Optical Network Configurations

[R1200CL]

2 hours ago, plissken said:

Jitter can only happen when data is x-fered. The faster the x-fer the less time you spend in the jitter-sphere.

Interesting. But since we’re not after speed, and at the same time minimum of jitter, any idea how that should be solved. (Without buffers). 
The speed is more or less decided by the music stream I would expect. 
 

[R1200CL]

2 hours ago, plissken said:

 

This is most likely the 'many' that insist my setup sucks....

Has people done that ? Really? (That sucks too). 
Not fully knowing your system, I’m sure it’s good. 
 

With a PC as endpoint and one GB buffer, you have solved some issues. But how if one would like to stream from Tidal and Qobuz, is there a way to buffer that stream ?

How huge buffer is needed. 
 

Please take some time to explain. (I use Roon, not JRiver). I like to understand. 

[R1200CL]

3 hours ago, plissken said:

I do know better though. I've implemented AVB and AES67 in broadcast environments.

That’s a whole other ballgame or ?

Even you aren’t benefit from that AES67 at home ?

 

How can AES67 help us reduce jitter and phase noise?

I think Roon has strong opinions why they didn’t go that route, so if you’re familiar with them, it would be nice to know and learn where or if they where wrong. I may add NAA also. 
 

3 hours ago, plissken said:

I welcome John and his 31 years of experience to any open public forum to go through this.

Well, that’s a better use of energy that your $8000 challenge. 
 

I’m sure Cris will be happy to facilitate this. 
 

But if you’re only in for professional network from 10GB and above, I can see the challenge of a meaningful discussion.
I’m willing to accept that your and @jabbr setups is alt least equal or probably in several aspects better than etherRegen. So is the cost, as well skills needed to get there. And I’m not after you give me a stressed eye pattern 😀

As an example. Very few of us are able to understand how we can benefit and set up a managed switch. I have one. User manual is huge, and I don’t have a clue how to have any practical use for it.

 

So you can have everything correct and “win” the debate, but still end up as “the looser”. 

What we need from your knowledge is something useful for most of us. 
 

3 hours ago, plissken said:

I'm in a constant state of learning.

Good. Hopefully you can share your knowledge 😀

I have learned a lot myself during the years I’ve been a member here. 

 

[R1200CL]

There are people saying JRiver sounds better than Roon. 

Maybe the reason for that can be because jRiver allows for buffer ?

 

What do you think ?

[R1200CL]

5 minutes ago, The Computer Audiophile said:

There are people saying the Earth is flat. Look hard enough and you’ll find people saying anything you wish. 
 

I recommend listening for yourself. 

Chris, I was looking for a possible explanation why there may be a difference in players. It really shouldn’t, as everything is digital, some some people hear a difference, and I was hoping maybe that buffer thing could be a valid explanation, or part of one. 
 

I think your answer didn’t help much.

 

Here is another question:

Will use of RAAT determine how buffers can be used ?

 

Is there a way to set up playing SW, so that people would agree, that it would be a fair test setup where you only tested the sound of the SW. (Sounds a bit bizarre maybe). 
 

 

[R1200CL]

 

Interesting observation. 

https://www.whatsbestforum.com/threads/taiko-audio-sgm-extreme-the-crème-de-la-crème.27433/page-46#post-587473

 

[R1200CL]

https://www.whatsbestforum.com/threads/taiko-audio-sgm-extreme-the-crème-de-la-crème.27433/page-58#post-596794
 

https://www.whatsbestforum.com/threads/taiko-audio-sgm-extreme-the-crème-de-la-crème.27433/page-177#post-645071
 

[R1200CL]

On 10/11/2020 at 3:01 PM, plissken said:

The music stream is not realtime. It's already sitting somewhere in it's entirety and can 100% be transferred as fast as you can manage to local storage/buffer.

