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  1. #1


    Member Since
    Aug 21, 2008
    Location
    Maryland
    Posts
    233
    Specs:
    2.66Ghz Penryn C2D iMac
    USB device Won't work verunless it's plugged into the first USB port
    Has anyone had problems getting USB devices to work unless it's plugged into the very first USB port on the back of the iMac 20" 2008 edition? I had purchased a new plug in for my Line 6 recording interface that allowed you to use POD Farm as an AU plug-in, in other words you could record the guitar/bass/vocals raw and manipulate the sound afterwards, where as before you had to choose a tone BEFORE you pressed record and you were stuck with it. For some reason, every time I tried to select it as an audio unit plug-in, it would tell me I had no Line 6 gear or iLok plugged in. After spending $50 on this, I called line 6's support line.

    The tech there told me that Apple's USB bus structure was a little funky and they're (Line 6's) products always needed to be on the first USB port or it was no dice for AU plug-ins, same if you had the iLok (a dongle for using the software without the hardware). He told me that Apple's other USB ports were partially crippled. This is all news to me, but low and behold his suggestion fixed my issue. He explained the laptops are the same way, he said Mac Pros have no issues though. Why would Apple intentionally do this to the iMac/Macbook/MBP USB bus? Has anyone else had this issue?

  2. #2

    hughvane's Avatar
    Member Since
    May 18, 2008
    Location
    Banks Peninsula, New Zealand
    Posts
    3,296
    Specs:
    MacMini 2.4, 8 Gb, OS 10.10 and 10.6; MacBook 2.4, 4 Gb, OS 10.6.8
    Mac USB power is not the best, generally regardless of model, but especially so with laptops, and I think the simplest solution will be to use a powered external USB2 hub. That should allow you to use any port on your iMac with any USB device. Some hubs have a port or two with 1000mA each. What is the power demand of your external device?

    Re Port 1 power, it may be that the bus sends a higher voltage to that port, but that's only my guess.

  3. #3


    Member Since
    Aug 21, 2008
    Location
    Maryland
    Posts
    233
    Specs:
    2.66Ghz Penryn C2D iMac
    For security reasons, Line 6 hardware only works when directly attached to the bus. So thats a no go on using a hub, I couldn't get it to work at all when I had it hooked to my USB/Firewire Combo hub. The midi keyboard and preamps work just fine when I have it hooked to the other USB ports on the back of the iMac, but using it's software as an AU plug-in in Garageband/Logic is broken due to Apple's USB bus limitations not allowing software to see the keyboard serial number. It's definitely an Apple issue, I can use this interface on my Lenovo T400 laptop no problemo, any USB port will work. I might bootcamp my iMac again as an experiment to see if this problem persists in Windows XP.

    It's funny, the support tech I talked to there had a MBP and had the same issues, he said they have tried recoding the firmware in they're devices 10 ways to Sunday and still can't get to work on other USB ports. I have read users of M-Audio USB interfaces can have the issues as well. I am glad I also have a MOTU 828 thats FW400 and also self powered, that bad boy sounds way better anyways!

  4. #4

    hughvane's Avatar
    Member Since
    May 18, 2008
    Location
    Banks Peninsula, New Zealand
    Posts
    3,296
    Specs:
    MacMini 2.4, 8 Gb, OS 10.10 and 10.6; MacBook 2.4, 4 Gb, OS 10.6.8
    I remember reading in other forums about using a USB 'splitter' (my terminology) in order to harness the power from two USB hubs for an external device that has high demand.

    I'm puzzled, in fact intrigued, to read that the use of a powered hub prevents use of your external device. To the best of my knowledge, using a hub doesn't significantly change anything in terms of interconnectivity. We learn something new every day .

    Yes, USB power on Macs is an old and recurrent issue, which is why some people stay with a Windows machine in addition to their Macs. I don't think the use of Win XP via Bootcamp will change the USB power issue, as it's hardware - not software - related.

    I'm going to suggest that you post your USB power issue on The macosxhints Forums - For discussing everything OS X... where there are some seriously knowledgeable people who may be able better to explain WHY the USB port 1 works where others don't, and to suggest a fix or a workaround.

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