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"Audiophile Grade" Ethernet Switches - The new generation - Printable Version

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RE: "Audiophile Grade" Ethernet Switches - The new generation - Stino - 11-Mar-2020

Well... the company for sure created some controversy. Which is not bad.

I was expecting a good white paper from Uptone to learn something from. The link provided by Confused, however, is below any of my standards. I'm really surprised they needed all this time to come up with such a document. They should have had a large lists of measurements and 'evidence' gathered during the design of their product, but seems not.

Anyways, it makes it easy for me to not by their product. Maybe to be convinced otherwise once I know someone in the neighbourhood that has one I could borrow... In the end, trying for yourself in your room, and trying to be unbiased by internet reviews and opinions, is what matters and where my money will be spend.


RE: "Audiophile Grade" Ethernet Switches - The new generation - Snoopy8 - 11-Mar-2020

(11-Mar-2020, 14:17)ofrappier Wrote: They don't are anti uptone AUDIO,  they just make measurements.

i believe in Audio analyser : https://www.ap.com/

Anyway, it's a Devialet forum not an uptone Audio forum.

So you believe uptone AUDIO
i believe ASR, serious forum.

each have an opinion, and could make it's own opinion, and it's good.

peace
ASR keep repeating that a good DAC = no need for the EtherREGEN. This is clearly wrong and should be called out and backed up by data.

Agree each of us are entitled to our opinions. Peace...


RE: "Audiophile Grade" Ethernet Switches - The new generation - thumb5 - 12-Mar-2020

(10-Mar-2020, 22:36)Superdad Wrote:
(10-Mar-2020, 22:32)thumb5 Wrote: ...  If it's all that bad one has to ask why can't the effects be easily measured?

We have measured them. At the clock input pin of several DACs. Just not ready to post the graphs. Cool

Alex, first let me say that I found the white paper interesting and it explains the principles behind the design of the EtherRegen quite clearly.  As someone who works daily with digital hardware the ideas were not entirely new to me and I can see in theory how ground plane noise could affect the output of a DAC.

That said, I remain sceptical about the extent to which that theoretical effect actually translates into reality, if one has a reasonably well-engineered DAC.  To be clear, I wonder whether the effect can actually be at a level that makes any audible difference (relative to other noise and distortion) at the output of the DAC, which after all is the only thing that really matters.

The white paper states that clock phase noise will cause sidebands around a pure tone played through the DAC, which seems plausible depending on the design of the DAC.  Presumably during the design of the ER and before it was launched to the market you've been able to measure the level of those jitter-related sidebands with some real DAC, or possibly several DACs, connected first to a standard commercial grade switch and then to ER to give "before" and "after" results.

That sounds like a pretty straightforward measurement given the right equipment, which I guess you must have if you're designing and building this kind of device.  So, would it not be possible to simply tell us the actual magnitude of this problem in the real world, and how much it's reduced by ER?  You'd need to specify the test protocol, what DAC you were using, etc. but naturally that's information you'd already have to hand I suppose.

Would it also be true to say that if the problem is significant in the real world it should be possible for it to be measured independently to verify your own results and consequently the effectiveness of the ER?

Unless I've misunderstood something, in which case please say, it seems to me that the tests carried out at ASR (leaving aside any subjective comments and subsequent discussion) attempt to measure exactly these jitter sidebands that your white paper predicts.  If you agree, could you comment on why their measurements didn't show the presence of these jitter sidebands?  Otherwise, what do you think was wrong with their measurement approach that caused the effect of the ER to be hidden?

Thanks.


RE: "Audiophile Grade" Ethernet Switches - The new generation - David A - 12-Mar-2020

