Audio Guru
 

I have done some research and have not found anything. I have 2 Type R 6x9, Alpine component set, and a MRX-F65 4 channel amp. I used 4 gauge for the power and ground. I made a bracket for my amp and hung it upside down in between the 6X9's. Everything sounded great. I noticed when putting all my interior back together the crossovers for the component set the coils on the inside were broken from the computer board. I have had my speakers for awhile now. So I disconnected the front speakers from the amp until I get some new crossovers. The rear speakers still sounded great. Now when I turn volume up the sound shuts off. Noticed ground got loose at the chassis ground tighten it. still cutting out. But the blue light on amp is still on but no sound. And the amp is very hot. The gain is only about 1/4 of the way turned up. Could it be because of the front not hooked up and power is not being used or the amp upside down. It seemed since I put my back seats in this is when it happened. Do not know what it is.

I've seen problems with some amps being upside down as they aren't able to cool properly.
You can either install a fan to keep air moving across it or mount the amp right side up.

What's the time frame from starting the car and it cutting out? Instantly when turned up no matter what or takes a bit?

Id check all amp connections(+/-/rem/speakers) then speaker connections, possibly check speaker resistance on the two 6x9"s.