Peavey TKO 80 frying bacon in the preamp

[nosaj]

I have a peavey tko 80 sounds like bacon frying in the preamp. Do 4558 get noisy like this?
Thanks,
nosaj

[g1]

Yes they can. I guess there is no graphic EQ bypass? That would help narrow it down a bit. Input IC always more prone to getting hurt by external forces.

[x-pro]

Power supply +/-15V maybe. Diod zener is noisy

[Jon Snell]

Insert a blank jack plug into J6.
That will identify where the noise is coming from.
4558 and other Op Amps are very much imune from power supply noise unless very severe.

[nosaj]

I've already identified its in the preamp using the inputs. Good thing this one has all the ic's socketed. Any chance the ic sockets need cleaning or is that a thing?
nosaj

[g1]

Any chance the ic sockets need cleaning or is that a thing?

Yes, that can be a thing. Usually pulling them out and reinserting will clear any oxidization unless you can see visible crud.

[nosaj]

cleaning helped a little. putting in 2 old rca 4558 from junk drawer solved it in posistions u1 and u3.
Thanks,
nosaj