Yeah Frank, I also forgot about Mackintosh.
Speaking of Sansui, I have a Sansui Six receiver down at my shop, that is connected to a Kenwood KR-5600 receiver, to give me independent volume controls for the machine area and the main area. I bought the Six at a yard sale for $20 bucks or so, and it came with the manual, which included schematics!
I also have a Sansui 5000A, but I'm not currently using it.
In the early '70's, a Sansui amp came into my dad's shop for repair. The right channel would intermittently fade out, sometimes blowing a speaker fuse. One time, with the unit cooking on the bench with a low wattage test speaker, we were finally able to catch the failure in action: the sound faded out, as the speaker cone slowly retracted, then the voice coil melted!
These amps were directly coupled to the speakers, with a +/- 34V DC supply. The drivers would fail, and force the output transistors into full conduction, which fried our test speaker. It turned out that Sansui had already corrected the problem with improved driver boards, but the replacements cost something like $50 each.