probably should have said that instead. \$\endgroup\$ Apr 28, 2022 at 16:12
  • \$\begingroup\$ You should use a monotonic "analog" "non-linear function", should be also "symmetrical. NB: can be also a non-linear "digital" multiplier. It must maintain the "fundamental" of the input "signal". \$\endgroup\$
    – Antonio51
    Apr 28, 2022 at 16:16
  • \$\begingroup\$ If you are ready to make some electronic circuit with transistors and diodes and resistors and capacitors you can easily introduce some distortion using a signal path going through some diodes. One problem with the example is that you got two diodes connected to a low impedance source (OpAmp). That is a bad design. It will create erratic behavior due to current saturation of the OpAmp, possibly catastrophic in a long term. But the idea of the two diodes in the feedback loop is a great approach for distortion. You could also use two channels and mix them to adjust the effect. \$\endgroup\$ Apr 28, 2022 at 16:51

1 Answer 1


A clean harmonic boost doesn't exist.

THD (total harmonic distortion) is a measure for distortion and clean Hifi enthusiasts aim to minimize THD as far as possible.

With respect to audio there are various simple ways to add distortion and create characteristic sound. Such as diode clipping and transformer saturation or using no feedback to linearize amplification stages. It's down to taste but one thing the "nice" distortions do all have in common:

They are prevented from producing very high order harmonics but only low index ones mostly. This is achieved by using only slight nonlinearities.ass opposed to e.g. hard clipping without filtering.


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