Pop sound coming from speakers

Hey All. I am having trouble with my new install. I am picking up a pop sound from my speakers when I step on the brake and the brake light comes on. My amps chassis' are not touching any metal as they are mounted to MDF amp rack. The grounds are good. Tested different rcas with no luck. Speaker wire is twisted type. Tried connecting additional ground to a different part of chassis(currently the 0ga and 8 ga grounds for both amps are bolted to the same "bare-metal" spot if that might be a problem) Also tried pulling out head unit to see if interference is coming from something near there, but nothing changed.

Any ideas? Maybe I need to wrap my signal or some wires with that noise deflecting foil?

Thanks in advance for any help.

A. 

I am also using the same wire to power my remote turn on. Soldered a second piece into first wire to make a Y. I have always heard that you can do 2 amps off 1 wire but 3 may be pushing the need for a relay.

Thanks again for any advice,

A.

That sounds like a ground loop problem.  Unplug the RCA's.  With the system on, if you step on the brakes, is the pop still there?  If so, the noise is entering your amp (probably through the ground).  If not, the noise is probably entering the deck's ground.

You said the grounds are good.  Did you reference them all back to the negative battery terminal?  What was the resistance reading?  Was your bare metal spot preexisting (i.e. a seat bolt)?  If so, drill a new hole and scrape clean the area.  Did you use the factory ground in the wiring harness?  You should ground the deck to the chassis, and also run a ground wire from the deck to the amps' ground (this is so they "see" the same ground to eliminate noise).  Also ensure the antenna has a proper ground. 

Using the same turn on for 2 amps is fine.

I am only getting the pop when ignition is on and  I hit the brake. I tried hooking up a portable cd-walkman as suggested by another member to see if the problem is coming from the head or amp. There is no pop with the walkman hooked up. So that means it's the head, right? I swapped the HU ground from factory to chassis with no luck. Tried different rcas and I unhooked rcas to see if noise was being picked up through speaker wires, but it's not.

The pop appeared when I added my 2nd amp for my high & mids. Before that I was running the speakers off the head. So does this sound like a Sony Crappy electronics problem related to now using the rcas and not the internal amp? Like heat building up causing interference?

I am replacing my head unit soon. I am just trying to decide which I want.

Best,

Angel