mooncalf777
Level 1 (8 points)
Desktops

Q: Does anyone have a workaround for the design flaw on 2005 PowerMac G5 which causes Sound Interference on outputs? (Audiophile, Sound Engineer)

Ok here's my problem - I have a Protools Digi 002 audio interface set up via Firewire 400 on a PowerMac G5 i was fortunate enough to be given last year. I've finally managed to hook up my home recording studio system, wire it in to the mixing desk etc, but when I listen to music coming back from the outputs of the Digi 002 there is a terrific cacophony of audio interference, so much so, that when i crank up the system i can move my mouse pointer between the dual monitors and it plays a different frequency of buzz. Every time i open a window, app etc there is more electronic noise.

 

It took me a while to narrow it down, but after reading this excerpt from wikipedia, it appears this was a common fault in that particular model until Apple released the revised B version of the G5(?);

 

'Early versions of dual processor G5 computers have noise problems. The first one is ground loop-based interference,[5] which sometimes causes noise leaks into the analog audio outputs. This bug was fixed in Rev. B G5.'

and

'Although the noise problems did not prevent the affected computers from working, they were problematic for audio professional and enthusiasts alike, especially for the liquid-cooled models, which had been expressly designed as mechanically quiet for discerning listeners.'

 

Well, that's no understatement - in fact it renders the mac completely useless for my requirements, as i need the outputs clean of digital noise for sending to outboard effects/EQ/etc

 

As this was a common fault, I was hoping someone might be able to shed some light on a work-around, as I can't imagine recording studios just ground to a halt until this was fixed by releasing a newer G5?

 

The only idea I have come up with so far is to purchase an Isolation Transformer, but i'm not entirely convinced that will solve the issue?

 

Any help on this matter would be greatly appreciated!

 

Thanks in advance

PowerMac, Mac OS X (10.5.8), Model no: A1047 (EMC 2061)

Posted on Aug 6, 2016 12:41 PM

by BDAqua,Solvedanswer
BDAqua BDAqua
Level 10 (123,462 points)
A:

Processor would be under Hardware in the Pref Pane if installed.

 

I don't think the command wou;d work without it installed, not sure.

 

Hmmm, I wonder if it was in Developer tools instead?

 

Might contact me on my site if you can't find it...

 

x704..net/bbs

Posted on Aug 11, 2016 1:58 PM

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Q: Does anyone have a workaround for the design flaw on 2005 PowerMac G5 which causes Sound Interference on outputs? (Audiophile, Sou ... more

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  • by BDAqua,Helpful

    BDAqua BDAqua Aug 7, 2016 8:56 AM in response to mooncalf777
    Level 10 (123,462 points)
    Aug 7, 2016 8:56 AM in response to mooncalf777

    Have you tried CHUD Tools & disabling NAP mode?

    Early versions of dual processor G5 computers have noise problems. The first one is ground loop-based interference,[5] which sometimes causes noise leaks into the analog audio outputs. This bug was fixed in Rev. B G5.

    The second noise problem came from the 'chirping' sound, which can be triggered by fluctuations in power draw. For example, showing and hiding the Dock makes a brief chirp. Many had blamed the power supply used in the G5 as the cause, but this theory has never been confirmed. A very effective work-around is to disable the CPUs' "nap" feature using Apple's CHUD Tools, but this was not recommended by Apple. This noise problem was not fixed until the dual core generation of G5s was produced, however it did not affect the "Late 2004" model (at least there have never been any reports). The power draw fluctuation was later attributed to the lack of power management features in the single-core processors.[6] Apple eventually posted the chirping bug information on its support site.[7]

    Although the noise problems did not prevent the affected computers from working, they were problematic for audio professional and enthusiasts alike, especially for the liquid-cooled models, which had been expressly designed as mechanically quiet for discerning listeners.

    https://en.wikipedia.org/wiki/Power_Mac_G5

    Just one last note on using the CHUD tools to disable the "Nap" feature on the Dual G5: restarting your machine re-enables "Nap." You may have already seen this on Apple's forums. Kind of a bummer - although, I rarely turn my machine off. In any case, running with "Nap" turned off today seems to have resulted in a noticeable increase in general speed/responsiveness for me (I'm still running the stock 512MB RAM, with another 1GB on the way).

