2020 Mac Mini (Intel) - Ground Loop Troubleshooting

[March Audio]

Hi

 

I talked about ground loops here:

As people have already pointed out grounding the Mac may help by reducing the noise currents flowing in the audio interconnect shields.  If it doesn't you can try a galvanic isolator.  Hopefully the cheap solution will work first.

 

https://intona.eu/en/products/

 

Edit:

I just looked at your interconnects and became a little suspicious about their construction.

 

Our Triple-Balanced Geometry uses a separate ground-reference conductor, so the cable's shield is never used as an inferior conductor.

 

This implies an increased resistance for the low signal conductor as its not using the shield which is the last thing you want if you have ground loop issues.  I suspect the shield is only connected at one end.

 

Try swapping these cables out for one of normal construction, with a thick low resistance shield.

 

[March Audio]

Hi 

 

Actually I was referring to the audio interconnects not the usb 😀

 

At the end of the day this is a fundamental flaw of single ended RCA systems where the low signal wire is also used to connect component grounds together.

[March Audio]

Ethernet is indeed a potential solution as it is galvanically isolated.  It achieves the same as the Intona USB isolator I mentioned above. 

 

Just be aware that mains filtering in itself wont solve this issue.  In fact it can make it worse.  Typical Mains RF filters have Y capacitors which connect line to ground. This can end up feeding mains currents into the low signal (shield).  Its the same reason why the SMPS for the Mac is introducing these noise currents and creating an audible hum.