Marantz Model 50 Integrated Amplifier For those who choose every component carefully, a pure and powerful amplifier is essential. MODEL 50 is the ideal integrated amplifier. With 70 watts per channel of unique Marantz current feedback power and HDAM SA-3 circuitry, MODEL 50 drives loudspeakers with total control. Six analog inputs, including a high-quality MM Phono stage, make it the centrepiece of streamlined and complex stereo systems alike.