Tucked partially beneath the right cheek's C panel extrusion is the heavy iron artillery of LL1689 Lundahl transformers and attendant 40mA/20H chokes.

Beneath the opposite panel lives the actual power transformer and a 120mA/10H choke from Basler electric.

Here we see the digital PCB...

... followed by the signal-path tube PCB with custom ModWright capacitors.

The power supply PCB exhibits four heat-sinked voltage regulators, two further ModWright capacitors, the valve rectifier socket and a small Japanese Tamura Microtran PSD3-20 split-form power transformer.

Finally a face-on look on the digital PCB with the BurrBrown PCM 1794 converter, Lattice LSIC and Nu-branded USB transceiver.

To drive big recto glass like Dan's NOS 5R4GYS or Emission Labs' enormous 274B, one simply undoes four self-locking nuts to remove the metal mesh from beneath the circular cover opening. No matter how tall and fat your rectifier of choice, it'll fit to imbue the deck with a slightly dangerous hot-rodded look. Vroom.