@thumb5 ,

Ian,

I've got an ER and it does make an audible difference compared to my previous Cisco switch, at least to my ears. Short of test results showing the effect the ER has and some kind of listening tests demonstrating that the effect is audible, there's always the possibility that I'm mistaken about hearing a difference. I'd be more prone to give some weight to that possibility if what I was noticing was simply a difference in some sonic characteristic such as bass, detail, or the like but the big difference for me is in how I respond to the sound. I've always liked attending to the contribution of individual musicians in the music I listen to (mostly jazz) so I would often focus on a single musician and attend to what they were doing against a backdrop of the sound of the other musicians. Since installing the ER I find I'm doing that much less frequently and instead focussing on the flow of the music and how different elements of the music work together as a whole and that has changed my impression of a lot of the music I listen to. That's a significant change in my listening approach and the only thing I can attribute it to is the ER. That's not the sort of thing you notice when you're doing A/B comparisons. It's a shift in the way I actually attend to the music and while it is caused by differences in some aspects of the sound, it is also quite a different thing to the differences in the sound. Since I installed the ER, the things that attract me in the music I listen to have changed. Something is different and it's not the sort of thing you notice by doing A/B comparisons, it's something that affects what things attract me in music rather than in how much things attract me. That's a qualitative change in what attracts me in the music and how I listen rather than a quantitative change in any characteristic of what I hear.

I too wondered about how why the jitter tests in the ASR don't show a difference and I went back and reread the white paper. On rereading I noticed a point I'd missed on first reading. That is that the jitter side bands cause a "burp" of current between the power and ground pins of the circuit which results in ground plane noise and the ER is designed to reduce ground plane noise. Perhaps what it does has little effect on the jitter measured in the output of the DAC and it's the reduction in ground plane noise that produces the audible benefit.

As well as jitter measurements, the ASR review also included jitter noise measurements but ground plane noise may not be revealed in the noise spectrum of jitter, it may be revealed in the signal to noise ratio of the analog output of the DAC.

We know from 50 years ago in the disputes about the whether amps with the same THD measurement could sound different that amps with the same THD measurement can have quite different harmonic distortion spectra, and from the early days of CD before jitter measurements were common that CD players with similar THD and IMD performance could sound different as a result of different jitter performance. Measurements tell you a lot about what you measure but they tell you absolutely nothing about what you don't measure. One of the big mistakes in the ASR review in my opinion is that while the reviewer measured things he felt should reveal the differences that the ER was claimed to produce, he makes a very strong assumption that he's measuring the right things and that the lack of difference in the measurements indicates that the ER isn't making a difference. If he's measuring the wrong things then his measurements are of no value. I think he's measuring the wrong things. There is, of course, his listening test but if those of us who hear a difference may be mistaken because we expect to hear a difference, then it's also possible that he didn't hear a difference because he expected not to hear a difference. Expectation bias certainly exists but anyone with an expectation is susceptible to it and people who don't expect to hear a difference are no less prone to it than people who do expect to hear a difference. Expectation bias doesn't give a damn about what your expectation is, all you need is an expectation of some kind and you're susceptible.

His listening report has no more intrinsic validity than anyone else's report and it's quite disingenuous of him to demand that anyone who doesn't hear the same thing as he did on a similar sighted listening test to the one he conducted should then conduct a blind listening test with multiple trials and achieve a particular success rate. You validate scientific tests with independent reproductions of the identical test procedure which achieve identical results. Sighted tests have lower validity than blind and double blind tests because they tend to yield more inconsistent results than blind and double blind tests. In my view he's being dishonest by implicitly claiming that his sighted listening test is intrinsically valid while the conclusion that there is a difference that others have reached on the basis of sighted listening tests are universally mistaken.

I've got no technical background in audio or IT so I'm guessing when I outlined above what I think may be going on in relation to the effect of clock phase noise but I do know that if there is an audible result then there must be a measurable difference in something, and I also know that you're only going to find that measurable difference by measuring the right thing. That means that if the very strong preponderance of listening reports stating that the ER does make a difference are correct are correct, then the measurements in the ASR review are measurements of the wrong things.

Alex and/or John may reply and say my guess about what's going on is wrong and give a different answer but the one thing I strongly believe is that the ER does make an audible difference and the reason I am believe that so strongly is because it's a lot harder for me to be mistaken about how the way I listen has changed than it would be for me to be mistaken about whether there is a difference in the characteristics of the sound I hear.


RE: "Audiophile Grade" Ethernet Switches - The new generation - Snoopy8 - 13-Mar-2020

There is a lively discussion in Audiophile Style that talks about jittter from Ethernet and what ASR is doing or not..
https://audiophilestyle.com/forums/topic/58661-uptone-audio-etherregen-objective-discussion-only/

Alex popped his head into it, saying that the ASR measuring instrument has too high jitter itself and thus cannot measure when John is trying to do.