 You may (dis)like this post:

Maybe we bring different switches to your $8000 challenge 😀

[R1200CL]

7 hours ago, barrows said:

Consider: if there was somehow a way which an Ethernet timing clock "embedded" its phase noise/jitter in the data, then the internet would not work because all of the accumulating clock jitter over hundreds, or even thousands of re-clocking steps would so corrupt the data as for it to become unintelligible.  The same could be said of streaming audio from the likes of Qobuz-if clock jitter is accumulating and "embedding" itself in the data, the sound quality of streaming audio would be hopelessly corrupted due to the hundreds of re-clocking steps on the way from the Qobuz servers to one's home (and indeed, I very much doubt also that these clocks are ultra low jitter ones, or that the power supplies used for the internet path from Qobuz to one's home are SJ designs, or even linear for that matter).

Barrows, you should know better than writing this. 
We’re not debating that Ethernet is error free. It is by definition. No one question that. 
(Well some do). Even if there is one or two bit errors, it doesn’t affect SQ. And you know it. 
 

Since we’re not discussing critical time synchronization over long distances, like the White Rabit project, let’s also keep the discussion after what’s happening your ISP modem. 
 

Also fiber will solve some issues, still it’s my understanding we are left with the phase noise issue, and possible some other gremlins that seems to be able to still travel with the digital signal. 
 

Q. What about fiber-optic interfaces? Don’t these block everything?

A. In the case of a pure optical input (zero metal connection), this does block leakage current, but it does not block phase-noise affects. The optical connection is like any other isolator: jitter on the input is transmitted down the fiber and shows up at the receiver. If the receiver reclocks the data with a local clock, you still have the effects of the ground plane-noise from the data causing threshold changes on the reclocking circuit, thus overlaying on top of the local clock.

[R1200CL]

2 hours ago, plissken said:

Which I also offer to you. I've made a proof of concept video showing how this can be done in real-time with me in another room swapping cabling while you listen.

We aren’t listening to the switch in your experiment. Rather the buffer. 
 

Wouldn’t we achieve the same with a WiFi USB dongle?

Music will play after we pull that connection.  
 

Do you accept to do it this way ? If no, why not ?

[R1200CL]

7 hours ago, barrows said:

The upstream clock in the switch is gone and technically cannot have any further influence on the sound quality once the file data is in the downstream buffer, and the Ethernet cable is unplugged.  The clock in the switch is not "embedded" in the data somehow, that clock is long gone when the data is in the downstream buffer, as data in a buffer has no clock reference at that point.  John Swenson has speculated that upstream clock phase noise does matter to downstream playback, but this can only happen when the Ethernet cable is in place (and is still unproven speculation).

To simplify, we can keep this related to fiber transfer. My understanding is fiber solves problem one, solved by the etherRegen. (Ref. White paper). 

Your statement above is more interesting to verify and understand better, as John says otherwise. 
 

This is all about understanding clock threshold jitter, and how it’s being affected further down the chain. 

We will just have to wait until the new products is ready for released. My understanding is he’s quite busy now. (Hopefully he has finished Sonore new products?)

 

[R1200CL]

1 hour ago, plissken said:

and getting as much xfer speed as possible (802.11AX or 802.3ae).

Not sure with paper says anything about speed. 

..as you said:

On 10/14/2020 at 9:41 PM, plissken said:

Considering that 100mbit is ~11 times overkill for 24/192 PCM data...

The only reason someone is promoting 10GB, is the expectation of less jitter. And we’re not 100% sure if there may be other effects we don’t see, (or hear😀). Examples effects of higher power demands. 

Reports say 10GB SFP+ sounds worse. And Finisar data sheets don’t show jitter measurements, as they do with some SFP data sheets. 

 

Even if buffers was the salvation, those that doesn’t have huge buffers (which is many), must still rely on the best possible Ethernet connection. And to 2000 ears, it has happened by the use of etherRegen. 
 

@plissken

Wouldn't it be same sound in your system if you added an USB disk to that PC, instead of network?

Should save you the hassle of unplugging the cable.

 

[R1200CL]

19 minutes ago, barrows said:

There is nothing "embedded" in the data when it goes into a receiving buffer, the data is perfect, and it contains nothing in terms of clocking, as their is no clock in the buffer, just the perfect data and nothing else.

