dude just listen to everyone.
If you haven't, change your fuses first. If you havent done that, then you may never locate the problem cause that could be it...
Next, if you think you have a dead amp, contact AQ... i have a 1200D and trust me, its no crap amp... coming from a Hifonics i noticed much cleaner power and my sub just working better, and the AQ runs cooler. But the guys at AQ are pretty cool, so give them a call if you can't find anything.
And for big 3, i had some voltage drop with my system, then i got an optima yellow top and big 3 in 0/1 gauge, works PERFECT now