Sonore opticalRendu

[André Gosselin]

32 minutes ago, barrows said:

@André Gosselin, Your 5G repeater downstairs is currently sharing its noise with your audio system, so I would indeed expect there to be an audio improvement adding an opticalRendu and opticalModule.

 

Best advice:

If you can, try to get that repeater physically away from the audio system, and certainly make sure wherever the repeater is plugged in is not the same circuit as the audio gear.  Then run a very short Ethernet cable from the Repeater to an opticalModule/FMC (with good linear power supply) and then optical fiber to a opticalRendu or Signature Rendu SE optical in the audio system.  The good news is that the optical cabling is very small and flexible in comparison with CAT 6, so it can often be hidden, or snaked under the floor, under carpet, etc.  Just do not put it anywhere it count be damaged (walked on, etc).  I actually need to finalize my installation here by drilling a hole from my second story work room (where the computer server, router and FMC are) not my living room where the audio system is (right now my optical fiber is just temporarily running along the baseboard and down the stairs).

 

I am not intimately familiar with 5G repeater devices, but I cannot imagine having that powerful wireless device broadcasting RF around the audio system is a good idea.

 

BTW, now might be a good time to mention again that the opticalRendu and Signature Rendu SE optical are new designs by John, which include improvements in performance in addition to the optical connection itself.  

Thanks for taking time to answer me. Very much appreciated.

[André Gosselin]

57 minutes ago, barrows said:

Best advice:

If you can, try to get that repeater physically away from the audio system, and certainly make sure wherever the repeater is plugged in is not the same circuit as the audio gear. 

(...)

I am not intimately familiar with 5G repeater devices, but I cannot imagine having that powerful wireless device broadcasting RF around the audio system is a good idea.

 

@barrows Moving the repeater far away would be difficult, since it is not dedicated to the rendu and is needed to connect by ethernet   other audio devices (another renderer and the Moon DAC). Right now it is located about 1m away from those devices, and 2 m would be the max.

Do you think that running an ethernet cable to the upstairs router and replacing the repeater with a classic switch would improve the setup, especially regarding RF broadcast ? An optical module would then be connected to the switch on one end and to the opticalredu on the the other.   Any switch you could then recommend ?

[barrows]

31 minutes ago, André Gosselin said:

Do you think that running an ethernet cable to the upstairs router and replacing the repeater with a classic switch would improve the setup, especially regarding RF broadcast ? An optical module would then be connected to the switch on one end and to the opticalredu on the the other.   Any switch you could then recommend ?

I cannot say absolutely for sure that the above would be an improvement, but it would be my preference.  When we get into relatively complex Networking options, it gets really hard to make precise recommendations, as the number of possible options is virtually infinite, and no one has tried them all.

In this case, a switch which has no WiFi capability would certainly be my preference vs. the 5G repeater, just to eliminate the potential for broadcast RFI in close proximity to the audio system (after all, most audiophiles will do many things to try and reduce the influence of outside RF interference; putting a powerful RF transmitter right next to the audio system is ill adivised in my opinion).  I have no experience with the various switches, but if you need a switch in order to have multiple Ethernet feeds, then I would expect the forthcoming "EtherRegen" switch from UpTone Audio would be the best choice and I think you could use its single fiber output to feed an opticalRendu/Signature Rendu SE optical.  As this is the Sonore forum I do not want to get into too much discussion about UpTones forthcoming product here, but you might run this question by @Superdad at the UpTone forums. 

[lestes]

Tonight I have finally had a chance to compare the the SFP port on my home Ubiquite EdgeRouter X SFP to the starter switch that came with Small Green Computer starter OR kit.  Mind you the starter switch with SFP is powered by a Small Green Computer power supply (as is my OR) and that setup used the supplied Fiber cable (an OS1 1m).  In the meantime I had gotten in a 10m 10Gtek OS2 cable to run from my router to the OR in hopes of trying it ($18), however I was having trouble configuring the EdgeRouter SFP to be part of the router switch (finally rectified today after hunting down the right how-to video).  

