I have a stock unit connected to a Sony 4-channel amp (max 80wx4) powering a pair of splits and a 10" sub.
No problems since today!!!
Everything is fine at low volumes, but at moderate volumes, the amp suddenly switches off and the offset light changes from green to red. When i switch the head unit off and on again, its starts working, but when i turn the volume up again, same thing
I have absolutlely no idea about these stuff, can someone solve this problem for me

 

How did you set your gains? It's possible that the gains are too high and the amp is overheating. Does it happen when the amp is cold? Also, how did you wire the sub? Is the sub 4ohms? Can this amplifier be bridged so you can run one sub on one channel? As you can see, we need more details.

 

I don't know what r gains
the amp isn't overheating. it also happens when the amp is cold.
The amp can be bridged so 2 channels r bridged to power the sub and the other two for the splits
is this enough information?
as u can tell, i don't know much about this subject

 

Gains are the input sensitivity the amp sees. If they are set too high, it can cause distortion quickly. Set them too low, you might not have enough power to hear the speakers as loud as you want to. There's a lot more to it, but this is the basics. I would try to turn the gains (input) down a little and see if you can turn it up louder than before as a test.

 

Who installed the amp? Take it back if it was from a shop. If it's you, maybe the wire connections are loose. Check the connection to the battery, the amp, and the ground.

 

Are your power and ground leads sufficient guage (thickness)? Are the power and ground cables the same thickness? How is your ground's connection to the frame/body of the car (is it clean steel where it makes contact)?

I fixed an install where the person was using ~22 guage wire for power and ground for a 200 watt amplifier... plus the ground was horrible. The symptom: low volume all was fine... when the volume was increased, the amp required more current from the electrical system, and since it was "starved" due to inadequate cable/grounding, it would shut off...

...changing the power cable + moving the ground fixed everything...

Just an idea...

 

I'm with shaner...my first instinct for these symptoms would be to check for proper grounding and proper wire thickness.

 

I triple that.