MM-1, Microphone amplifier with headphone output. The MM-1 is a microphone amplifier with 12/48V phantom power and 12V T power, HP filter, and limiter. Both input and output are transformer balanced on XLR connector. Gain up to 66dB in 11 steps. Balanced monitor input on Tele (TRS), Headphone output with separate levels for mic/monitor. Powered by 2 AA batteries or external 5-17 VDC.