 

First, having the 10m OS2 cable at home for a few days I compared it to the 1m OS1 cable  in the SGC kit.  There is about a 1-2% difference among the two cables in my system (SGC kit...the OS1 isn't long enough to compare direct from the EdgeRouter).  I'd characterize the OS1 as more detailed and the OS2 to have a little more body.  One concern I've had with the OR has been a lack of body.  There has been so much detail that it is overwhelming and I have been waiting for the body to fill in, or hoping it would over the last few days of listening (7 days in total).  So the OS2 is preferred in the SGC setup so far.  Still I was hoping more body would come.

 

I'll cut to the chase here...The Ubiquiti EdgeRouter X SFP brought the body and clarity beyond my expectation.  It's a league better than the SGC switch (not made by them).  The funny part is the switch is $99 + power supply and the router is $80 (5 port version).  The 10m cable was around $18 delivered.  It has me wondering two things...how much better can this get with a replacement power supply for the EdgeRouter and would the OpticalModule be better than the current connection direct from the router (it is an additional step)?  The body and detail is simply fantastic.  For the reasonable outlay of funds I think Sonore has really hit a home run.  There is just the matter of experimenting with setup and I hope to get more thoughts from this forum group.  

 

Just to be clear my previous setup was Ubitquiti EdgeRouter to SGC Switch with SGC Power Supply via Audioquest CAT7 cable (10m) and the switch connected to OR via supplied 1m Fiber Cable.  This has been meaningfully bested by Ubitquite EdgeRouter to OR via 10m OS2 cable.  

 

I am eager to hear other experiences from all here.  

 

 

 

 

 

 

[cat6man]

On 6/3/2019 at 12:28 AM, JohnSwenson said:

Of course that depends on how much money you want to spend. The best sound will be from an opticalRendu and opticalModule. Plug the opticalModule into the switch with a short Ethernet cable, plug your existing optical cable into the opticalModule and the other end of the fiber cable into the opticalRendu.

 

If you don't want to spend that much the least expensive upgrade is an opticalModule in place of the existing FMC. There are various options with ultraRendus with intermediate cost.

 

An opticalRendu connected to the existing fiber cable, without the opticalModule at the switch end, is going to sound considerably better than the microRendu with the opticalModule feeding it. I still think it will sound better than an opticalModule feeding an ultraRendu, but the best is the opticalModule feeding the opticalRendu.

 

Lots of ways you can mix and match the parts.

 

John S.

 

hi john/jesus:

 

i want to see if i understand this correctly, as i may have missed something important here.

 

are you saying that an opticalModule, with short ethernet from my network switch, will sound better than simply using the single mode optical SFP output from my network switch?

 

i guess i 'heard' folks saying that the cheap optical converters were not very good (and my experience is that they made my ultraRendu sound worse) but i had thought that the optical connection to the opticalRendu cleaned things up.

in other words, i thought (hoped?) that the opticalRendu made the uplink source irrelevant

 

so, what is the consensus on SFP at network switch==>opticalRendu vs. having the opticalModule do the conversion to optical?

 

since i'm away from home on travel, I'll give you all a week to resolve this critical question for me

 

i'm not really interested in "is A is better than B", more like 'what give the BEST' sound

 

 

[vortecjr]

3 hours ago, cat6man said:

 

hi john/jesus:

 

i want to see if i understand this correctly, as i may have missed something important here.

 

are you saying that an opticalModule, with short ethernet from my network switch, will sound better than simply using the single mode optical SFP output from my network switch?

 

i guess i 'heard' folks saying that the cheap optical converters were not very good (and my experience is that they made my ultraRendu sound worse) but i had thought that the optical connection to the opticalRendu cleaned things up.

in other words, i thought (hoped?) that the opticalRendu made the uplink source irrelevant

 

so, what is the consensus on SFP at network switch==>opticalRendu vs. having the opticalModule do the conversion to optical?

 

since i'm away from home on travel, I'll give you all a week to resolve this critical question for me

 

i'm not really interested in "is A is better than B", more like 'what give the BEST' sound

 

 

There is a form sponsor and a whole stupid thread here on CA telling people to do silly things. We build sensible products with audiophile design considerations and we don’t try to over sell the products or expect our customers to embellish the end results. We are simply giving you practical advise on different setups. If your network already has optical capabilities by all means use it. If you don’t already have an optical network or want to experiment further add a opticalModule feed from RJ-45 to obtain the optical network. What I can say is that the people who have tried the opticalModule liked it, but only you can tell us if you like in your system. 

