What is a Preamplifier?

A preamplifier, often called a preamp, is an audio device that boosts very weak audio signals to a usable level before they are processed, recorded, or amplified further. It is commonly used with microphones, instruments, and other low-level audio sources.

Microphones and some instruments produce signals that are too quiet to be recorded directly or sent into mixing equipment. A preamplifier increases the strength of this signal to line level, which is the standard level required by most recording and audio processing equipment.

Preamplifiers are found in many types of audio equipment, including audio interfaces, mixing consoles, microphone preamp units, and instrument amplifiers. In addition to increasing signal level, some preamps also shape the tone of the audio signal, which is why certain analog preamps are valued in music production for the character and warmth they can add to recordings.