Melco S100 Ethernet Switch Measurements

[Confused]

This month's edition (October?!) of Hifi News and Record Review features a review of the Melco S100 Ethernet switch.  Most Hifi News reviews feature a "Lab Report" section which details measurements of the product reviewed performed by Paul Miller's Miller Audio Research. (AVTech)

 

A copy of the review per the link below, see the "Lab Report" box on the right.

 

https://www.melco-audio-masters.com/uploads/1/0/1/5/101505220/hfn_oct_melco_s100_reprint-low.pdf

 

It is interesting that the measurements do actually show that the Melco provides a reduction in jitter at the DAC, at least when the Melco is used with a Lumin D2, not so much when used with a Mytek or Arcam DAC.  (no measurable difference for the Mytek DAC, 1psec reduction for the Arcam DAC)

 

So this seems to back up the view that if your DAC is "properly engineered", then stuff like audiophile switches should not matter, however, it does go against the view that it is absolutely impossible for a switch to make any difference in any circumstances. 

 

Of course, how much of an audible difference you will get from a reduction in jitter from 15psec to 10psec is yet another topic for debate.

[Confused]

1 hour ago, jabbr said:

It would be far more interesting to repeat the comparison against a 10G fiberoptic switch that costs a bit over $100

I agree. 

 

To me, it is interesting that HFN managed to measure any kind of difference with the S100.  Don't misunderstand this, I do not think that the difference measured itself would enable me to pass an @plissken style blind test, I just find it interesting that anything was measured.  So yes, a similar test with fibre, maybe a similar test with other "audiophile" type switches or indeed a range of standard network switches.  Would there be a range of measurable results?

 

And why the different measurements for the Lumin versus the Mytek?  What actually caused the different results between these two?

 

I do not think a a reduction in jitter from 15psec to 10psec is going to create a difference I could pick up in a blind test, but I still think there might be something to learn here.

[Confused]

On 9/23/2020 at 11:30 PM, Superdad said:

Says the network jockey playing with data analyzer bits to the chip engineer (John Swenson) of 31 years who actually designed the power networks Ethernet switch chips and PHYs and understands and measures what happens at the lowest levels.

Mindful that this is posted in the objective area, I think is highly appropriate that you mention that John Swenson measures what happens at the lowest levels.  Why then is there such a reluctance for UpTone Audio to publish any measurements?

 

I started this thread because I was genuinely interested that HiFi News had measured the Melco switch and found differences at the DAC.  Why is this?  What mechanisms are in play? 

 

I note the augments of some that what is measured is not audible, but I remain curious of what is actually happening, specifically what is causing what effect.  I think there might be something to learn here, and with better understanding maybe we can find a difference at the DAC that might indeed be audible.  There is much talk of things that can be heard but not measured, but if we can actually measure differences at the DAC, this this at least provides some credibility to perceived sound quality changes.   I am a happy EtherRegen user, but it would be nice to have some objective evidence that the reason that I like my EnterRegen in the system is based on something real, rather than some kind of placebo effect.  

 

So If JS has measured to the lowest levels, why not publish the results?  Otherwise all I am left with are the reasonably logical arguments from @plisskento convince me that I am indeed just kidding myself.

 

 

[Confused]

16 hours ago, plissken said:

 

Miska pointed out that they are measuring with shielded cable. This is most definitely not recommended. The UTP cabling is common mode noise rejection by design. The shield is not and it's also tying two network devices together over their ground plane. With such devices potentially plugged into different wall outlets on different circuits or even different buildings given the 100 yard length spec you get into oddities of current flow.

To be clear, Miska stated that he would guess that the differences (between Melco and standard switch) would go away if a standard UTP6 cable was used.  So maybe this is likely, but we do not know.

 

He also stated (accurately) that HFN doesn't tell what other equipment was connected to the switch and through what kind of cable.

 

We can all speculate, for example, I would guess that Paul Miller knows enough about ground currents that he would not connect any other equipment to the switch using a shielded cable.  But it is just a guess, so maybe not.  That said, it would definitely have been more interesting if the test was performed with the Melco cable and with a standard UTP6, but is was not (as far as we know), so we are left guessing.

 

Unless anyone is able to reproduce the test and try this, we will not know for sure.

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18 hours ago, firedog said:

Wow, those measurements show a tiny difference. Is it audible? There is such a thing as "good enough" performance - meaning that slightly better measured results aren't audible. Both subjectivists and objectivists need to remember this, I think. 

 

The main takeaway I have from those measurements is that I'd rather get an item like the Arcam or the Mytek that doesn't need "improvement", as opposed to the Lumin, that needs "help". 

I agree that the measurements show a tiny difference and mentioned in my own post that they are unlikely to be audible.

 

Although you are contradicting yourself very slightly, you state the issue does not matter and state it is not audible, then state you would rather have the Arcam or Mytek that does not suffer from the issue.  It either matters or it doesn't.

 

All of this is missing the point though. as I stated before, there is a measured difference and I am interested as to why.  Pure open minded curiosity, with the thought that there is just a chance that there is something to learn here.  Maybe it is a simple ground issue and using a UTP6 cable would make it go away, but maybe not.  @MarkusBarkusstated it well in his earlier post, and like him I am "just leaving the door open" a little bit.  

[Confused]

3 minutes ago, firedog said:

Not really. It's just a preference for something that seems to have a better design. In situations where devices all measure well, I'd probably go for the one that had the best feature set/UI, anyway.

Yes, I get that and understand the point, its pretty much how I see things too as it happens.  Apologies if I was being a bit pedantic.

 

It does beg the question though, if you were considering the Mytec, Arcam and Lumin, would you ignore the issue picked up by HFN and go for the Lumin, assuming it had the best the feature set/UI, and other measurements were comparable?  Or would the fact that Lumin alone had this issue and so was maybe not "engineered" quite so well maybe put you off a touch?