[earthpeople]

First, I'm using the S/PDIF coax jack on my motherboard, a Gigabyte GA-P55-UD3. I am also using a Cooler Master GX750 power supply. I can't think of anything else that may cause the noise.
 
Now, I get noise from my amp when my DAC is connected to that jack. Even when the DAC isn't on, I get noise in the amp with the volume all the way down. If I pull the coax cable out of the DAC, then there is no noise.
 
I've tried the same setup using my DVD player playing a CD instead of the computer and there is no noise at all.
 
Some of the things I've tried include;
-Changing the power outlet group I plug the amp into
-Removing the USB and audio plugs that allow USB and audio access at the front of the case
-Moving USB devices out of the way of the S/PDIF jack
-maybe one or two more I can't remember
 
nothing has solved the issue. I'm wondering if anyone can give me some ideas about what to do. I am willing to get a PCI soundcard if it will work, but I don't want to buy one just to hear the same things.
 
This also happens when I use the USB port for audio. I've heard of devices for USB that allow just the signal to pass through and not the surrounding power or whatever. Is there anything like that for S/PDIF?
 
I also have an optical out on my motherboard and I've heard those do not have such noise issues, but there are problems regarding jitter or other limitations, I don't really know. It would be great if someone can give me a briefing about it. In any case, I would also considering getting an optical to coax adapter.
 
Thanks for any help.

 

[Dalamar]

Most likely a ground loop or ground noise.
 
Plug everything in the same outlet, if that doesn't help you'll have to isolate it somehow, probably with a device/cable that doesn't connect the ground. I advise just using the optical out if your dac supports it; the jitter bunch around here are full of nonsense. If anything's jittering, they've probably been overdosed on caffeine.

 

[earthpeople]

Thanks for your thoughts Dalamar.
 
I had been keeping everything on a power strip from one outlet, but I thought I would try since I recall reading that it solved such problems before.
 
So assuming it is a ground issue, using optical out would essentially solve it, right? And if I use an optical to coax adapter, there shouldn't be a difference as they are digital signals? If so, I'll probably pick up one of those adapters and give it a shot. Something like this or this.
 
 
Other ideas are welcome still!

 

[Dalamar]

http://www.amazon.com/Cables-Go-40429-Dual-Output-Digital/dp/tech-data/B001DF2KC2/ref=de_a_smtd should work, but it looks like http://www.amazon.com/Cables-Go-Coaxial-Optical-Converter/dp/B0002J2MV4/ref=sr_1_3?s=electronics&ie=UTF8&qid=1281939624&sr=1-3 is one way: coax to toslink, not the other way around.
 
The former seems a bit expensive, IMO.
 
Perhaps: http://www.monoprice.com/products/product.asp?c_id=104&cp_id=10423&cs_id=1042302&p_id=2948&seq=1&format=2
 
They also have coax to toslink for $100 less than the lolface, lol http://www.monoprice.com/products/product.asp?c_id=104&cp_id=10423&cs_id=1042302&p_id=2947&seq=1&format=2

 

[earthpeople]

Well, I bought an optical cable and the optical to coax adapter, and after some shipping problems, I received it today. Hooked it all up and... still noise. I guess this means the noise is in the signal itself. I don't have any ideas other than to try a dedicated soundcard on a PCI slot, but even then I'm not sure if it'll solve it.

 

[wavoman]

I have used SPDIF coax-to-optical converters to eliminate SPDIF coax grounding problems with great success, so indeed you have a MOBO audio noise issue.  And you are right that this could cause problems with a PCI soundcard.  Drew at moon-audio mods the superb M-Audio 192 by using an isolating transformer in the SPDIF output -- bet that solves the problem.
 
And Drew will usually take returns -- explain the whole problem to him, he is very, very easy to work with. 

 

[earthpeople]

Thanks for the idea wavoman. Unfortunately, I can't really afford to swing that much money (I had to pay tuition just the other day

). Even the stock, non-modded M-Audio 192 is too much for me right now, I can't imagine how much a modded one would cost.
 
As of right now, I'm streaming from foobar to my PS3 and using the optical out on that. It's a bit roundabout but it's playing without noise. The only issue is that when I play lossless files, they skip and pause. I guess I just can't get anything to work perfectly, heh.

