ETHERNET CABLES

I wanted to provide a few more details that may be helpful. What is important to remember is while there is signal degradation that occurs in the channel (cable) the processing inside the network receiver and transmitter (pre-equalization) overcomes the signal degradation. Plus, we are talking about a very short run between audio components. The engineers who designed the Ethernet system know what they are doing.

Ethernet cable consists of 4 twisted pair conductors, so 8 conductors total. Each twisted pair carries a differential signal meaning the voltage on the pair is not referenced to ground, but is the difference between the voltage on the two conductors that form the pair. The audio world understands this as being very similar to a balanced audio cable. Therefore, if noise or interference does couple into one or more of the pairs it does not matter because it will for the most part couple into both conductors, which will not change the value of the voltage difference between the two conductors. This takes care of noise, EMI, RFI that may couple into only conductor, and any small amount that couples into only one conductor is accounted for by the slicer that I described above. This is a good link.

As to shielding/grounding, it usually unnecessary unless there is a specific reason and can actually harm the audio outcome. One reason it is not needed is because the signal is a differential signal as discussed above, and the signals values are not referenced to a ground, but to the other voltage value of the two twisted pair. Second, the shielding with grounded will couple one device chassis ground to another. If/when once devices ground is at a different voltage than the ground value of a second device, then couple these two together with a grounded end to end shielding will couple the bad or non-zero ground into the other device(s). In my opinion, if this finds its way into analog devices such as the DAC, where the analog signal exists, that could spell trouble. One might think ground is the same everywhere, however each device may have leakage, coupling, interference, or a bad ground. We don’t what that device’s poor or different ground to leak into other device chassis.  We don't want that coupled from one device to the next.  Trust the designers of the Ethernet system. Grounded/shielded cables can be needed for industrial applications or where specific issues exist, but not for typical 3 foot runs in an audio system.

This is a good link that explains the issued better than me, with multiple posters each providing the information slightly different with pictures. I find this help me understand.

Finally, as to retiming, the data gets retimed at every network device, such as at the switch or router or streamer. This can be performed by retimers, or other hardware in the network interface This is all taken care of so we don’t need to worry about it. This link is a good screen shot because it shows the eye diagram I reference above, with and without re-timing. Notice the improvement due to the retiming module Keep in mind, the digital signal is completely regenerated within the network interface after retiming anyway.

The Audioquest write-up is from the marketing department.  The first paragraph may have validity for analog signals but neither their long grain copper nor the polyethylene insulation will make an audible difference to a digital signal. The second paragraph basically supports their use of CAT7 cable, and/or any other CAT7 cable.

Frankly, I find it amazing that there's so much focus on what could possibly go wrong with a 3-10ft network cable.  Considering the audio isn't transmitted at 1Gb frequencies, then even lowly CAT5 will suffice just fine.  Any decent network cable will do fine.  If one is to believe there is a sonic difference between network cables on a digital signal, then please explain how the signal didn't degrade to unacceptable levels through transmission from the storage server in Qobuz, Tidal, Apple, Amazon, etc., in the hundreds or thousands of miles to your streamer.

@rbmarsh Bingo, forget the miles upon miles of cable that's laid out, or the numerous amount of routers and switches it has to go through. Don't worry though, the 1 meter blue jean ethernet cable is going to clean it all up. 

When a CAT cable runs from a switch to a streamer, there's a situation very simple,  but complex to remove noise.

The switch and endpoint chassis are at different potentials, this is the same as for analog,  noise current starts to flow.

When shielded cables are used, the conductive noise travels far better than unshielded. The exception could be to bond both the switch and endpoint to the same ground, but several meters apart, that's not going to work. Don't use shielded network cables for audio 

Since magnetic fields and differential circuits are supposed not to influence each other, they do. The CAT cable by induction picks up noise from power cables in your house. Any of this noise ends up what you hear. Remove it, and the sound is clearer, since you're not listening to noise.