Re: laptop causes noise when plugged in to AC - anyone else?

["Krispen Hartung" <info@krispenhartung.com>]

I take it back. It was an Audio Ground Loop Isolator. It completely killed 
the hum and noise. This one is just RCA, and probably meant to go between 
the laptop sountcard out and some other input device.  I am sure other 
companies make them, especially for pro use.  But, if unplugging the power 
supply of a lapop makes the hum go away, then an isolater will mos likely 
do 
the trick.

http://www.radioshack.com/pwr/product-reviews/Car/Accessories/Car-A-V-accessories/RadioShack/p/2062214-Ground-Loop-Isolator.html

Kris


----- Original Message ----- 
>> I had this problem and solved it by lifting the ground pin on the 
>laptop 
>> power supply... done easily with a, less than a dollar, 3->2 prong 
>> adapter from the hardware store..
>
> that's possibly what I'd do too ;-)
>
> ...but wherever you see that technique mentioned there's always text 
> saying "don't do it, it's not safe!".
>
> Standard  solutions (apart from using batteries)are
> 1) get a psu that's designed to run without earth connection
> 2) use isolating transformers on the audio (some affect on sound)
>
> Krispen's "RFI filter" also looks a good solution, if he'd tell us 
>whether 
> it's for the audio or the mains.
>
> andy
>
>
>>
>> -cpr
>>
>> Quoting Per Boysen <perboysen@gmail.com>:
>>
>>> This was up on the Ableton Live forum many years ago, since Ableton
>>> used to run very well on Windows in the pre Mac/Intel days. I've never
>>> had this problem myself, mostly having used Macs and probably had a
>>> bunch of luck with the one PC laptop I've had for audio. As I remember
>>> that thread most people seemed to load up there batteries before the
>>> gig and not use the power adapter. Everyone that had the issue
>>> reported that the problem disappeared on batteries. And this is the
>>> first time in a long time I've even heard about this problem, I
>>> actually thought it was history by now.
>>>
>>> Greetings from Sweden
>>>
>>> Per Boysen
>>> www.boysen.se
>>> www.perboysen.com
>>>
>>>
>>>
>>> On Sat, Feb 7, 2009 at 10:08 PM, J Johans <parispro00@hotmail.com> 
>>> wrote:
>>>> just curious if this is common or if im the lucky winner-
>>>> my dell vostro seems to dirty my power when i have it plugged in-
>>>> it causes my 2 fantom sound modules to emit some weird noises....its 
>>>> low
>>>> volume but stil annoying...sounds like there is a squirrel in my 
>>>> headphones-
>>>> when i unplug the power adapter for the cpu...the noises go away
>>>> just curious if anyone else has had this problem..?
>>>> only pc?..
>>>
>>>
>>
>>
>>
>
>