I suspect bad ground in the rear of my car. Can someone confirm some facts?

I usually have one 12" sub, but I am in the middle of upgrading, and only sending my sub 450 watts at 4 ohms. The other day I put in a box with two subs sending 2 ohm load with 750 watts, and pushed my system hard for half an hour or so, and when I came home, I noticed my sub amp was extremely hot. After 30 mins or, I tried turning on the system, but only front stage amp turned on. I figured my sub amp was blown. It did not smell or anything.

I then quickly put in another amp, and heard some bass, so I secured the new amp in place. After turning the system on again, all I heard was loud tone sound coming from the subs. Sounded like a loud test tone, so I unplugged the subs quickly. Then this new amp started to smoke.

Just a little while ago, I checked my ground in the trunk, and noticed the surface paint was not scraped off. My front stage amp has no problems. Both amps are grounded with one ground cable.

Surely bad ground, but is it causing my sub amps to act this way? Everything else appears good.

 

A solid ground is critical to amplifier performance and yes I have witnessed amplifiers display odd behaviour such as yours when there is a poor ground.

 

Thanks for your reply. I went to a car audio shop today. They ran some tests on subs, amps, etc. They did repair my ground, as it was bad, but they said they did not believe bad ground caused it. They figured my first amp was pushed too hard, and stopped working. It does not smell burmed though, but I should have warranty. Pain in the bum. The second amp may have been faulty or about to die, so the staff blamed it on coincidence. They assured me, that all looks good, and I should not be afraid to hook up another amp. That's a load off, but will see. I am out of sub amps right now.