Question Ground Loop Issue After Rebuild

Apr 18, 2022
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Over the last few days I have been tearing my hair out trying to chase down a ground loop that has manifested in what was previously a good config

My original config was....
Aorus X570 Pro Motherboard
Ryzen 7 5800 X
32 GB G-Skill Trident Z
Inno 3D GTX 1080
Sound Blaster AE-9
TP-Link Wifi-AC internal card connected to internal usb header
EKWB Watercooling loop with EK Fans connected to motherboard
2 x Corsair red LED Fans
Corsair AX760i PSU
Phanteks Enthoo Pro Case.
Corsair K70 Keyboard
Logitech G502 Mouse
BenQ BL3200 monitor

Sound System connected to PC via analogue cables
Pioneer SC-LX72 AV Receiver
B&W Front and Center Speakers
Logitech satellites
REL T7/x Subwoofer

Everything running from one extension cord.

Everything was awesome. No issues at all.

Last week I bought a Lian Li O11D Evo Case, a Seasonic GX-1000 PSU and some Corsair RGB fans.

Rebuild went smoothly however I now appear to have a ground loop in the system which is barely noticeable on desktop when moving the mouse but becomes very loud when launching into any game. Toggling Vsync on/off makes no difference.

So far I have tried, in order and all without success
Switched to a GTX780 GPU
Unplugged the Display Port cable
Switched back to the Corsair PSU
Disconnected the Corsair RGB controller from the motherboard and all fan power cables other than the 2 on the radiator.
Disconnected ALL the case cables (USB/Sound/RGB) except the switch connector
Completely removed the Sound Card
Completely removed the wifi card
Disconnected the Sub from the Amp and tried various combinations of speakers connected to the amp to eliminate the speakers from the equation.

As it stands my system now consists of
Lian Li Case with only the power switch block plugged in.
Aorus Mobo with same CPU/RAM
GTX1080
EKWB Watercooling Loop with two RGB Corsair Fans (RGB not plugged in) connected to Mobo
Corsair PSU

Rebuilding back in the Phanteks case is no longer possible as it was donated to another family member who was visiting at the start of the easter break - hindsight is a wonderful thing, never expected to encounter this! Also I don't have an AMD air cooler available to eliminate the EK Loop from the equation.

As far as raw hardware is concerned in my mind I've got what was a known good config, with the exception of the fans which I'm reluctant to unplug (along with the pump) in case of damage to the CPU. In researching this issue I've yet to find anything to suggest fans would be responsible for a ground loop issue, similarly with the case - the only physical link to the other components is the on/off switch which shouldnt be an issue?

I have got a Harmon Kardon bluetooth speaker that has a 3.5mm input jack so I connected that to the onboard audio and it's mains power charger on the same extension cord as everything else and no ground loop noise was present.

I know there are hum defeating devices I could buy that may fix this but they are not guaranteed to work and more importantly there wasnt an issue before I changed anything so I'm reluctant to spend money at this stage.

In short - what the <long string of expletives> could possible be causing the ground loop and how can I eliminate it? I am utterly baffled where this has come from to the point where I am now wishing I had never started this upgrade.

Any advice or suggestions for other steps I can take would be massively appreciated.
 

kanewolf

Titan
Moderator
Over the last few days I have been tearing my hair out trying to chase down a ground loop that has manifested in what was previously a good config

My original config was....
Aorus X570 Pro Motherboard
Ryzen 7 5800 X
32 GB G-Skill Trident Z
Inno 3D GTX 1080
Sound Blaster AE-9
TP-Link Wifi-AC internal card connected to internal usb header
EKWB Watercooling loop with EK Fans connected to motherboard
2 x Corsair red LED Fans
Corsair AX760i PSU
Phanteks Enthoo Pro Case.
Corsair K70 Keyboard
Logitech G502 Mouse
BenQ BL3200 monitor

Sound System connected to PC via analogue cables
Pioneer SC-LX72 AV Receiver
B&W Front and Center Speakers
Logitech satellites
REL T7/x Subwoofer

Everything running from one extension cord.

Everything was awesome. No issues at all.

Last week I bought a Lian Li O11D Evo Case, a Seasonic GX-1000 PSU and some Corsair RGB fans.

