Here is an Electret Condenser Microphone – ECM preamplifier circuit based on ultra low noise BC650C transistors. Due to difficulty of finding BC650C, instead of them, as you can see in the schematic, ...

Electret microphones are capable of high-quality output, and are prized for their smooth frequency response. However, unlike other types, they can’t simply be plugged directly into a mixing desk.

In the Aug. 10 issue, we wrote about the centennial of condenser microphones. Let’s look more closely at electret condenser microphones. Fig. 1: The few components that make up an electret microphone.