Small, simple modulation circuits. As small as possible...

[zenpeace69]

Hey,
 Just looking for some modulation circuits that are really simple and tiny.  I want to thank all the people who gave me some ideas about fuzz and overdrive circuits that are tiny, but didn't seem to get any response for modulation circuits.

Anyhow, any really simple ones?  They don't have to be too tweakable.  The simpler the better.  I plan on using them in very small modules to be put into a feedback loop.  

thanks!

[Fret Wire]

http://www.runoffgroove.com/phozer.html

[strungout]

Check out tim Escobedo's circuit snippets http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html lots of small simple circuits there.

Ciao.

[petemoore]

Stik a LED/LDR [better get a good LDR] together, [shielded from outside light, enclosed]  use the LDR to attenuate output, and the LED on the blinking LED using the 555 timer [on a separate power supply if you don't like ticks]. I believe the timer/blinker is a 555, a few R's a 100k pot and a cap.
 You should be able to get some modulation using an LED/LDR setup with very few parts. But it could take some figureing.

[Mark Hammer]

Here's one I've never seen before.  Be the first kid on your block to own one!

Clipping diodes will clip less if you stick a resistor in series with them.  So, imagine you have a one-op-amp clipper with a pair of back-to-back diodes in the feedback loop and a big feedback resistor (lets say 470k) for lots of gain.  Now stick a resistor in series with the diode pair (let's say 39k) to reduce their clipping action.  Now stick an LDR in parallel with that resistor so that it can be varied from full resistance to darn close to zero ohms.  Voila, in principle you now have the makings of a "Rotogrind" pedal, where the intensity of the distortion varies with an LFO, a little like someone gunning their engine at the lights.