Easy way to get intermodulation distortion?

[Electric_Death]

I was curious if anyone knows a way to introduce some desirable intermodulation distortion into a B.O.D. pedal.
I would think specific cap and resistor filters utilized in 2-3 stages is all it should really take.

[R.G.]

My experience is that "desirable intermodulation distortion" is an oxymoron, much like "jumbo shrimp" or "military intelligence". 

A multiplier or ring modulator produces almost pure intermod, but all forms of distortion produce some of it. The holy grail of most distortion quests is to produce harmonic distortion without any intermod; that's what the soft, low order distortion produces.

Look into ring mods and multipliers.

[Transmogrifox]

See the part of the circuit with the diodes connected between the drains of the differential pair.
http://www.geocities.com/transmogrifox/ScorchedEarthPage.html

This produces plenty of intermodulation distortion.   It's nice and blatty and nasty like intermod should be.

[Electric_Death]

See the part of the circuit with the diodes connected between the drains of the differential pair.
http://www.geocities.com/transmogrifox/ScorchedEarthPage.html

This produces plenty of intermodulation distortion.   It's nice and blatty and nasty like intermod should be.

Ahhhh thanks man, very simple as I suspected.  I modded my TS7 about a dozen times and it's intermodulation was outstanding but, it went in for surgery one final time and unfortunately flat lined
Hopefully that works with my Insanely Clean Overdrive circuit.

[blanik]

plug an electric piano into a big muff...! sounds amazing! 

[Electric_Death]

I think maybe I've used the wrong terminology.
I'm trying to get frequency intermodulation so there is a very slight envelope/wah effect from the overdrive I'm tinkering with. I know that really just means getting some frequency spikes really close to one another in the response curve that will collide. That's why I'm assuming the right filters between each gain stage should achieve this and suspect somebody knows the right cap and resistor values to use and the sequence to arrange them in.

If not, I'll just fiddle until I figure it out god willing I don't kill the circuit in the process

[Electric_Death]

Just an update.
At the sacrifice of a lot of gain, a resistor and cap in parallel with another resistor then shunted to ground is giving the frequency intermodulation I desire. Basically a really high value cap and resistor with a low value resistor to ground. I suppose another cap in parallel with the ground resistor will yield even more with of course, even more sacrifice to the gain.

Time to design and build a higher gain circuit I suppose.

[Transmogrifox]

What you have describes sounds like something I have obtained by introducing a bias shift to the clipping stage that is signal - dependent.  This is basically an envelope follower fed with the signal so that the signal level modulates the clipping symmetry.

The solution you have indicated above sounds very similar to what I did. 

From the circuit I linked earlier, try sticking a large cap from collector to ground on one side of the differential pair output.  That will serve as a DC storage cap to modulate the clipping threshold in response to signal envelope.

This will help you maintain gain.  This concept can be applied to about any kind of clipping circuit.  For example, signal going into a TS type clipping stage just needs a resistor in parallel with a pair of resistors, where one has a series diode and cap shunted to ground.  This will cause the bias level to shift when signal is present.

I usually get this effect by accident, when I have done something wrong or connected a wire to the wrong place in the circuit.