Optical Network Configurations

[vortecjr]

16 hours ago, jabbr said:

@vortecjr I want to comment on the fact that I’m not meaning to say that a 10G switch is better than your bespoke FMC: opticalModule where I understand that it was designed with attention to clock & noise. I’m commenting instead regarding the $25 FMCs or the $100 SFP switches (1Gbe) for which I can’t make any comment on the amount of jitter etc on the wire ... I can’t say either way whether jitter “gets through” these interfaces because I haven’t seen tests — end to end tests aren’t required for 10/100 Mb or 1 Gbe. It’s reasonable to make a high quality FMC for the home audiophile. I can say that jitter doesn’t accumulate and pass through the 10G+ systems because that’s tested for (end to end jitter)

 

I mention this because early on in this thread we recommended cheap FMCs and switches, but I’ve personally moved on from that. (they work fine)

Understood. Let me know if there is anything i can do to help you in your endeavors.

[matthias]

2 hours ago, Miska said:

In this respect it would interesting to compare air gap isolation (WiFi) and optical networking...

 

+1

 

Matt

[Superdad]

On 7/16/2019 at 3:41 PM, vortecjr said:

Yet some people here claim they can here it’s affects. Maybe those people found to have this special gift can be rewarded an S to wear on their chest:) Seriously, what John is proposing is more for completeness than it is for practice listening advantage compared to other things like power supply noise which is easily measured. 

 

Really Jesus?  Then why bother using a Crystek 575 in the opticalModule and optical/ultraRendus? Put a $1 XO back in if you don't believe it make a difference. 

[vortecjr]

Really Alex? Do you claim to hear the difference in the noise floor at the output of your DAC? If you do I have an “S” for you:)

 

I’m talking about structuring things in the order of importance based on measurements. I maintain that the power supply is the foundation of that structure and because it’s easily verified with measurements. Obviously I believe in John’s work and insisted on the oscillators we use. These oscillators finish off the low noise design because of John’s work on the power circuits that feed them. This and other design considerations are for completeness simply because good enough is not best. 

[Superdad]

17 minutes ago, vortecjr said:

Really Alex? Do you claim to hear the difference in the noise floor at the output of your DAC? If you do I have an “S” for you:)

 

Well, not the "noise floor" but certainly the effect of jitter/phase-noise. 

And you can remember the 2015 history here as well as I do:  

During development of the ISO REGEN--before even putting on the Silanna GI chip--we built two identical versions of an überREGEN, with the one and only difference between them being the version of the clock.  One had the $1.05 Crystek C3391 (as used on the original USB REGEN and microRendu v1.3 and earlier), the other had a $9.70 Crystek CCHD-575.  Took all of 30 seconds to hear the significant difference between them.  

Shortly after--same or next day--either John or I called you (can't remember who) raving and suggesting you try out the CCHD-575 on the microRendu. You did, and that became the microRendu v1.4 board which you offered as an upgrade until the ultraRendu came out.

 

I guess I am just puzzled about why, with your own first-ear and ample anecdotal reports from your own customers, you today seem to be dismissing the relevance of phase-noise/jitter on packet-data interfaces.

Yes, I know we have not yet the measured proof.  [Would either of us like John to stop all product development and problem-fixing work on Sonore and UpTone products to finish the "Golden Gate Bridge clock-block test system" that he and I have been funding for the past two years?] But between the logical hypothesis he has put forth and the many improved-clock products selling and being discussed, I sure don't think people need to be branded with an "S" just for giving the matter consideration when they hear differences. 

 

Of course it won't be very long until the theory of blocking the upstream phase-noise fingerprint of Ethernet is put to test in the market. EtherREGEN puts the Ethernet signal through active LVDS digital isolators and ultra-low-jitter differential flip-flops--with separate power and clocking domains.  Lots of people will be able to compare it to your opticalModule FMC, which, while using a single instance of one of the chips chosen for the  EtherREGEN, and using the same CCHD-575 reference clock, does not have an isolation moat or flops to produce a fully isolated output.  

