Ok. Here’s an update that should hold some value to all G5 users with noise problems. You may see this post in several places. I'm posting it any where I see fit. My ordeal has lasted a little over 4 months. I’m very happy to report it’s over!

Here’s a little background information. I’m on my third Dual G5 2Ghz. The first two were replaced at my request due to the well-documented noises coming from the machine itself, noises in the audio chain and fan noise. All three machines produced almost identical results as far as the noise(s). So after getting the third machine back to my studio, powering it on and hearing the same damned noises, I decided I’m in it for the long haul and I’ll wait for Apple to fix it. So I used Ground Isolators, Line Levelers and CHUD Tools. These just proved to be a work around. Basically, I was just dealing with it, hated it, but I was still determined to wait it out.

Now, since getting news of the “official Apple fix” (the latest power supply) as well as the information on ground loops, I decided to have this latest power supply installed. I’m VERY HAPPY to report that it has corrected the problems. I wanted to let everyone know because I’ve been in these forums since the very beginning of this issue and followed all of your progress as well as Apple’s progress. It’s been extremely frustrating at best.

I think my particular situation/configuration qualifies very well to report on, because of my varying hardware / software, and since I went through three G5s.

Here is a basic list of the hardware and software most used on my system. All of the Audio Outputs have been tested since the power supply change. I have NO unwanted noise on any of them. The ambient “chirp” still comes from the power supply itself but is just barely noticeable and only when I set “energy savings” for CPU to “highest”. If left in “automatic” you don’t even hear the chirp. I stress that to hear the chirp you need to kneel down and put your head next to the machine. But again, as far as the audio outputs there is NO NOISE. I turned all volume levels to maximum, opened Reason 2.5 (which used to cause the most noise created by graphical navigation) started moving scroll bars and dragging windows etc… Still no noise. So to sum this up I’ve tested the following with no ground loop isolators or line levelers and NO CHUD TOOLS.

Apple onboard sound (analog out), PCI soundcard and an external USB audio device. None of these had any of the noises that I / We are so familiar with. Thank you!

Sorry I don’t have a firewire audio device to test with.

HW

Mac Dual G5 2.0 Ghz w/1 gig of ram
Apple 17” Studio Flat Panel
Digidesign M-Box (usb)
M-Audio Audiophile 2496 (pci-x new version for G5 voltage)
G5 on-board audio
Beringer audio mixer
Harmon Kardon / Apple “Sticks & Subwoofer”
Event Tuned Reference 8 Studio Monitors

SW

Digidesign Protools LE 6.2.2
Logic Audio
Cubase SL 2.0
Apple Soundtrack
Apple Garage Band
Reason 2.5
Live 1.5
Spark LE
Peak LE 3.2

Sorry for such a long post but I think the information is valuable. It proves that this G5 noise problem can be corrected. To be honest, I feel like I finally have the computer I was so excited about purchasing 4 months ago. However, I won’t soon forget the frustration, inconvenience, time and money spent on this issue. I hope this fix will last forever.

Salvie

Depite Apple's "solution" the problem is not always fixed.

Read more >>
http://www.arstechnica.com/wankerdesk/0 ... noise.html

I'd just like to add that I am now sending back my dual 2.5 G5, the fifth replacement this year, because of the chirping issues which are as present today as they were on my first G5 back in December 2003.

I knew there wasn't going to be a easy resolution to the problem because it's a design flaw.

All Apple can do at the moment is trial and error new power-supply units until one is found that minimizes the effects.

I'm sure with the next manufacturing batch this issue will be resolved, unfortunately this takes a lot of time to produce a new part. My logic places it with the next revision of the PowerMac G5, the Dual core 970MP's, it would be solved then and perhaps Apple will provide a replacement.

For those who got stuck with one and can't live with the noise, especially in the audio channels, then of course determined trial and error methods have to be employed. For this is best done in person if possible, shipping back and forth isn't really a good option as damage occurs in shipment.

For those who have the noise, it's audible and not in the audio channels, keeping one's CPU's busy seems to help.

Running Folding@home works very well for me.

I only hear the slight chirp when I power down to play a game at first launch.

Other than that, my PowerMac G5 is a hell of a beautiful machine and I'm very happy.

This is news to me...
Have been running Blackmagic Designs Decklink Extreme on Dual G5 and this system has been performing excellently for two years now.
FYI built a dual Xeon machine 2.6Ghz XP Pro 2 Gig of memory and tried out the Decklink card it was PATHETIC to use, and simply could not capture SDI from a Sony DigiBeta machine/crashed and froze ALL the time!!!
The 720 x 576 Pal DV pictures rendered out in MPEG4 look simply stunning on the G5.
Am also running Digidesign HD x 3 units and HD Sync on latest machine fantastic. Simply put I would put up with 'chirping noise' because the PC 'equivalent' simply CANNOT keep up with the power and performance of the G5.
Cheers,
Russ

i too have a noise problem and i do use firewire. the noise is the chirping sound that gets louder when using the mouse. noticed it right away and have done everything ground-wise that i can think of. it appears that it may be worth it to email apple and get a new power supply.
thanks,

HW
G5, 2gb,
1.5gb ram
160gb hard drive
Mackie Universal controller
digidesign 002 rack

SW
osx 10.3.4
protools 6.4
soundtrack 1.2
reason 2.5

This was the solution that worked for me. What a relief.