This 4-tube amplifier with 6W of output was found in an American manual from 1947. The sound quality is excellent.
When the AC Power line fails, the transistors in this circuit are biased to conduce the current to...
This circuit hás a Power output of more than 1 W. It is used in small experimental or low power...
This circuit was found in Philips documentation from 1967. The components are of the time, being...