So I used to have a car, and in that car I had a 12" sub and an amp to power it. Now at school, I no longer have a car, but I've still got the equipment from before. I wanna run the sub in my home theater system, and know I need a convertor from 120AC to 12DC, but my question is, how many amps to I need to power such a set up? Is 3 reasonable? If not, what should I need? The amp should be putting out about 300 watts. Thanks in advance, guys. I'm kinda clueless on this stuff.