The design begins with standard 1/4" instrument input with a thru-put to feed your tuner or your on-stage amp. The ultra-quiet active circuit at once converts the signal from high to low impedance to reduce susceptibility to noise. The signal is then buffered and balanced for long cable runs to the PA system. 48 volt phantom provides the power, so the SB-1 does not require batteries or external supply to make it work. You simply plug in and you are ready to go.