Ethernet connection for best sound quality

Lots of paths to streaming music.  Fewer paths to high end audio streaming.  I studied the options for a couple of years and tried various ways to stream- including using my laptop.  I have a CD Transport and DAC that sounds quite good and as satisfying as vinyl.  I can stream 44.1/16 now and it sounds the same as the CD to me.  Hi res streaming sounds even better and on par with hi res files stored on my streamer.  I qualify this by saying this is based on my hearing and the level of the rest of my audio gear.

Modem- bought my own- stopped using the ISP’s modem.  Added an iFi low noise power supply but didn’t noticed a difference directly.

Router- WiFi 6E router also with an iFi low noise power supply.  Can’t say that did much for the sound either but I feel better knowing the low noise power supplies are there.

[I am no longer using FMC’s in my chain from router to streamer]. Best bang for the buck, I found is to put a fiber optic link between the router and the streamer.  I had two FMC’s with 5V LPS’s and Finisar SFP’s (they insert into the FMC’s).

Bought an audio grade ethernet switch.  This replaced the fiber optic link.  This is the next level up in sound but dilutes the cost/performance ratio.  Also, thinking that the fiber optic link combined with the audio grade network switch would be even better- turns out it is not.

Silver plated ethernet cables.  These make a difference in the sound.  Don’t have to spend a lot- just need to be shielded and silver plated copper wire.  Silver wire might work too but I doubt it makes much of a difference.

Streamer- if you want high end audio get a streamer.  Sure, it is likely based on a NUC. My streamer has an expensive linear power supply.  Absolutely necessary for high end audio.  That is something you don’t get using a PC.  I use a streamer for Roon running ROCK.  The processor has one job to do in a design for music streamer.  I also like the sound better just sending PCM to the DAC.  The less processing the streamer does the better in my system.  Let the DAC do most of the work.

The best sounding DACs and the best Streamers are not necessarily in the same box.  The best sounding streamers/servers will have high quality linear power supplies- something a PC does not have.

I have a CD Transport with I2S going into my DAC.  It sounds amazing.  Before this DAC/Transport combo I would listen to 1/2 to 1 CD and then switch to vinyl- and that was with a very good CD player at the time.  Now I listen to mostly digital.  It sounds so good and more convenient than playing vinyl.  (Vinyl still rocks).  So when I got my streamer and a good USB cable I was surprised to find that my ripped CDs to FLAC files on my music server via USB sound the same as the I2S out of my transport. 

It comes down to the gear and how well it implements the inputs/outputs.  

Here we go.  Another merry go round of discussion between the people who have hifi systems, have experimented and tried various configurations and are willing to share their experiences vs the people with little to no hifi experience but in their close mindedness, I have the answers attitude proclaim that audio enthusiasts are delusional.  It’s the “Emperors New Clothes” scenario, they claim and they are the clever little boy calling out the truth.

Yes, we often come across boxes or gadgets or tweaks that turn out to be not so good.  Not everything is a home run in audio.  The hobby requires an open mind and a willingness to try things that we think shouldn’t work but does and conversely some things that should work but don’t.

My favorite tweak of all times is using a bulk magnetic tape eraser on my CDs.  It was a heated topic in the early 1990’s.  CDs are digital and use a laser.  Bits are bits and light is not affected by magnetic fields and so on.  So I had to try it for myself.  Bought a bulk tape eraser at Radio Shack for $19, kept the receipt so I could return it.  I demagnetized a CD with it and amazingly the CD sounded better.  Not a subtle change either.  People still debate how it works or why it shouldn’t work.  At any rate I still use my bulk tape eraser.  And yes, I laugh when I see these $300 CD clarifiers on the market that merely do that same thing as my $19 device.  As always, Caveat Emptor.

First, claiming to know why a bulk eraser works on CDs is a red flag.  I have a Zerostat.  I use it on my records.  Tried it on CDs back in the day and it did nothing.  
It is obvious you have not tried an audio grade Ethernet switch in a stereo system but you already “know” it doesn’t do anything.  
I’m an engineer but when it comes to hifi I don’t pretend to know what will work or always how it works. I know isolating an amplifier from vibration works but no idea why transistors are sensitive to vibration- tubes maybe. 
Most in this hobby are applications specialists.  We don’t have to know in detail how digital or the internet works.  We apply boxes, cables and tweaks to achieve the best sound possible.   Sometimes not knowing that something should not work is how breakthroughs happen. 
Somebody thought to put bicycle wheels on the first airplanes.  It solved the problem of takeoffs and landings.  More sophisticated landing gears followed.  Likewise, the discovery’s we make today in streaming will become standards in a few years possibly.