AK30 PLUS is a twin-source retrofit side mounted acoustic instrument preamp with 2 band EQ, presence control and low battery indicator. Based on the AK15, the AK30 PLUS features AER's standard piezo under saddle pickup and a single microphone, each addressable by separate fader. The microphone is dependant on the Piezo volume. It can be used for a wide range of instruments, if you need tone and volume controls directly accessible. AK30 PLUS can be phantom powered by AER amps without having to remove the battery.