edison bell electric pick up

As you know, up until the mid-1920s, almost all disc (and cylinder) records were recorded and played back by purely mechanical means. Electrical recording, with microphones and valve (tube) amplifiers, appeared ~1925, and within a year or two, electrical replay arrived also. Here is an example of an early electric pick-up. You fitted it in place of the sound-box on your spring-driven gramophone (phonograph), and connected it to your wireless (radio) set, and the music played back through the audio amplifyin