Thanks! Golf in the morning and big dinner is waiting! Wait, I do that on non-birthday too 
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I asked Lumin which fiber optic mode is preferable for audio purpose, and I just got an email back from them saying that most of their users prefer single-mode over multi-mode fiber optics.
It could be that for audio purpose the single-mode is the way to go. Anyway, I will compare both when I receive my single-mode modules/cable in mid July, or later.
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Indeed. They have a recommendation at the very bottom of their support page:
https://www.luminmusic.com/support-fibre.html
I tried the Corning ClearCurve but I still prefer the Corning SMF-28 to it. Bonus, itâs cheaper. This prompted me to call Corning earlier this year to ask them what the differences between these two cables were. They didnât say much (two different Corning âspecialistsâ were not well trained) but they did send a couple of links.
I will give Fosco the benefit of the doubt that they are using the better (ZBL) of the two ClearCurve cables:
But the SFM-28 still has lower distortion/loss, which probably explains why I ended up liking it better:
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These are good information. I may try SMF-28 too!
This is all a bit of a nonsense.
The performance specifications for fibre cables are measured in kilometres. Probably the only measurement of consequence for a domestic installation is bend radius. The fibre cabling from my server to streamer is 40m, 25m and 15m cables coupled together, and there are a few tight turns. So if you are using conduit, best to keep it quite large to avoid sharp turns.
Both multimode, bought 4 years ago, cost about $50 in total.
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Thanks for the info. Like in any audio cable, material/technology must have an impact.
However I just want to mention that the main reason behind starting this topic was based on testing the effect of a potentially better connector (ultra low loss).
We all know audio cable connectors (analog or digital) are important. For the ethernet cables, good RJ45 connectors have a great impact on the cable SQ. Those who are familiar with Telegärtner RJ45 connectors will sure agree Some time ago, my friends and I experimented modifying various budget audiophile ethernet cable by replacing their cheap RJ45 connectors with high quality ones from Telegärtner and every time there was a very noticeable improvement in SQ. This is why we started digging to find optical cable with lower loss connectors.
We thought that the scientific rationale for trying to optimize digital signal transfer with ultra low loss connectors from Optospan cables was valid, despite the fact the cable material may also influence (unfortunately couldnât control for that). Anyway, the end result was clear. This inexpensive test turned out to be be very positive to our ears and just wanted to share that with people also interested to tryâŚ
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If you read Telegärtnerâs own website, the main purpose of their RJ45 connectors is to make it quick and easy to attach connectors in a confined space and where it is not possible to do a continuity test. It is not about performance, just practicality. The cable wires are still crimped in exactly the same way as when you use a crimping tool.
Of course, this is rarely an issue with domestic ethernet cabling. I use a crimping machine, it is a little fiddly, but I can get a connector on and tested in about 5 minutes, compared to 1 minute to attach a Telegärtner.
A crimper costs about $20 and a tester about $10. The Telegärtner are about $15 each. Normal plastic connectors cost a few cents.
I have a very cheap left-over 30m CAT5 that Iâve used to do continuity tests when each end is on different floors of the house.
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If you had installed one yourself before, you would know right away that these have nothing to do with cheap connectors. Itâs not at all only about practicality.
Other sources of information from that you have probable seen claim that Telegärtner RJ45 connectors use a patented combination of geometry and circuitry to minimize the inevitable impedance mismatch that occurs as when a cableâs 4 twisted pairs are laid out in a straight row. The circuitry is real and this is what the inside looks:
Obviously itâs not only about practicality. For example, the cable manufacture QED, who is a respected manufacturer with reasonable (not esoteric) approaches in their designs and produce generally affordable cables, mention this about their reference ethernet cable: âAny impedance mismatch between the cable and the equipment itâs connected to can cause the signal to be reflected back and forth. Thanks to its precision-engineered, gold-plated Telegärtner plugs with 360-degree shielded die-cast zinc bodies, reflections are minimised and all of the signal is delivered to the load.
Telegärtner was just an example to emphasize on the importance of connector on the sounds of digital signal. You are welcome to try and experiment by yourself if you want. You might conclude the same as AQ claims about the use of Telegärtner RJ45 connectors: âthe scale of this performance difference is slap-in-the-ears obvious and indicative of the difference all connectors make, and installers who compare these connectors will have the opportunity to hear for themselves just how big a deal a connector can be.â
I will stop here talking about the Telegärtner connectors. The point here is to evaluate what are the best cable options for audio in fiber optic networking.
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I do have one Telegartner terminated CAT8, I bought it for AV and that was how it was supplied. Apparently it has some bandwidth advantage that is irrelevant for audio and probably AV, but CAT8 is apparently avery high bandwidth cable.
The little green circuit is simply to align the signal path from the Telegartner configuration to the standard required. The are no active components.
As far as impedance, the impedance of 2cm of CAT cable is about 5nH (Thatâs nano-Henryâs). I can live with that. I havenât read any of the marketing guff you refer to. Anyway, only 4 of the 8 strands are active.
Once a standard connector is plugged in, the part with the shield removed will be inside the device.
The QED cable you refer to is ÂŁ200 in the UK. I have a long bit of AQ Pearl that I cut to length and can make a 1m cable from it for ÂŁ5. So in my mind ÂŁ200 is a fortune for such a cable.
