Noisy ethernet cables

@erik_squires , You probably want to stick with shielded Ethernet, regardless of the Cat #

Why? Many devices don’t have connectors that support the shield connection. Worse, shields connected at both end are prone to creating ground loops. They are designed for high speed communication of digital data, not for ensuring the lowest analog system noise. Shielding one end can work, but still back to the issue of whether your connection supports the shield.

This is another one of those audiophile group thinks (not offence @erik_squires ). People just assume shielding must be better, therefore it must sound better. Shielded at both ends cable was designed for noisy commercial environments, not for your typical home use. The shields are to protect from external noise, in a high noise environment. It was not targeted at home environments. The shield at both ends is a recipe for ground loops where they would not have existed with unshielded cable..

Only 1 end of an Ethernet connector needs to be shielded to work, and it’s nearly impossible to cause a ground loop via Ethernet cables. Ethernet signals are inherently isolated and balanced. There’s no galvanic path from them into the devices they connect to (barring PoE). I could see a streamer maker use a grounded plug which causes a loop, but that’s really bad design.

@erik_squires , sorry that is wrong.

Many shielded ethernet cables ARE shielded on both ends, and that shield connects to case ground on both ends. Audio circuits often have capacitive couping to case ground if not a direct connection from the DC ground to case. Surprisingly many linear supplies use a grounded plug, as do most things with metal cases and integrated AC supplies.

POE, if compliant to the specification is also galvanically isolated.

If you don't know how your shielded cable is built, you are better off in most cases not using a shielded cable because to your point, the data portion of the transmission is galvanically isolated.

Many shielded ethernet cables ARE shielded on both ends, and that shield connects to case ground on both ends

Oh, so wrong. ALL shielded ethernet cables have shields at both ends.

The cable shield is end to end, with the RJ 45 connectors on both sides having a shield connection. That doesn’t mean the equipment maker is forced to use a shielded socket or to ground it. No shield connection on the socket, no ground connection there.

and that shield connects to case ground on both ends.

Only if the equipment designer makes it a choice to do so.

The shield on an Ethernet connection is not carried by the signal wires inside the jack, but on an outer foil like connector. It’s hard to see, but here:

As a streamer maker, you can either ignore that shield, or keep that shield separated from the rest of the system. You are not obligated to connect this shield at all, or to the equipment case.

Don’t confuse the shield on an Ethernet cable with the case and safety ground connection that is made to an AC outlet. They are two different things. There is no safety requirement that a signal cable be case grounded, and in fact lifting or isolating signal grounds whenever possible is good practice.

@erik_squires ,

Except the Ethernet connector, metal shell, where the connector plugs into, is usually connected to the metal enclosure to improve the EMI. Even before shielded Ethernet cables were common, most connector shells were metal to form a seal with the metal enclosure for EMI purposes. I am well aware of Ethernet implementation (hence why I know POE is galvanically isolated if done to the specification).

Signal grounds very commonly have capacitive connections to case grounds where they exist for noise reasons.

In the average home environment, unless you are co-running your Ethernet in long run in parallel with a seriously noisy AC like in industrial/commercial, there really is no need for shielded. There simply are not the noise sources to make a difference. As you noted, it is already galvanically isolated.