Objective-Fi Optical Networking & SFPs

[MarcelNL]

just check used switches etc, there are plenty to go around some....I found a 10Gbe switch in a day and it cost me half of retail.

 

I'd have to hear the 1421, I'm too far gone to dare say that something will sound the same without auditioning.

[Abolive]

28 minutes ago, R1200CL said:

Purchase the $99 Mikrotik. That’s replacing both TP Link mc220l -> Zyxel. And you even get a managed switch. Not bad at all. 

You are right, I had a look at it, but brain fart in my precious post, I have the telly AND the Nuc to connect 😅

[Abolive]

@R1200CL thank you very much for your advice. I'll go for this solution 👍

[tategoi]

2 hours ago, R1200CL said:

Go 1421. That’s cheaper, and same technology inside. 
 

I predict same results SQ as with the more expensive 1475. 
 

 

Here is my advice on fiber. Copied earlier posts in other threads. 
 

Use single mode fiber and DFB laser ("distributedfeedback" versus FB (Fabry-Perot) Finisar 1421 is good, and should be found cheap on eBay. 
https://audiophilestyle.com/applications/core/interface/file/attachment.php?id=82650

 

You can also use SFP+ mudule. 
https://audiophilestyle.com/applications/core/interface/file/attachment.php?id=82648

 

You may check comparability with your switch/router. EtherRegen works with both.

If you have a 10GB switch, You can’t normally use 10GB SPF both places. I think most users could stay away from 10 GB modules. There is absolutely no reports on better SQ. 

You want yellow cable with blue connectors. 

 

I would say that a DFB laser(1421 & 1475 ) is technologically better than a Fabry-Perot (1321 & 1324) laser. And usually more expensive as well. 
DFB has better (lower) Relative Intensity Noise (RIN). Jitter numbers is better as well. 

 

If this means better SQ, I can’t say, but this is one reason I recommend DFB laser for SFP modules. Just to be sure 😀

 

 

Here is a link to the matrix of all the current Finisar (now owned by a company called "II-VI") transceivers:

https://app.boxcn.net/shared/static/51oh3iddtgitlc9h4cpaap1ijziv575v.pdf

(Thanks for finding that table Superdad. It lost it before). 

1475 is very expensive but I found that 1471 is priced more reasonably. Would 1471 also a good substitute? I could not find the 1421 in my part of the world. 

[MarcelNL]

try Mouser or similar large electronic component supply companies, I received the 1475 within 3 days delivered straight from Texas.

[R1200CL]

22 hours ago, tategoi said:

1475 is very expensive but I found that 1471 is priced more reasonably. Would 1471 also a good substitute? I could not find the 1421 in my part of the world. 

I can’t find 1471. Do you have a data sheet?

[tategoi]

1 hour ago, R1200CL said:

I can’t find 1471. Do you have a data sheet?

https://www.digikey.be/htmldatasheets/production/1229260/0/0/1/FTLX1471D3BTL-Specification.pdf

[tategoi]

11 hours ago, MarcelNL said:

try Mouser or similar large electronic component supply companies, I received the 1475 within 3 days delivered straight from Texas.

The Mouser here only has stocks on the FLTX1475D3BCL but I read that the last 3 letters must be BTL. 

[MarcelNL]

hmm....let me see, as mouser ships from one location AFAIK

 

2 available:

https://nl.mouser.com/ProductDetail/II-VI-Finisar/FTLX1475D3BTL?qs=sGAEpiMZZMv0NwlthflBi7FcgewVIDdNmLLpSh5jyIU%3D&countrycode=DE&currencycode=EUR

[R1200CL]

On 2/8/2022 at 12:02 AM, tategoi said:

Would 1471 also a good substitute?

I would think so, but you may run into trouble, but i really don't know.

 

"The FTLX1471D3BTL is a “limiting module”, i.e., it employs a limiting receiver. Host board designers using an EDC PHY IC should follow the IC manufacturer’s recommended settings for interoperating the host-board EDC PHY with a limiting receiver SFP+ module"

 

https://www.lightwaveonline.com/optical-tech/article/16649832/technology-advances-for-sfp-limiting-module-designs

 

[Franciscogaston]

About Fiber and RJ45.

