car, ps2 electrical noise problem.

I'll try to make this as clear as possible. I have run into an electrical noise in my car. I have a 1/2 DIN Pyle Screen. Hooked up to it is the video input for the playstation - nothing else (aside from power etc). The playstation is powered from a 12V converter (12VDC to 8.5VDC for the PS2 slim) which has been mounted behind the dash, +12VDC from a cig lighter. The audio goes (for now - getting a JL cleansweep soon) to a usa-spec adapter (aux input, along with ipod input). EVERYTHING is grounded to the radio at the same spot. (usa-spec, playstation, screen, cig lighters, etc etc). When the ipod is on (through the usa-spec unit) everything is fine. Power on the 1/2 DIN screen. still good. Turn the usa-spec input unit to AUX input (from ps2) - still good. The problem comes when I plug in the ps2 (power). Slight noise with it off (high pitched) - gets worse when ps2 is turned on, and even worse when it is accessing my external 2.5" WD passport drive. NOTE: So far, this is all with the engine OFF - so not an alternator whine with increasing RPM, just a CONSTANT WHINE. The noise STOPS when the AV connector for the PS2 is disconnected (thus no RCA cables attached to the usa-spec input, so nothing to the radio). The power STOPS when the power cord is removed. I tried: 1. Leave the PS2 hooked up to the car (A/V) but plugging it into a 120V wall plug. NOISE GOES AWAY 2. Leave the ps2 hooked up to the car (A/V) and plugging the 12V converter that I am using into a 12V outlet (from another source other than the car. THE NOISE GOES AWAY. With this, I have determined that the noise is not a PROBLEM with the 12V converter (NOT INVERTER!), but somehow how it is wired up (to the cig lighter). [as the 12V converter works fine with no noise when the power is coming from another source other than the car that the ps2 is hooked up to] Can ANYONE help me figure out how to solve this? I have also tried putting a ferrite bead on the +12V of the power to the 12V converter, on the ground, as well as the cable going directly to the ps2, and nothing helped.

NOTE: I just tried powering both the screen and the ps2 directly from the battery. STILL NOISE. So it looks like it is the power supply that is doing this. Any suggestions on a good 12V power supply for a ps2, or anything I can do to the current setup to eliminate the noise?

Go to your local stereo shop and tell them that you need to see if a ground loop isolator will fix your problem.  They should let you bring one outside and try it to see if it will fix your problem.  They sell for 20 bucks or so. 

Just ordered a couple from just about the only good audio/electronics shop left in this city. I have tried an RCA type ground loop isolator to no avail. The part that I am waiting for is a DC line noise filter (wire in AFTER? the 12V converter?) and see if that does the trick Should it be before the 12V converter or after? Guessing after as that is the part causing the noise. unless it is on the ground line that is causing the problem, which in that case it would be BEFORE the converter