What size is the buffer in opticalRendu and it must have neen a good reason copied it to microRendu 1.5 ?
By size, I suppose time is interesting to, but I think I have sound one or two seconds after pulling the plug.

Any reason not to make the buffer bigger ? 

[R1200CL]

Getting interesting this, as we moving towards buffers, and how data is stored or moved further down. (With or without clock threshold jitter).
 

Maybe even the sample rate of music matters ? Meaning there is (I hope I’m right) much more data that must be processed and clocked with DSD512 or PCM768. Will it affect the possible amount clock threshold jitter ?

I suppose you would then also would need a bigger buffer for the same time frame of music. Hm. Not that it should be an issue. Just a thought. 
 

 

 

[R1200CL]

3 hours ago, jabbr said:

that itself hasn't been demonstrated

Do you agree that clock phase noise (threshold jitter) exist as described by John ?

@plissken: You may comment as well. 

 

[R1200CL]

37 minutes ago, jabbr said:

Are we talking about the phase noise in a specific product?

Not yet 😀

 

Good, so we agree it exist and can be measured. 
So obviously a good clock is essential, agreed ?

 

[R1200CL]

@McNulty Yes you can. You need special termination tools. 
https://michael.stapelberg.ch/posts/2020-08-09-fiber-link-home-network/

[R1200CL]

3 hours ago, fds said:

A pair of FTLX1475D3BCV transceivers has just arrived. Looking forward to try them with the CSS610 MikroTik switches later. This will be my first use of a 10GB fiber connection in my audio system. Will report back.

So you will test against your opticalModule as well as the opticalRendu ?

I’m looking forward to the results. On paper it shouldn’t work. 
Edit. It’s a dual rate module will work. 
 

@jabbr

I think you have been using SFP+ 10 GB modules with success in 1 GB SFP equipment. 
Is this correct ?

[R1200CL]

29 minutes ago, fds said:

The pair of FTLX1475D3BCV transceivers will be put into my two CSS610 MikroTik switches. The first CSS610 is connected via copper ethernet to the server. The second CSS610 is connected via copper ethernet to the oM. Inside my oM and oR I use a pair of PlanetTech transceivers (which I like a lot) or Finisar SFPs (not SFP+) still to be tested/run in.  With the FTLX1475D3BCV transceivers a 10G fiber connection will be created between the two CSS610 switches.

That CSS610-8G-2S+IN looks fantastic for $99. 
Still it would be very nice if you can confirm that the 10GB modules or the present SFP+ modules, will work directly between the switch and either of the Sonore devices. 
I couldn’t find the data sheet for that switch, but I expect the SFP+ cage to be both 1GB and 10GB compatible. As it is with the other cheap Mikrotik switch. 
 

[R1200CL]

I wonder what in theory sounds best.
10GB switch with SFP modules inserted or a switch with SFP cage getting a SFP+ modules.

 

[R1200CL]

 

1 hour ago, jabbr said:

Agree! The trend in the newer SFP28 and QSFP28 adapters is that they auto negotiate lower speeds eg you can typically connect a QSFP28 single mode LC-LC cable to a 1Gbe SFP single mode module and it will work. (1000base-LX)

So this SFP28 should be better to use then. Less possibilities for problems.

 

https://ii-vi.com/product-category/products/optical-communications/optical-transceivers/?product-max-data-rate=16g-32g&product-wavelength=1310nm-band

 

The modules is more expensive. Some very much more. 
 

Not so easy to understand what ought to be the best one. All same DFB laser. 
 

[R1200CL]

10 hours ago, jabbr said:

Depends on what you mean by “best”. If you mean “tightest eye pattern/lowest phase error” then a SFP28 module in an SFP28 port (25 Gbe) or a QSFP28 (100 Gbe) is “best”,

I think we discussed importance of eye pattern before, so yes. 
Also I suppose your answer would be the same 1GB vs 10GB, so on paper 10GB should be chosen. 
 

But you can’t measure or create an eye pattern without a clock ?

So wouldn’t the measurements depending on switch connected to ?

