Some basic spec:
Amplifier Stage - NE5534 as input stage driving output stage comprising BD139/BD140 matched pair.
THD+N comes in around 0.005% after operating temp reached. Nominal impedance 330 ohms. Designed to drive studio monitor headphones primarily (AKG, Sennheiser, et, al).
E-Volume - Uses Burr-Brown PGA2231. There is no tone control!
Power Supply - Traditional transformer, diode bridge and reservoir capacitor design delivering 18 - 0 - 18 with regulators to 15-0-15. Special transformer design made by Lehman in Durban, South Africa for ultra-low losses and temperature rise in a confined space. Also includes a compact, sealed switching PSU for the 12V supply for digital and display.
Digital Audio Path - Uses PCM9210/1 (same chip featured in ONKYO, DENON, ARCAM, etc) as a receiver. S/PDIF feed-through in processor. The processor does NOT alter the digital audio, it merely extracts peak levels and info i.e. sampling rate, jitter, etc.. Usable sampling rates 44.1kHz thru 192kHz. 16 thru 24 bit word per channel.
Audio I/O - One analog line level input, two TOSLINK optical. One analog LINE OUT (post D/A converter)
Processor - ST Microelectronics STM32F072RBT8 ARM Cortex M0. Programmed in C using Atollic TrueStudio / emIDE or plain vanilla GCC C compiler.
User Interface - Vacuum Fluorescent graphics 122 x 16 pixel Noritake / Itron. Rotary encoder and GPIO managed via dedicated ASIC (Xilinx XC9572XL with code in Verilog and VHDL)
On-board storage - EEPROM/FLASH M95640W high endurance (1M cycles +) to cope with storing volume control
Remote control - Infra-red. Extended NEC protocol with a custom code in the address field.