Rebuild went smoothly however I now appear to have a ground loop in the system which is barely noticeable on desktop when moving the mouse but becomes very loud when launching into any game. Toggling Vsync on/off makes no difference.

So far I have tried, in order and all without success
Switched to a GTX780 GPU
Unplugged the Display Port cable
Switched back to the Corsair PSU
Disconnected the Corsair RGB controller from the motherboard and all fan power cables other than the 2 on the radiator.
Disconnected ALL the case cables (USB/Sound/RGB) except the switch connector
Completely removed the Sound Card
Completely removed the wifi card
Disconnected the Sub from the Amp and tried various combinations of speakers connected to the amp to eliminate the speakers from the equation.

As it stands my system now consists of
Lian Li Case with only the power switch block plugged in.
Aorus Mobo with same CPU/RAM
GTX1080
EKWB Watercooling Loop with two RGB Corsair Fans (RGB not plugged in) connected to Mobo
Corsair PSU

Rebuilding back in the Phanteks case is no longer possible as it was donated to another family member who was visiting at the start of the easter break - hindsight is a wonderful thing, never expected to encounter this! Also I don't have an AMD air cooler available to eliminate the EK Loop from the equation.

As far as raw hardware is concerned in my mind I've got what was a known good config, with the exception of the fans which I'm reluctant to unplug (along with the pump) in case of damage to the CPU. In researching this issue I've yet to find anything to suggest fans would be responsible for a ground loop issue, similarly with the case - the only physical link to the other components is the on/off switch which shouldnt be an issue?

I have got a Harmon Kardon bluetooth speaker that has a 3.5mm input jack so I connected that to the onboard audio and it's mains power charger on the same extension cord as everything else and no ground loop noise was present.

I know there are hum defeating devices I could buy that may fix this but they are not guaranteed to work and more importantly there wasnt an issue before I changed anything so I'm reluctant to spend money at this stage.

In short - what the <long string of expletives> could possible be causing the ground loop and how can I eliminate it? I am utterly baffled where this has come from to the point where I am now wishing I had never started this upgrade.

Any advice or suggestions for other steps I can take would be massively appreciated.
Few questions. What country and what voltage mains ? Do all the AC connections have grounds? Have you checked for an outlet with incorrect polarization ?
 
Apr 18, 2022
5
0
10
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United Kingdom which is 230v I believe? Standard UK plugs with ground pins as provided with all the devices.

I dont know how to check the socket polarization but its worked perfectly since we've lived here (12 years) and wont have been touched since the house was built (35+ years), is that likely to be possible under the circumstances?
 

kanewolf

Titan
Moderator
United Kingdom which is 230v I believe? Standard UK plugs with ground pins as provided with all the devices.

I dont know how to check the socket polarization but its worked perfectly since we've lived here (12 years) and wont have been touched since the house was built (35+ years), is that likely to be possible under the circumstances?
This is what you use to test your mains connections -- https://www.amazon.co.uk/QUILLE-Socket-Display-Neutral-Testing/dp/B07GNPKHQ9
 
Apr 18, 2022
5
0
10
0
Thanks for the link, will order one shortly. I do have to question why it would be necessary to test this given that, electrically speaking, i think my setup is as close to what was a known good setup as it is possible to be. By all means correct me if I'm talking rubbish :)

If the wall or extension sockets had incorrect polarization before the rebuild surely this sort of issue would have manifested earlier? I have been using them for over 10 years with my build going through multiple component, case and PSU changes before landing on what was a perfectly working setup a few days ago.
 

kanewolf

Titan
Moderator
Thanks for the link, will order one shortly. I do have to question why it would be necessary to test this given that, electrically speaking, i think my setup is as close to what was a known good setup as it is possible to be. By all means correct me if I'm talking rubbish :)

If the wall or extension sockets had incorrect polarization before the rebuild surely this sort of issue would have manifested earlier? I have been using them for over 10 years with my build going through multiple component, case and PSU changes before landing on what was a perfectly working setup a few days ago.
AC Mains wiring can fail over time. I am just trying to eliminate possibilities. An overheated terminal can have high resistance. It is a useful tool to have in your box, and not too expensive.
 

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