Network Switches

If I am using a pair of FMC’s ie. TP Link MC100CM’s at router and then a BJC CAT6 to a single source ie. an Aries streamer, does adding a switch somewhere to the chain make a difference? Or does going fibre with the FMC's already provide enough isolation to cover it.

I only have a single source.

@mikey8811  I was using similar optical isolation with dual opticalModules from Sonore each powered by its own SGC 5V power supply. I replaced the one downstream with the EtherRegen. Kept the opticalModule upstream. This change provided an audible positive SQ difference for me. EtherRegen gives us more than optical isolation. Read the technical details if so inclined:

https://cdn.shopify.com/s/files/1/0660/6121/files/EtherREGEN_User_Guide.pdf?90

Having said this, each system is different. You will need to try for yourself if you really want to know for sure.

@thyname I am unsure if that will work for me as my optical modules are not Gigabit but only 100 Mbps.
From what I have read I believe switches like these and the SOtM one need a Gigabit connection.
The reason I asked is because I was under the impression that switches are used only when you have more than one upstream or downstream connection.

It will surely work. But you will have to remove your fiber modules completely. In fact, this was how it was meant to be for the majority of applications, where there is no optical/ fiber presence 

There is no such thing as an audio network switch. They ALL work on digital mostly ethernet packets. It is LUDICROUS to think otherwise.

PS: I worked for Cisco for 17 years as a software technical lead and I am now at Broadcom as a principal software engineer, who makes the chips for these switches.

It doesn't matter that you work at the ASIC level. It doesn't matter if you understand clock domain boundaries. It doesn't matter that the base clock for Ethernet is 25Mhz (WAAAAY beyond hearing). It doesn't matter that there are PCI-e bus, USB bus, FSB, CPU clocks, paging going on constantly. All that sitting between the Ethernet port and the input on the DAC.
It doesn't matter that 10Gbe that is routinely affordable now can transfer ~ 2 CD's worth of information in a single second and you can pull the cable on many playback computers and appliances and the music will still play.
But go on ahead and keep presenting logic. Could you get one of your PHY guys into the thread?