In about July, I installed a subwoofer with a 350 watt Alpine amp in my car. It worked great for two months but no it is just shutting off after about two minutes when the car is running. I think that the alternator is simply not putting out enough power quickly. I am wondering if this problem could be fixed by adding a capacitor to the amp setup or if the only remedy is adding a larger alternator. FYI: The Amp requires a twelve volt power source.