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Melco S100 Ethernet Switch Measurements


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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.

Windows 10 PC, Roon, HQPlayer, SOtM sMS-200Ultra, tX-USBultra, Paul Hynes SR4 (x2), Mutec REF10, Mutec MC3+USB, Devialet 1000Pro, KEF Blade.  Plus Pro-Ject Signature 12 TT for playing my 'legacy' vinyl collection.

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8 minutes ago, R1200CL said:

Where can I find such a reasonable priced 10G fiber optic switch?

 

I see your point with a 10G switch, and could be well worth testing with measurements. 


Mikrotik CRS305-1G-4S+IN

Eric


Ubuntu Studio Linux box (i7-9700, 8 cores, 16GB RAM, Intel X520-DA1 NIC, Roon, HQP) > fiber optic > MikroTik CRS305-1G-4S+ > fiber optic > opticalRendu (HQP NAA) > Holo Cyan (DSD version) > Nord One UP NC500MB mono blocks > Klipsch La Scala — digital volume control with HQP via Roon client

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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.

Windows 10 PC, Roon, HQPlayer, SOtM sMS-200Ultra, tX-USBultra, Paul Hynes SR4 (x2), Mutec REF10, Mutec MC3+USB, Devialet 1000Pro, KEF Blade.  Plus Pro-Ject Signature 12 TT for playing my 'legacy' vinyl collection.

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2 hours ago, Confused said:

Would there be a range of measurable results?

 

Would there be same sample to sample variance? Either switch or streamer?

 

Again here is the problem: If you start playback on the Lumin D2 and pull the plug how long does it continue to play for?

 

Let's say you get 30 seconds at redbook. That means the data was transferred and buffered up locally 30 seconds ago.

 

So I would like to see this repeated with 48Khz 60 second sample played and then measured while playing out of buffer with the cable pulled.

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27 minutes ago, Miska said:

As I suspected, in this case too, the ethernet isolation is spoiled by use of STP cable:

https://www.melco-audio.com/products/c1ae/

So likely source for the differences are ground currents through the cable shield. HFN doesn't tell what other equipment was connected to the switch and through what kind of cable, because now in this case it matters greatly.

 

Does the Lumin D2 have a shielded RJ45 port? Good catch. That's why I would like to see a write up of the entire testing regimen.

 

Critical thinking for the win 🙂

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23 hours ago, plissken said:

Again here is the problem: If you start playback on the Lumin D2 and pull the plug how long does it continue to play for?


Please do your homework 😀

 

The signal from the switch with jitter, noise etc, has already been injected into the buffer. 
You should have learned this by now if you had paid attention to John Swenson’s post. 
 

Besides I think this also depend on clock in the Lumin as well. 

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4 hours ago, Miska said:

One can use shielded STP cables only in very specific circumstances, where both sides of the connection are connected to the same common ground point by some other means.

This is so true, and is probably only relevant to a very few people here at AS.


The rest of us that has been discussed this here at AS the last 3 years, should keep on with un-shielded cables (like blue jeans), or use JSSG360. And fiber. 

 

If we where building professional network from scratch, indeed we could (or should) use network that applies with the official standards. 
I don’t know how this would affect etherRegen as an example in the loop, but I suppose this is when that earth screw comes handy.

I think first problem that would occur is created by the supplied modem from the ISP. They are normally not grounded. Of cause can be solved. 
 

(I read rest of your post after writing). You are so correct what you’re saying. And it can even be more complicated. If the PCB is connected to chassis etc. 


Thinking of this, does any streamer or streaming DAC comply with 10GB networking standards. Wouldn’t that one day be a requirement as well. 
 

We need to standardize on fiber (or wireless) in our audio network. 

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3 hours ago, R1200CL said:

Please do your homework 😀

 

The signal from the switch with jitter, noise etc, has already been injected into the buffer. 

 

Jitter is time domain error. It can't exist in a buffer. John will tell you that. Buffers represent clock domain boundaries.

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8 hours ago, plissken said:

Jitter is time domain error. It can't exist in a buffer. John will tell you that. Buffers represent clock domain boundaries.


That’s interesting, cause then clock phase noise (which I understand as jitter) should be removed by buffers. And good clocks wouldn’t matter. But they do. I probably need to do my homework as well then 😀

Maybe I’m mixing tings. Thanks for telling me. 
I noticed the new 1.5 version of microRendu has better buffer instead of better clock, so that statement can’t just be marketing BS. 
 

Do you have equipment available to measure switches ?

And would you be interested in doing some ?

 

I just got a Cisco 2960 G version. As an example, should I expect equal measurements from the RJ45 as the SFP port ?

 

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6 hours ago, R1200CL said:

And good clocks wouldn’t matter. But they do. I probably need to do my homework as well then 😀

 

Sure clocks matter. The one on your DAC the most.

 

My JRiver system can buffer up to 1GB of data. My 10GBe connection maxes out at ~330MB/s.

 

I concatenated a ~45 minute album into one .wav file and flac'd it to 445MB.  I start playback and in the time it takes from clicking play to unplugging my network cable the entire song is in buffer.

 

What does any switch $20 or $2300 or any upstream clock have to do with it then?

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