ETHERNET CABLES

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.

@dpop  I’ve only looked at a few ’high priced’ ethernet cables and gave up after finding each one was shielded.

Being cable manufacturers, they didn’t specify if one end only was grounded. Even if the cable is grounded at one end the shield resistance will come into play and it’s more or less mechanical protection. Now this is a problem for length say 10m and over.

Short cables may not matter much, less than 2m, now there you could bond the two chassis together to avoid shield current, but like USB cabling that high impedance noise is difficult to remove.

I use the DX filters in pairs for the ethernet from the router PC, to the EtherRegen, each time there’s a shielded cable, the sound is rough, stage height tanks, treble splashes, just a disaster. Consequently all ethernet cables are UTP, Cat5e. Often tempted to use exotics, but if they are shielded, there’s no improvement, so why bother.