API Audio 512c Mic Pre, Mic Preamp, The 500 series, 65 dB gain, Microphone input on the front and back, Line / instrument input jack, 20 dB pad-switch, 48V phantom and phase switchable, LED-VU meter, Lownoise preamp (-129dB), Circuit design with the API2510 and 2520 operational amplifiers, Requires API Lunchbox 500-6B or 500VPR 10Slot rack