 

[anwaypasible]

Quote:

Well, I bought an optical cable and the optical to coax adapter, and after some shipping problems, I received it today. Hooked it all up and... still noise. I guess this means the noise is in the signal itself. I don't have any ideas other than to try a dedicated soundcard on a PCI slot, but even then I'm not sure if it'll solve it.

duh.. of course you are still going to have the same problem because the electricity that is feeding things has a problem.
what you need to do is determine whether the power supply is feeding the motherboard problematic electricity or if the motherboard is taking good electricity from the power supply and making it nasty.
the only way to get passed the motherboard's nasty power is to plug something directly into the power supply .. and the only way to get something good from the power supply is to replace the power supply because building a circuit to correct such nasty electricity isnt ethical and/or cost effective, meaning it is cheaper to replace something rather than try to patch it.
 
i would suggest trying to overclock your motherboard and steer some of that nasty energy to the processor (northbridge/southbridge/ram also)
maybe you have excess electricity specifically to make the overclock more stable.
maybe you already have overclocked the motherboard and the components are like drained batteries and the would work better if they were full of electricity... one or the other which is why i said try to overclock.
 
i cant help but think your motherboard isnt very rock-solid considering an electrical noise issue.
 
to the guy that used an adapter to fix his/her problem .. chances are that the analog coax was on a circuit that was causing the problem and by switching to the optical circuit there was no more problem because that output jack was being unused.

 

[earthpeople]

Well what do you know, overclocking my processor solved it. I never would have guessed to try that. I've had my RAM clocked up but I put my CPU back down to stock speeds after I tested to see how high I could push it. I guess the trade-off of heat for silence will have to do. Thanks, anwaypasible.
 
About the motherboard; I looked up many reviews, both professional and user, and they were positive over the large majority. electric noise out the S/PDIF outputs isn't something people really comment on, heh, otherwise I would have gone with something else in the first place. Oh well.

 

[anwaypasible]

its probably not a bad motherboard, there are situations where the components are cranky when they are full of electricity .. there are other situations where they components are cranky when they arent acting like a full battery.. so it was well worth a shot to try and change the 'battery level' by overclocking (or reducing speeds to stock)
 
anyways, you are welcome.. glad you solved a problem on my account

why bother posting if it isnt productive i say ..

 

[wavoman]

Quote:

...used an adapter to fix his/her problem .. chances are that the analog coax was on a circuit that was causing the problem and by switching to the optical circuit there was no more problem because that output jack was being unused.

 
No, it was a digital SPDIF coax that had a grounding issue, as acknowledged by the engineers at Wadia (a Wadia DAC in a CDP was receiving the signal).  This was Wadia's fault, since other DACs (Benchmark, Matrix) had no problem with the same SPDIF coax connection.  Could have fixed it at the Wadia end clearly, but (given the particular way the Wadia had been installed) it was faster and easier to put a pro SPDIF coax-to-optical converter (not consumer junk) in the path and bump the Wadia input selector one notch up -- problem solved.  Note the digital SPDIF output from the PC MOBO is still in use ... did not switch to the PC's optical out ('cause it doesn't have one).

 

 

[Yoga Flame]

Quote:

First, I'm using the S/PDIF coax jack on my motherboard, a Gigabyte GA-P55-UD3. I am also using a Cooler Master GX750 power supply. I can't think of anything else that may cause the noise.
 
Now, I get noise from my amp when my DAC is connected to that jack. Even when the DAC isn't on, I get noise in the amp with the volume all the way down. If I pull the coax cable out of the DAC, then there is no noise.
 
 

I am shocked and awed that overclocking fixed the problem. I would have gone with using a USB -> S/PDIF transport like the Teralink-X2 or something similar. Happy that your noise problem is gone though.
 
What still puzzles me is that the noise remained even when the DAC was turned off. This suggests that the problem is not in the digital-to-analog conversion, or even in the digital realm at all. I would have guessed that analog noise from the PC was passing through the coaxial cable into your DAC, and then to your amp. But the noise remained even while using optical, so that's a mystery to me.
 
Actually, how was your optical-to-coaxial converter being powered? Maybe the same noisy power that plagued your PC also affected the converter.
 

 

[earthpeople]

The noise was also there when I used a USB DAC, so I'm not sure if that would have worked.
 
My optical-coax converter has a wallwart for itself. Since it isn't getting power from the PC, I don't think it is a case where the noise is picked up after the conversion.
 
Like I mentioned earlier, I never would have guess overclocking would work if it wasn't suggested by someone else. I'm just happy it's all good now after all that stress and trouble I went through trying to figure it out.