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Weird interference - Ground Loop?

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Weird interference - Ground Loop?

Postby dickiefunk » Fri Nov 26, 2010 3:47 am

Hi,

I'm getting some odd interference or ground loop with my gear at the moment.

I'm getting a high pitch faint whining sound coming through my AE22 monitors and this can get louder when my computer is busy!

I know that the AE22's are not shielded but the weird thing is that this has started to happen since I moved my monitors further away from my computer monitors!?

Recently I got a sub to go with the AE22's so there is double the cable length now which may be the issue?

I've started to remove various wall-wart or line-
lump power supplies, especially any universal voltage types to see if this helps but haven't found a culprit yet!

Over the past week I've been making some backing tracks onto mini discs and today I noticed that this whining noise has come out on them? This hasn't happened before despite this noise being there?
As far as I can tell I've not changed anything so am REALLY confused as to why this may be happening!!???

HELP!!!
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Re: Weird interference - Ground Loop?

Postby Paul White » Fri Nov 26, 2010 10:24 am

In my experience this problem is caused by a ground loop in the USB or Firewire connection between the interface and computer. Sometimes it can be solved by running the interface from a PSU rather than bus power, and with laptops if often goes away if you switch the computer to battery rather than mains operation. Sadly, sometimes the only fix is to change the interface, because although interface designers generally blame the internal grounding inside the computer, some have managed to adapt their designs to avoid the problem while others have not. As a rule this type of noise only affects the monitoring and doesn't come out on the recording so if not too loud you may be able to live with it.
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Re: Weird interference - Ground Loop?

Postby dickiefunk » Fri Nov 26, 2010 10:39 am

Hi Paul,

Thanks for the reply. I'm using a Focusrite Saffire Pro 24 DSP interface. I've tried powering the interface from the power supply but still have the same problem!

I'm going to try and isolate a few things to see if I can find the cause.

It is weird that I got this noise on the backing tracks I recorded on the minidisc recorder though?
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Re: Weird interference - Ground Loop?

Postby Zukan » Fri Nov 26, 2010 10:43 am

What mobo are you using?

I had the 'whining' hell for over a week and tried every damn thing known to man: changed fw card, changed fw cables, changed and updated graphics drivers, checked every damn cable and so on. I contacted Martin as he is the myth of all things ground loop and we spent a few years trying to resolve it until he found a really useful article on changing certain settings in the bios. I had bought a new pc running the 3g bios and after a couple of settings were changed the noise completely disappeared.
I did find initially that the noise was even worse when running graphics and listening back in WMP. I updated drivers and it did abate it a bit. I changed fw cables and that helped too but the noise was still there. It was only after the bios changes that the noise disappeared.

Just saying it might be worth an eyeball m8.
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Re: Weird interference - Ground Loop?

Postby dickiefunk » Fri Nov 26, 2010 10:50 am

Hi,

I'm using a Gigabyte GA EQ45mS2 mobo :-

http://www.gigabyte.com/products/product-page.aspx?pid=3279#ov

I've never delved into the computer bios so this is unknown territory for me!

Also, I am using the Graphics card drivers that came with Windows 7 for my N-Vidia 8400 card.
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Re: Weird interference - Ground Loop?

Postby dickiefunk » Fri Nov 26, 2010 11:25 am

I've just tried taking all devices that use wall-wart power supplies out and tried moving my interface to a position away from my gear with and without it's power supply. I also tried unplugging my TFT displays but still get the same noise / interference!

When I just turn the interface and speakers on there is no noise. When I turn my computer on and the firewire driver connects to the interface that is when the noise kicks in!

Could this be an issue with the Saffire Pro 24 DSP , computer or both?
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Re: Weird interference - Ground Loop?

Postby Zukan » Fri Nov 26, 2010 11:27 am

I could run you through the bios changes as it is a Gigabyte mobo but if you've never done it before I would be a bit hesitating about doing it.
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Re: Weird interference - Ground Loop?

Postby . . . Delete This User . . . » Fri Nov 26, 2010 11:36 am

dickiefunk wrote:
When I just turn the interface and speakers on there is no noise. When I turn my computer on and the firewire driver connects to the interface that is when the noise kicks in!


repeat that stage with Saffire PSU and without Saffire PSU...

is there ANY difference at all?



also, try changing the firewire cable for a brand new one....
they really are fussier and more delicate than people realise....

(see the D'OH moments thread for a post by persuazion for an example)


and make sure the Saffire PSU, all the AE speaker Mains, and the computer are plugged in to the same extension block.... ( this will require a 6 way rather than a 4 way trailing lead)


get someone's laptop and try the same things......
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Re: Weird interference - Ground Loop?

Postby dickiefunk » Fri Nov 26, 2010 11:38 am

Zukan wrote:I could run you through the bios changes as it is a Gigabyte mobo but if you've never done it before I would be a bit hesitating about doing it.

Thanks.

I'm a little hesitant in doing so because I don't want to risk messing up my computer.
If this doesn't sort the problem is it straight forward to return it to it's original settings?
How complicated is it to do this?

Has anyone else come across this problem with a Focusrite Saffire Pro interface? Could there be an interface issue?
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Re: Weird interference - Ground Loop?

Postby Zukan » Fri Nov 26, 2010 11:43 am

Dickie,

I am also using a Saffire and a Gigabyte mobo.
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Re: Weird interference - Ground Loop?

Postby dickiefunk » Fri Nov 26, 2010 11:47 am

idris y draig wrote:
dickiefunk wrote:
When I just turn the interface and speakers on there is no noise. When I turn my computer on and the firewire driver connects to the interface that is when the noise kicks in!


repeat that stage with Saffire PSU and without Saffire PSU...

is there ANY difference at all?



also, try changing the firewire cable for a brand new one....
they really are fussier and more delicate than people realise....

(see the D'OH moments thread for a post by persuazion for an example)


and make sure the Saffire PSU, all the AE speaker Mains, and the computer are plugged in to the same extension block.... ( this will require a 6 way rather than a 4 way trailing lead)


get someone's laptop and try the same things......

Just tried this and still have the same problem but maybe a fraction quieter but am unsure about this.

Could anyone recommend a high quality firewire cable?
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Re: Weird interference - Ground Loop?

Postby dickiefunk » Fri Nov 26, 2010 11:49 am

Zukan wrote:Dickie,

I am also using a Saffire and a Gigabyte mobo.

This is good to know

So I guess apart from trying a new firewire lead it looks like it could be something to do with the mobo's bios?
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Re: Weird interference - Ground Loop?

Postby Zukan » Fri Nov 26, 2010 11:53 am

Could be. Def was for me.

Might be worth doing the bios thingy and then if that doesn't work go back to original settings and try again.

Idris's suggestion of using the powered bus against the Saffire psu is a good start. I did the same thing with no effect but now with the bios changes I can use the psu again with no conflicts.

But Dickie, it's not just the bios. It could be any number of things and graphics drivers, cables and the actual fw card are the first port of calls.

Worst case scenario give me a bell and I will try to run you through the bios business.
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Re: Weird interference - Ground Loop?

Postby dickiefunk » Fri Nov 26, 2010 12:01 pm

Zukan wrote:Could be. Def was for me.

Might be worth doing the bios thingy and then if that doesn't work go back to original settings and try again.

Max's suggestion of using the powered bus against the Saffire psu is a good start. I did the same thing with no effect but now with the bios changes I can use the psu again with no conflicts.

But Dickie, it's not just the bios. It could be any number of things and graphics drivers, cables and the actual fw card are the first port of calls.

Worst case scenario give me a bell and I will try to run you through the bios business.

Ok thanks! I'll try a new firewire cable first and update my graphics drivers.

What would be a decent high quality firewire cable?
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Re: Weird interference - Ground Loop?

Postby dickiefunk » Fri Nov 26, 2010 1:34 pm

Hi Zukan. Just one more question if I may.

Was there any side affects or reduction in performance when you made the bios changes?
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Re: Weird interference - Ground Loop?

Postby . . . Delete This User . . . » Fri Nov 26, 2010 1:40 pm

i get my "mission critical" firewire cables from Lindy


their higher quality premium ones are reliable and pass every test i can think of.... and even at 10 metres (twice as long as firewire is supposed to be capable of) are bullet proof in terms of reliability and compatibility.



http://www.lindy.co.uk/usb-firewire/firewire-cables/6-pin-to-6-pin/


choose the length you need..... don't get longer just because you can.
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Re: Weird interference - Ground Loop?

Postby . . . Delete This User . . . » Fri Nov 26, 2010 1:43 pm

i'd note that Zukan's Saffire Pro is the older Pro26 , not the same generation of hardware as the Pro24


that said when i tested the pro24 i found no problems like this....


(and i still use the pro40 and pro56, indeed, i'm monitoring thru the Pro40 right this minute, and now i think about it, i've still got another Pro26 floating around somewhere or other.... )
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Re: Weird interference - Ground Loop?

Postby Zukan » Fri Nov 26, 2010 1:51 pm

dickiefunk wrote:Hi Zukan. Just one more question if I may.

Was there any side affects or reduction in performance when you made the bios changes?


No, none at all.

Another thing you can do prior to bios changes etc is to go to Focusrite's website and they have a video tutorial about changing certain preferences in device manager. That can help too. However, as Idris has pointed out, mine is the older 26 i/o and my problem fixing was centred around the older firmware.
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Re: Weird interference - Ground Loop?

Postby . . . Delete This User . . . » Fri Nov 26, 2010 2:00 pm

Eddie..... it's Idris.

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Re: Weird interference - Ground Loop?

Postby Zukan » Fri Nov 26, 2010 2:35 pm

Sorry

Image
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Re: Weird interference - Ground Loop?

Postby Zukan » Fri Nov 26, 2010 3:25 pm

Yep, I like infinite cassoulet resource (ICR).

Btw, your dragon thingy isn't working m8.

Or do I need to rephrase that?
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Re: Weird interference - Ground Loop?

Postby Martin Walker » Fri Nov 26, 2010 3:32 pm

Hi df!

Have a read of this PC Notes column of mine from a year ago, since it includes details on how to cure nasty noises with some Gigabyte motherboards by changing a BIOS setting.

www.soundonsound.com/sos/dec09/articles ... 1209.htm#3

Hope it helps!


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Re: Weird interference - Ground Loop?

Postby dickiefunk » Fri Nov 26, 2010 4:16 pm

Martin Walker wrote:Hi df!

Have a read of this PC Notes column of mine from a year ago, since it includes details on how to cure nasty noises with some Gigabyte motherboards by changing a BIOS setting.

<a href="/sos/dec09/articles/pcnotes_1209.htm#3" target="_blank">www.soundonsound.com/sos/dec09/articles/pcnotes_1209.htm#3</a>

Hope it helps!


Martin

Hi Martin,

I just looked at this and noticed that the ‘C1E CPU Enhanced Halt state’ is already disabled!?

I'm getting this noise coming out when I record to my mini disc player aswell!?
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Re: Weird interference - Ground Loop?

Postby dickiefunk » Fri Nov 26, 2010 4:22 pm

Hi Zukan,

Was this disable the ‘C1E CPU Enhanced Halt state’ change that you made in the bios?
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Re: Weird interference - Ground Loop?

Postby Zukan » Fri Nov 26, 2010 4:28 pm

I made a few changes: C1, C3, C4, C5, C6 and C7.
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Re: Weird interference - Ground Loop?

Postby dickiefunk » Fri Nov 26, 2010 4:36 pm

Zukan wrote:I made a few changes: C1, C3, C4, C5, C6 and C7.

Ah right! Could you let me know what changes you made exactly?
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Re: Weird interference - Ground Loop?

Postby Zukan » Fri Nov 26, 2010 4:42 pm

I'll have to restart my pc and get in the bios but I think I disabled C3,6 and 7 as a start and then checked again to see if it worked.

I can't restart the pc now as I have an ongoing upload taking place.
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Re: Weird interference - Ground Loop?

Postby dickiefunk » Mon Nov 29, 2010 4:05 pm

I've just done the optimization suggestions from the Focusrite website and still have this odd high pitch whining noise!

I noticed that when wiggling the jack plugs on the Saffire's outputs this can cause the noise to increase?

Zukan,

Will you have a chance to let me know what the changes you made in the bios were?
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Re: Weird interference - Ground Loop?

Postby Zukan » Mon Nov 29, 2010 4:35 pm

Am about to give a class Dickie.

If tomorrow is good we can Skype and go through it?
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Re: Weird interference - Ground Loop?

Postby dickiefunk » Mon Nov 29, 2010 5:31 pm

Ok Zukan.

I'm pretty much narrowing it down to either the computer or interface now!
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