An unusual single-ended tube amplifier
Output stage is 2A3 or 45 with a power pentode actively loaded, mu-follower output stage.
Sansui SW-15-4 output transformers, yes, push-pull transformers, since no DC running through the output transformers.  Output coupling capacitors are 4uF oil can capacitors.
Fixed bias, set automatically by a high gm pentode with reference to the plate voltages of output tubes.
Input stage is also actively loaded using 6KT8 triode-pentode composite tube
Bias can be adjusted for tube rolling
5AR4 tube rectifier
4, 8, 16 ohms output selectable.
Very low distortion
Some extra power output achieved as compared with usual similar types of amplifiers
AC heater for output tubes, with active cancelling circuitry to lower the hum
Excellent sounding.