A preamp is a “pre amplifier” and, as the name suggests, it prepares the signal coming from a pickup or microphones for further amplification. There are a number of reasons to get a preamp: It can boost a low signal. It can clean up a signal so that it sounds better coming through the amp. An external preamp may improve your sound quality significantly, if you work with low output dynamic microphones, and instrument pickups. Browse our favorite preamps from a variety of manufacturers.