By being designed by the same mind, with similar voltage regulators, some of the same chips, and the same reference clocking, the comparisons between opticalModule and EtherREGEN will be a very fair test as to if galvanic isolation (via optical) and a simple reclock is enough--or if complete isolation of data/power/clock domains results in further SQ gains for DAC-connected renderer end-points.

 

I know you Jesus, so I know my frank talk above possibly is making you hot under the collar.  So let me finish with two points:

1) I really don't know the answer to the questions raised as I have yet to hear with my own ears an EtherREGEN or an opticalModule. (Full disclosure, I hope/expect the results to be good as I've already spent/bet close to $100K on seeing this through. )

2) EtherREGEN functions as a full multi-port switch, and thus will find much broader usage than your fine FMC. (This despite that we both know the Sonore/UpTone fanboys love to make a ruckus and conflate all this stuff together. )

 

Good times ahead!

--Alex C.

[jabbr]

2 hours ago, Superdad said:

 

Really Jesus?  Then why bother using a Crystek 575 in the opticalModule and optical/ultraRendus? Put a $1 XO back in if you don't believe it make a difference. 

 

Alex, there is a long history of using low phase error clocks in modern networking equipment — as I’ve said, and provided the easily available links to test methods to meet standards defined in modern Ethernet specs ... I do see the reasoning behind designing 1g and 100m Ethernet interfaces using modern techniques.

 

That said upstream phase error is known not to be transmitted to downstream links in anything approaching an additive fashion otherwise 10Gbe -> 400Gbe networks wouldn’t work! 

 

There are cases, such as the Solarflare Flareon line, whose clocks exceed the baseline 10G requirements, and these cards have been designed to have exceptionally low latency for use in high speed trading environments. 

 

In any case the meme that upstream phase error somehow infects the network network and thus gets transmitted to the DAC, appears not to be the case assuming modern jitter standards are used. 

 

Regardless of which specific clock you use, I would trust that if your and Sonore’s products both meet the end to end jitter requirements of 10G, then you effectively have complete isolation from upstream jitter. Rather than speculating otherwise an eye pattern would be the most appropriate way to demonstrate otherwise eg vary the upstream jitter and show the effects on the downstream eye pattern. Short of this, the current evidence is against you.

[jabbr]

28 minutes ago, Superdad said:

Of course it won't be very long until the theory of blocking the upstream phase-noise fingerprint of Ethernet is put to test in the market. EtherREGEN puts the Ethernet signal through active LVDS digital isolators and ultra-low-jitter differential flip-flops--with separate power and clocking domains.

 

The theory has already been tested extensively by networking equipment that conforms to post-2002 Ethernet standards. Upstream phase noise fingerprint IS NOT appreciably transmitted downstream in compliant equipment.

 

Any particular idiosyncrasies of USB are an entirely different issue, but we are talking about fiberoptic Ethernet here. 

[vortecjr]

1 hour ago, Superdad said:

 

Well, not the "noise floor" but certainly the effect of jitter/phase-noise. 

And you can remember the 2015 history here as well as I do:  

During development of the ISO REGEN--before even putting on the Silanna GI chip--we built two identical versions of an überREGEN, with the one and only difference between them being the version of the clock.  One had the $1.05 Crystek C3391 (as used on the original USB REGEN and microRendu v1.3 and earlier), the other had a $9.70 Crystek CCHD-575.  Took all of 30 seconds to hear the significant difference between them.  

Shortly after--same or next day--either John or I called you (can't remember who) raving and suggesting you try out the CCHD-575 on the microRendu. You did, and that became the microRendu v1.4 board which you offered as an upgrade until the ultraRendu came out.

 

I guess I am just puzzled about why, with your own first-ear and ample anecdotal reports from your own customers, you today seem to be dismissing the relevance of phase-noise/jitter on packet-data interfaces.

Yes, I know we have not yet the measured proof.  [Would either of us like John to stop all product development and problem-fixing work on Sonore and UpTone products to finish the "Golden Gate Bridge clock-block test system" that he and I have been funding for the past two years?] But between the logical hypothesis he has put forth and the many improved-clock products selling and being discussed, I sure don't think people need to be branded with an "S" just for giving the matter consideration when they hear differences. 

