DIY RAT synth noise

[dudiluty]

Hi.

A few weeks ago i decided to build a Proco RAT. Today i put everything in the box and it works. But...

When i turn the gain knob past 3 i got a lot of noise. Like a squeeling synth.......

Anyone knows what this could be ? I already isolated the wiring, checked solderjoints, replaced the IC..

I'm using a LM308 and 3x alpha 100K log pots.

Thanks.

 

[dudiluty]

Should replacing the 30pf cap solve the problem? Maybe a higher value?

To tame the opamp..

 

[devastone]

Do you have excessively long wire runs? If so, try tidying up your wiring, at high gain stray long wires can pickup extra noise, capacitively couple, etc... To start, just open the box and see if moving the wires around affects the noise.