preamplifier[prē am′plə fī′ər]
preamplifier definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
in a radio, phonograph, etc., an auxiliary amplifier for boosting the voltage of a weak signal before it reaches the input of the main amplifier
preamplifier definition by American Heritage Dictionary
The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
An electronic circuit or device that detects and strengthens weak signals, as from a radio receiver, for subsequent, more powerful amplification stages.