The SS412 source selector is a completely passive design with absolutely nothing added to your audio signal path. That means no power required, no electronics used and no distortion will ever be added. The chassis is made from .090" steel, meaning it is 3 times thicker than most chassis. Four pairs of RCA inputs allow for connection to all your sources, and one pair of RCA jacks to go to your amplifier. Connection of the SS412 is easy. The rear panel 1-4 RCA's connect your input source signals. The Out RCA on the rear panel goes to your amplifier or other device. Volume knob sets the level.