Well, all righty then!
The electronics are done and all I need to do is some cleanup of the cabinet.
I'm fairly sure the cabinet covering is vinyl. I used Griot's Garage Interior Cleaner to clean it up. It looks good now.
There is also a white trim strip going around the amp that is definitely vinyl. I used Simple Green and scrubbed it with a toothbrush and it's nice and white (instead of being dingy) now.
This picture actually may be helpful to someone down the road who's recovering one of these. I think Valco put the white trim on first, then laid the grey and white covering down and trimmed it so it met up with the white.
I really like that covering. Unfortunately I don't think anyone is making reproductions of it. It's pretty cool and totally different than tweed or tolex.
Love the Supro logo. The amp was really clean to start with and now it looks almost new.
I've been watching these Jay Leno's Garage videos on You Tube and he keeps saying how much he likes unrestored originals. I can relate.
This amp was part of a lap steel set (I have the steel too in my queue). If you found this under the Christmas tree in 1961, you'd be thrilled.
In the days before the Zip Code system was used in the US, there were postal codes. Chicago 51 was Valco's. Some people on the interwebs think it's a model number!
The chrome also polished out very nicely. I used Mother's Mag Polish. I tried a test on a small area of the silkscreening and it didn't remove any at all, so I polished the whole control panel.
Also polished the knobs with Novus #2 Plastic Polish.
The tremolo varies the cathode bias voltage on the first stage of the preamp. It's absolutely insane! At slow speeds you can hear the volume go to zero for an instant. I put in a different value cap in the circuit to slow it down (see the last post). If you REALLY slowed it down you could get it to do the "on/off" volume thing I'm sure.
This is a great little amp. Sounds terrific, has a lot of volume for such a small amp, and has tons of vibe.