We Need To Talk About Ones And Zeroes

The digital data rides on an analog signal that can pick up noise.

High-end computing ≠ High-end audio where we care how it “sounds”

Doesn't matter.  The question is whether that noise makes it past the Ethernet interface. 

May not matter as much for streamers since ethernet is galvanically isolated from grounds noise.

Technically only if you use unshielded cables.  Though the signal pairs are balanced, transformer coupled there is usually a little cap that goes around them for the shield, if used. 

But the point is still the same, your noise levels are not additive.  You don't get the additive noise of every server, switch and router not to mention Internet provider's equipment.  All you have to worry about is the noise from your router to your devices and how you isolate them.

An astonishing 10 bits (roughly) are used for every 1 bit of the signal.

As I read it's 3:1.  https://en.wikipedia.org/wiki/Compact_Disc_Digital_Audio

Philips also recognised the difficulty of trimming resistors in their resistance ladder DACs, and only bothered to decode the most significant 14 bits.

I fear this is misreading the eight to fourteen modulation (EFM).  In any event, this was 43 years ago and hardly worth discussing to consider the value of Redbook PCM vs. DSD.

My backed-up assertions are

1. Streaming does not guarantee packet delivery nor bit-perfect accuracy
2. Ethernet on its own does not guarantee packet delivery nor packet accuracy nor packet timing
3. USB when used for streaming does not guarantee error-free delivery

At this level, absolutely nothing guarantees error free delivery. This is a straw-man argument where one picks and chooses what they feel is error free or not.

The question is, is it audible?  I'd say no.  What you hear is the quality of the streamer's performance and the original stream.  There are legitimate arguments to be made about any given device's jitter performance or DAC reproduction and that's about all.

So enjoy your cheapie cables. 

Having said this, having heard horror stories of lightning traveling down the cable modem and taking out multiple PCs, TVs and other devices at once without leaving any visible damage I use medical grade Ethernet isolators at the end of long (30') runs. 

Ahhh, the power of buffers and asynchronous output.

What I think many are missing is the idea that streamers are not like the phone of old, with effectively one solid circuit between the caller and listener.    There are two separate processes going on at once.  The part that feeds the buffer and the part that doles out the end result.

For pre-recorded media the buffer/bucket can be 30s big or bigger.  The part that gets the stream feeds it into the bucket ahead of time.  The idea is to have enough time that when the TCP/IP stream says "I’m missing packets" or "I have a broken connection" it has time to communicate back to the source and re-request the missing data or start the stream again.  It’s a subtle science here in making the guess as to what the best strategy is to get things going again and when to declare surrender.    If you stream music in your car you have no idea how much your phone is relying on these buffers to get you through the bridge without interruption. 

Here I monitor my Internet access very closely and have failover Internet so when my cable Internet goes away my cellular Internet takes over.  The process takes about 10-20 seconds.  I can tell you that this has happened repeatedly and this has not affected my music.  Of course there are severe Internet events which eventually stop everything but the power of my streamers to driver right over those bumps is a testament to how resilient this whole process is.

While the feeder is busy fixing up the missing data your DAC or TV still has those 30s of data to offer you, so hopefully the stream gets fixed before the bucket is empty. 

We keep talking about noise.  Ethernet is naturally galvanically isolated to a few hundred volts.  It has to be.  Fiber of course is as well.  The bigger issue in my mind are either surges which are high enough to break through that isolation or your Ethernet cables leaking into your AC or interconnects.

Noise in network transmission is not additive.  My router doesn't add noise to the signal from the cable provider.  Any noise is between my router and the next device down.  Reliability is additive, but not noise.  If you have an Ethernet cable capable of 1GigE with no packet loss and no jitter then congratulations, you've done all you can.

The issue that then remains is jitter on the output.  The input and output streams share a buffer and making sure that they do not interfere with each other is another subtle science, which I’m sure is now tackled by a variety of low level libraries available for the particular microprocessor your streamer uses.  I’m not saying they are all equivalent, but that how well your streamer handles this matters.