Help with Sundown SAE-1200d

[notoriousJ]

I bought a Sundown Sae-1200d(don't if it's v1 or v2) but it made a funny noise when I hooked it up later that night to make sure it worked. He played it on his system for me for a short time but it was music around 50hz and got loud. I too could get it that out of it but when the lows hit it began to make clippy weird noises that are foreign me. To fix this I moved my remote wire away from my power wire which stopped that mostly, however on louder volumes it would either continue to make these noises or trip the amp.
My voltage bottomed out at 11 something Volts on a multimeter with previous amps but the sundown amp wouldnt drop to 12. (tripping protect at 12.8v).
Soon after i replaced wire with Big 3 and soon to get a battery, unfortunately something gave in and now it only makes noise on low volumes mabe 10% of the time I try to hook it up.Tested mosfets and all of them are the same reading so I think they are all good, other than that I don't know what else to check.
I don't know much about amps at all so I figured I would ask everyone else.Pictures can be posted if you tell me what you need to see, everything on the board looks fine. The amp is no longer warrenty so thats why I'm resorting to forums. Cost me $275 to buy and I would like to get as much back out of it as possible. I am on a bit of a budget.Any other info you need just ask, as stated I don't know a whole lot in the amp department.
If you want to you can txt me at 317-502-7447. I do work most days and if not that I'm at school.