This 2-tube amplifier was found in a Japanese publication of 1964. The circuit has excellent sound quality. The power supply is not given and must provide a voltage of 300 V.
This circuit was found in a 1970 IEEE publication. The circuit functions as a voltage controlled...
Found in a 1968 American documentation, this circuit uses an operational amplifier that is...
This circuit was found in an old documentation from 1968. The voltage gain is 70 and the...