It started as a Millett Starving Student hybrid amplifier. It uses 12AU7 tubes as voltage gain and MOSFETs as current gains. The MOSFETs are loaded using the heaters of the tubes.
The transformer has a 30-0-30 ouput, which is what made this project possible.
I built a voltage multiplier identical to the one in the SOHA II, giving me ~180V at its output. This rail is regulated down to 138V using a TL783 linear regulator and powers the tubes. Each triode operates at 70V/2mA. Each tube has its triodes paralleled.
I built a high-current 25V rail for the MOSFETs from the same transformer taps, regulated using an LM317.