A resonator assembly includes a resonator, a collector-amplifier, as well as a timbre tray, one or more timbre pieces, and a detector holder. The resonator assembly, designed to be attachable to a conventional acoustic guitar, improves the quality and volume of the conventional guitar. A wood or metal timbre piece or a varying combination thereof may be used according the user's sound preference. The resonator, the collector-amplifier, the timbre holder tray and the detector holder are preferably made from thin brass.