Harman Kardon HK 3770 2-Channel Stereo Receiver with Network Connectivity and Bluetooth 120W X 2 high-current, ultra-wide bandwidth amplifier Complete connectivity including a phono input, FM/AM radio, home network DLNA, vTuner Internet radio, iOS Direct with built-in DAC (digital-to-analog converter) or audio file play via USB Bluetooth for high quality audio streaming from a broad range of devices Subwoofer output. Input sensitivity/impedance: 250mV/27k ohms Harman Kardon remote app provides control through iOS and Android platforms