AF companion amplifiers are designed to add powerful amplifier channels to AF bit processor amplifiers. A plug-and-play signal input harness is included to make connection to AF bit amplifiers straightforward. AF companion amplifiers are also perfect for use with systems controlled and managed by a standalone bit processor, such as a bit One HD Virtuoso. AF companions have a “straight wire” architecture, without analog preamp functions such as crossover filtering, and are intended for use with external processors. AF M4D boasts four high-fidelity amplified channels 90W x 4 @4Ω*, 150W x 4 @2Ω* with the audiophile sound of the latest generation Audison D-Class technology. Higher switching frequencies, steeper filtering, and higher-tolerance components deliver sound above and beyond the expectation of Class D – in an amazingly compact package! The audio band is extended up to 40 kHz earning the coveted High-Resolution certification. Bridging channel pairs results in 300W x 2 @4Ω*, guaranteeing flexible and powerful performance. *Output Continuous Power (RMS) @14.4 VDC, 1% THD, all channels driven.