There are filters for ethernet that justify its utilization due to the ethernet noise which affect the signal going to DAC. I plan to test ENO filter ,800€, (network accoustics) and let you know if it is a difference. If there is such difference with short distances, not industrial ones, instead of using filter with RJ45 the other option is start with a router with optical ouput and utilize a device like Optical Rendu from smallgreencomputer.com, with optical input and usb output to the dac, so I get a galvanic isolation and no noise from ethernet, aside the absence of emi interferences that come into the Cu cables and affect the signal quality.

I have not yet experienced both solutions, filter or optics, and as well economic evaluation of both.

Instead of a Router with optical output it could be used a swicht with optical output.

If testing the ENO filter by network accoustics I ear clear differences, the following decissionis either filter ethernet or go optical network.

If anybody have experience already please share it

[jabbr]

On 2/12/2022 at 6:18 PM, Franciscogaston said:

About Fiber and RJ45.

There are filters for ethernet that justify its utilization due to the ethernet noise which affect the signal going to DAC. I plan to test ENO filter ,800€, (network accoustics) and let you know if it is a difference. If there is such difference with short distances, not industrial ones, instead of using filter with RJ45 the other option is start with a router with optical ouput and utilize a device like Optical Rendu from smallgreencomputer.com, with optical input and usb output to the dac, so I get a galvanic isolation and no noise from ethernet, aside the absence of emi interferences that come into the Cu cables and affect the signal quality.

I have not yet experienced both solutions, filter or optics, and as well economic evaluation of both.

Instead of a Router with optical output it could be used a swicht with optical output.

If testing the ENO filter by network accoustics I ear clear differences, the following decissionis either filter ethernet or go optical network.

If anybody have experience already please share it

 

There is lots of back and forth on ethernet filters vs optical. Ethernet filters are designed for and are used to reduce leakage currents in the endpoints induced by common mode noise which might travel down the copper Ethernet cable.

 

fiberoptic cannot transmit common mode noise so I just use it. I mean if you are going to spend thousands on fancy ethernet cables and hundreds on filters why not get an opticalRendu (or fitlet) and be done with it? You don't need to worry about upsteam jitter nor common mode noise.

[PYP]

29 minutes ago, jabbr said:

 

There is lots of back and forth on ethernet filters vs optical. Ethernet filters are designed for and are used to reduce leakage currents in the endpoints induced by common mode noise which might travel down the copper Ethernet cable.

 

fiberoptic cannot transmit common mode noise so I just use it. I mean if you are going to spend thousands on fancy ethernet cables and hundreds on filters why not get an opticalRendu (or fitlet) and be done with it? You don't need to worry about upsteam jitter nor common mode noise.

I started with the eR to reduce noise, then added an opticalModule.  Interestingly, the opticalModule did further improve sound quality until I added a second eR at which point the optical solution wasn't needed -- two eRs sounded better.  Just my setup, but the optical solution I tried did not eliminate all the noise.  Perhaps it is different if one runs fiber from the router...or perhaps the eR eliminates other kinds of noise.

[jabbr]

On 2/19/2022 at 8:26 PM, PYP said:

I started with the eR to reduce noise, then added an opticalModule.  Interestingly, the opticalModule did further improve sound quality until I added a second eR at which point the optical solution wasn't needed -- two eRs sounded better.  Just my setup, but the optical solution I tried did not eliminate all the noise.  Perhaps it is different if one runs fiber from the router...or perhaps the eR eliminates other kinds of noise.

 

Since we are on the objective subforum, let's try to look at this:

 

1) there isn't a direct correlation between network noise and the noise you hear.

2) I can't guess as to what noise either of the devices you listened to injected into your audio system, or if they did without measurements.

3) compliant 10Gbe and faster network devices have to be tested using expensive equipment to ensure that the do not transmit jitter and differential mode noise (in the case of copper). Fiberoptic does not transmit common mode noise (directly)

4) without measuring, its hard to speculate why two devices in series would be better than one.

