This commercial radio for the AM band was sold in Japan in the 1960s. The circuit has an IF of 455 kHz and is powered by batteries. The push-pull output gives a good audio power.
We found this circuit in a 1968 Electronics World. The potentiometer should be set to trigger the SCR...
We found this circuit in a documentation from the 90s. It lets frequencies around 1 kHz pass,...
This wired intercom circuit was found in a March 1965 Radio Electronics. The circuit uses two...