Another amp I bought from Enzo as part of his shop liquidation/retirement. He is a legendary tech in Lansing, Michigan, if you didn’t know. Guess someone never followed through with getting this thing going and it was an abandoned piece that hung around the shop for many years never picked up.
Bottom pops off for servicing and it’s all point to point with components mounted to tag strips, pots, tube sockets, etc. Old Sprague caps are from 1973 and still going. Had a bit of an uneven output because the 82K plate load resistor for the one side of the phase inverter was about 50K. The 100K read within tolerance. Mostly just needed some cleaning and a bias. Could be a cool test bed since it has four identical channels easily mod-able on tag strip. Running gain stages in series for high gain could be cool too.
Has thirteen tubes in all. Need lots of preamp tubes for all those channels and tone stacks. Can push up to four cabs but really it is just a non-selectable 4 ohm minimum output no matter how many speaker jacks you use. Has reverb but you can hook up an external unit and select between internal and external reverb on each channel.
Earth Stagemaster PA2000 schematic