[GK] spends most of the time so far talking about the high voltage power supply design. For the particular tubes he had on hand he needed +200V, -400V, -550V, and 6.3VAC for the CRT heater.

What we could perhaps all agree on, though, is that getting 300 volts out of a USB power supply is ... the safest looking circuits we’ve seen in recent memory. Every high voltage part is hidden ...