PCB - top view
Loop gain analysis
THD OPS3 20V
BG7 - old school, very classic front end with j-FET input and single ended voltage amplifier. Huge amount of amplifiers are using exactly same topology.
Soft-clipping VAS adds a bit of flavor into the old design. THD measurements are very good. Lots of dynamics and micro details for sure it is not a boring IPS board, it likes to play music very loud :D
ES series lovers will like it for sure.
Loop gain analysis: