Laptop power supply - ground loop/dirty power..

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beatnick
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Laptop power supply - ground loop/dirty power..

Post by beatnick » Tue Oct 04, 2005 7:29 pm

Hi,

I'm hoping someone can help me out.

I have a HP laptop/M-Audio FW410 and when I have the laptop power supply plugged in I get this really dirty noise coming through, when I unplug the power it's 100% gone.

I have heard of people taking out the ground pin of their power supply's but i'm a little hesitant to do this.. it just seems dodgy. :?

Has anyone had a similar problem? Or possibly taken out there ground pin?

Any help/comments greatly appreciated.

Cheers,

Nick. :D

Tarekith
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Post by Tarekith » Tue Oct 04, 2005 9:40 pm

Most of my friends use ground lifts, as do I.

Machinate
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Post by Machinate » Tue Oct 04, 2005 10:30 pm

My ibm psu has a non-grounded connector - say no more...
mbp 2.66, osx 10.6.8, 8GB ram.

beatnick
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Post by beatnick » Tue Oct 04, 2005 10:43 pm

Tarekith wrote:Most of my friends use ground lifts, as do I.
Cheers Tarekith, yes I have tried DI's with ground lifts but it's still there. :(

beatnick
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Post by beatnick » Tue Oct 04, 2005 10:44 pm

Machinate wrote:My ibm psu has a non-grounded connector - say no more...
Cheers.

beatnick
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Post by beatnick » Mon Oct 10, 2005 3:44 am

Anyone??

inis
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Post by inis » Mon Oct 10, 2005 5:37 am

You want a ground loop isolator i believe. There was a post not too long ago about them, so just search and you should run across it pretty quickly. I believe the one that was most recommended (by someone who had tried many expensive ones on the market) was a cheap one that radio shack sells. Anyay, that should solve your problems, and you wont have any fears about fucking up your power adaptor.

lordpink
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I had that problem

Post by lordpink » Tue Oct 11, 2005 3:36 am

I had the same problem with a Dell laptop. Ebtech had two solutions that break ground loops that I've used. They have a HE2PKG, which I own 3 of for different setups. They go between the offending laptops audio connectors and the rest of your setup in the signal path to break the ground loop.

Then they came out with the HUMX which the power supply plugs into to somehow break the ground loop there. That was cool because now its not in the signal path. So now I use that on my recording setup instead of the HE2PKG's. But this is made for USA-style mains, so I don't know what the plugs look like in New Z.

SongCarver
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Post by SongCarver » Tue Oct 11, 2005 4:06 am

does this work on laptops that have only two prongs on the plug (rather than the usual 3)?

combo of my powerbook and guitar makes a hum(subtle... but comes up when using distortions) when using a USB interface, but if i touch the powerbook the hum stops. The problem is that the hum is there even when running off battery.

when using my MOTU 828 there is no hum (but it's a 3 pronged plug)

any idea?

lordpink
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Post by lordpink » Tue Oct 11, 2005 1:41 pm

My laptop has a 3 prong cord, so I don't know for sure. The HUMX probably won't work for 2 prong cord.

The HE2PKG probably would work, since it breaks the ground loop by having a transformer so the laptop is on one side of the transformer and the outside world is on the other side. The two sides of the transformer are electrically isolated.

elektrovert
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Post by elektrovert » Tue Oct 11, 2005 2:48 pm

The isolator that was talked about in the previous thread (from Radio Shack but also availible in Maplins) was inserted into the chain at the output of the soundcard before the mixer.
Aparently it works great, it's primarily designed for use with car stereos but works really well with pc's.

search for it.
it only costs £8.00!! 8)

lerky
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Post by lerky » Wed Oct 12, 2005 6:18 pm

get an extension lead, take out the ground pin, insulate with electrical tape.
Plug in your power supply to the extension lead.
problem solved/

a lot of worry about this is unfounded.

I checked with electrician/technician

had mine like that for about a year now

nebulae
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Post by nebulae » Thu Oct 13, 2005 6:33 pm

What you guys need is the Ebtech Hum X. I've used it for over an year and wouldn't even consider recording or playing live without it. It kills the hum at the source, from the power, and doesn't dick with your audio. Granted, it's $50, but it's the safest thing to do with your investment. The $2 ground lift is cheap, but I'd be seriously worred about something zapping either me or my lappie in a DJ booth with tons of power running around.

I can't praise this little device highly enough...

http://www.audiomidi.com/Hum-X-Ground-H ... P4803.aspx

ethios4
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Post by ethios4 » Wed Jun 14, 2006 5:21 pm

Does anyone know of a power conditioner that also eliminates ground loops?

Do all power conditioners eliminate ground loops?

Michael-SW
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Post by Michael-SW » Wed Jun 14, 2006 6:25 pm

lerky wrote:get an extension lead, take out the ground pin, insulate with electrical tape.
Plug in your power supply to the extension lead.
problem solved/
Amen. If you do it with a power strip instead, you will get multiple ground isolated connections for your whole set up.

I'm on the european system where the grounding prongs are metal strips on the side of the power plug. I just tape my power strip's ground prongs with duct tape. Works like a charm. Costs nothing.

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