This Public Address amplifier was found in an American publication from 1947. The circuit uses 5 tubes and a transformer source.
Shown in Radio Electronics June 1953, this circuit needs a small adjustable source of 0 to 3 V and...
This circuit is suitable for the calibration of old analog oscilloscopes. It was found in...
This circuit was found I a 1965 Radio Schack documentation. The transistors are from that time,...