Amplifier HI-FI MACHINE No 3 works in pure class A,  output power is 2 x 40 W / 4Ω.

  Actually it is an amplifier of the output power 2 x 200 W but it works in a special regime.

  The reqiured value of the quiescent current for the input output power 40W/4ohms in the pure Class A is


 If we chose a value of 2.5A for a channel, the value of the quiescent current  for both channels is 5A and there is necessary to divert a losing output power higher than 300W from the amplifier in a state without the signal.

 The adjusted value of the bias current 5A is permanently controlled by two amperemeters placed on the top part of the effacing capacitors of the total capacity 200,000 μF.