 

I don't worry about this and use professional grade equipment. Also isolate my audio area with a robust transformer, and no cheap SMPS  power supplies in the audio area.

[PYP]

56 minutes ago, jabbr said:

I don't worry about this and use professional grade equipment. Also isolate my audio area with a robust transformer, and no cheap SMPS  power supplies in the audio area.

While I don't have the expertise or equipment to measure what cheap SMPS do, I certainly agree with you since I can hear the difference and it isn't subtle.    Compared to a quality LPS, the sound is thin and can be tipped up in the highs.  Not like live music.  

 

The measurements I would like to have for all equipment is:  1.  the noise that the component injects into the system, and 2. the components ability to reject noise coming through the power cord.  

 

Personally, I found that large isolation transformers can be a mixed bag.  When I had a DIY hypex module-based amp, the dynamics were reduced by the transformer (nice Bryston).  

[Franciscogaston]

Just for information of everybody. I did try for a few daysan ethernet filter. EVO, connected before the input of my streamer and from the swicht. The improvement of quality of the sound was very very significant, a lot mor of definition clarity and separation of instruments. Ver Good. It cost is high, near 900 € plus cables.

It proves that either the router is introducing noise that deteriorate the musical signal or as well the signal coming from the net is polluted with noise. There are some technical explanation about,  if bits are bit how it can happen. Actually the base for the explanation is the ditter and the noise coming, finally a bit is an increase of voltage (analog) wich is not perfect. See  https://youtu.be/Elo6cQ1UW1l

I imagine that very high end equipment could have in their structure filters to cancel all those bad effects.

So after this test I am now going now just to test a swicht with optical output and a converter from optical to RJ45 to input in the streamer.

[Archimago]

So guys...

 

We're 8 pages into optical networks / SFP networking discussions. Is there any objective evidence (I include controlled listening A/B testing) that this makes a difference?

 

Considering that we don't listen to ethernet data, but analogue output from DACs, has anyone ever shown objective benefit after all this time?

 

[R1200CL]

Hi  @JohnSwenson

How is your measurement’s going ?

 

If I remember correctly, you said you may have a way to measure “noise” being showed on DAC output depended on the digital quality input. But you needed to build the equipment for measuring your self. 
 

Is there any progress in this project you can share ?
 

So fare I think it’s beyond no doubt that phase noise matters. Even @barrows surprisingly had to agree a better clock could improve the already superb opticalRendu. 
 

@Archimago

I’ve been told it’s possible to measure the noise in the streaming algorithm in use from the various streaming services. And there is a difference. (And I also know what service won). I think the experiment was done in Netherlands.

But this noise has nothing to do with sound quality at all. But it’s an interesting observation. 
 

As I’m also a bit fascinated about the possibility to have external clocks remotely located.
Below is a reply I got those guys that probably have best knowledge about these things. 

 

I was also thinking as the ultimate solution, the streaming services or Roon could implement a remote clock. 
However, it seems to me this isn’t a way to go. The phase noise numbers isn’t good enough. (Maybe someone will disagree). 

Still all digital signals locally over fiber is what I believe to be the future.

———————————————-

Dear Andreas, 

Apologies for the delay in responding, I was busy with conferences in the last couple of weeks. 

First let me clarify: 
- in TiFOON, we look at clock signals delivered over fibre, but not usually using ethernet protocols. The technologies we consider interact with the physical layer directly. In many cases this means we use dark fibre, or at least a piece of spectrum like one ITU DWDM channel. For ethernet-based time and frequency transfer, see White Rabbit. 
- also, in TiFOON, we look at techniques combining optical frequency transfer with "normal" time and frequency transfer, like 10 MHz and 1 PPS signals. Optical frequency transfer means that the light wave transmitted in the fibre is itself the clock signal. This method achieves the best relative instability. One approach we have persued is to simply send both an ultra-stable laser signal and the signals of a commercially avaialble RF-over-fibre system through the same fibre, separated in wavelength. 