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The problem is that audiophile cables are a massive source of profit margin, and with the chunk of the market now taken by digital signal cable and ethernet (copper and fibre), manufacturers and vendors want to make similar profits just as they did on the analogue cables they now donât sell.
Unfortunately, digital and ethernet cables are used all over the world in vast quantities and are proven technology in that there has to be no data loss.
An ethernet cable will either work or it wonât. In my first attempt at fibre I bought single mode and it didnât work, which is why I ended up with multi-mode.
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I respect your point of view and I donât want to really argue on the claims from manufacturers. Our reading was just a trigger to see if some of this may apply to optical networking.
Knowing that reflection in digital signal an be harmful (Technical Article: Digital Audio Cable Reflections and DACs | Audio Science Review (ASR) Forum) and that it can also be problematic for optical networking (except when distances are over 40km) (How Reflections in Optical Fiber affect Bit Rate), we asked ourselves:
- With short distances as we have in home networks, could it be more of a problem? could a better signal transmission coming from an optimal connection reduce reflection?
- Can we hear the improvement if there is any?
In our case, it was a yes 
Now, letâs see if we were the only ones to hear something positive from this or some other forum members will feel the same or notâŚ
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My ethernet cables are all less than two meters in length, and unfornately I hear difference easily on all of them. When I added the switch, the ethernet between it and the streamer makes more difference than the ethernet cable between the satellite and the switch. But there is obvious difference.
In my system the digital cables make as much difference as analog cables. When I tried the Shunyata Omega USB cable from the streamer to MK2, it blew my mind! It improved the sound so much! It still remains as one item that improves the SQ most in my digital chain, more than the streamer or the switch!
I will find out if fiber optic link matters or not soon.
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I hear differences in ethernet cables, itâs noticable, although not a lot, in the initial 24 hrs of swapping. After that, my brain tells me it sounded the same compare to before swapping.
I donât hear any differences with fiber optic cables, with either 10G or 1G spf modules. Even though I do hear a noticeable improvement swaping from cat6 to optical.
Iâm going to stuck to my ears and not playing around with trying to find the best fiber + spf combo.
Iâm sure in some systems different fiber +spf would sound different, Iâm just glad in my system that is not apparent at all.
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Iâm just going to post this.
Digital data down fibre or ethernet cannot change musical signals on different cables, thatâs not possible with the way digital packets are processed unless youâre talking over vast distances, or you just have really poor quality ethernet.
What are Network Packets and How Do They Work? (techtarget.com)
If your sound is changing with different eithernet or fibre cables itâs because either theyâre injecting information into the stream, or that thereâs something wrong with your transport that is being affected by changes on the network or something wrong with your DAC at the other end thatâs changing packet information as itâs received. From the output processor to the receiving processor (transport to DAC in most cases), there is no change to packets along the network, any changes would result in that packet being discarded.
Digital packets are not even closely similar to analogue signals.
If a digital signal is sent that gets modified in transit, it would be rejected at the other end as it wouldnât match in signature and therefor is bad data, and would be re-requested from the source.
Iâm not saying youâre not hearing a difference, but Iâm telling you, itâs nothign to do with the cables, unless theyâre injecting data packets themselves to âmodifyâ the audio signature.
I realise this is contentious, and perhaps if you have really poor network switches injecting a lot of noise, on ethernet, thereâs an argument that it could influence the sound, but that would be due to poor equipment, but optical cables cannot carry analogue signals, thereâs no conduit, itâs just vacuum in glass which cannot conduct electricity. You want to be looking from your transport to your bridge, or investigate your DAC as those are the packet processors.
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I do not agree nor disagree with others on the views of cable SQ differences. There are enough debates on cables already. I just know that once I heard the difference, there is no going back to being a non-believer anymore. It is pointless to convince others because for assorted reasons, some just donât hear any difference.
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Are you then suggesting that fibre can in fact transmit electrical signals?
I am not suggest that all! It transmits light! So, it should not make any SQ difference! But who knows, I did not believe powe cord would make any difference before.
I thought the fact that digital data is sent in packets with error-rejection could be safely assumed, but obviously not.
@dchang05 I think a lot of audiophiles have been successfully conditioned by the audio media in conjunction with manufacturers and some dealers to believe things have to be expensive to be any good and there will always be something better when you have more cash available. The rest is just your brain applying this whereas the science is totally clear and unambiguous and well known.
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That isâŚ, unfortunatly, possible.
Edit: a few expensive cables make great improvement from my own experience. There are many more probably donât!
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I guarantee, do a blind test with a $5 dollar standard network fibre cable, and a $10,000 dollar audio line of optical, if youâre hearing a difference, itâs nothing to do with the cable, itâs not physically possible, UNLESS thereâs some micro circuitry within the connector side of the cable thatâs creating and injecting packets into the stream, thereâs no other way it could manipulate the sound on a fibre setup. And this is definitely feasible, microcircuits are extremely powerful these days, the tech you can build into a USB head for instance can include a WiFi module to connect to nearby networks, and a microcomputer that can hack the device itâs connected to and transmit that data over the wifi network, all that combined into a standard USB connector. These are common place, especially on public power ports (never use them).
Same with optical cables from CD players or DACS, as you say, itâs just light signals through glass, there is no noise outside of whatâs been packaged at the bridge as no possiblity for electrical transmission.
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