Why do I need a switch?

OP:

The ifi iPower adaptors should work well and minimize AC noise generation. RELATIVELY affordable given the usual markup on anything that says "audiophile" on it.

I run my DAC on a Power X version, and then use the next level down for my streamer, and network switch in my HT. 

https://amzn.to/3zqmTUm

So been doing some reading on credible EE related websites, and I found this interesting tidbit:

While Ethernet is DC blocked by a transformer there is also a 1000-2000pF capacitor around the transformer to reduce common mode emmissions.

I wonder if these Ethernet isolators, like iFi or Tripp Lite or Everstar keep that cap in place?

Look at Figure 2, specifically at C2 and C3.

At no point will it improve the signal, and the standard certainly doesn’t state that.

Not an argument I ever made, except in the cases of shielded Ethernet, in which case I could see only grounding one end as being a good idea. 

@fredrik222 Yeah, you also don’t believe in published standards, so you we did go through this and we decided you didn’t know what you were talking about.

Interesting you are changing your tune now, a month or so ago you assured me there was no reason for them ever. Now you are saying there is. We’ll get you there.

Under normal operating conditions it does not do anything at all, it is even says that in the specs you share.

I’ve never claimed it did a thing for audio. :) What they do, which is useful for me, is add about 4kV of breakthrough voltage, forcing potential surge currents to find a path upstream instead of downstream.

I actually do use a switch, but could care less about the audiophile tweaks. I have 5 devices in my HT that need Ethernet. I have a 50' run from my Wifi router to the outlet at the entertainment center which goes to a cheap 1 gbit switch to feed all 5 devices. 

I keep the switch power supply on the "dirty" side of my power conditioners.

I do use a hospital grade Ethernet isolator immediately before that switch, but its’ a surge thing. If lightning were to come down the 50’ from my router it would take out a lot of gear.

OP:

Tp-Link makes them for $20 each, plus the fiber.

The outside coax surge protector I use is this one:

https://amzn.to/3FO9KIg

I don't think you are going to get better sound, but anything with copper that goes through the outside wall of your house can be a surge path.

I use an outside gas discharge based surge protector on the coax and air gap via Ethernet to fiber converters.