Sound-boosting equipment (4)
(Other definitions for amps that I've seen before include "Spam (anag)" , "Current measures" , "concert gear" , "'Units of electric current, in short (4)'" , "Basic units of electric current" .)
(Other definitions for amp that I've seen before include "Current measure" , "Map of electric current" , "A flow of one coulomb per second" , "It helps you hear" , "Unit of electricity, in short" .)