Have pair of computer speakers, BW-180H but no power supply. Receptacle on back is not labeled with voltage requirements & polarity so I can safely substitute a generic power supply. Need to know, is it an AC or DC volts that it takes, the actual volts, the milli-amp need, & polarity - is the center pin + or -? . Need info sheet or manual or just the info read off the back of the power supply block for a BW-180H Multimedia computer speaker system. BW = "Benwin" imported by AlltekVision (out of business.)