[R1200CL]

On 6/3/2019 at 5:04 PM, André Gosselin said:

to one of which an ultrarendu is connected (PS: LPS-1) . The ultrrendu connects over USB to a Moon 780D DAC.

 

If you’re planning to use the LPS-1 with the opticalRendu, be absolutely sure that  Moon 780D isn’t require any Vbus power. You can probably test this out upfront, by blocking usb power between the two devices, unless the DAC user manual is very clear about this.

It maybe work with Vbus as well, but you should expect to push the LPS-1 into and over its limits. Anything above 100mA you can forget.

 

Also remember that all previous reports from users before, stats that the LPS-1 and the LPS-1.2 added SQ to any Rendu. 

[JohnSwenson]

The understanding of "isolation" in digital audio has been my passion for at least 10 years. There is a LOT of misunderstanding on the subject floating around in audio circles.  Here is a quick summary of my current understanding and how the current products fit in with this.

 

There seems to be TWO independent mechanisms involved: leakage current and clock phase noise. Various amounts of these two exist in any system. Different "isolation" technologies out there address one or the other, but very rarely both at the same time.  Some technologies that attenuate one actually increase the other. Thus the massively confusing information out there.

 

Leakage current is a property of power supplies. It is the leakage of AC mains frequency (50/60 Hz) into the DC output. It is usually common mode (ie exists on BOTH the + and - wires at the same time, this makes it a bit difficult to see. There seems to be two different types, one that comes from linear supplies and is fairly easy to block, and an additional type that comes from SMPS and is MUCH harder to block. An SMPS contains BOTH types. They are BOTH line frequency.

 

Unfortunately in our modern times where essentially all computer equipment is powered by SMPS we have to deal with this situation of both leakage types coming down cables from our computer equipment. There are many devices on the market (I have designed some of them) for both USB and Ethernet, most can deal with the type from linear supplies but only a few can deal with the type from SMPS.

 

Optical connections (when the power supplies are completely isolated from each other) CAN completely block all forms of leakage, it is extremely effective. Optical takes care of leakage, but does not deal with the second mechanism.

 

Clock phase noise

 

Phase noise is a frequency measurement of "jitter", yes that term that is so completely mis-understood in audio circles that I'm not going to use it. Phase noise is a way to look at the frequency spectrum of jitter, the reason to use it is that there seems to be fairly decent correlation to sound quality. Note this has nothing to do with "pico seconds" or "femto seconds". Forget those terms, they do not directly have meaning in audio, what matters is the phase noise. Ynfortunately phase noise is shown on a graph, not a single number, so it is much harder to directly compare units. This subject is HUGE and I'm not going to go into any more detail here.

 

Different oscillators (the infamous "clocks" that get talked about) can have radically different phase noise. The level of phase noise that is very good for digital audio is very difficult to achieve and costs money. The corollary is that the cheap clocks used in most computer equipment (including network equipment) produce phase noise that is very bad for digital audio.

 

The important thing to understand is that ALL digital signals carry the "fingerprint" of the clock used to produce them. When a signal coming from a box with cheap clocks comes into a box (via Ethernet or USB etc) with a much better clock, the higher level of phase noise carried on the data signal can contaminate the phase noise of the "good" clock in the second box. Exactly how this happens is complicated, I've written about this in detail if you want to look it up and see what is going on.

 

The contamination is not complete, every time the signal gets "reclocked" by a much better clock the resulting signal carries an attenuated version of the first clock layered on top of the fingerprint of the second clock. The word "reclocked" just means the signal is regenerated by a circuit fed a different clock. It may be a better or a worse clock, reclocking doesn't always make things better!

 

As an example if you start with an Ethernet signal coming out of a cheap switch, the clock fingerprint is going to be pretty bad. If this goes into a circuit with a VERY good clock, the signal coming out contains a reduced fingerprint from the first clock layered on top of the good clock. If you feed THIS signal into another circuit with a very good clock, the fingerprint from the original clock gets reduced even further. But if you feed this signal into a box with a bad clock, you are back to a signal with a bad fingerprint.

 

The summary is that stringing together devices with GOOD clocking can dramatically attenuate the results of an upstream bad clock.

