Stereo single ended pentode amp with triode mode. Battery generated grid bias on output stage. 6J7 pentode input stage.
Two nested global feedback loops.

Edit 2014: I'm still using this amplifier for computer sound with a pair of modest Cambridge Soundworks speakers I picked up for $15/pr... It sounds pretty good. At a recent get together it was the toast of the town, it was very synergistic with the owner's loudspeaker system - in pentode mode at that.