[Tarttett]

I have a problem with ground loop noise with my desktop computer and amp. It seems like both are responsible for it in some way. I can hear noise coming through the amp with my desktop but not with my laptop. However another amp that I have has no problem when plugged into either.

What exactly am I hearing from my computer anyway? Why can I hear buzzing when I scroll a page? Why is the sound different when I scroll with my mouse wheel and when I scroll with the scroll bar? Why can't I hear any noise being generated when I type? Why is swapping between previews of different windows so loud?

 

[Roseval]

ground loop noise = a hum at 50 kHz

Swap plugs, try same/different outlet

Why can I hear buzzing when I scroll a page: sounds like you are using USB for audio. Try another port.

 

[PurpleAngel]

Can we assume the headphone amplifier is connected to the computer's line-output/headphone jack?
Try plugging the power cords to separate wall outlets.
Use separate power strip,s plugged into separate power outlets.
Connecting a DAC, with an optical input, between the computer and the headphone amplifier, would hopefully solve the electrical noise issue.

 

[Andrew_WOT]

If everything fails, this thing works 100%
https://www.sweetwater.com/store/detail/HumX--ebtech-hum-by-ground-loop-hum-exterminator

 

[Tarttett]

My amp is connected to a DAC with RCA cables, and my DAC is connected by USB. The problem is there with every USB port.
All of my equipment besides my monitor is connected to a single power conditioner strip which is plugged into a UPS. I unfortunately don't have any real flexibility with my power arrangement. The most separation I can do right now is to have my computer, monitor, and laptop on the power conditioner and have my DAC and amp directly on the UPS which doesn't fix it.
I'll have to think about trying an optical connection. I'll also probably make a thread later asking about USB grounding devices. The only ones I can remember right now are iFi audio's.
I'm still wondering what exactly the cause of the problem is. If it's the amp shouldn't I have the problem with both my laptop and my desktop. If it's the computer shouldn't I have the problem with both amps? I'm also still confused about what the cause of the noises are. Why does scrolling pages and swapping windows make noise?

 

[technobear]

My amp is connected to a DAC with RCA cables, and my DAC is connected by USB. The problem is there with every USB port.
All of my equipment besides my monitor is connected to a single power conditioner strip which is plugged into a UPS. I unfortunately don't have any real flexibility with my power arrangement. The most separation I can do right now is to have my computer, monitor, and laptop on the power conditioner and have my DAC and amp directly on the UPS which doesn't fix it.
I'll have to think about trying an optical connection. I'll also probably make a thread later asking about USB grounding devices. The only ones I can remember right now are iFi audio's.
I'm still wondering what exactly the cause of the problem is. If it's the amp shouldn't I have the problem with both my laptop and my desktop. If it's the computer shouldn't I have the problem with both amps? I'm also still confused about what the cause of the noises are. Why does scrolling pages and swapping windows make noise?

I have a desktop that does this and a laptop that doesn't. Some amps are susceptible and some are not.

It's ground plane noise travelling along the USB cable and then onto the analogue interconnect. Class D amps seem to be more susceptible in my experience. If optical is an option then that is one answer. If you want to keep using USB, you will need an isolator. The cheapest is the iDefender I think. You may need to attach a 5V USB PSU to the iDefender to fully crack the problem. I cracked it with an iGalvanic but that is expensive - I was lucky one came up cheap on the forums.

 

[Tarttett]

Why is the noise different depending on what I do? Shouldn't the only difference be in volume as a result of how much work my processor is doing?

I believe I shouldn't need a PSU for the iDefender since my DAC isn't USB powered. Do you know of any other devices that fulfil the same role? It's annoying that I saw one that was roughly equivalent in a thread just a few days ago. I think it was coming across that that actually led me to iFi audio in the first place.

 

[Dawnrazor]

Why is the noise different depending on what I do? Shouldn't the only difference be in volume as a result of how much work my processor is doing?

