Something else you could look at to reduce network line noise is presented in this article by Michael Lavorgna titled, "Electrically Isolate Your Networked Audio" - a relatively inexpensive add in the audio world:
https://www.audiostream.com/content/electrically-isolate-your-networked-audio
I power mine with a LPS.
https://www.audiostream.com/content/electrically-isolate-your-networked-audio
I power mine with a LPS.