    Matthew S. "

    http://www.xlr8yourmac.com/G5/G5_noise_tips.html

  • by mooncalf777,

    mooncalf777 mooncalf777 Aug 7, 2016 8:36 AM in response to BDAqua
    Level 1 (8 points)
    Desktops
    Aug 7, 2016 8:36 AM in response to BDAqua

    Hi and thank you for your reply!

     

    I've downloaded CHUD and tried to figure out which of the programs I need to use to disable NAP mode. Is it Saturn, Shark, Big Top, SpindownHD etc etc, as CHUD seems to be a combination of various different applications.

     

    I've uploaded a video of the issue here https://www.youtube.com/watch?v=yijBYqOQNdI

     

    this might help make sure i'm asking all the right questions and describing the issues correctly?

  • by BDAqua,

    BDAqua BDAqua Aug 7, 2016 9:51 AM in response to mooncalf777
    Level 10 (123,462 points)
    Aug 7, 2016 9:51 AM in response to mooncalf777

    In the Processor Pref Pane if you installed Chid Tools I believe...

     

    http://blogs.oreilly.com/digitalmedia/2007/07/quiet-your-noisy-g5-mac-audio.html

     

    You can also use a script...

     

    http://hints.macworld.com/article.php?story=20051110105729848

  • by mooncalf777,

    mooncalf777 mooncalf777 Aug 7, 2016 1:00 PM in response to mooncalf777
    Level 1 (8 points)
    Desktops
    Aug 7, 2016 1:00 PM in response to mooncalf777

    @BDAqua hi again, yeah i'm really not quite understanding this - i don't have experience as an application programmer, so these tools, while i'm sure they're really useful in the right hands, aren't really helping very much! :/

     

    I've looked in the System Prefs pane but there is no new item listed as 'Processor', so i'm not sure what that part means..

     

    I tried entering the 'hwprefs -v.....' line in the BIOS during startup and was met with

    'WARNING: Could not determine processor information

    WARNING: Could not determine memory controller information

    WARNING: Could not determine operating system information

    ERROR: nap not supported by this processor type'

     

    I'm assuming this was because i entered the command prompt before this information had booted up,in other words perhaps it was too early in the command list? I dunno..I just want to get this **** thing working properly! argh

  • by mooncalf777,

    mooncalf777 mooncalf777 Aug 7, 2016 1:02 PM in response to BDAqua
    Level 1 (8 points)
    Desktops
    Aug 7, 2016 1:02 PM in response to BDAqua

    hi again, yeah i'm really not quite understanding this - i don't have experience as an application programmer, so these tools, while i'm sure they're really useful in the right hands, aren't really helping very much! :/

     

    I've looked in the System Prefs pane but there is no new item listed as 'Processor', so i'm not sure what that part means..

     

    I tried entering the 'hwprefs -v.....' line in the BIOS during startup and was met with

    'WARNING: Could not determine processor information

    WARNING: Could not determine memory controller information

    WARNING: Could not determine operating system information

    ERROR: nap not supported by this processor type'

     

    I'm assuming this was because i entered the command prompt before this information had booted up,in other words perhaps it was too early in the command list? I dunno..I just want to get this **** thing working properly! argh

  • by BDAqua,Solvedanswer

    BDAqua BDAqua Aug 11, 2016 1:58 PM in response to mooncalf777
    Level 10 (123,462 points)
    Aug 11, 2016 1:58 PM in response to mooncalf777

    Processor would be under Hardware in the Pref Pane if installed.

     

    I don't think the command wou;d work without it installed, not sure.

     

    Hmmm, I wonder if it was in Developer tools instead?

     

    Might contact me on my site if you can't find it...

     

    x704..net/bbs

  • by mooncalf777,

    mooncalf777 mooncalf777 Aug 11, 2016 2:03 PM in response to BDAqua
    Level 1 (8 points)
    Desktops
    Aug 11, 2016 2:03 PM in response to BDAqua

    aha!!! found it! thank you!

     

    yes it was in Developer/Extras/PreferencePanes/ there's a file in there calledProcessor.prefPane

    click on that to install 'Processor' into the System Preferences folder and hey presto  - there it is under hardware!

     

    Click on that and you get the window with 'Allow Nap' on it.

     

    Phew!

  • by BDAqua,

    BDAqua BDAqua Aug 11, 2016 7:09 PM in response to mooncalf777
    Level 10 (123,462 points)
    Aug 11, 2016 7:09 PM in response to mooncalf777

    Great news, tjanks!

     

    Oh, dod it solve the noise problem?