I bought a used pontoon boat and the stereo worked for a few weeks. When it quit, I bought a cheap head unit and hooked it up the same as the last stereo. It lasted a few weeks and poof, it was shot. I thought it was the fault of the stereo and the seller honoured the warranty and replaced it. I carefully read the instructions for install and it appeared the other stereos were hooked up wrong. Hooked up the new one and again after a short while it quit working. Now I am wondering if the amp is causing this. Here is what I have: Head unit 45 watts x4, four speakers Kenwood KFC 1653 MRW 4 ohm rated at 50 W RMS, Amp is Kenwood KAC-M1804 400 W amp. I guess my question is do I need to use an amp with my system and if so, should I replace my amp in case it has caused my issues ?