PA880 Overheating. Please help.

cmo_player

Hello, I have a PA880 connected to a Polk 12' DXI. First of all it sounds amazing. But after about 30-40 minutes of listening to music at a moderate volume (not ear blasting, but loud enough to where you would have to turn it down to hear someone talking), the bass will shut off and back on after maybe 10 seconds, stay on for a couple seconds, then back off again, and this is a repetitive cycle. When this happens the amp gets extremely hot. Like way to hot to touch. About 5 years ago my brother gave me his car which had this setup installed where it was mounted in the trunk. I recently got a new car and had this setup installed in it, re wired and everything. I had the same overheating issue then, and I still do in my current car. It's mounted in the trunk of my current car. Never had any popped fuses on the amp. And since I had this overheating issue in two vehicles, I don't believe it's a ground issue. I got a very reputable audio shop to install it in my vehicle that I have now, so I don't think it's a wiring issue.
What could be causing my amp to overheat like this? And is there some sort of fix?
Any help would be appreciated.

[Deleted User]

Hello,
In very general terms an amplifier will generate high amounts of heat when it is working to generate high amounts of current. There are two things that effect the level of current draw, one the requested playing volume and second is the load impedance. As the impedance becomes lower more current can be produced (makes sense since impedance is a measurement of the opposition to current, less opposition means more current). As the playing volume becomes higher the amount of work (power) needed increases. Transistors have a characteristic called "thermal runaway" which means as they get warmer they can generate more current and as they do that they get warmer.
So, either one of three things are happening in your case: 1). the playing volume exceeds the capability of the amp's protection circuit 2). the speaker load has changed somehow 3). the amp's protection circuit is defective and triggering too soon.
As a test try and reduce the playing volume slightly and see if it stops shutting off.