Amp worked fine for 1year, all of a sudden it...

Hello,

I got this set up for a year now, a sony 500w amp with an xplod sony 300w subwoofer ...

I got my battery changed last week and 2 days later my Amplifier turns off, at high volumes, I saw the exact same problem on another post, but the "help" didn't help, or let's say I don't nessiceryly know what a 4 gauge wire and a 8 gauge wire are, and why my setup started doing this just now, after one year! (is my battery giving out too much volts, or too much amps?

it seems to be getting real hot on the outside (like when I put my hand on it I feel a little pain the first touch but after a while my hand gets used of the heat!? is that an overheating problem?

it sometimes happens and sometimes it just doesn't for a while! I don't want to go back to sony and give it for service!? they'd only want more money! I'm even thinking of buying a new one!? please help me!

(It does this also when the device is cold)

I checked the wireing already, and everything seems fine! (I connected the Amplifier to a random MP3 player and had the same problem for a while, and all of a sudden .. it stoppen, and started working normally!)