Amp Problems (Turning Off)

90% of the time the amp works but over the course of a week it "may" be getting worse. At first I would notice no bass at high volumes then I saw my subs were not working. Turning the head unit off then on would fix this. The other day I had my volume all the way down and heard a popping (this was when I first started the truck up) and that has only happened once. Today turning the head unit off then on did not immediately fix the issue. Amp is a JL Audio XD600/1 and a 4 gauge wiring kit.

Ive had the system installed since October 2013 with no issues. Tuned to manufacturer's specifications with a multimeter.

What is the suspected problem?

 

Sounds like the amp was originally going in to "protect mode". A state in which it doesn't operate in order to cool down. It's either a bad ground causing too much resistance in the amp, not enough ventilation, using more watts than the amp can produce for an extended period of time, etc
It sound like you've now blown a fuse...
Check fuses. Then find better ventilation or another place to put the amp...

 

I don't really know what's up with your amp, but if you are referring to the THUMP THUMP sound your sub made when you started your car is due to a power surge/spike and/or interference. That is why many people buy what is called a "Remote Turn On Relay/Delay" which will turn the amp on a couple seconds after the head unit powers up, so there is no surge. It depends how bad the popping was, but it is not a good thing.

 

Ill put my money on Grounding. Recheck all your ground connections, and depending were you grounded sand the connection location to have metal on metal. You set you amp with a DDM with no load on it most likely, as most alpine manuals suggest. Once you have a load on the amp the parameters are ever changing. You may have set your gain adequately but your grounding connection or your power connection " may " be the issue.
Check the resistance between your Battery - Terminal and the - Post on your amp. You should see under 55mohm

 

I would suspect low voltage or weak grounds. Cleaning your connections, including the battery, might be a simple fix.

 

Any update OP?