[brianlanning]

I have an alpine head unit. It's one of the cheaper ones. It's maybe
3 months old. I have it hooked up to coax speakers in the back through
the amp in the head unit. The sub rcas go to an amp and two 10s in the
trunk. I have two more amps on order to drive the coax speakers. But
I have to tolerate my problem for another week while they get here.

I used to be able to crank the system just like this and get plenty
loud. Now, it's acting like the amp is overheating and shutting down.
With all four speakers going, I can play it at a reasonably loud, but
normal listening level for maybe 5 or 10 minutes. Then it starts to
cut out. Then it goes out completely leaving only the subs going. I
can turn it off for 5 or 10 minutes, then it works again. If I fade
the speakers all the way to the front, it lasts much longer, maybe 45
minutes. But it will eventually shut down.

This is new behavior, only within the last two or three weeks. I
haven't changed anything. It worked for a couple months without ever
shutting down no matter how loud I played it. I can feel the heat sink
in the back of the hu. Sometimes it's really hot when it shuts down.
Other times, just warm. There seems to be enough airflow back there.
The heater's not on so it's not blowing on the back of the hu.

So the question is, did I hurt it somehow? I would think it would just
fail completely if I did. I guess I don't care much because I won't be
using the inboard amp after this weekend. So what's happening?

brian