I have a XM skyfi boom box. When I ordered it, it did not come with the ac/dc adapter. The user manual states that it requires a 12V, 1500mA adapter, with a unified polarity type jack. I have found a few websites that sell adapters, but they have a few other options. They have switching, regulated, positive jack, reverse jack. At this point, I don't know what power supply I need to get. With the info that the manufacturer provided, what kind of power supply would suffice in my situation. Any help is greatly appreciated.