If you know these mono-block amps, you know how coveted they are. Perfect for your 5 channel home theater, or bridge two together to create a 250W amplifier. It is has hard to get a higher quality amplifier without spending considerably more than this price point. The total harmonic distortion is very low for this level of power output. This is a deal, these usually sell for $150 each (x 5 = $750). The Marantz MA500 monophonic (single channel) amplifier is designed for home theater and high quality systems. Offering high power into 8 or 4 ohm loads, the MA500 can deliver high performance even with the most demanding signal conditions. Specifications Rated Power 125W / 8 ohms ... 180W / 4 ohms THD <0.05% @ 8 ohms ... <0.09% @ 4 ohms Input Sensitivity/Impeance 1.0Vrms / 30K ohms Frequency response 10 ~ 100K (-1dB 1 Watt) Signal to Noise Ratio >116dB Damping Factor (8 Ohms) 200 Power Requirement 120 V AC, 60 Hz Power Consumption (Full Power at 8 ohms) 230 Watts Weight (lbs) 13.2 lbs (6.0 kg)