Self oscillation filter?

[SISKO]

Im planning on building a filter for guitar pedal use with a resonance control that when maxed, itll oscillate.
Is there any circuit for this?
I tried tim escobedos QyD VCF. It did oscillate but only on the high travel of the pot. Also tried the DOD FX-25, but this did not oscillate.
I know a ladder filter would be great for this, but theres no guitar pedal adaption for this

[space_ryerson]

You could build the korg monotron ms-20 filter. There's a thread with a schematic here.

[DDD]

"T.M.K." by Tim Escobedo is what you're looking for. 
It also can be controlled with guitar volume and tone knobs as well as with it's own controls.

[SISKO]

You could build the korg monotron ms-20 filter. There's a thread with a schematic here.

Yeah! It was the first filter I tought about. Anyway, I wanted to know if there where others similars circuits that I didnt know.
Im gonna read that thread, I know Tim Escobedo has a similiar circuit for this http://folkurban.com/Site/9VpoweredMS20SallenKeyLPVCF-690.html

"T.M.K." by Tim Escobedo is what you're looking for. 
It also can be controlled with guitar volume and tone knobs as well as with it's own controls.

T.M.K. is a great little circuit! But im looking for another effect. I know T.M.K. is a fuzz with lots of possibilites, one of them is oscillation. But Im looking for something similar to EHX MicroSynth (the filter section) or something like this http://www.youtube.com/watch?v=YQXAegFyb9A at 2:17

[DDD]

AFAIK The Muse are fond of using Fuzz Factory. Maybe...?
Also, emitter follower with frequency-dependent positive feedback is good for you? It has a resonance peak followed with sharp highs roll-off, and easily oscillates.
By the by, one BJT totally 

[SISKO]

Matt Bellamy (Muse`s guitarist) started to use (and abuse!) the FF on the second album. This video was done before he get to know the FF.
He uses this kind of filter on a lot of songs, and AFAIK this sound came from his Roland VG-8 Guitar System.

Also, emitter follower with frequency-dependent positive feedback is good for you? It has a resonance peak followed with sharp highs roll-off, and easily oscillates.
By the by, one BJT totally 

This sounds pretty interesting! Although I dont fully understand the "frequency-dependent positive feedback" part, or at least how to achieve with only one BJT!
If you could enlight my way here, I would be truly thankful

[DDD]

Pls take a look at the schematic here:
http://valueguitar.by.ru/projects/pr0012/Zvox1.jpg
The central part of the circuit is just an "emitter follower with frequency-dependent positive feedback".
The filter begins with R22 (200 k) and ends at the left pin of R9 (2,7 k). Also omit D5 and D6 diodes.
Pots control frequency and Q-factor.
5,6 pF capacitor from ground to the base terminal of Q2 is very important since it can reduce oscillation at all.
The circuit is very sensitive to the components values. Play with them a little bit and you'll get quite controllable oscillation.
The filter is not pretty good, but it's pretty simple.

[SISKO]

Sorry for my late reply!
That circuits looks interesting Im going to breadboard it and see how it comes!
Thanks for the circuit