Microphone preamplifiers can have an incredible influence on the tone of the source being recorded. Specific microphone preamplifiers from well known name brands are coveted for the sonic imprint they impart onto recordings. In the latest entry to our How To Listen Series, Fab Dupont and Chris Mara (producer, engineer, and owner of the Nashville based recording studio, "Welcome To 1979") sit down with four different flavors of microphone preamplifiers for the purpose of quantifying the characteristics each contribute to the final sound of the recording.