This amplifier, whose mounting on a printed circuit board was described in Radio Electronics of October 1960, has 35 W of power. The power supply uses a transformer and a set of 5 tubes.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...