SteelPhil

Your amp was the top of the line EH 275, with the EH 185 amplifier chassis. About 30 were produced and were popular with the top-of-the-line guitar models Electraharp, ES 300 and the EH 275 lapsteel. They were made from 1940 - 42. It had 18 watts of power. Yours looks like an earlier one due to the individual Treble and Bass tone controls. Later ones had a single Tone control. Guitar and amp production was severely curtailed during WWII.