Is this cap cooked?

[GlennW]

I just got an old Peavey solid state amp. It seemed to work fine at the guy's house. I took it home and played it some and when I turned it off it made a pop.

Then I took it apart to clean it and while vacuuming the chassis I noticed this black cap. It's the one under the piece of masking tape in the pic. I think it's connected to the on/off switch, or that 3-way polarity rocker switch, not sure.

Anyway, I thought it looked burnt. Most I've seen like that are brown with writing on them. This one's just solid black as far as I can tell, and was wondering if it could be part of the pop when I turned the amp off.

Is it cooked?

[Gtr_tech]

Its just a black coating....its fine.

[GlennW]

Cool! Thanks.

[Jag]

Looks like a MOV (metal oxide varistor) to me. It would be there for surge protection.

[J M Fahey]

Agree, it *is* a varistor. Color is often black, or blue in modern Fenders.
It's wired either across the transformer's primary leads or across the (opening) switch legs, so it absorbs some of the inductive peak that appears when you switch the amp off.
Without it, that amp should thump even more.
Thump is a reality of life, somewhat annoying but not damaging.

[Enzo]

Varistor across the mains? I don;t think so.

Looks more like a THERMISTOR wired in series with the mains as an inrush limiter.

WHat model is the amp?

[GlennW]

It's a Peavey Special 130, 1986 I believe. This thing is ridiculously LOUD. I have it on 1 and have to back the volume off on the guitar.

It makes a funny noise when turning it off; a muffled pop followed by a whoosh sound, like slowly unscrewing a Coke bottle.

[Enzo]

Special 130

Yes, that is a CL60 thermistor in series with the mains, used as inrush limiter.

[GlennW]

Thanks, Enzo. This amp has a Scorpion Plus speaker. I've been searching around and found the SP-12825 speaker has a SPL of 98.7 and the S-12825 has a SPL of 94.9. I'm going to try a regular Scorpion S-12825 in hopes of quieting the amp down a bit without changing the tone. While I was searching I saw on the Peavey forum where you called the Special 130 a "Scorpion Killer". I'll keep those words in mind, and the Scorpion Plus in the closet just in case.

[überfuzz]

Circuits with some patina smells better.

[jmaf]

This thing is ridiculously LOUD. I have it on 1 and have to back the volume off on the guitar.

They use linear volume pots, so from 0 to about 3 you'll think this thing is the loudest in the universe but from 3 to 10 it only increases about 30% in volume.

[J M Fahey]

Oi JMAF, quem é você?
Abraço.

[GlennW]

They use linear volume pots, so from 0 to about 3 you'll think this thing is the loudest in the universe but from 3 to 10 it only increases about 30% in volume.

That's good news. I'll try it with hearing protection.