Re: (Offtopic) Humming on ibook2 audio port?

[William R Sowerbutts <will@sowerbutts.com>]

On Thu, Jan 10, 2002 at 03:19:18AM +0100, Siggi Langauf wrote:
>> On my iBook2 (600/DVD+CDRW) I can hear a low frequency humming on headphones
>> plugged into the audio jack. The hum is only there when the system is plugged
>> into the mains. I live in the UK and it sounds like it's around 50Hz, which
>> would match the frequency of our AC mains supply.
>> 
>> Does anyone else get this or is it just me with the dud headphones/ibook? ;)
>
>I don't get this, but I'm sure it's the usual problem: you have grounded
>your iBook with more than one wire, creating a "ground loop" into which
>power supply wires can induce some current.
>Typical candidates for the second wire are your ethernet or modem cable.
>Try to unplug them (and anything else that could be connected to ground
>level), and I'm quite sure the humming will go away, even if the power
>supply is connected.

Hmmmm. I don't think that's it -- the only cable connected to my machine is
the power cord (and the headphones). So there's only one path to ground.
Unless the wireless network counts? ;-)

I might complain to Apple. It's quite irritating.

_________________________________________________________________________
William R Sowerbutts                                  will@sowerbutts.com
Coder / Guru / Nrrrd                                http://sowerbutts.com
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