Noise through firewire audio device 27" iMac

Question

I am using ProTools 9 with the MBox Pro audio interface (8in - 8out).  I am experiencing an intolerable noise floor that I have narrowed down to coming from the firewire port itself off my new iMac i7 27' with 8G RAM with the 2G graphics. I have not even received my Apple Care package yet; that is how new we are talking!!
Note that I tested against my MacBook Pro which is impressively quiet (all references to "quiet & noise" have to do with the firewire output), and exhibits none of these symptoms: The iMac powers up/boots and a few clicks can be heard while it locks in with the MBox. There is an almost immediate faint high-pitched whine that can be heard, very faint unless you were to turn the volume up, but something like the sound you would hear on a video taken from an airplane. Once ProTools opens, or any program that has some meat on the bones, the whine boosts up even louder.  This time it is an unacceptable "not good for business" noise. If you scroll the dock, or move the arrow across the dock, it sounds like white noise you would hear as if thumbing through stations on an AM radio.... and truthfully, because it is coming from my now questionable investment, way worse than an AM radio. This "dirt" coming from my firewire port is so strong, even after turning the Mbox off, this noise is bleeding right on through to my mixer anyway - even the AM radio noise when scrolling!
If you let the computer sit at a modest volume, once the screen saver kicks in, every picture that comes up has it's own noise, sort of like you're hearing voltage spikes from a utility transformer... so I am wondering if this could be a bad graphics card since it seems closely related to what changes on the screen? Anyone who is having these sound issues, please share.  Last note: None of these conditions changed with relocation of my monitor speakers, new cords, screen resolution adjustment, or monitor brightness adjustments.

Answer 1

" So make no mistake, this is an issue that should be taken into consideration by Apple to address and initiate corrections in the electronics/power supply/materials or perhaps the internal design.
My follow-up post was an explanation of how I resolved the issue, but for the price, most who experience this will feel should have been resolved before their iMac was even assembled."
James230,
I have to say I do not agree with this comment.
Apple can not be made accountable for electrical systems that are not up to today's standards and codes and causing noise on your power line.
You state in your second post that the power in your area as no Earth ground and that the ground prong of your house's electrical system is grounded on conduit.
In the end grounding to conduit is the same as grounding to earth since the water intake for your house IS in the ground so all pipes connected to it are acting as a ground to earth.
The problem is that there is so much stuff connected to the water pipes, like a water heater, kitchen sink, washing machine, etc. that can create interferences, and make it a very noisy ground.
"like the battery back-up, the AC connected to it is simply charging the battery but the actual power running the laptop is through the battery.."
Not true.
The UPS solution you used is the right thing to do, but not because of the battery.
The battery in a UPS is NOT powering your equipment when you have normal electrical power on. It will only be used when the power goes out.
Same thing goes for your laptop, the battery will only be used when it is not getting power from a wall outlet.
The electricity is powering your power supply which is powering your laptop and charging your battery as needed.
Remove the battery from your laptop and it will still run from power from a wall outlet.
You are getting a cleaner ground because most decent UPS devices available today are equipped with power conditioning and noise filtering circuits that will eliminate most of the noise created by inadequate grounding.
Also note that using a ground lift like you first suggested is not only dangerous for your equipment but could also be seen as "abnormal conditions" that could be used as a reason by any equipment maker to void the warranty on their equipment if a electrical problem was found to be the cause of damages.
They could say: "Sorry, your equipment was not properly grounded, so we are not covering these repairs."