Hi,

I just bought a new PC and Focusrite Saffire 6 USB soundcard. When I plug in my Focusrite I get a constant hiss / noise. It's there before I even install the drivers. I also tried plugging in my old Firebox (firewire) and that creates the same problem (even though it worked fine on my old PC).

The noise isn't there when windows is booting up. Only once in Windows does the noise start.

I have all the latest drivers (soundcard / motherboard) and windows is up-to-date.

What could be causing this?!

Possible ground loop?

http://www.soundonsound.com/forum/showflat.php?Cat=&Number=222392& page=0&view=collapsed&sb=5&o=365&fpart=1#222392

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http://soundcloud.com/richie-royale
http://www.mixcrate.com/richieroyale

Have you set your Windows audio preferences to use the Focusrite Saffire?

Yes. I've also disabled the onboard sound as I read that might cause issues. But no difference. I've also tried plugging the computer / speakers into the same socket extension to try and resolve it, but if anything that made it worse.

It seems to be the USB that creates the problem. Even if I just touch the USB cable from the Saffire on any of the computer USB ports (not plugging in, just touching), then it creates the noise. But only when windows is booted. On bootup there's no noise at all.

I'm running out of ideas!

Quote nutman:

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Yes. I've also disabled the onboard sound as I read that might cause issues. But no difference. I've also tried plugging the computer / speakers into the same socket extension to try and resolve it, but if anything that made it worse.

It seems to be the USB that creates the problem. Even if I just touch the USB cable from the Saffire on any of the computer USB ports (not plugging in, just touching), then it creates the noise. But only when windows is booted. On bootup there's no noise at all.

I'm running out of ideas!

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What computer? If a laptop, does the problem go away if you disconnect the power supply and run on batteries?

Do you still get the noise through headphones connected directly to the Saffire, with no powered speakers connected?

Its a desktop PC.

If I turn off my speakers and use headphones then the signal is clear through the headphones.

So why do the speakers pick it up? Doesn't that suggest that the cables are picking up interference? But that doesn't explain why I didn't get any using my previous PC. same cables. 1/4 inch jack out the interface to XRL into my sub. Then XLRs from sub to left/right speakers.

I've also tried changing the leads from the Saffire to my sub, using the RCA outs instead of the 1/4 inch. Same issue

Edited by nutman (11/05/12 01:05 PM)

Quote nutman:

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Its a desktop PC.

If I turn off my speakers and use headphones then the signal is clear through the headphones.

So why do the speakers pick it up? Doesn't that suggest that the cables are picking up interference? But that doesn't explain why I didn't get any using my previous PC. same cables. 1/4 inch jack out the interface to XRL into my sub. Then XLRs from sub to left/right speakers.

I've also tried changing the leads from the Saffire to my sub, using the RCA outs instead of the 1/4 inch. Same issue

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It's not likely a line level connection will pick up interference. Does it vary if you move the cables between Saffire and speakers around?

It suggests to me that there's a ground loop between THIS computer and the power supply for the speakers.

Quote Exalted Wombat:

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It's not likely a line level connection will pick up interference. Does it vary if you move the cables between Saffire and speakers around?

It suggests to me that there's a ground loop between THIS computer and the power supply for the speakers.

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Doesn't vary if I move the cables around. How would I resolve the ground loop if that's the case?

Hi nutman, and welcome to the SOS Forums!

As EW mentions, your problem does sound suspiciously like a ground loop, so I suggest you have a read of the sticky thread I created in our PC Music forum entitled “Click here if your desktop/laptop audio contains strange noises”

www.soundonsound.com/forum/showflat.php?Cat=&Number=222392

Lots of step-by-step advice in there - hope it helps!


Martin

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YewTreeMagic

Hi and welcome nutman.
I was a bit worried that in your first post you said the noise was there "Before I even installed the drivers"
Now it is almost universal with usb AI's that you install drivers etc BEFORE you let the interface anywhere near the PC!

I doubt that it will cure the noise, I am pretty sure you are a candidate for a pair of SoS special leads, but it might be worth cleaning out the Focurite software and starting again, "from the book"? And I assume Win 7? I had a problem with this with my ZED10. Windows sets the gain too high, A&H, bless 'em, soon got me sorted.

Dave.