Rockville RPA60BT V2 1000 Watt 2-Ch USB Bluetooth DJ/Pro/Karaoke Amplifier Mixer, Black. Rockville RPA60BT 19 1000 Watt 2-Channel USB and Bluetooth Karaoke Receiver/Amplifier/Mixer. 19 rack mountable (removable rack brackets) digital hybrid amplifier/receiver. THD: > 0.1%. Input Sensitivity: 400mv/33 KOhm. Frequency Response: 20 Hz – 20 kHz. Signal to Noise Ratio: 80 dB. Tone Characteristic: 100Hz-10KHz 12dB. Front Inputs: 3.5MM front aux input, (2) 1/4 Mic Inputs, USB Input. Rear Inputs: RCA, Optical, Coaxial. Rear Outputs: Preamp output for an external additional amplifier or powered speaker. Sub preamp output to connect a powered subwoofer or an amplifier. Rear Speaker Terminals: Banana plug / binding post outputs for 4 speakers (2 on Channel A and 2 on Channel B).