Marantz MA500 Mono block Amplifier THX 125W / 8 ohms or 180W / 4 ohms &lt;0.05% @ 8 ohms &lt;0.09% @ 4 ohms 10 ~ 100K (-1dB 1 Watt) 230 Watts 13.2 lbs (6.0 kg) 19"D X 3.5"W X 6"H