Matrix M-Stage Headphone Amplifier 2012 version with upgraded power transformer and redesigned circuit Powerful output that can drive high impedance headphones (up to 600 Ohms) High quality components including ALPS VR, Nichicon caps, OPA2134 Op-Amps, etc Can be used as a pre-amp with the line output on the back panel Gain selectors can set 0, 10, 18 and 20 dB gains