DELL XPS 9570 intermittent ground loop noise

Dear 'community', 

It seems I have finally solved, on my own, the issue with the audio card. The ground loop is related to the Windows power management.

So, since there is no way to disable it after the last Windows updates, we have to do it by regedit. 

The regedit class is the following: 

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e96c-e325-11ce-bfc1-08002be10318}

you have to locate the class registry key for 'RealTek Audio' in my case it is 0006 (you find it in 'DriverDesc' value = RealtekAudio)

 go to the PowerSettings key and change the following values:

IdlePowerState = ff ff ff ff

PerformanceIdleTime = ff ff ff ff

and add a further binary key: 

PM_EAP_Mode = 03

Reboot the laptop and the problem should be solved. 

I hope it can help anyone who is experiencing the same frustrating issue.

In my opinion windows power management is the cause of a bunch of problems which mainly affect audio and network cards, but I suppose even other peripherals.

It is clear there is something which doesn't work with the drivers, and adding a stupid option to disable the power management  would be extremely easy, so I don't understand why DELL doesn't obligate the hardware productors to work on it, or to simply change productors to get the necessary 'quality' which we deserve, since we pay a lot of money for the brand, or just for it I am afraid.

We are practically alone coping with these issues. Thank you DELL. 

Best.

D.