 

The latest devices form Sonore take on BOTH of these mechanisms that effect sound: optical for blocking leakage and multiple reclocking with very good clocks. The optical part should be obvious. A side benefit of the optical circuit is that is completely regenerates the signal with a VERY low phase noise clock, this is a one step reclocking. It attenuates effects from upstream circuits but does not completely get rid of them. This is where the opticalModule comes into play, if you put an opticalModule in the path to the opticalRendu you are adding another reclocking with VERY good clocking. The result is a very large attenuation of upstream effects. It's not completely zero, but it is close.

 

The fact that the opticalRendu is a one stage reclocking (which leaves some effects from upstage circuits) is why changing switches etc can still make a difference. Adding an OpticalModule between the switch and opticalRendu reduces that down to vanishingly small differences.

 

So an optical module by itself adds both leakage elimination and significant clock effects attenuation. TWO optical modules in series give you the two level reclocking .

 

An opticalRendu still has some significant advantages over say an ultraRendu fed by a single opticalModule, the circuitry inside the opticalRendu has been improved significantly over the ultraRendu. (it uses new parts that did not exist when the ultraRendu was designed). In addition the opticalRendu has the reclocking taking place a couple millimeters away from the processor which cuts out the effects of a couple connectors, transformers and cable. The result is the opticalRendu has some significant advantages.

 

An opticalModule feeding an ultraRendu does significantly improve it, but not as much as an opticalRendu. So you can start with an opticalModule, then when you can afford it add an opticalRendu, also fed by the opticalModule and get a BIG improvement.

 

I hope this gives a little clarity to the situation.

 

John S.

 

 

 

 

[vortecjr]

Great post John...thanks!

[MagnusH]

Good explanation, but I don't understand why an accurate clock would matter for an ethernet transmission? Its a packet based protocol with no time dependencies in it, and it transports binary data and has error correction. Jitter exists on a low level, but not in the same way as for example for a time-dependent transmission over SPDIF. Instead jitter in ethernet can cause bit-errors, but in a home environment that rarely happens and if/when it does it will just trigger a resend.

I am not one of those "bits are bits" people, I know clocks and isolation matters a lot for audio-formats like USBAudio and SPDIF, but in the case of ethernet I don't understand how a good clock would affect sound quality.
 

[vortecjr]

57 minutes ago, MagnusH said:

Good explanation, but I don't understand why an accurate clock would matter for an ethernet transmission? Its a packet based protocol with no time dependencies in it, and it transports binary data and has error correction. Jitter exists on a low level, but not in the same way as for example for a time-dependent transmission over SPDIF. Instead jitter in ethernet can cause bit-errors, but in a home environment that rarely happens and if/when it does it will just trigger a resend.

I am not one of those "bits are bits" people, I know clocks and isolation matters a lot for audio-formats like USBAudio and SPDIF, but in the case of ethernet I don't understand how a good clock would affect sound quality.
 

He is not saying that it affects ethernet transmission and the transmission is bit perfect. What is he saying is that the noise signature of one oscillator in the sequence can be picked up in subsequent oscillators. This is my understanding based on many conversations with John and he will chime in as needed.

[MagnusH]

38 minutes ago, vortecjr said:

He is not saying that it affects ethernet transmission and the transmission is bit perfect. What is he saying is that the noise signature of one oscillator in the sequence can be picked up in subsequent oscillators. This is my understanding based on many conversations with John and he will chime in as needed.

Ok, that might well be the case. But once you add an optical transmission like fiber, that all goes away, so any clocks before the fiber won't matter as long as the data was delivered correctly. In fact, nothing before the fiber should matter at all, provided the data was delivered correctly (the FMC after the fiber will matter though).

[MagnusH]

Ahh, I think I understand. He means that the clock(s) before the fiber influence the clock after the fiber, so you can end up with more electronic noise from electronics before the fiber due to the extra "work" the last clock(s) has to do.

[cat6man]

Thanks John.  A very cogent summary.

 

I understand the jitter issue and how complex it can be (going back at least to Duttweiler's classic paper in the BSTJ on jitter accumulation in repeater chains!).  It also explains why some folks have reported that multiple jitter reduction devices in series can be beneficial, but of course YMMV depending on the specifics of your system.

