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Regebro
Joined: Sep 12, 2004 Posts: 61
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Posted: Sat Aug 12, 2017 4:08 am Post subject:
Fixing ground noise |
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I built a new computer, with a new nice power supply from a known company and everything.
Buuuuut, as soon as I turn it on, noise comes out of my speakers. This happens every time I have any form of ground connection between the computer and the rest of the setup. (I have a mixer, various equipment connected to that, and powered speakers connected to the mixer).
It's not ground hum (I get that if I connect anything to a set of power-plugs on the other side of the room, though, so I don't).
Why does this happen and what do I do?
Edit: I thought it was a ground connection via the power cable, but it was not, I had missed a USB cable. No, it happens when you connect some sort of chassi ground. |
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Regebro
Joined: Sep 12, 2004 Posts: 61
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Posted: Sat Aug 12, 2017 9:37 pm Post subject:
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Could lifting he ground of the PC work? |
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Regebro
Joined: Sep 12, 2004 Posts: 61
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Posted: Sun Aug 13, 2017 12:40 am Post subject:
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The answer was a "yes". Putting a ground-cheater plug in the computer made that noise go away.
I looked around for a plug that lifts the ground in a better way than just disconnecting it, but I can't find one. Hints are welcome. |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Sun Aug 13, 2017 4:37 am Post subject:
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Ah yes, USB sucks
There are USB isolators - such a thing would break the ground loop too. Something like : http://www.bb-elec.com/Products/USB-Connectivity/USB-Isolators/USB-Isolators.aspx
You can also get ground loops from MIDI stuff that is not up to specs btw (MIDI should be grounded on one side only, sometimes both sides are). _________________ Jan
also .. could someone please turn down the thermostat a bit.
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DES
Joined: Feb 28, 2003 Posts: 794 Location: New Jersey
Audio files: 8
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Posted: Tue Aug 15, 2017 6:39 pm Post subject:
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Tripp Lite used to sell an isolator/filter that you plugged into the wall then plugged your equipment into it.
Is the power supply a line-lump/transformer type or is it a desktop style in-the-case type? If the later I would be raising a lot of noise with the manufacturer...it should not be putting noise on the AC line or ground. Who was the power supply manufacturer? _________________ Dave
www.davesneed.com |
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Regebro
Joined: Sep 12, 2004 Posts: 61
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Posted: Tue Sep 05, 2017 1:56 am Post subject:
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It's a Thermaltake, shockingly. It's one I had lying around, more or less unused but out of warranty. Can't be bothered to change it, too much work.
Yikes, isolators are expensive!
I'll go with just lifting the ground. Cheap and works. |
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mode
Joined: Sep 30, 2017 Posts: 17 Location: SE England
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Posted: Sun Oct 01, 2017 3:51 pm Post subject:
Re: Fixing ground noise |
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Regebro wrote: |
Why does this happen and what do I do?
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Could be your LCD screen. Your post reminds me of why I stopped using mine with my laptop. |
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Regebro
Joined: Sep 12, 2004 Posts: 61
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Posted: Wed Oct 04, 2017 2:59 am Post subject:
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No, I get it even with the screen unplugged and disconnected. When I get time I'll try with another power supply. |
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mosc
Site Admin
Joined: Jan 31, 2003 Posts: 18197 Location: Durham, NC
Audio files: 212
G2 patch files: 60
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Posted: Wed Oct 04, 2017 10:09 am Post subject:
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Computers, especially laptops, are notorious. I use ground lifters on ALL the power connections in my studio. Actually, I break the ground connections on every power cord. Do this and you will never get any hum.
Except, some USB gear is poorly designed and when you hook it up you get nasty hum and noise. As Blue Hell said, a USB isolator will work wonders. It's not just cheap equipment that has bad USB circuits. I have an Allen & Heath mixer that requires and isolator. _________________ --Howard
my music and other stuff |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Wed Oct 04, 2017 10:55 am Post subject:
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Ah no, not only cheap USB stuff does it, actually it is behaviour "designed into" USB, the standard was not made for studio audio but for gadets rather ... being grounded on two sides it's just asking for trouble... firewire is (or was, rather) better, ethernet is OK too. _________________ Jan
also .. could someone please turn down the thermostat a bit.
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Regebro
Joined: Sep 12, 2004 Posts: 61
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Posted: Sat Nov 11, 2017 7:48 am Post subject:
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Finally today I switched from the Thermaltake to a BeQuiet. Problem solved.
I only use USB for MIDI, maybe that's why it works. Now I only get noise from the computer working on my audio outs, but I'll guess I have to live with that until I decide to mix in the computer and ditch the mixer.
I did discover that my OSC OSCar also creates a ground loop (after I changed to a proper plug so it's actually grounded), I suspect the power supply there as well. Old electrolytes perhaps? |
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