Why do I need a switch?

@tonywinga 

So from the router I’m running a Netgear Powerline. One end is plugged into a UPS and the other is plugged into the same outlet my integrated is plugged in. It’s because of the Powerline device that I went with the Ethernet to fiber setup.  Maybe it could be adding noise. 
FYI, I can’t hear the difference between WiFi from the Nighthawk router and using the Powerline.

NETGEAR Powerline adapter Kit, 2000 Mbps Wall-plug, 2 Gigabit Ethernet Ports with Passthrough + Extra Outlet (PLP2000-100PAS) https://a.co/d/cKOpK93

So you are using some type of Wi-Fi device?  That changes the game.  

1) Put the fiber section between the router and the Powerline device and see if that sounds different.

2) Try to run an ethernet cable from your router to your music server with and w/o the FMC’s in the chain- if you can to compare the sound.

I bought a long ethernet cable and ran it from my audio grade network switch, which is after the FMC’s, to my TV at the other end of the house.  The picture looked so much better that I ended up working 6 hours running that cable through the walls and under the house to the TV.  Running an ethernet cable to the 2nd mesh router at that end of the house made the TV picture just about as good but since I had to run one cable to that end of the house it wasn’t much more to run two.

@curiousjim 

So, I was thinking about getting a Denafrips Iris DDC to do the reclocking job, but haven’t made any firm decisions yet.

I bought a Denafrips Hermes a couple of months ago for the similar reason, plus to try converting USB out of my streamer to AES/EBU that I could input into my DAC.  The Hermes and Gaia offer more options for clocking, particularly if you have a Denafrips DAC, but my first step was to try it as a converter and hopefully send a lower jitter signal to my DAC. 

Regarding the sound, it seems to sound at least as good as running a USB direct from my server to my DAC.  This may say more about my server and DAC since they have quite high quality USB interface boards.  At the least, I can say putting the Hermes in the chain does no harm sonically but, again, I did not even use the clock function so there is probably considerably more potential to be had.

Digital is about clocking and power supplies. This is where switches and USB reclockers come in. On Ethernet, the fibre route works up to a point since it doesn‘t suffer from EFI/RFI noise incursion. Alas, the converters themselves aren‘t the best time keeping devices and create distortions of their own. Ethernet can be made to work, but only with a lot of effort. In my case, I employ three switches with associated linear power supplies after the router. The router, which only has the system as client and its own LPS is followed by a simple Netgear router after a 25ft line, this in turn is followed by a LHYaudio Ocxo switch which I can‘t recommend highly enough, which is again followed by an Etherregen, which is clocked by a Antelope 10m clock. Power supplies are LHYaudio and Sean Jacobs for the Etherregen. From the LHYaudio switch onwards cables are 50 cm in length and top quality cat8 throughout. This setup is the result of 3 years experimentation

And btw: on the USB link reclocking and galvanic isolators are required, again with LPS.

@tonywinga 

I’ll try moving the fiber to the router end of things and see if I hear anything.

 I have a 100’ Cat 6 cable, but it has to go down and cross the hallway before I can connect it to the server. Not wife approved!😁