Among the tasks solved with the help of electret microphones, one can distinguish the sound of large rooms (for example, conference rooms, temples, etc.) with a relatively large distance from the sound source, which requires high sensitivity and noise immunity. Industrial microphones for such purposes are quite expensive and, in addition, require an autonomous power source for the preamp. The purpose of this development was to reduce the cost of manufacturing a highly sensitive and noise-proof microphone, without significant loss of playback quality. The basis is the scheme [1] of a balanced preamplifier, powered directly from phantom power (+48 V) of a mixing console: Balanced Preamp Electret Microphone Circuit Diagram Its main disadvantage is excessive amplification, leading to clipping of the microphone-sensitive microphone inputs of the console. In addition, the electret microphone supply [2] is not rational enough, as well as the temperature-dependent displacement of the transisto...