DROKxae; IRAUD200 Hi-Fi Class D Digital Amplifier Board 500W For KTV/Stage/Home Car Voltage Range: DC  20 to  85V (when supply voltage less than  40V, two 3K/3W resistors need to be replaced 1.5K/3W resistance) Maximum output power: 350W/8 distortion &lt;0.1% ; ( 85V supply) 700W/4 distortion &lt;0.1%; ( 70V supply) 900W/2 distortion &lt;1% Overvoltage protection values:  85V;Overheat protection value: 85  C;Voltage Magnification: 33 times Input Sensitivity: 1.5V (RMS);Input impedance: 6K;Frequency response :0-50KHz  3dB 10W/8;Residual noise voltage: 200uV;Dynamic range:&gt; 100dB Application:HI-FI Class D stage or KTV amplifier, home theater multi-channel amplifier, car amplifier and battery-powered power amplifier (needed boost device).