volume up and down

whats up yall? im new here and really need some help. just had 2 alpine amps,door speakers and 1 12"sub put in my 02 mercedes. it sounds great when its playing rite, but the sound keeps going up and down. its like the power goes from 100% to 30% instantly.  its like somebody is in my trunk playing with a toggle switch. i caint take no more. the local sound shops cant find a problem so i hope i can get some clues to whats going on.Let's get it!!

Maybe the power supply is not stable, check whether the GND is right connected to the chasis.keep doing, running, learning

Did they use a line-out converter for your install? Start there looking for loose wires. Also does your stock radio have an auto-volume feature? If so disable it and see if the problem persists. Do both amps cut out when the volume drops? Does this happen while driving, idling? Is it repeatable, or does it happen completely at random?

Is there a mute button on the factory radio?  If so, when you press the mute button, does it completely silence the sound or does it attenuate the sound?

Yes, they did use a converter but as far as I can tell all the wires are ok there. It happens completely at random when the volume is at about 50% or less. But when I turn it up loud it will stay playing longer but eventually it kicks out again. And yes bothamps kick out. Ill have to check the auto volume and mute.Let's get it!!

Yes, they did use a converter but as far as I can tell all the wires are ok there. It happens completely at random when the volume is at about 50% or less. But when I turn it up loud it will stay playing longer but eventually it kicks out again. And yes bothamps kick out. Ill have to check the auto volume and mute.Let's get it!!