[Reece]

Very odd. That switch looks like telephone switchboard equipment, and the Federal name on it would bear that out. If that's a speaker plug shown on the rear, it appears to have a jumper across two pins: that would be to cut the B+ to the output tube in case the speaker were unplugged with power applied, to avoid running the tube with no load. I think it's a homebrew: the socket hole on the rear shows signs of having been "worried" out with a saw and file rather than punched. And screws are used everywhere, some too long, rather than rivets. The knob is very early thirties. This could be a power amp someone cooked up, with power supply too, to add to a twenties radio to get operating juice and speaker power. The other plug on the rear must be for power out to the radio.