The CPA-50 is a multiple stereo input, 50 watt compact audio amplifier for four or eight ohm speakers. The CPA-50 has three stereo line level inputs, two RCA connectors, one 3.5 mm mini jack and a separate microphone input with independent gain control. The audio inputs are mixed at a 1:1:1 ratio. The amplifier also has an input for Premier Mounts external volume control, WP-50, or any third party controller. The CPA-50 switches to energy-efficient operation after 20 minutes without input signal.