 

2 days ago I ordered the $99 Mikrotik 610-8G-2S+IN . The two SFP+ ports should cover my needs. 
I like to investigate if this switch somehow can be used to divide network traffic to my audio only by using its web interface. SFF+ for audio.

It has been said by some, that dedicated network sounds better. Probably because of less traffic. 
I don’t expect this way to it will actually work as a separate network. (QOS) I think one should create a subnet. (Different IP address). Which I also have the possibility to do. I have used ipCop for many years. Changed to iPfire last week. (Almost equal UI). This firewall (as many others, as well as some management switches) has the option to create subnets and using firewall rules to open up for communication between the physical divided networks. And my HW used for the firewall allows me use SFP. But this for later discussion. 
 

That 100GB SFPQ28 modules fits any SFP port is interesting. And if I understand you correctly, you’re saying SFP28 and SFPQ28 has a higher probability to work between various of 1GB connected devices. 
 

Now that it has been confirmed that the 10GB FTLX1475D3BTL works very well with the tested devices, it could be attempting to test SFPQ28 as well. I looked up price just for one. More than $1000. I guess chips in switch’s that supports 100GB isn’t cheap either. 
I think most wold spend 2,5K and above on other items in their audio chain than on SFPQ28 modules. 
 

There must be a limit where the quality of item used in your digital chain is considered as good enough. 
Either we’re talking about phase noise numbers for clocks or implementation of fiber in HW communication standard between devices used for audio. 
 

I don’t know what prices was when the 10GB modules first came to market. They been around for some years now. The latest data sheet for the 10GB FTLX1475D3BTL is dated April 1017, so quite new I would say. And at $100 price, it’s possible for most of us to test out. I definitely will one day. 
 

I would expect the quality of the items used in the switches and endpoints matter more than trying better SFP/SFP+/SFP28/SFPQ28 modules. 

I hope some day @JohnSwenson will explain more about what devices to focus on on the digital chain and how everything is connected and can be measured. I think what he is doing in this area is quite ground braking. My understanding is he planning to show how phase noise can be measured throughout the whole chain. Maybe the choice of SFP’s will be understood better as well. I do expect the receiving HW to matter a lot also. 

 

Also the chip manufacturers play an important role. If I understand @Superdad correctly, it’s hard to get the best chips. Long lead times. Low availability, or even not available any more. Making these special products John design, a challenge just to meet the market demands.

 

[R1200CL]

I feel a bit responsible for starting this latest fiber optics discussion. 
I think the subject has been enlightening enough now to not making any more confusion. 
 

I did based on knowledge from this tread as well as internet search, found several sources stating it won’t work. Hence I was afraid @AfterDark. started something that could turn out to be problematic. 
 

Now we know better. And the discussion would happen sooner or later. I think better up front. Now we just have to wait for that one guy that won’t be able to make this 10GB FTLX1475D3BTL to work in his specific setup 😃

Edit:

@jabbr SFPQ28 / SFP28 fits SFP cages ?

[R1200CL]

29 minutes ago, pl_svn said:

whilst at it... anyone (@Superdad?) knows if this will work with the EtheRegen? 😶

 

thanks

To answer this correctly, one must know what’s in the other end. With a Mikrotik switch it won’t as it’s a 10GB SFP+. With a Cisco 2960 or almost any FMC, it should work. 
This the area I myself misunderstood.  Hopefully I’ve got it right now. 
 

Orange cable indicate multi mode fiber. Type of laser unknown. 
I assume the modules itself are dual rate. As we now know, that doesn’t matter. 
 

FTLF1421P1BCL (or FTLF1421P1BTL) with yellow cable will always work. They are cheap on eBay. 
 

[R1200CL]

42 minutes ago, jabbr said:

No QSFP28 modules most certainly do not fit SFP ports.

Ops. 
I think I just may created some confusion.

https://www.optcore.net/archive25874/
 

SFP28 is compatible with SFP’s.

 

I think you’re saying if one do happen have a QSFP28 in one end, like you do, you could have SFP/SFP+/SFP28 in the other end. Which even could be the EtherRegen.