Oscillations

[farky]

Hey folks.

I'm in the final stage of my guitar synth project.  Unfortunately, the 
filter circuit that I pirated from Craig Anderton is giving me 
oscillation problems.  The circuit is called the "Super Tone Control" in 
his EPFM book.

If I could hear some general troubleshooting ideas when dealing with 
oscillations, boy, that would be great.  

I like the thing I made.  It's pretty rudimentary but it has straight 
guitar, square, tri, sine outputs and a low octave square output.  Also, 
there's an attack delay/vca, a vibrato circuit, and a VCF that uses a 
voltage sweep that's triggered off the detection of an input signal.  I 
stole some ideas, others are mine.  I've been able to get some pretty 
tweaked tones.

toby