4-Channel Class D Full-Range Amplifier, 150 W x 4 @ 1.5-4 ? This compact multi-channel powerhouse employs our Single-Cycle Control switching design and R.I.P.S. technology to deliver 150 W x 4 or 300 W x 2. Tight power supply regulation keeps distortion down and maximizes sound quality. When using the HD750/1 or HD1200/1 to drive a subwoofer system, the HD600/4 is the ideal satellite amplifier, delivering huge dynamics with pristine resolution. From a pure sound quality perspective, we invite you to compare the real-world, in-car performance of this amplifier to any other amplifier on the market, of any type, at any price. It can also be deployed on its own as a very capable 3-channel system amplifier with 150 W x 2 to the satellites and 300 W x 1 to a subwoofer system. This amplifier features a brushed aluminum finish with black powder-coated cast alloy heat sinks and bottom panel. A black powder-coated, gasketed cover is also provided to protect the controls.