a device in the amplifier circuit of a radio or phonograph that increases the strength of a weak signal for detection and further amplification.
Origin of preamplifier
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
an electronic amplifier used to improve the signal-to-noise ratio of an electronic device. It boosts a low-level signal to an intermediate level before it is transmitted to the main amplifierSometimes shortened to: preamp
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Online Etymology Dictionary, © 2010 Douglas Harper