CARBON PUBLIC ADDRESS MICROPHONE IN FRAME, 1930's

Carbon Microphone for Public Address applications, fitted into a box with an on/off switch. Also in the box is a transformer to change the impedance of the device from low to standard 300ohm balanced line, a battery is required to drive the unit, which is wired to the input of the transformer and there is a space in the box for this.

"Reisz" type microphone

Nortel Collection

A1324