What's that 25W 50-ohm resistor at the bottom for? A power attenuator?
Nope, heatsink
This amp is VERY simple, its got 4 knobs (volume, treble, bass, cut), no master volume. The guy who designed it, Ken Fisher, thought that master volumes, effects loops, and other things degraded tone. Now, he is dead and his amps are going for 40K

BTW, the orange drops are actually not my favorite. I like the yellow Mallory ones better. But, I'm sure those orange drops will do the charm for you
I've got a set of SOZO's lying around but I'm trying to build it as close to stock as possible the first time around, then after a few months, if I feel like it needs something, I'll change it.