This sensitive three-transistor circuit was found in Electronics Now magazine and is earphone-readable. The tuned range depends on the coil.
This is the project found in a 1981 publication, but it is still viable. It is a simple AM...
This commercial earphone receiver was manufactured in the 1960s in Japan. It was powered by a 9 V...
This circuit was found in a European publication from the 1980s. The transistors can be the BC548...