This source unit has a MOS-FET (Metal Oxide Semiconductor Field Effect Transistor) power amplifier capable of delivering 4 x 45 watt of high quality sound with superior linearity and less distortion than conventional power amps even with the volume cranked up.Front 2-channel auxiliary inputAn auxiliary Input jack is located on the front of the unit for easy access. Simply connect to an external audio source to enjoy its sound in stereo.