Issues with PC "noise"
Jan 10, 2019 at 1:01 PM Thread Starter Post #1 of 27
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oscaracso

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Hiya,

I have been using this website for a while but never thought to make an account. I have found some help on this issue but I need it in some more simple terms as I am quite a newbie.

My setup is my PC connected by USB (which also powers) my Audioengine D1 DAC (which has a small built in amp). This is connected by RCA to my Little Dot MK2 tube amp which my Sennheiser HD 6XX's are plugged into. When I plug them straight into the DAC there is no background noise while no music is playing but when plugged into the amp, there is a small amount of interference type noise which spikes when I scroll with my mouse or open up an app.

I think the issue lies with the amp as adjusting volume on this changes the amplitude of the background noise, although I'd like to keep this on high volume to get full colour from the tubes.

I wondered if anyone could, in simple terms, explain to me how to fix this issue if possible (seems to be something to do with ground loops but I'm slightly puzzled on how to fix it) - https://www.diyaudio.com/forums/pc-based/325887-remove-pc-noise-using-usb-dac.html

Many thanks!
 
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Jan 10, 2019 at 1:30 PM Post #2 of 27
Try plugging the Little Dot MK2 power cord into a separate surge protector and separate wall socket, from your PC & DAC power connections.
 
Jan 10, 2019 at 6:48 PM Post #4 of 27
oscaracso said:
Good idea but I've done that and I'm still getting noise - related to what I'm doing on my PC
Click to expand...
Try not using the audioengine D1 and connect the PC directly to the LD MK II, see if you still get the noise.
You might try using the optical connection, between PC and DAC.
PC > optical > DAC > LD MK II
Try shielded RCA cables, for connecting the DAC to the LD MK II.
Otherwise I'm guessing your LD MK II is slightly defective.
 
Jan 11, 2019 at 4:37 AM Post #5 of 27
PurpleAngel said:
Try not using the audioengine D1 and connect the PC directly to the LD MK II, see if you still get the noise.
You might try using the optical connection, between PC and DAC.
PC > optical > DAC > LD MK II
Try shielded RCA cables, for connecting the DAC to the LD MK II.
Otherwise I'm guessing your LD MK II is slightly defective.
Click to expand...
I still get the noise with the LD MKII plugged straight into the PC. I don't have optical option. I'm pretty sure even non shielded cables wouldn't pick up computer noise outside of the computer a metre away.

I think it's something to do with a ground loop issue which I don't really understand. I don't think it's defective if it's noise from inside the PC.
 
Jan 11, 2019 at 5:33 AM Post #6 of 27
If the noise is specific to ground loop 50Hz/60Hz hum, either:
- Remove all ground connections from the AC adapter. But, if your equipment housing is made of metal and your home ELCB board is not functioning or specified wrongly, the equipment MAY become dangerous to touch.
- Have additional ground wire cable (with thick gauge copper) connected directly to each AC plug ground. I used this method in some of my projects. The idea is to get all the ground voltages of the equipment as electrically close as possible. That will reduce ground loops significantly.

EDIT: Read your post on diyaudio, "The frequency of the buzz will CHANGE based on the PC usage and seems to be tied to the FPS when in a game". This is NOT ground loop hum. With this new info, it's probably either electrical noises generated by HDD head-seeking (test with SSD) or an electrically noisy video card (use another card to test). If your OS is really ancient, like Win98, it could also be IRQ-related (swapping PCI-E/PCI/video cards to different slots MAY solve this). Good luck!
 
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Jan 13, 2019 at 7:30 AM Post #7 of 27
purplesun said:
If the noise is specific to ground loop 50Hz/60Hz hum, either:
- Remove all ground connections from the AC adapter. But, if your equipment housing is made of metal and your home ELCB board is not functioning or specified wrongly, the equipment MAY become dangerous to touch.
- Have additional ground wire cable (with thick gauge copper) connected directly to each AC plug ground. I used this method in some of my projects. The idea is to get all the ground voltages of the equipment as electrically close as possible. That will reduce ground loops significantly.

