State-of-the-art: multiple inputs, volume and tone control, and a separate power switch, with fuse.
In 1946, this was an upscale amp - it was probably sold alongside the new National Steel guitars. Designated the '510', the amp had 5 tubes and a 10-inch Rola field-coil speaker.
I think this amp sat unused for several decades because of a broken power switch.
1946 National / Valco Supreme Amplifier
The circuitry remains just as it was in 1946, except for the addition of a three-conductor power cord.
Amazingly, the capacitors and other components are still in good working order, after 72 years. The next time someone says that electrolytic capacitors only have a lifespan of 10 years, remember this amp!