[linux-audio-user] hum from laptop soundcard

[Frank Barknecht]

Hallo,
Paul Winkler hat gesagt: // Paul Winkler wrote:

> On Sat, Apr 19, 2003 at 12:33:25PM +0200, Frank Barknecht wrote:
> > One can also try to cut the earth of the laptop's powers supply if
> > one has a death wish... ;) I mean, don't do that. 
> 
> I have the same buzz problem on my laptop...
> i wouldn't physically cut the prong, but I have used one of those
> little 2-prong to 3-prong adapters - common in the US, you can find them
> in any hardware store here, i assume there's an equivalent elsewhere.
> You probably know the type - about 1 inch square, it's got a standard US 
> 3-prong outlet on one side and a 2-prong plug on the other, 
> with a little tab that you're meant to screw into the center screw of 
> the wall outlet.
> If you ensure that the tab doesn't contact anything grounded, 
> voila, ground is broken.
> 
> is this a safety hazard?  I'm not really sure.
> Be careful.

Actually I'm also not sure, if it must be a safety hazard. I read
about this solution and I also asked Acer, if they could provide a
2-prong plugged cable for their laptops. They wrote me, that in
Germany they are not allowed to supply such a cable for their laptops,
but I could try to find one somewhere else... 

I guess, that the case of a laptop is well isolated from its innards,
and also a lot of cases are plastic, so it seems.

But if it's not isolated, the user would be the ground connection
chosen, and that'll hurt. ;)

Then the epanorama docs say "Do not do this", because it's
"potentially very dangerous":
http://www.epanorama.net/documents/groundloop/problem_solving.html

They call the plug-solution a "cheater plug":
http://www.epanorama.net/documents/groundloop/cheater.gif

ciao
-- 
 Frank Barknecht                               _ ______footils.org__