Back in the day, RCA made theater amplifiers as you describe, up to and including the potted transformers. These things were massive and usually rack-mounted.

The logos were enameled medallions, so if they were removed, you would have no other indication of the maker.

https://thumbs.worthpoint.com/zoom/i...6b2b59c8f9.jpg

When theaters started replacing tube systems with solid-state and multi-channel systems, many thousands of these amps got trashed, and a vanishing few found their way into other hands.

Peter Wieck
Melrose Park, PA