This 6-tube two-channel amplifier was found in an American documentation from 1947. The circuit is two-channel with a separation of bass and treble.
This circuit was obtained in a 1960 documentation of General Electric. It is applied in the...
This receiver was found in a documentation by Gernsback from 1960. The circuit uses high impedance...
This circuit takes advantage of the LC constant of a capacitor and the coil of a relay to...