Optical vs Ultra Rendu.

Your setup would be modem>(via ethernet cable)router>FMC>(via optical cable)OpticalRendu>USB in on dac. OpticalRendu $1500 plus FMC $25 or so, $6 optical cable, plus lps for opticalrendu and FMC (optional lps). Get good power supply for OpticalRendu, best you can afford.

At some point you may want to look into getting a switch rather than going out from relatively noisy router.

imho the upgrade to the optical rendu is definitely worth it, it is a noticeable improvement in my system, to my ears

+1 @arafiq 

It looks like the bundle is called the FMC bundle on their website. The price changes automatically when you choose it. I got a $49 extra when I clicked it. You can also choose to get a better power supply, an LPS, which also adds a bit extra to the total price. You do need the FMC bundle unless you already have an optical converter.

I too asked the same question when I was purchasing their products. The optical Rendu seemed to be the same as the ultra Rendu with a built in media converter for the +$700 bump in price. I went with the uR and decided to use two media converters to make the optical filter :

router > ethernet cat 8 > $15 switch > cat 8 > i5 Transporter.

Same switch > cat 8 > FMC > Fiber optic > FMC > cat 8 > uR > USB cable to DAC.

I had completely solved all power problems in my system to achieve a superior black background. The above still had grunge :

1. I added a LPS with a Y adapter to power both FMC = better

2. I added a LPS to the Transporter = better

3. I replaced the LPS power chords with Pangea Audio AC-14SE MkII = better

4. I wrapped my fiber optical cable in bubble wrap. It seems they are sensitive to vibrations. = better

5. I replaced the 3 post switch cat 8  ethernet cables with Pangea Premier SE = way way way better, but STILL some remaining niggly grunge!

I had not bought into the $700-$2000 ethernet switch nonsense. I had bought my $15 plastic covered  switch from Home Depot. I did try a more expensive switch and sent it back because I could hear no improvement. I rewired post switch and removed the FMCs. LISTENED. Then I added the FMCs back in. They were definitely improving the sound, by a lot!

6. I ordered a iFi iPower X Ultra Low Noise AC/DC Power Supply for the switch. I took out the FMCs again and installed the new PS. WHAM!! The sound came into complete focus. I reinstalled the FMCs again and now all the grunge had disappeared. The background is black and transparent to source. I now can hear exactly what Qobuz is offering. It is easy to parse all the different sound qualities offered to us.

So, no, I have not tried the oR, but I am satisfied that I am getting the best sound and saving about $500 in the process. Of course I have 9 boxes and associated cables, but I try not to think of that.

This was a 2 year journey. I learned a ton along the way. I hope it is helpful to someone else.

I too had less than successful experience with audiophile switch, YMMV. With my second ethernet out of server, switch is made superfluous, only adds detour with another added ethernet cable and switch. I use lps on my router, nice upgrade, router only feeds server, no return of signal back to router, simply goes from server to, in my case FMC. With ethernet and optical the shorter the path the better. Very few servers offer second ethernet out, with exception of Antipodes and Sonicorbiter I9, which is optical out. I simply don't understand this omission with most servers since it requires the above roundabout with either switch or router.

Most servers designed without separate streamer in mind which creates the need for switches for those who want to try separate streamers or streamer/dac, usb out of server not for everyone.