RE: "Audiophile Grade" Ethernet Switches - The new generation - thumb5 - 13-Mar-2020

@David A  - the reason I asked particularly about the jitter-related sidebands is that UpTone's white paper specifically said that they are an expected result of clock phase noise which the ER is meant to eliminate.  Ground plane noise is the mechanism by which the clock phase noise causes the jitter sidebands, according to the white paper (not the end result).  The ground plane is also said to carry noise caused by leakage currents, which would also be apparent at the DAC output.

So, these two causes (clock phase noise and leakage current), which happen to be carried into or through the DAC via ground plane noise, either cause significant perturbations in the output of the DAC or they don't.  UpTone's white paper specifically says that "ordinary" switches will cause jitter-related sidebands in the output of the DAC, which is one of the things ASR's test was sensitive to, as well as other forms of noise and distortion.  In other words, I understand that ASR were measuring exactly what UpTone say should be measured -- that is, what the white paper says the ER will change.

In short, if the perturbations described in the white paper are significant without ER, it lseems to me that ASR's test was properly designed and had enough resolution to measure them.  That is what I was asking Alex to comment upon.

(Yes, there is a discussion to be had about what magnitude of effect is audible, but the measurements seem to show no differences with or without ER down to better than about -140 dB which I think we can probably agree is good enough.)

By the way, I did also say that I wanted to limit the scope of my question to the measurements themselves excluding the subjective comments or what followed; I agree with you that the latter parts had little value.


RE: "Audiophile Grade" Ethernet Switches - The new generation - thumb5 - 13-Mar-2020

(13-Mar-2020, 00:32)Snoopy8 Wrote: There is a lively discussion in Audiophile Style that talks about jittter from Ethernet and what ASR is doing or not..
https://audiophilestyle.com/forums/topic/58661-uptone-audio-etherregen-objective-discussion-only/

Alex popped his head into it, saying that the ASR measuring instrument has too high jitter itself and thus cannot measure when John is trying to do.

Thanks for the link, I'll take a look.  As has already been pointed out, though: if measurements have already been made, publishing them would end this to-and-fro discussion, and surely that's something UpTone would want to do -- assuming they reflect what UpTone have already claimed.  If they haven't yet been made then I personally wouldn't describe ER as a properly engineered product (I stress, this is just my personal opinion).  So, the simple question is: why not just publish the measurements?

There is talk of jitter measurements at the clock pin to the DAC; I'm not sure I understand why that is helpful to know, except during the design of the ER.  Surely what matters is the analog signal coming out of the DAC, no?


RE: "Audiophile Grade" Ethernet Switches - The new generation - David A - 13-Mar-2020

@thumb5

As I said, I'm also trying to understand what's going on and that's difficult for someone like me without a background in electronics and IT. Trying to put my thoughts into words and throwing them out in public is one way of hopefully attracting someone who can make things clearer for me if my guesses are wrong.

This stuff makes my head hurt. All I'm really sure about is how my listening has changed since getting the ER.


RE: "Audiophile Grade" Ethernet Switches - The new generation - Confused - 13-Mar-2020

@thumb5

The question of measuring the analogue signal at the DAC output was raised over on Audiophile Style: (not exactly a definitive answer from John Swenson though)

https://audiophilestyle.com/forums/topic/58648-discussion-of-the-uptone-jswenson-etherregen-white-paper/?do=findComment&comment=1035563


RE: "Audiophile Grade" Ethernet Switches - The new generation - thumb5 - 17-Mar-2020

(13-Mar-2020, 00:32)Snoopy8 Wrote: There is a lively discussion in Audiophile Style that talks about jittter from Ethernet and what ASR is doing or not..
https://audiophilestyle.com/forums/topic/58661-uptone-audio-etherregen-objective-discussion-only/

Alex popped his head into it, saying that the ASR measuring instrument has too high jitter itself and thus cannot measure when John is trying to do.

It seems from these two posts on ASR that Alex was mistakenly referring to specification for the digital inputs of the AP test equipment, which aren't relevant to the measurement that ASR carried out based on the analog output of the DAC fed by the ER, and that the test gear is more than capable of measuring the levels of jitter UpTone refer to at the DAC clock (whether or not that is the right thing to be measuring).