rat parasite noise after mod

[add4]

I modified my rat (AMZ fat rat mod with LM308 + beavis lube pot + one switch for putting diodes in the feedback loop, or on hard clipping, and one switch for the clipping diodes (stock, led, fet) ) everything works perfectly except that i get some small crunch noises when i play, i can't hear them with a lot of distortion, but with the less it's noticeable. like crackling sounds, or a very bad sounding distortion.
I kept the 30pf cap between the pins of the op amp.. could it be caused by the slew rate of the opamp anyway?
Does anyone have an idea of what causes this kind of noise and how to remove it?
the pedal would be my best drive pedal if i could fix this
Thanks in advance