A state-of-the-art RF-over-fibre system like ELSTAB (commercially available unter name OSTT) achieves an Allan Deviation of 3e-13 at 1 second averaging  for the 10 MHz signal, and a time deviation of a few ps for the PPS signal.  Ref: https://doi.org/10.1109/TUFFC.2015.2502547 (available for free here). The phase noise of the 10 MHz is about -105 dB @ 1 Hz and - 120 dB @ 10 Hz. Ref: https://doi.org/10.1051/0004-6361/201730615 
 

[Franciscogaston]

Hi, as i have already reported here my test with the EVO filter which clearly showed a much better Musical quality. It prove for me the noise and ditter coming with digital data from router and internet fiber.

I did ask to Dr Weiss manufacturer of an excellente DAC 501, advice about installing optical fiber and he answer to me that he does not expect any difference in his DAC either using Cu or Optical fiber in his DAC due to its internal architecture.It could be that in high end DAC the internal hardware is able to cancel the ditter and noise effects coming from Internet. But in any case what it is proved is that the galvanic isolation obtained with the optic is positive.

See the video https://Youtube.be/Io4SDi5hLxs

My question is if only the galvanic isolation of the fiber cancel noise and Ditter It seems not.

 

[jabbr]

On 4/30/2022 at 7:16 PM, Archimago said:

So guys...

 

We're 8 pages into optical networks / SFP networking discussions. Is there any objective evidence (I include controlled listening A/B testing) that this makes a difference?

 

Considering that we don't listen to ethernet data, but analogue output from DACs, has anyone ever shown objective benefit after all this time?

 

 

It is rather easy to show that fiberoptic ethernet does not transmit common mode noise which results in leakage currents. Such leakage currents are widely considered relevant in hospital/ICU settings where there is the theoretical risk of cardiac events.

 

In any case Ethernet leakage currents are measured by industry. There are electrical measures (filters, isolation transformers) to mitigate, however fiber trivially eliminates.

 

Do leakage currents aka ground loops cause audible problems? Obviously. They have been measured forever and the audible effects well documented.

 

So its more than measureable. We don't need controlled A/B listening tests to want to eliminate ground loops. There are many ways to eliminate ground loops. I, for one, use multiple methods including fiber ethernet, isolation/balanced power transformers and balanced audio circuits.

 

 🚫 common mode noise

 

[muski]

Quote

 

Has anyone else tried the Finisar FTLX8574D3BCV SFP+ module?

 

I noticed on the Small Green Computer site that the Sonore Signature Rendu SE II now comes with the Finisar FTLX8574D3BCV SFP+ module. I ordered a pair from Mouser and installed them in my OpticalRendu and TP-Link MC220L connected by Jeirdus 20M 10G OM3 cable.

 

Wow, what a shocking improvement over over the TP-Link TL-SM311LM SFP. I had tried a few other SFP and SFP+ modules including the Finisar FTLF1321P1BTL and the 10Gtek AXS13-192-10SFP+, but hadn't heard any difference between them. I was beginning to think all SFPs sounded the same...

 

But with the FTLX8574D3BCV a wider soundstage, less harshness and improved mid-bass suggest that these modules really reduce noise. At $128/pair, that was the highest ROI audio purchase I've made in a long time. I wonder if the OM3 (vs OM1) cable is also helping here?

 

Looking forward to adding the new Sonore OpticalModule Deluxe next.

 

Cheers,

muski

 

[tategoi]

I am not surprised by your finding. I had a chance to play with a few SFPs and my observation is FLTF1321P1BTL < FLTF1324P2BTL <<< FTLX1471D3BTL. The biggest jump is from 1324 to 1471. A friend bite the bullets and bought FTLX1475D3BTL he reported that the 1475 is superior to the 1471. 

[GoodEnough]

Can I ask for advice regarding the set-up of a StarTech ET91000SFP2 FMC?

Does anyone know which DIP switch settings are optimal? I'm using just the one ET91000SFP2, and it will be taking an ethernet cable from my Netgear Orbi mesh satellite, and passing optical to my EtherRegen.

My SFPs are a collection of Finisar 1318, 1321, 1471 (whichever will sound best in the new Startech)

Thanks
Mark