This 1940s circuit is both a radio and a wired amplifier. The 5-tube radio has a loop antenna and tunes to the medium wave band. In the intercom version, the audio amplifier stage is used. The circuit shown is for two channels.

This 1940s circuit is both a radio and a wired amplifier. The 5-tube radio has a loop antenna and tunes to the medium wave band. In the intercom version, the audio amplifier stage is used. The circuit shown is for two channels.