anyone seen anything like this before?

[nosaj]

Trying to date this amp it sounds awesome with a bass
tag says "RCA MI-38618A s/n C1885"

Rubber stamped on chassis is 102661. Tube lineup is 6SJ7 6SL7 6V6 6V6 5Y3

Any info would be greatly appreciated, it appears to have been bolted on a wall its a 10watt pa with a single gain control no other controls, output 4,8,16, 70v.

Just trying to get more info on it.

Thanks,
Jason

[Chuck H]

It's a PA amp. Probably intended to be built into a room or hall for entertaining. You'll probably want to refurb those rusty transformers a little, replace the big cardboard multi cap, clean the tube sockets and jacks and check components for extreme value drift. Nothing more to do unless you want to change it to a different circuit.

With really rusty transformers (like those), if they're working correctly, I use a scotch brite pad to sand with the grain and a stiff duster to clean off the surface rust and then repaint with black Rustoleum spray paint. Don't use high temp paint. The transformers should never get hot enough to cure it and it remains soft. AES use to carry a good selection of multi cap cans. Any contact cleaner from your local electronics store is fine for jacks and tube sockets.

You might find that with an EQ pedal in front for shaping and boosting that little amp sounds good for 6 string guitar as well just the way it is.

Oh... DO discharge the old filter capacitor before working on it and installing a proper grounded cord and bleed resistors in the power supply is probably a good idea for safety.

[nosaj]

Transformers are not really as rusty as they appear something about the lighting when I took that picture. There is no loose rust on the transformers, it appears to be just surface. So I guess you don't subscribe to the rust = tone theory if it's not gotten into the laminates?

[Chuck H]

Not really. It's my understanding that rust needs to go pretty deep before it actually starts to notably affect the performance of a transformer. I'd still clean and repaint them just to stop further oxidation.