Optical vs Ultra Rendu.

The easiest way to get what you need if going with OpticalRendu, as mentioned above get the FMC bundle from smallgreencomputer. Your setup would be:

modem>router via ethernet cable> server via ethernet cable> optional switch via ethernet cable>FMC (included in bundle) via ethernet cable>OpticalRendu via optical cable included in bundle>dac via usb cable. If you get the bundle no need to worry about getting proper FMC, can be confusing as there are different type optical connectors. Don't worry about lps for everything but the OpticalRendu, the lps sold by smallgreen computer is fine, you could always try other lps at later date.

Great to see more people getting into optical. I recently tried optical after coming across Tom Gibbs’ article. There he invites the reader to try a $100 optical experiment to see how it affects their system. Because my streamer (iFi Zen Stream) doesn’t have optical-in, I converted the line from ethernet to optical and back immediately before the line enters the streamer. The difference with the optical line in place was very big, and I have a modest system. I went with a pair of media converters and transceivers from TPLink, and I went with a 1M optical cable from Monoprice. I big layer of grunge was removed from the sound.

I was recently chatting with an iFi rep, and the rep told me iFi was working on something optical. I think it’s just a matter of time before other streamer manufacturers figure out what Sonore’s already found.

@sns I didn’t realize that slowing down the signal to 100Mbps might be a good way to reduce noise further. That’s interesting. I’ve seen someone suggest that noise created by the extra energy required for SPF+ and single-mode are reasons that the lower standards of SPF and multi-mode might make them better for audio. Like you, I’m waiting for a company to put out a purpose built media converter for audio/video. I also want to see whether optical affects the HT picture.

There is an excellent office switch you can buy cheaply called the Cisco 2960. Despite huge production this business/office switch was still hundreds of dollars when new back in the day as it is built very well with an excellent internal power supply. Bought Used it is only a few tens of dollars these days. These switches have a great reputation in the audio world as the sound quality is comparable with the best audio switches. And it has an optical output which will connect directly to the OpticalRendu > via usb to dac.

Modem/Router > via Ethernet to Cisco 2960 switch > via optical to OpticalRendu

Also you would connect the Cisco 2960 via Ethernet to your Server.

Like all optical connections you need a little SFP module to be inserted into the OpticalRendu optical port and the Cisco optical port. I suspect that the Optical Rendu comes with one so you will just need to buy a compatible one for the Cisco. They only cost a few dollars.

@high-amp I may have assumed too much with my above scenario for your setup. While server is technically feeding the FMC, your ethernet connection to the FMC would come out of router, assuming you don't have switch.

A couple reasons why some use switches in addition to routers. One is they may have an excess of devices on network such that router doesn't have enough ports. Second is router is noisier environment than switch, therefore, switch is acting as filter, some may have better clocks and/or fiber out (Cisco switch mentioned above is one, UptoneEtherRegen another), and then adding the lps is adding to filtering effect. Also gets rid of complexity, getting rid of FMC and another ethernet cable.

Yes, the SFP modules need to be compatible, the OpticalRendu uses LC type connector, it does come with the unit. And yes, slowing down to 100Mbps and single mode are reportedly better, although the single mode not universally reviewed as superior. The purpose built FMC is the Sonore OpticalModule, presume this will result in further reductions in noise and provide better clocking vs. generic FMC's.

The reason I believe some find switches effective in their setup vs mine where I didn't is due to second ethernet port on my server. In my case router or noise is ONLY feeding my server, second port feeding first FMC completely filters network noise, the rerouting or detour required by adding switch only serves to complicate my network path, more direct path superior for me.I assumed cleaning network feeding prior to server would provide superior sound quality, in my case the added complexity  trumped the lower noise floor resulting in more info but cookie cutter images, totally unnatural, and this with audiophile switch with built in lps.  For those without second ethernet port on server, one is forced to use usb from server (usually noisy as it comes directly off motherboard) direct to dac or back to router or switch in order to add streamer, the router dirty, switch cleaner. For most comparing a second ethernet port out of server vs router or switch is impossible as their server's don't have the second ethernet port. I understand the point I'm making here is therefore moot to most, I keep reiterating the second ethernet port in threads because this was one of the most effective network optimizations I've experienced over the years I've been experimenting with network optimization. I would suggest for anyone looking to get a new server, and planning on running a separate streamer now or in the future they get one with second ethernet port! Another point here is that what's downstream of server is far more important than what's upstream, true in my experience and I've been told this from a number of personal conversations with the people at Uptone and Network Acoustics.

Thanks all. 

sns - I do not have a server, if I purchase a bundle from SGC the Sonictransporter i5 would be my music server.

My current router is a combo router/modem, an older Netgear AC1750 so the only reason I presume I would need a switch would be for a optical line for the Rendu. 

There hasn't been much emphasis on modems in most of these "Digital" conversations. My older Netgear AC1750 works great but should I consider upgrading it? It has been discontinued so this is the only this is the only link I could find for it:

https://www.staples.com/NETGEAR-AC1750-Wi-Fi-Cable-Modem-Router-C6300/product_822201