Let’s just for a moment assume that changing the SFP or the Fibre will have no impact. But there is more in the chain:
FMC: Decoupling the power supply from the mains did bring an improvement.
FMC: Replacing a StarTech FMC with a TRENDnet FMC did bring an improvement
Torben
No need to merely “assume”, it’s objective science fact. 
Addressing analog aspects like a quieter Power Supply for the media converter, and better constructed Media converter itself have already been discussed endlessly in other threads. I see no point in rehashing that all over again.
OK - Than there is no need for further discussion
Torben
I have read parts of this thread and been swamped by some of the technical information given . I use an Optical Converter with ethernet wired input and then sfp optical output to a D-Link unmanged switch sfp input and it works really well . On another forum there was chatter about a better sounding cable which if I am honest I was mystified as to how that works the cable was Cisco SFP-10G-A0C2m or change the number in front of the last m to what length you need.
Now on checking I found that the original Cisco cable bought from them or a network company was really expensive . However I was given a link to an e-bay seller which was £18 delivered which is much more in my league of speculative try outs. This arrived to day and the network was switched off the current cable removed and this one inserted . Given the packing and visual condition this is either a brand new Cisco cable or one in mint condition .
Rebooted the system and left everything time to get reconnected and settled . Then put on a few tracks and was very surprised that as had been said there is a difference using this cable and a very beneficial one . It may be me fooling myself or as is often sited the placebo effect but not really too bothered . This cable works and works well . If you use optical cables and sfp then if you can find one at a sensible price I would say buy it and try it yourself .
@Bencat - Hi Andrew
What SFP where you using before?
Here a PIC of the original label - Cisco SFP-10G-A0C1m:
Torben
I just had a quick google on this and can only find “compatible” cables coming up. It’s the first time I’ve seen cables with a captive SFP module so living and learning!
I often use these type of cable at work, usually the Ubiquiti ones. SFP DAC cable - Direct Attach Cable. Handy for linking devices that are stacked in close proximity.
Active Optical Cables (AOC) and Direct Attach Cable (DAC) are two different things.
Andrew where talking about AOC.
Torben
Have you ever wondered why dCS don’t fit an SFP option? They could have on their new Lina range and also as part of the Apex upgrade.
An SFP option would reside on the network board, and the network board was not part of the Apex upgrade.
They have obviously been planning the Apex and Lina for years, if dCS thought SFP offered a performance edge don’t you think it would have been rolled out?
There is a feature request to add SFP to dCS products, but as usual dCS does not comment on future upgrades:
Lumin X1 and now Linn Klimax have SPF, I considered both before buying Auralic and then moving to dCS. Maybe the replacement ranges will feature SFP, be surprised if they don’t, not least to be feature competitive.
I’ve tried all sorts of IT related tweaks over the years, I decided SPF wasn’t a deciding factor in choosing a digital front end, nor do I worry overly about the type of SPF / Fibre / AOC / DAC (passive or active) that I use in my system, totally fine that others will disagree and feel funds/effort worthwhile but I didn’t hear any worthwhile/any difference so moved on.
I’ve concentrated my tweaks on the mains supply, cabling, power supplies, racks and physical isolation products.
As @Ermos ponts out this is would be a hardware upgrade. These are rare occurences and costly and in his case requiring replacement of the rear panel to provide a port. Fittng a replacement panel to Vivaldi or Rissini? Rhink in thousands of whatever currency unit you favour.
Maybe more likely to be part of some future model if at all.
Aye, the Lina is new though so I would have thought it would have been an ideal candidate if dCS were gonna buy into SFP sockets. Who knows what the future holds, anyway I won’t be swapping my Rossini Apex out for years, maybe never.
Well I guess everyone needs a hobby…
shakes head and wanders off
I settled on the Finisar FTLF1318P3BTL too, as a gigabit single mode capable LC device.
Well I have been using Cisco sfp cable after a couple of listens to others . They were the best for me and yes I am going to say they sound better but appreciate this is going to be doubted by others . Then I became aware of DAC ago cables , these are replacements for optical cables but using copper wire instead . So as they are not that expensive got a cheap pair under £20 for the two . You can all guess what comes next , they make a difference and it is a positive one . Best option is Amphenol sfp+ DAC cable which uses Skewclear cable . But even the cheap generic ones I used make a difference . Another plus for me was being copper wire the shorter the cable the better so that made things tidy . Many will read this and shake their heads and say it can not make any difference but at low cost you can try it for yourself .
