conrad-johnson MF2550 Stereo Power Amplifier Power: 250 watts per channel RMS both channels driven into 8 ohms from 20Hz to 20 kHz at no more than 1% total harmonic distortion or intermodulation distortion. Sensitivity: 2 V rms to rated power. Frequency Response: 20Hz to 20 kHz +0/-.3 dB. Hum and Noise: 100 dB below rated power output. Phase: Phase correct. Input Impedance: 100 kOhms