Any one ever seen one of these before? Single ended 6v6 with one 12ax7. Diode rectified with 6" speaker. All the voltages are very high. I found a schematic online showing 400vdc on the plate of the 6v6. When it's first switched on the voltage is around 540vdc on the 6v6. This drops to about 450vdc when the tube heats up. Filament voltage is around 7.5vac without the 6v6 installed, I have not checked filament voltage with the output tube in. The schematic does not show an AC input voltage but the front panel says 120vac. Schematic does show 720vac across the PT but I measured about 840vac. It appears to be the original PT but I couldn't find it with a web search. I think the amp is late 1960's and if I'm reading the transformer codes properly it was built in mid to late 1968. Output trans #'s - T2640 5246744 PT - 330 T3037 5246821 Any info on this amp would be greatly appreciated.