I believe I shouldn't need a PSU for the iDefender since my DAC isn't USB powered. Do you know of any other devices that fulfil the same role? It's annoying that I saw one that was roughly equivalent in a thread just a few days ago. I think it was coming across that that actually led me to iFi audio in the first place.

agree with @technobear its ground plane noise.

One of the reasons its hard to get stellar sound from computers is because of all the noise.

Have you checked if the outlet itself is actually grounded? I had exactly what you describe and it was all because the building outlets werent grounded even though they had 3 pronged outlets.

 

[Dawnrazor]

If everything fails, this thing works 100%
https://www.sweetwater.com/store/detail/HumX--ebtech-hum-by-ground-loop-hum-exterminator

I bought one and well it didn't work. I just kept it because one never knows.

I did fix mine. It was my switch. New switch fixed it. And IIRC one of the xlrs had an issue.

 

[Kishimotosan]

I had a hum in my amp which was plugged in to the same power strip as my computer. When I plugged the amp in to a separate power strip it stopped the hum.

I would suggest eliminating all the variables by starting fresh at a different outlet. Try your amp and dac with the laptop or desktop at another outlet. If you don’t hear the noise slowly add things back to the chain until you hear it. Your goal is to eliminate all variables that could be the source of noise and then find it by testing as you add components back to the chain.

 

[Andrew_WOT]

I bought one and well it didn't work. I just kept it because one never knows.

I did fix mine. It was my switch. New switch fixed it. And IIRC one of the xlrs had an issue.

I have 4, my amps and dacs are all plugged in, or it's buzz city otherwise.

Wikipedia has good article on ground loop and solutions.

 

[technobear]

From the description given of the nature of the noise, this is not a ground loop/hum problem. This is simply transmission of noise from the groundplane of the computer to the amp via the DAC.

I'm not sure why the OP thinks CPU duty would affect sound volume. USB is a digital signal. It would be a very broken computer if CPU duty affected the accuracy of its data.

It might be necessary to add a PSU to the iDefender simply because only this way does it fully break the ground connection. It doesn't have to be an expensive PSU. Any USB-ended phone charger or powerbank will do.

I highly recommend adding an iPurifier2 or iPurifier3 at the input to the DAC for better sound quality but this alone won't stop the ground plane noise. I've tried. Other USB decrapifiers are also unlikely to stop this noise. The only device I know that will definitely stop it is the iGalvanic which is what I have ended up with.

I don't know why laptops often exhibit this problem much less. I have an Acer fanless laptop that doesn't have the problem at all. Desktop PCs on the other hand, seem to be very noisy on the ground plane. My DACs are all immune to this. If I plug headphones into the iDAC2, iDSD or ADI-2 DAC, I hear only silence (without the iGalvanic). My XTZ power amp which is a class D type, doesn't like the ground noise at all and emits a high pitched whine which can be heard to change when the mouse is moved and so on. The DACs don't isolate the ground between USB input and analogue output so the noise passes right along. An isolating DAC would probably solve the problem but they tend to be expensive models.

 

[Tarttett]

I haven't checked that the outlet is grounded.

I unfortunately am not in a position to do any testing with different outlets right now. I only have one close enough to my space. I would need to temporarily move all of my setup to the other side of the room or get some power strips/extensions.

According to iFi a power supply isn't required for DACs that aren't USB-powered.

Are balanced lines able to filter ground plane noise?

 

[Dawnrazor]

I haven't checked that the outlet is grounded.

I unfortunately am not in a position to do any testing with different outlets right now. I only have one close enough to my space. I would need to temporarily move all of my setup to the other side of the room or get some power strips/extensions.

According to iFi a power supply isn't required for DACs that aren't USB-powered.

Are balanced lines able to filter ground plane noise?

When I had the issue that sounds exactly like the one you are having, I had balanced outputs from my Lynx soundcard but the noise was there the whole time. With a grounded outlet it went away. Balanced lines only filter noise picked up by the LINES. If the noise is in the signal it passes through.