Microphone preamp

A microphone preamp (microphone pre-amplifier), most commonly called mic preamp, is a device used to amplify the voltage taken from a microphone to a higher, more usable level. Most microphones must be used in conjunction with a microphone preamp to function properly.

The Technical Details
The output voltage on a microphone is very low; a microphone preamp increases that level by up to 70dB to a +4dB level output which is used by other external audio effects, for audio recording, and for live sound. The circuitry inside the microphone preamp has a great effect on the sound of a microphone, from the way the microphone reacts due to impedance changes, to adding coloration from transformers or vacuum tubes (valves), op amps, transistors, and all the other circuitry used.

In Use
Most audio engineers would assert that a microphone preamp affects the sound quality of a recording just as much as the microphone itself. Different combinations of microphones and preamps can achieve a wide range of tone, character and mood. Microphone preamps come in many shapes and sizes, and vary greatly in price from a few dollars to many thousands of dollars. Many mixing boards or desks have microphone preamps built in. There are also a plethora of external preamps from which to choose, which is great for adding the exact tone and feature set one needs for setup.

Some preamps exist as one part of a channel strip, which can include other kinds of audio recording devices such as compressors, equalization (EQ), noise gates, and enhancers.

Examples

 * Microphone preamp external
 * Microphone preamp in mixer
 * Microphone