I have a Kenwood x789 receiver, 705 component front speakers and a JLAudio 10w3v2 sub running off of a 70x4 amp. The A channel powers the front door speakers and the B channel powers the sub.
If I listen with the volume up pretty loud, after a few minutes, the sub and front door speakers either cut out some or all the way at times, then fades back in, until I turn the volume down.
Does this maybe sound like a bad amp or a wiring issue? I had the system installed by an audio store near me and they are determined to figure out the problem, but they haven't yet. The sub is in mono, the sensitivity is not maxxed out but it cuts out after a while. The rear door speakers are off of the head unit and when the sub and fronts kick out, the door speakers remain on. It sure sounds like an amp problem, like it's overheating(the chassis does get hot), but as I had someone else install the system, I am not very stereo installed inclined.
Does anyone have any suggestions that I can try or have the installer look for? BTW, this is installed in a 2005 GMC Sierra that had the factory Bose system.
Thank you!

 

i would hope that the installer has already thought of watching the power light on the amp whenever the speakers cut out. if it's going out, then the problem is obviously the amp or it's power wiring. otherwise, you should just double check your speaker wiring, because you may have shorted something out. stereo troubleshooting sucks ***, because rarely do people have the same complicated problems.

 

How is the JL sub wired? Is the sub a D4 or a D2?
D4 in parallel = 2 ohms (too low of an impedence)
D4 in series = 8 ohms (will work)
D2 in parallel = 1 ohm (way too low of an impedence)
D2 in series = 4 ohms (will work the best for your application)
If the impedence is too low, it can definitely cause the amplifier to get hot, shut down & go into protection. Your front stage would also shut off since that amplifier uses the same power supply on both the front and rear channels.

 

What AMP?

70wx4 is not a description.

 

It's a Kenwood 8452 amp. The sub is a D2 wired in series. It is testing at 3.8.
I'm taking it back on Saturday and either they will get it working right or they are going to take everything out, put it back to stock and I'll go elsewhere or read up on car audio and do it myself. It's really pissing me off now. Can't listen to my music the way I want to.

 

Have you checked the fuses in your engine bay and amp? Perhaps that is contributing to the problem.

 

I haven't checked the ones in the engine bay, but the fuse on the amp appears to be fine.
I'm just wondering if it might be a bad amp.