Closer inspection showed…

… the dual-mono AKM AK4497EQ 'Velvet Sound' Asahi Kasei PCM/DSD converter chips and an FPGA…

… plus copious use of digital isolation transformers at the inputs and outputs.

On the power supply end, we look at…

… one of the voltage regulators in closeup whilst…

… finishing up with the joint army/navy 6922 in their ceramic sockets and French-made SCR capacitors. The transistor outputs use 4 x class A-biased Texas Instruments OPA 604 opamps.