strange pulsating noise

[axevictim]

hi could anybody help,ive just finished a distortion pedal,everything works fine until i turn the gain control three quarters of the way up and the i get this pulsating machine gun firing type sound also one of the LEDs which i have used for a clipping diode starts to flash in time with the pulsating noise. The pot is a 470k linear.Any suggestions as to what it might be causing this.Thanks.

[jefe]

(a little bump for your thread)

I wonder if you are getting what's called "oscillation"? I've only read about it, never experienced it myself. The fact that you described the noise as "pulsating" made me think "oscillating". Sorry I can't help you debug it, but I think plenty of people around here have dealt with it before.

[DavidRavenMoon]

Try moving all your input and output wires away from one another, and if possible, use shielded cable.

With high gain circuits you have to keep certain wires, and even parts on the board, as far from each other as possible, or some signal can jump from one wire or trace to another and get the oscillation going. Oscillation is just like feedback, only in this case at a lower frequency.

Also, check to see if you have any electrolytic caps wired in backwards.