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noise when powerbook is plugged in


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  • noise when powerbook is plugged in

    I am really a fan of stereo micing from a distance, but I haven't done it too much for a while now because my powerbook makes a very high pitched squeal when it is plugged in. I can get some recording done by unplugging it, but this is really a drag. Is there any way to queit things down? Maybe I could put it in a case and use a cordless mouse? mmmm

  • #2
    The problem only happens when my Presonus Firepod is plugged in, so I thought it might be the firewire port... so I bought a little pcmia cardbus to firewire adapter to see if that would silence the squeel. No luck! I'm going to return it and see if a high quality cable helps and if not I'll just build an enclosure... and take it to the hilt with shag carpet!

    I went to the apple store and they really thought it was the interface itself. They thought maybe it wasn't grounded right, but I notice that the laptop squeels for a few seconds after I unplug the interface, so I think they might be wrong.

    Sorry to vent! Let me know if you have input on this problem with the firewire making an audible squeel. This is really a big problem for me and any help would be very appreciated!


    • #3
      found this article on acoustic noise in apples supprt pages.

      Changing the processor settings to "reduced" under the energy settings in system preferences seems to help my noise. I'm not just being picky either, this sucker is pretty loud! It's a little like the noise samples on their page but much more constant and high.


      • #4
        YEp, this is what I guessed. Basically, when you are ru8nning off the battery you are running in reduced power mode. WHen you are plugged in that is not the case. Which will make the PB run hotter. Which would likely kick in a fan. I am pretty sure they have at least one if not two fans in them.


        • #5
          Could it be a fan? It's a very very high pitched buzz that sounds more electrical. The reduced processor setting really limits me track and plugin wise. Asking around (presonus, apple people too) it seems that there was a bad batch of G4 powerbooks that have power management issues and audible noise. My last powerbook was replaced due to a bad power management unit as well! Should I shell out the $300 to get it worked on and possibly fix the problem, or should I sell the powerbook to a college student who wouldn't care about the buzz? mmmmm thing is it could be a Firepod issue for all I know. It's sure hard to pinpoint troubles.

          too much thinking out loud! I know this issue might not be relevant to many people, but it's cost me a lot of heartache and if my trials can help anyone else in the future who searches these board, well... that's what it's all about!


          • #6
            You have a ground loop hum. Try lifting the ground on the powerbook power supply or on the other equipment connected to your mixer. I wrapped scotch tape around the ground lug on my laptop to solve this problem. Other people will tell you that it's dangerous to lift the ground. I agree, especially if you're standing in a puddle of water.

            This problem is so irritating. After you've spent thousands on gear, you find out that it doesn't perform if plugged in. I had a Fantom-X and Motif ES with this problem. Because of it, I couldn't use the USB MIDI and had to revert to standard MIDI connections that are optically isolated. Makes Yamaha's MLAN ads look like a joke. The cable clutter is still there.


            • #7
              Thanks for giving me a lead! I reset the PRAM and the PMU today but had no luck. I also should mention, that nearly EVERYTHING I have plugged into this computer since using the FIREPOD has absolutly fried. I always have considered myself to have a bit of bad luck with things not working... but it seems that anything Tube based that is plugged into this setup develops bad problems (2 mics, 2 preamps have gotten weird crackles) tubes need replacement at least once a month... also, my Layla 24 died on this laptop, and I have been mildly shocked through the Firepod. Is my problem with the electric grounding on the firepod, or with a busted PMU on the laptop? The grounding of my house? My powerstrip says it's gournded!

              I know I am asking way too many questions and wearing thin here. Are there any professional options for trouble shooting a bum setup? I am just going to start to sell things piece by piece and start over again until things start working unless I can get some serious help. I know COMP USA does apple service for a flatrate... could they troubleshoot at all?