 

So let me re-phrase my question more carefully to this esteemed community:

 

If you have an optical connection from their network router to your opticalRendu, have you tried adding an opticalModule in between?

Do you hear further improvement?

Please share your results with this forum and include details such as network router equipment, how you are powering your various network devices and what DAC you are using.

 

Thanks everyone!

 

 

[MagnusH]

54 minutes ago, cat6man said:

It also explains why some folks have reported that multiple jitter reduction devices in series can be beneficial, but of course YMMV depending on the specifics of your system.

Thats for time-dependent transmissions like PCM over USBAudio or SPDIF. Etherneet is not time-dependent so it has no jitter problem like that (it has jitter on a very low level that can cause bit-errors, but thats unrelated).

[barrows]

@JohnSwenson,

 

As you suggest: 

 

"The contamination is not complete, every time the signal gets "reclocked" by a much better clock the resulting signal carries an attenuated version of the first clock layered on top of the fingerprint of the second clock. The word "reclocked" just means the signal is regenerated by a circuit fed a different clock. It may be a better or a worse clock, reclocking doesn't always make things better!"

 

It would appear that if the above is actually what is happening, the implications for music streamed from the Internet (Tidal, Qobuz, etc.) would be extreme.  I am guessing that many relatively poor performing clocks (from a  phase noise perspective) are involved (maybe hundreds?) in getting a Tidal stream to ones' home system, what do you think?  Some have suggested that Internet based playback sounds worse than the same locally stored files (hard to be sure the file is the same though, unless a checksum is run...).  Would it be an appropriate conclusion to say that if your statement above is true and correct, then music streamed from the internet is hopelessly compromised?  Also it appears there might also be implications for any music music sharing over a Network, including as is done regularly in music production, if that clock phase noise is somehow accumulating, along with the data...

[MagnusH]

There are only 2 things that can affect sound quality when data is passed over ethernet: the data itself (i.e. bits) and whatever electronic noise that hitches a ride with the data. And with this in mind, I find it very hard to believe anything before an optical transmission can affect the sound quality if the data itself is delivered as it should (underrun of buffers can be left out, it simply don't happen in normal home environment).

 

The only thing that might be possible is that reclocking after fiber might result in less CPU/memory/whatever used if the data had a good clock since before, and hence result in less electronic noise. I assume @JohnSwenson is talking about this (but using fancy words like fingerprints, noise signature etc). But the more I think about it, the less I believe it will have any effect.

[JohnSwenson]

6 hours ago, MagnusH said:

Ok, that might well be the case. But once you add an optical transmission like fiber, that all goes away, so any clocks before the fiber won't matter as long as the data was delivered correctly. In fact, nothing before the fiber should matter at all, provided the data was delivered correctly (the FMC after the fiber will matter though).

All the optical does is block leakage, it doesn't get rid of clocking issues at all (it can actually make them worse). The fact that it is optical does not automatically apply some universal quantum time scheme that mystically aligns edges perfectly, If you send in a pulse, then another that is 50ns apart, then another at 51ns, then another at 49, that difference gets preserved at the receiver, the optical does not magically force all of them to be exactly 50ns.

 

The raw data coming out of the optical receiver goes into a chip that rebuilds the Ethernet signal using its own local clock, that is done with flip flops inside the chip, these flop flops behave just like any other flip flops, again no magic here. I was trying to avoid re-iterating what I have said before on this, but it looks like I'm going to have to do it anyway.

 

So how come this reclocking with a new clock is not perfect? As edges from the input stream go into a circuit each and every one of those edges creates a current pulse on the power and ground network inside the chip and on the board. The timing of that pulse is exactly related to the timing of the input data. The timing of the input data is directly related to the jitter on the clock producing the stream. This noise on the PG network changes the threshold voltage of anything receiving data inside the chip, especially the local clock going into the chip. This means the phase noise spectrum of the data coming in gets overlayed on top of the phase noise spectrum of the local clock. It's attenuated from what it is in the source box, but it is definitely still there.

 

THAT is how phase noise gets from one device to the next, EVEN over optical connections.

 

If you look at this in a system containing all uniformly bad clocks, you don't particularly see this, since they are all bad to begin with. BUT when you go from a bad to a very good clock you can definitely see this contamination of the really good clock by the overlaying of the bad clock. This is really hard to directly measure because most of the effect is happening inside the flop flop chip itself. You CAN see the effect on the data coming out of the flip flop.

