ETHERNET CABLES

Everyone keeps focusing on the cable and noise that may couple into the signal on the cable, but the key here is what occurs after the signal leaves the cable in the Ethernet receiver. In a 3 or even 10 foot run, a tiny amount of noise can couple into the signal. However, in the receiver, the received signal is compared to reference or threshold values and based on this comparison an entirely new signal is created. The received signal (and any noise) is effectively discarded. The newly created signal is output at the correct voltage level without the noise. This new signal could be transmitted for another 300 feet (or some other distance based on data rate) or passed on to the internals of the streamer for further decoding. At each hop in the communication path, the signal is re-created and retimed thereby creating an entirely new and clean signal.

While analogies are often imperfect (and I am told, mine are often terrible), think of a piece of blank 8.5x11 inch paper sent through the mail. The post office may crumple it or bend it such that when received at your house, it is crumpled (noisy). However, the person receiving the paper can tell that it is blank piece of 8.5x11 inch paper (albeit crumpled) and they get a brand new piece of paper out of the drawer and toss the crumpled paper in the trash. The received paper was just used as a reference to know what size of new paper to pull from the drawer. Same with an Ethernet receiver. It compares the voltage value of the received signal to a threshold value, to create an entirely new signal (without noise) and the received signal (with noise) is discarded. This is unique to the digital domain and does not occur in the analog domain.

In a PAM4 system, typical of Ethernet, the signal is transmitted at one of four voltage levels, such as 0, 1, 2, or 3 volts. The received signal will vary some what due to noise and effects of the channel. For example a signal originally at 2 voltes, that is transmitted over a long cable run, could be received at 2.2 volts or even 1.7 volts. It would be compared to the four voltage levels and an entirely new clean signal at 2 volts outputted, which is the closest voltage value. The original signal is effectively discarded. This is the benefit of digital communication over analog communication over long distances (and short distances).

Based on this method of operation, the tiny improvement a better cable provides will not yield a different outcome when the signal is re-created.  A signal transmitted at 2 volts might be received with a shitty cable at 2.1 volts and with a amazing cable at 2.08 volts (small improvement).  Both will be compared to the threshold values (0 volt, 1 volt, 2 volts, 3 volts) and the receiver will output a clean 2 volt signal.  

Peace.

@nonoise  

My post was deleted when I asked you put up any evidence for your point. Regardless, there is no evidence for this. I've posted several links showing why noise in ethernet is a non-issue for residential applications. 

And you analogy about streaming TV vs Blu-Ray really shows your lack of understanding of anything relevant at all. The primary difference is bitrate for video and multichannel audio, and it has nothing todo with any type of noise at all. Cable TV is also using a lower bitrate, and is typically compressed with lossy compression. 

Here's one link that explains it to you:

@12many ​​​​@fredrik222 I’d love to believe you guys that Ethernet cables make no difference, and I totally get where you’re coming from about the physics saying they should make no difference. But, I’ve heard enough people here say they not only make a difference, but a pretty sizable difference. In fact, everything in streaming seems to make a big difference. I started streaming from my iPad through an upgraded lightning to USB cable, which was a big improvement over the Apple Camera Adapter, but when I added an iFi Zen Stream things improved exponentially and actually surpassed spinning CDs. So, I bought a mid-priced Wireworld Starlight 8 Ethernet cable I’m gonna try out between my router and streamer and see if it makes a difference versus a garden variety Ethernet cable. If I hear no difference, I’ll just return it. But at least I tried and accepted MAYBE there’s something I didn’t know and just trusted my own ears. You know, CDs were “perfect sound forever” until they finally figured out how to measure jitter, timing, and noise that turned out to be BIG problems and why many audiophiles just stuck with vinyl until manufacturers figured it out. I might hear no difference between the two Ethernet cables, but if I hear a difference maybe sometime in the future they’ll be able to measure it and explain why. But if not I’ll just return the Wireworld cable and no biggie. I also just upgraded from a very decent Apogee WydeEye professional digital cable, which I’ve loved and stuck with for 10 years, to an Acoustic Zen MC2 that is notably better in absolutely every parameter — not even close in a direct A/B comparison. At some point in the past someone would’ve said there couldn’t be any difference because it’s just ones and zeroes (and yes, they’re both 75-Ohm cables), but here we are. I guess what I’m saying is, rather than just blindly walling it off why not just try a “better” Ethernet cable and if you don’t hear a difference just return it? What’s the harm? Worst case is you’ll just prove your point to yourselves, and if not you’ve benefitted from better sound quality and learned something. That’s a win-win either way in my book.

Great analogy @12many

Now add to that crumpled piece of paper a pound of peanut butter sprinkled with sand that was packed into that parcel thoroughly coating every mm of that paper

You will work harder and longer to clean it up to determine that it’s a piece of blank paper 8.5x11. Now your hands are dirty with all the crap you just dealt with to understand what you’re dealing with, you reach into a drawer to pull out a clean piece of paper but you marred it because your hands were dirty. You have a perfect 8.5x11 piece of paper except the remnants of peanut butter and sand. That’s noise that you worked long and hard to clean up but ended up with on a final product.
All digital signal, data packets, etc is nothing but a digital signal being carried thru a copper wire by means of an analog signal that is susceptible to emi, rfi and ground noise. Are you venmoing me a dollar? Will my bank see it as a dollar or $.99.9999 On a receiving end the data packets unfolded properly.
However we’re talking audio and digital to digital and digital to analog conversion that happens inside your audio components. In an ideal world it would have no effect on the final product, all DACs would sound identical and cables wouldn’t matter. Unfortunately in our world it does not work that way and everything matters  

I have extensively tested several ethernet cables for several days of critical listening each. I eliminated the possibility for bias as after 1-2 days of listening you begin to hear the true character of the cable (or its effects on a component) without initial impressions getting in a way.
All cables I have tested sounded different. With one causing slight listening fatigue due to a slight hump in the presence region, another sounding hyper detailed which really worked out for me during low level listening, and another just being dead nuts neutral without emphasis on any particular band.
This is my experience in my system that I consider objective as I have spent considerable amount of time critically listening to each option and even reverting back to see if my results match.
The point I’m trying to make is the theories expressed in this and other discussions on this subject are simply what they are - theories and assumptions. Most if not all the contributors who angrily try to convince others that it cannot be because in theory it’s impossible, have never tried or tested it for themselves, don’t have the systems that can reveal these differences, don’t or can’t afford higher end cables or systems or just simply don’t have the ear to hear the changes between the cables.
It’s all good. But there’s no reason, especially without having any experience behind your belt, to tell me what I hear or don’t hear.

+1 @audphile1 and jibes well with my post above.