 

Of course it won't be very long until the theory of blocking the upstream phase-noise fingerprint of Ethernet is put to test in the market. EtherREGEN puts the Ethernet signal through active LVDS digital isolators and ultra-low-jitter differential flip-flops--with separate power and clocking domains.  Lots of people will be able to compare it to your opticalModule FMC, which, while using a single instance of one of the chips chosen for the  EtherREGEN, and using the same CCHD-575 reference clock, does not have an isolation moat or flops to produce a fully isolated output.  

By being designed by the same mind, with similar voltage regulators, some of the same chips, and the same reference clocking, the comparisons between opticalModule and EtherREGEN will be a very fair test as to if galvanic isolation (via optical) and a simple reclock is enough--or if complete isolation of data/power/clock domains results in further SQ gains for DAC-connected renderer end-points.

 

I know you Jesus, so I know my frank talk above possibly is making you hot under the collar.  So let me finish with two points:

1) I really don't know the answer to the questions raised as I have yet to hear with my own ears an EtherREGEN or an opticalModule. (Full disclosure, I hope/expect the results to be good as I've already spent/bet close to $100K on seeing this through. )

2) EtherREGEN functions as a full multi-port switch, and thus will find much broader usage than your fine FMC. (This despite that we both know the Sonore/UpTone fanboys love to make a ruckus and conflate all this stuff together. )

 

Good times ahead!

--Alex C.

Alex your history is wrong. Adding a better oscillator to the microRendu had nothing to do with the development of your ISO Regen and neither of you called me to suggest this change. Sonore had updated the oscillator on the Rendu SPDIF/i2s unit’s with good results. We bought the oscillators, we had them measured and sorted by phase noise, and we had them installed. This was something that Barrows and I did on our own. Subsequently, Barrows and I wondered what would happen if we did the same with the microRendu and I authorized Barrows to mod a unit as a test. He did, he liked it, and I asked John to update the design for the 1.4 release. No sense to argue this point because I have all the emails. Anyway, since we could not measure why it sounded different in the microRendu I made a conscious decision to always call the change a hardware update, which it was, and I tried never to refer to it as an “upgrade”. I felt then and continue to fell today that if we can’t measure something that we should do our best not to comment about sound quality in the absolute and allow our customers to decide for themselves. Yes we have options and yes we try to guide people.  

 

The above should answer some of your second question but I will expand on things so you understand my position. I have high hopes that John will make the measurements and the world will be in a better place knowing the answer to the question. However, right now I can measure differences with a wide range of power supplies. Yet I have a very difficult time seeing any difference with a power supply or oscillator upgrade someplace upstream on my network. The simple fact remains that the differences in the power supplies at the endpoint are easily observable at the output of the DAC. Even if John proves his hypothesis via measurements its affects are something that is relatively small comparatively speaking.

 

The branding of “S” is only for those claiming super human capabilities and not those providing honest feedback about their systems. If I don’t make this distinction everyone would get an “S” and that would undermine its significance:)

 

The rest of your post sounds like marketing pitch to gain market share. The opticalModule is a fiber media converter made by Sonore which is needed by our opticalRendu and can also be used with other RJ-45 gear such as our micro/ultraRendu. We are making this FMC because we owe it our customers to offer them a complete solution. Your switch will be a much more expense alternative and that is fine by me.

 

I don’t get hot under collar about this stuff because I do this for fun:) 

[rickca]

52 minutes ago, vortecjr said:

Anyway, since we could not measure why it sounded different in the microRendu I made a conscious decision to always call the change a hardware update, which it was, and I tried never to refer to it as an “upgrade”. I felt then and continue to fell today that if we can’t measure something that we should do our best not to comment about sound quality in the absolute and allow our customers to decide for themselves.

Why would you offer an update that you're not sure is an improvement?  

[asdf1000]

3 hours ago, jabbr said:

Rather than speculating otherwise an eye pattern would be the most appropriate way to demonstrate otherwise eg vary the upstream jitter and show the effects on the downstream eye pattern.

 

Hi @JohnSwenson, on this point jabbr brings up, can you share eye patterns of an ultraRendu output?

