[LAU] My Tascam US-122

Martin Horn martin.horn at ostec.org
Wed Aug 13 15:31:07 EDT 2008

I am an electrical engineer myself and here are the facts again:

If the device has no metal parts which are able to carry a voltage there is
no use for a ground earth, although a lot of notebook power supllies have
one (The reason is that they have standardized connectors and there are
standardized cables for these which are just cheaper because they are used
for a lot of other devices as well which might need a ground earth).

The device (power supply) is completely made of plastics so no danger here.
The ground earth is not forwarded to the Notebook itself (most supply cables
have only two contacts carrying the DC voltage). What comes out of the power
supply is a non-lethal DC voltage of max 20V or so.

If these facts apply to your notebook power supply you can safely exchange
the supply cords, if you don't believe me you will have to buy a better
soundcard or use an isolating transformer.


On Wed, Aug 13, 2008 at 9:03 PM, Arnold Krille <arnold at arnoldarts.de> wrote:

> Am Mittwoch, 13. August 2008 schrieb Martin Horn:
> > On Wed, Aug 13, 2008 at 3:18 AM, Shawn Wallis <miesco251 at gmail.com>
> wrote:
> > > When I unplug my AC for my laptop, the noise stops...  WHen add
> > > brightness to my laptop screen I get less noise...
> > I suppose your laptop has an earth connection on the power cord. Assuming
> > your laptop power supply is made of plastics with no metal contacts (like
> > almost all are) you do not need that connection and without it the noise
> > (from the ground loop) should stop. Just put some kind of isolating tape
> > over the metal contacts from the earth ground (maybe two layers, because
> it
> > might get cut when plugging in) and your ready to go. If you don't want
> to
> > carry that tape with you all the time you should try to exchange your
> power
> > cord (those from electric shavers looking like an "8" work sometimes).
> And here came the advice of the stuff you shouldn't do.
> Yes, it might fix your problem. BUT WHEN ENGINEERS ADD A SEPARATE EARTH IT
> Excuse the screaming, but following that advice is actually playing with
> your
> life... only do that if you have a death wish.
> Arnold
> --
> visit http://www.arnoldarts.de/
> ---
> Hi, I am a .signature virus. Please copy me into your ~/.signature and send
> me
> to all your contacts.
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> administrator to do so...
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