Building a Harmonic Distortion Generator

[dabbler]

I am wonderning how hard it would be to build something like a simplified hardware version of this VST plugin:

DSP/FX

I want to experiement with odd vs high order distortion and the balance between the 2. Another option would be to just buy the plugin and play it through foobar - however foobar doesnt have online radio capabilities which i listen to alot.

I am thinking of this as a possible first real electronics project. My only experience is building alot of mediocre 2 way speakers

[tomchr]

You can create 2nd harmonic distortion by asymmetrical clipping. An op-amp with a diode in the feedback path will do that... Say one 1N4148 with anode on the output of the opamp and cathode on the (-) input of the opamp. And perhaps three 1N4148 in series with anode on the (-) input and cathode on the output of the opamp. The signal input would be the (+) input of the opamp. In parallel with the diodes you may have to add a resistor - 10 kOhm would be a reasonable starting point. This to prevent oscillation at low amplitude.
This would give you a circuit that clips at about +0.7 V and -2.1 V. Drive it with a 1 V signal and you get strong even order harmonic distortion. Drive it with a 2.5 V signal and you'll get the odd orders as well.

~Tom

[dabbler]

Would this be a suitable first project? I would probably need an existing schematic to start this. Otherwise I might start reading up a bit more about designing and building tube amps. Can anyone recoommend a good book?