About the amplifiers
- All the amplifiers are "whole symmetric", which gives lower distortion
and allows to feed the amp with wide range of voltages : from +/- 5V to
the full voltage.
- The amps have also a soft-clipping circuit, which subdues almost to
zero the "transistorish" distortion, when the amp is
driven with too strong signal. This, in conjunction with lower supply
voltage gives sound similar to vacuum lamps. This needs
a deeper explanation, I guess.
- These amps were designed to be "bimonaural", which means it has
a separate power transformer for each channel. That's how they reach
>100dB channel separation.
- Take care of these final pics on construction.