Amps cutting out

[SSGEN-3]

First I had two cheap 12" subs hooked up to 2 (bridged) 2 channel amps in my car and they were working fine but because they were only cheap there wasn't much bass.
I upgraded to a 12" cadence sub powered by a (bridged) 2 channel coustic amp and it was working fine, never missing a beat even when the volume was turned up.
I then upgraded to a cadence 15" sub which was powered by a (bridged) 2 channel response amp that I had in my old car, this was working fine for a while then I was driving to work with the volume down low and the amp started cutting in and out (I have a little bass remote for the amp in the car which has a little led on it and the led was turning off when the sub stopped working so I guess it was the amp not the sub that was stuffing up) then stopped working all together.
I was checking it out on my lunch break (a couple of hours later) and it was all working again, however on my way home it started stuffing up again so I thought the amp may have been overheating or something.
I put the 12" cadence sub and coustic amp back in the car until I got a bigger amp to power the 15" sub, however now this amp is doing the same thing, cutting in and out then dying. I turn the volume right down to around 3 or 5 for a while and the amp starts working again but as soon as I turn the volume up a bit it cuts out again.
Would the problem be with my head unit or wiring, or are both the amps just not powerful enough for the subs? I've checked all the fuses and everything seems to be fine... Why do they keep stuffing up?

[Cobez]

This may sounds dumb, but is it earthed properley? Did you check the big fuse from the battery and all the cable connections there?

When you earthed the amps, did you sand away the paint on the bit of the car body you earthed it on so it was bare metal??

[SSGEN-3]

I've been fiddling around with the amps and I think the problem is with my remote wire. I tested the power and ground wires and they seem to be fine, so it looks like I might have to pull my head unit out and check the remote wire.

[StoneX]

If it's turning back on at low volume, it shouldn't have anything to do with the remote wire, as the remote wire current draw is constant no matter what the volume is...

It would most likely be a power supply problem, so either not enough power is getting to the amp via the power wire or not going back properly via the ground wire.

[garfa]

what are the gains at mate, could be its going into protection mode.