Well, I am just curious whether it is shutting down due to over-heating or distortion. I suppose Mike can always blow a fan on it and see if it shuts down at the same level as before. If it does, most likely there is a clipping circuit in there that causes the shutdown.

I'm also curious because I have a very low end Denon and I have not been able to get it to shut down with one hour of playing at max (7.1). Of course it doesn't sound good when it's maxed out. And no, I haven't blown my tweeters .