 

1. ultraRendu alone

2. ultraRendu + opticalModule

3. ultraRendu + etherRegen

 

Using your LPS-1.2 to power everything.

 

I know you're working on measurements for analogue output of a DAC and that will likely take time. That's fine of course - I understand that is a complex undertaking.

 

But eye patterns of the above should be simple enough?

 

In your own development work so far, do you see eye pattern improvements going from #1 to #2 to #3 ?

 

 

[R1200CL]

1 hour ago, Em2016 said:

1. ultraRendu alone

2. ultraRendu + opticalModule

3. ultraRendu + etherRegen

 

Using your LPS-1.2 to power everything.

And please add the opticalRendu 😀

(Which works fine with the LPS-1.2, as long no, or below 100mA Vbus power drawn from the opticalRendu).

[asdf1000]

4 minutes ago, R1200CL said:

And please add the opticalRendu 😀

(Which works fine with the LPS-1.2, as long no, or below 100mA Vbus power drawn from the opticalRendu).

 

Best to start small... ask too much, and we'll get nothing... Just be patient.. one step at a time...

 

[R1200CL]

2 hours ago, vortecjr said:

However, right now I can measure differences with a wide range of power supplies.

Is this something you can make public ?

 

Like between the following ones:

iFi SMPS

SGC PS

Sonore Ultra PS

LPS-1.2 both at 7 and 9 V

 

Any other top specified PS like the JS-2 and Paul Hynes ones. 
And maybe add the PS used in the Signature Rendu SE version. 

[vortecjr]

4 hours ago, rickca said:

Why would you offer an update that you're not sure is an improvement?  

I explained this in my post above. However, I’m happy to expand on it though. First let me explain that the main oscillator in the microRendu directly drives the USB output and the processor which indirectly drives the network. Same applies to the ultraRendu. The opticalRendu is the first of our Rendu to have dual low noise oscillators one for the network and one for the USB and CPU. Anyway, during production of the microRendu the lower noise oscillator was not yet available and when it become available it was a natural progression in the design to utilize it. We ran a batch or two of these 1.4 boards so existing customers would not have to purchase an ultraRendu. Understand that John’s hypothesis on why any of the matters was not yet formulated or shared with me until much later so we were simple shooting for lower phase noise. BTW the original oscillator in the microRendu was better than what others were using at the time and is still better than what some are using today;) 

[vortecjr]

4 hours ago, Em2016 said:

 

Hi @JohnSwenson, on this point jabbr brings up, can you share eye patterns of an ultraRendu output?

 

1. ultraRendu alone

2. ultraRendu + opticalModule

3. ultraRendu + etherRegen

 

Using your LPS-1.2 to power everything.

 

I know you're working on measurements for analogue output of a DAC and that will likely take time. That's fine of course - I understand that is a complex undertaking.

 

But eye patterns of the above should be simple enough?

 

In your own development work so far, do you see eye pattern improvements going from #1 to #2 to #3 ?

They are not as simple as you think. To answer your question though we do not have plans to publish them at this time. 

[vortecjr]

4 hours ago, R1200CL said:

And please add the opticalRendu 😀

(Which works fine with the LPS-1.2, as long no, or below 100mA Vbus power drawn from the opticalRendu).

BTW there is an “S” award available for those promoting silly things for selfish reasons. A 100 mA swing is enough to drive the combination into a wired state and damage things. 

[vortecjr]

3 hours ago, R1200CL said:

Is this something you can make public ?

 

Like between the following ones:

iFi SMPS

SGC PS

Sonore Ultra PS

LPS-1.2 both at 7 and 9 V

 

Any other top specified PS like the JS-2 and Paul Hynes ones. 
And maybe add the PS used in the Signature Rendu SE version. 

I have all these measurements and a few more, but not the Paul Hynes power supply. These power supplies are different and each has a value / price point. I have consistently said and will continue to say just use the best power supply you can afford. 

[jabbr]

9 hours ago, Em2016 said:

In your own development work so far, do you see eye pattern improvements going from #1 to #2 to #3 ?

