How to identify tube amp

They are push-pull amps using octal tubes as finals and 9-pin miniutures as driver and phase splitter. They appear to be made by a skilled home constructor rather than being commercially produced.

Since we are speculating, I would guess a 12AX7 followed by a 12AU7 with KT88/6550 as outputs. The fact that there are no tubes in them may be indicative of problems. Remove the bottoms and look for any burn marks or bulging capacitors, check all fuses for continuity using a multi tester before bringing the amps up with a variac. Don’t want to let the blue smoke out.

Well, the amp is executed on a circuit board, rather than point to point. To me, that and the red Wima caps might indicate a small production commercial amp, but the physical aspects, such as the woodwork and that inner chassis scream home brew.

Whatever the answer, the builder had considerable skill, the ground buss being laid out very nicely. The bias scheme appears to be fixed bias rather than cathode bias. I would stick with my original guess, though the finals could be EL34 rather than KT88/6550. Is there any way you might find the tube set for the amp? Otherwise the schematic may have to be reverse engineered.

Maybe other amp builders on the forum can see further into the build than I.