 

This process happens all the way down the chain, Ethernet to USB, USB into DAC box, and inside the DAC chips themselves, finally winding up on the analog out.

 

Wherever reclocking is happening, how strong this overlay is depends primarily on the impedance of the power and ground network, both on boards and inside chips. A lower impedance PG network produces lower clock overlay, higher PG impedance give stronger overlay. 

 

This is something that is difficult to find out about a particular chip, the impedance of the PG network is NEVER listed in the data sheets! I have somewhat of an advantage here having spent 33 years in the semiconductor industry, spending a lot of time designing PG networks in chips, I have some insight into which chips look like good candidates for low impedance PG networks.

 

On a side note, because Ethernet and USB are packet systems the receiving circuit CAN use a completely separate clock, the frequency just has to be close enough to handle the small number of bits in the packet. If it is a little to slow or too fast the difference is made up in the dead time between packets.

 

To reiterate none of this has ANYTHING to do with accurately reading bits, this is assumed. It IS all about high jitter on network clocks working its way down through reclockings to the DAC chips and hence to audio outs. All the work done on DACs in recent years has cleaned up the signals so dramatically that these effects are getting to be audible in many systems.

 

John S.

[lumos]

1 hour ago, JohnSwenson said:

 

 

So how come this reclocking with a new clock is not perfect? As edges from the input stream go into a circuit each and every one of those edges creates a current pulse on the power and ground network inside the chip and on the board. The timing of that pulse is exactly related to the timing of the input data. The timing of the input data is directly related to the jitter on the clock producing the stream. This noise on the PG network changes the threshold voltage of anything receiving data inside the chip, especially the local clock going into the chip. This means the phase noise spectrum of the data coming in gets overlayed on top of the phase noise spectrum of the local clock. It's attenuated from what it is in the source box, but it is definitely still there.

 

 

Dear John,

 

I am in awe of your patience. I used to believe that everything in the digital domain was the same until I saw that data in an oscilloscope and realised that, in fact, nothing in the digital domain is really digital at all. States do not change instantly from a 0 to a 1, there is a leading edge slope and a trailing edge slope. You now have the problem of deciding at what voltage will you say the state has actually changed. Is everything in the chain doing it the same, or even consistently. As Rob Watts at Chord demonstrates, the human brain is incredibly sensitive to timing errors and its impact on the sense of realism. 

 

But none of this really matters. I don't really have a good sense of hearing and I always go to the bother of double blind testing new equipment. I start off being cynical and sometimes I am proved wrong (my microrendus were better than my Sonicorbiters and my Ultrarendus are better than my microrendus. The Uptone Audio power supplies made a positive impact. When the DAC test revealed that I had preferred the Chord Mojo to my Naim DAC in nine out of 10 tracks I sold my Naim DAC. I have never been able to discern a difference with interconnects, power cables, speaker cables. 

 

So for me John has earned some trust in an industry where very few do. This is not homeopathy, here John explains a real mechanism of action and the price of the equipment feels very much like cost plus as opposed to the usual "how much can we charge whilst keeping a straight face" strategy. 

 

The only data point the matters is do we like what it sounds like. If I love the sound then nothing really matters. And the optical rendu plus module will not even buy you a power lead with a wooden ring on it.

[Account Closed]

And, the pertinent question is:

 

Does any of this actually matter in the final output of the DAC?

 

I look forward to John completing his test gear to actually measure and see.

 

It is true that networked audio will never be perfect but it is all we will get going forward. The days of any media being delivered by optical disc or any other physical media are drawing to a close. We will need to embrace all these repair and reconstruct strategies to the extent they actually work and are affordable.

 

Right now, the biggest problem we all have is the lack of quality modems, ONTs, gateways and routers. Most people likely use the junk provided by an ISP. Also, unless you are on a fiber system, your data is coming in on a copper wire shared system originally designed for analog TV.  Keep in mind also that the entire internet was never designed for audio or video. It was originally a system for the military to transmit nuclear launch codes and was later adapted for emails, reports and spreadsheets. The only real concern was whether a one or a zero would be consistently discernible as such at the final  receive point (re missile launch above).