 

A few points. I’d like to keep the discussion here about compatibilities between different fiberoptic Ethernet equipment eg various SFP modules, switches, NICs, FMCs and endpoints.

 

@vortecjr has made it clear that the LPS1.2 power supply is not appropriate for the opticalRendu, so let’s discuss equipment that is intended to be compatible. 

 

Eye pattern testing is not required for 1000base-X (1 Gbe) — I just suggested that it might be used to settle the issue about the effectiveness of fiberoptic isolation. 

 

My understanding is that the opticalRendu ships with a specified Multimode SFP but if folks want to report success with other SFPs including single mode, that would be on topic here and useful for the community in general. I’m not asking Jesus to bless that.

[jabbr]

4 hours ago, vortecjr said:

I have all these measurements and a few more, but not the Paul Hynes power supply. These power supplies are different and each has a value / price point. I have consistently said and will continue to say just use the best power supply you can afford. 

 

The power supply used to power the opticalRendu is more important than merely for the SFP module and network clock because it’s also supplying the USB and many DACs are bus powered. In all cases the USB touches the DAC.

 

For the FMC I think any reasonably good PSU would suffice, eg linear if the FMC is near the audio equipment. The fiberoptic cable will not transmit leakage current!

 

Professional equipment uses SMPS — I assume well designed because the jitter specs are very tight. But they don’t use really cheap wall warts!

[vortecjr]

5 hours ago, jabbr said:

 

The power supply used to power the opticalRendu is more important than merely for the SFP module and network clock because it’s also supplying the USB and many DACs are bus powered. In all cases the USB touches the DAC.

 

For the FMC I think any reasonably good PSU would suffice, eg linear if the FMC is near the audio equipment. The fiberoptic cable will not transmit leakage current!

 

Professional equipment uses SMPS — I assume well designed because the jitter specs are very tight. But they don’t use really cheap wall warts!

All good points.

[vortecjr]

5 hours ago, jabbr said:

 

A few points. I’d like to keep the discussion here about compatibilities between different fiberoptic Ethernet equipment eg various SFP modules, switches, NICs, FMCs and endpoints.

 

@vortecjr has made it clear that the LPS1.2 power supply is not appropriate for the opticalRendu, so let’s discuss equipment that is intended to be compatible. 

 

Eye pattern testing is not required for 1000base-X (1 Gbe) — I just suggested that it might be used to settle the issue about the effectiveness of fiberoptic isolation. 

 

My understanding is that the opticalRendu ships with a specified Multimode SFP but if folks want to report success with other SFPs including single mode, that would be on topic here and useful for the community in general. I’m not asking Jesus to bless that.

No worries and much appreciated.

[asdf1000]

5 hours ago, jabbr said:

@vortecjr has made it clear that the LPS1.2 power supply is not appropriate for the opticalRendu, so let’s discuss equipment that is intended to be compatible. 

 

If you look closely I never mentioned the opticalRendu by the way... 😉

[R1200CL]

10 hours ago, vortecjr said:

These power supplies are different and each has a value / price point. I have consistently said and will continue to say just use the best power supply you can afford. 

So can you share what to expect from a parallel setup of two LPS-1.2 using @[email protected] boxes ?

 

Will use of his boxes degrade the excellent SQ the UltraCaps is so well known for, or is this a setup you can’t endorse as well ?

 

[barrows]

@jabbr, Are you able to recommend a specific, single mode, 1 Gbe SFP module for use with the Sonore optical products off the top of your head?

I am interested in testing single mode fiber in my set up (Although RMAF preparations and product building is keeping me very busy right now). 

[jabbr]

20 minutes ago, barrows said:

@jabbr, Are you able to recommend a specific, single mode, 1 Gbe SFP module for use with the Sonore optical products off the top of your head?

I am interested in testing single mode fiber in my set up (Although RMAF preparations and product building is keeping me very busy right now). 

 

You cant go wrong with either Finisar or Avago 1000base-Lx eg https://www.finisar.com/optical-transceivers/ftlf1318p3btl

 

or Cisco https://www.cisco.com/c/en/us/products/interfaces-modules/1000base-lx-lh-sfp/index.html which exceeds the baseline specs