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Question

Electrical noises when connecting my speaker to mobo.

Jun 5, 2019 1:07PM PDT

I have a very loud electrical noise issue when connecting my motherboard audio to my powered monitor speakers.
My speakers are Yamaha MSP 5 Studio and my motherboard is Aorus Z390 Master.
The very strange thing is that they both work perfectly otherwise, the only problem i encounter is when I connect theese certain speakers to my motherboard.
I have connected multiple headphones/speakers to my mobo and they work perfectly
I have connected multiple devices to my speakers and they work perfectly.
I have also tried about 15 different cables.
I am literally broken at this point and I don't know what to do anymore.
I have made a video showcasing the problem that I have.

View: https://www.youtube.com/watch?v=nW64NDYiJag


I tried every setting in bios and I have tried every setting in windows since this issue appears only when I open up windows as shown in the video.
I am almost certain that it is an mobo issue since the speakers worked perfectly until I connected them to this mobo also they are 2 so the chance there is something wrong with both of them is really low.
My opinion is that the noise is the type of noise that headphones make when the impedance is too high and this motherboard has an integrated amp while other devices only have a DAC.



I think that the motherboard does not recognize that the monitors are self powered and tries to amplify them as it would do to a pair of headphones.
I think that what I need to do is disable the motherboard amp somehow but I have looked throughout every bios setting and read the user manual thoroughly.
I am desperate and willing to try anything any help would be appreciated thanks !

Discussion is locked

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Answer
A very common problem.
Jun 5, 2019 1:28PM PDT

That's the old "picking up internal PC electrical noise" problem. There is no fix that always works. You can try isolators and such but all this has been discussed for decades.

My advice is to use speakers that work since most folk don't have electrical or electronic design background to tinker and try to fix it. Even I don't fix these as the time is usually lost half the time. I find it more productive to use speakers that work without the headaches.

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No.
Jun 5, 2019 2:07PM PDT

I am sorry but you are wrong. I have conected theese speakers to other simmilar pc's and they worked just fine. Besides this noise is WAY too loud to go as normal PC electric noise. (as I showcased in my video)

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You can go down that road.
Jun 5, 2019 2:17PM PDT

I'm just an electronics designer with a lot of work mitigating RFI in designs. The noise is typical and so is your response.

As to the loudness, the emissions and the reception varies with each PC. Since you have a variety of PCs you will have some that are fine and a few with this issue.

Be sure the audio output in Windows is near %100 since once in a while a new tech will have the volume output from the PC as say 2% and with amplified speakers you will be gaining up the noise because.... SNR!

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The diffrence is too big.
Jun 5, 2019 2:54PM PDT

I am sorry if I sounded disrespectful but as I tried to showcase in that video the difference in sound is humongous to be simple electrical interference.
I tried to showcase by connecting to a laptop but and it was obvious the difference was night and day, but I have also connected it to other desktops and the results were exactly the same.

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Which proves that
Jun 5, 2019 3:13PM PDT

It varies from PC to PC. This is a typical problem and nothing unique going on. Your newer techs will lose days trying to fix this. At the shop we won't accept this because, most of us have electronic design backgrounds and know what is going on.

Yes, confusing to the new techs.

You can try other audio cards or the usual USB audio stick which is under 8 bucks on Amazon. That fix is so common I always have the cheap audio USB stick in my call bag.

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PS. If we were at the shop counter
Jun 5, 2019 3:20PM PDT

I could hold a short 5 minute talk and chat about antenna theory which is something basic to understand why this happens.

Your speaker setup is good at picking up a range of RF. As you change to another PC the PC source frequencies (not audio but RF) changes and what picks up these signals get worse or better.

You can try ferrite beads but I find them hit of miss without a good spectrum analyzer and more gear. The best fixes I've used over the years is the beads or chokes along with USB sound stick or changing to another make and model speaker set.

The cost to even look at this at a repair counter is $150 here and they usually won't accept this for repair if the shop is competent.