This socket allows you connect an external sound source of your choice and can be used for playing backing tracks into your unit. Please not the volume of music/backing track is controlled by the volume on the external sound source itself. Clean & Drive On-board studio quality reverb. Reverb gives you a sense of the space that you are in. A dry guitar signal can sound a little dull. Adding the right about of reverb provides the guitar signal with ambience and brings it to life. Features Headphone socket 1 x 8” Custom Driver 20 watts RMS 3 band EQ Specifications Supply Voltage ~100V, ~120V, ~220V, ~230V, ~240V 50/60Hz Factory Option Mains Fuse Not user changeable Power Consumption 30W Output Power Rating 20W Loudspeaker 8'' Custom Designed Driver Features Rugged Construction TEC Tube Emulating Technology Headphone socket Reverb AUX In (10K Input Impedance) EQ Passive bass, middle, and treble Input Impedance IMOhm/47pF