A microphone is a transducer and as such is the source of much of the coloration of an audio mix. Most audio engineers would assert that a microphone preamplifier also affects the sound quality of an audio mix. A preamplifier might load the microphone with low impedance, forcing the microphone to work harder and so change its tone quality. A preamplifier might add coloration by adding a different characteristic than the audio mixer's built-in preamplifiers. Some microphones must be used in conjunction with a preamplifier to function properly (e.g., condenser microphones)[original research?].
Some preamplifiers 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.