 

Thanks to John and others for all their efforts.

[Albrecht]

10 minutes ago, lumos said:

Dear John,

 

I am in awe of your patience. I used to believe that everything in the digital domain was the same until I saw that data in an oscilloscope and realised that, in fact, nothing in the digital domain is really digital at all. States do not change instantly from a 0 to a 1, there is a leading edge slope and a trailing edge slope. You now have the problem of deciding at what voltage will you say the state has actually changed. Is everything in the chain doing it the same, or even consistently. As Rob Watts at Chord demonstrates, the human brain is incredibly sensitive to timing errors and its impact on the sense of realism. 

 

But none of this really matters. I don't really have a good sense of hearing and I always go to the bother of double blind testing new equipment. I start off being cynical and sometimes I am proved wrong (my microrendus were better than my Sonicorbiters and my Ultrarendus are better than my microrendus. The Uptone Audio power supplies made a positive impact. When the DAC test revealed that I had preferred the Chord Mojo to my Naim DAC in nine out of 10 tracks I sold my Naim DAC. I have never been able to discern a difference with interconnects, power cables, speaker cables. 

 

So for me John has earned some trust in an industry where very few do. This is not homeopathy, here John explains a real mechanism of action and the price of the equipment feels very much like cost plus as opposed to the usual "how much can we charge whilst keeping a straight face" strategy. 

 

The only data point the matters is do we like what it sounds like. If I love the sound then nothing really matters. And the optical rendu plus module will not even buy you a power lead with a wooden ring on it.

Very nicely said.....

 

"As Rob Watts at Chord demonstrates, the human brain is incredibly sensitive to timing errors and its impact on the sense of realism. "

 

Also, - from Rob Watts. FWIW,  (and to continue with an analogy), this is similar to the listener detecting something "wrong" when an instrument is out of tune.

 

Cheers,

 

 

[MagnusH]

If chip fail to completely reclock a digital transmission, so that old clocks is still within the transmission, would not a simple buffering get rid of them? For example, write one package to a memory as soon as its received, and have another chip read the package and clock it from scratch before sending.

An easy way to understand this: a file copied from Internet on the other side of the world and written to disk does not contain anything but the actual binaty data. And when the file is read, no trace whatsoever of how many reclocking was done is present.

 

Now imagine this approach was done at the last step before the DAC (in this case inside OpticalRendu). Whatever problem related to timing/phase will be removed since its not a reclock but a new clocking from available data, and of course the fiber takes care of all electronic noise upstream.

I think this is basically the same way that PLL inside DACs handles jitter related problems over SPDIF.

[Superdad]

43 minutes ago, MagnusH said:

If chip fail to completely reclock a digital transmission, so that old clocks is still within the transmission, would not a simple buffering get rid of them? For example, write one package to a memory as soon as its received, and have another chip read the package and clock it from scratch before sending.

 

Please re-read what John wrote.  This is about the impact--of imperfect timing--on the ground plane of the power networks.

This is where our sophisticated EtherREGEN will come in--with isolated power/data/clock domains using ultra-low jitter differential flip-flops and isolators.

[incus]

57 minutes ago, Superdad said:

1 hour ago, MagnusH said:

If chip fail to completely reclock a digital transmission, so that old clocks is still within the transmission, would not a simple buffering get rid of them? For example, write one package to a memory as soon as its received, and have another chip read the package and clock it from scratch before sending.

An easy way to understand this: a file copied from Internet on the other side of the world and written to disk does not contain anything but the actual binaty data. And when the file is read, no trace whatsoever of how many reclocking was done is present.

 

Now imagine this approach was done at the last step before the DAC (in this case inside OpticalRendu). Whatever problem related to timing/phase will be removed since its not a reclock but a new clocking from available data, and of course the fiber takes care of all electronic noise upstream.

I think this is basically the same way that PLL inside DACs handles jitter related problems over SPDIF.

 

In fact, read everything that John has written on this forum before you ask these questions.

[MagnusH]

All my reasoning has been on the premesis that a fiber-based solution like OpticalRendu is used (or something like GigaFOIL or even cheap FMCs). On its own, I don't doubt at all that EtherREGEN will give benefits, but any problems on a ground-plane will certainly not pass a fiber.