EDIT: Read your post on diyaudio, "The frequency of the buzz will CHANGE based on the PC usage and seems to be tied to the FPS when in a game". This is NOT ground loop hum. With this new info, it's probably either electrical noises generated by HDD head-seeking (test with SSD) or an electrically noisy video card (use another card to test). If your OS is really ancient, like Win98, it could also be IRQ-related (swapping PCI-E/PCI/video cards to different slots MAY solve this). Good luck!
Click to expand...
Hi thank you for the help,

I don't think it is a ground loop hum now after some trouble shooting as the noise is related to what I do on my PC and increases as I change the amplifier volume. I run windows 10. It may be to do with running my DAC through USB although I hear none of these noises directly through my DAC. Any advice?
 
Jan 13, 2019 at 7:52 AM Post #8 of 27
Tube amps are a blessing and a curse! They add so much to the music but are inherently noisy and finicky.
I second the recommendations of trying better shielded interconnects and isolating the amp to a different electrical outlet. Also, having large appliances or dimmer switches on the same circuit as your outlet can cause tube noise.
Tubes are also sensitive to WiFi and cellular signals. Some tubes are more sensitive than others. Do you have other tubes you could roll?
 
Jan 13, 2019 at 7:56 AM Post #9 of 27
FastForward said:
Tube amps are a blessing and a curse! They add so much to the music but are inherently noisy and finicky.
I second the recommendations of trying better shielded interconnects and isolating the amp to a different electrical outlet. Also, having large appliances or dimmer switches on the same circuit as your outlet can cause tube noise.
Tubes are also sensitive to WiFi and cellular signals. Some tubes are more sensitive than others. Do you have other tubes you could roll?
Click to expand...
I have put it on a completely different set of outlets. I don't think it lies with wifi signals as other things unrelated cause noise - any activity on computer. I don't have any tubes I could roll but I'm not sure that would help. The noise sounds like it's coming from my motherboard circuitry. Could possibly be to do with using USB ports although why do I not hear this through my DAC. I don't have optical output on my PC.
 
Jan 13, 2019 at 8:29 AM Post #13 of 27
oscaracso said:
Hi thank you for the help,

I don't think it is a ground loop hum now after some trouble shooting as the noise is related to what I do on my PC and increases as I change the amplifier volume. I run windows 10. It may be to do with running my DAC through USB although I hear none of these noises directly through my DAC. Any advice?
Click to expand...

The electrical noise generated within the PC is being passed into the DAC via the USB cable. One of the best way to isolate the electrical noise is to use optical fibre rather than electrical cable to link the DAC and PC. Try that, if your DAC has an optical input. Does you PC use HDD? If yes, that could be generating the noise, test with an SSD to rule that out or in.
 
Jan 13, 2019 at 8:32 AM Post #14 of 27
purplesun said:
The electrical noise generated within the PC is being passed into the DAC via the USB cable. One of the best way to isolate the electrical noise is to use optical fibre rather than electrical cable to link the DAC and PC. Try that, if your DAC has an optical input. Does you PC use HDD? If yes, that could be generating the noise, test with an SSD to rule that out or in.
Click to expand...
Yes I think you've hit the nail on the head. My PC does use HDD - should I just turn off my PC and unplug the HDD and just use with my SSD? I don't have optical fibre output on my PC - my dac does have optical input.Should I buy a soundcard to get optical output?
 
Jan 13, 2019 at 8:49 AM Post #15 of 27
Does your PC have HDD activity LED? Does the "crackling" noise occur when the LED flashes? That's should indicate the head-seeking motor is creating the electrical noise. If there's no other noise sources, using SSD only should eliminate the noise.

If that does not work, then try the optical output card. That should eliminate all electrical noise generated by the PC.
 
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