I have a Directed D600 amp with a Directed 15 inch sub, my amp is getting power, the light comes on, but the sub wont hit. I hooked the sub up in my friends car thinking it was the sub that was messed up and it worked just fine. I also went bought a new amp because they told me the out puts on the amp could be blown. I connected the new amp and it still wont push the sub. What could the problem be? Could the RCA wires be bad or somthing? i just dont understand how the amp is getting power but the sub wont work.