This is a review and detailed measurement of UpTone Audio's Ethernet "audiophile" switch. It is on kind loan from a member. The EtherRegen costs US $640.The EtherRegen as the name indicates, "regenerates" and Ethernet signal. This is a functionality that is provided with any Ethernet switch that exists in the market. There are however claims of improvement which I will get into later. For now, the EtherREGEN comes in the same small aluminum enclosure rest of UpTone products come in:Even though this seems to be the "back," it is the business end of the unit in that it has one special port ("B") that is supposed to be isolated from the ports on the other side:The power supply is private branded but I am assuming that is just a sticker and UpTone has not really applied for FCC and regulator certification itself. This always puzzles me as companies like UpTone make a lot out of noise in audio yet they don't get their products (as required by law) certified for emissions per FCC or CE. For all you know the EtherRegen may be creating a ton of more high frequency noise ("EMI") than a cheap but certified Ethernet switch.Note that the AC cable to the power supply is quite short. So you may have to replace that to have better reach.Anyway, back to the audible claims, we read such on UpTone's website:Starting at the bottom, data integrity is not an issue whatsoever in home LAN networks as evidenced by the fact that you are having no problem using your networked devices without this box. I monitor my 48 port switch form time to time and I have yet to find a single error on any of its ports.Since Ethernet is designed to go long distances (100 meters/330 feet) by design it has to tolerate differential in ground potential, noise, etc. As such claims of better performance here -- without measurements to show the same -- is immaterial.Perhaps the biggest issue with claims of audio improvement is that your DAC is so far removed from Ethernet that little you can do upstream can impact it. Ethernet has a clock but that is used for communication on the wire. Once a packet (chunk) of data arrives, it is put in memory in the operating system. At that point, it no longer has any timing information much less a clock. It is the responsibility of the application to associate timing with it. And such software notion either works, or doesn't. If it doesn't your music will stop or drop out. None of that timing has any relationship whatsoever with the clock that the DAC eventually uses to play data sent to it. It is the audio application together with the DAC (and or Operating System) which determine timing.To wit, you can transfer said networked data to a memory card and put it in a player that has such a card, and play it. Surely at that point, there is no sense of timing as the device is not even reading from the network then.Just in case someone doubts my qualifications on any of this, I worked on one of the first Ethernet interfaces back in 1984 or so which cost some $25,000 (?) and plugged into a $300,000 minicomputer. I worked on the TCP/IP protocol in Unix operating system that interfaced with that which powers the entire Internet and your home network. I also worked for two companies that produced end to end encoding, streaming and playback of AV content on the Internet (a start up which then got acquired by Microsoft). I can go down to even lines of code if you like to describe what is happening here.Problem withe above argument is that you have to take my word over that of UpTone folks and that may not be an easy decision. So we resort to objective measurements to see if addition of EtherRegen changes the sound waves coming out of a networked DAC.As luck would have it, I just received the Matrix Audio's Matrix i streaming DAC. It retails for US $990 and prior Matrix products have provided exemplary performance. So we know it is not the "limitation" in such tests. I could use my PC for testing but there is no such going on in a PC that there is no hope or prayer that any noise from an Ethernet switch would make a difference. In other words, I am doing what I can to help the EtherRegen do its thing.I powered on the Matrix i and selected Network input. I connected its balanced XLR output to my analyzer for the tests you are about to see (at the end, I also tested RCA but made no difference). First our usual dashboard of 1 kHz with just my cheap, generic TP-LINK gigabit switch feeding the Matrix i via Roon streaming:Our highest distortion product is at less than -120 dB, assuring 100% transparency (best case dynamic range of human ear is 116 dB).I disconnected the cable from my generic switch and used the same cable to feed port A on EtherRegen. I the used one of the nicer, short Ethernet cables I have to go from A side of EtherRegen to Matrix i:Even though there are usually run to run variations in such a measurement, it is remarkable how stable both the Matrix i and my Audio Precision APx555 analyzer are. Output voltage and frequency are essentially dead on. Distortion+noise is varying by a fraction of a dB.Next I connected the Matrix i using the Port B of EtherRegen:Nothing changes.Words like "jitter" are used in UpTone marketing so perhaps the improvement lies there. So let's run that test but go nuts by increasing FFT length to whopping 1 million points:You see a difference? I sure as heck don't.There is actually a bit of jitter around our main tone of 12 kHz. But EtherRegen does nothing to reduce that either. A few odds and ends are there too but at levels below -140 dB, absolutely not a concern audibly.Let's confirm port A and B on Ether Regen:Nothing there either.Maybe the goodness comes at higher frequencies than 20 kHz:Once again, Ether Regen provides no improvements whatsoever. It is as if it is not there which is what the architecture suggested all along.We could stop here but why not turn some other stones. "Noise" is another thing audiophiles worry about. So let's run the same test as above but this time, with nothing playing:Whether we look at this up to 20 kHz or 90 kHz, there is absolutely no difference in the noise output of the Element i with generic switch or either port on EtherRegen.Let's go really crazy and run this measurement to 1 Megahertz:All three graphs land on top of each other (last graph was yellow so dominates in color).Half-way through the test, I start to smell what resembled like overheating electronics. Decades of repairing electronics has sensitized my nose to such things.I get my nose close and realize it is the Ether Regen that is cooking! You could easily small it through the ports. While I still could hold it, it was running quite warm. I took an IR scan of it:Case temp is between 36 and 40 degrees C. I worry how hot the internal components are running and whether the junction max temp is too close for comfort.AC Power measurements showed that the switch is consuming 7 watts. That may not sound like much but for everyday electronics, it is good bit of power. We will have to see in a few years whether these things fail or not. If my math is right, running EtherRegen will cost you $9/year at 15 cents a killowatt-hour electricity cost.The beautify of how streaming audio works allows us for a very clever AB test. Both the host and client have fair bit of memory that they store Ethernet content into. With audio playback consumer data at a rather low rate, you can actually switch Ethernet cables and be able to play the music uninterrupted!I connected one wire to Matrix i Ethernet port from my cheap switch, and another to Ether Regen.So I started with my generic switch connection and started to stream some of my reference quality content. While the music was playing, I switched Ethernet cables, this time having Port B of EtherRegen feeding the Matrix i. There was absolutely no audible difference. I then switched back to generic switch feed. No difference. I switched back to EtherRegen. No difference. None. Nothing.Computer, networking and streaming architecture instructs us that an external switch cannot have any effects on an Audio DAC. But it is always good to put some hard data behind this. And that is what the measurements show. That no matter how deep we dig down in the waveforms coming out of the DAC, no difference exists between a cheap, generic switch and UpTone EtherRegen. Even when going down to incredible -160 dB which is equivalent to a 27 bit audio word (3 bit more than any 24 bit content), there is still no difference.Measurements conclusively demonstrate that EtherRegen did not change jitter, noise or distortion of the DAC. It further had no impact on its clock speed, or output voltage.What is that? You hear otherwise? Well, I tested it and there is no audible difference either. I suggest you repeat my test. If you do hear a difference, have someone switch cables behind your back. You can do this quickly, or wait days or weeks to switch. Just don't look and keep a log of 10 trials. If you can tell better than 8 out of 10 times that there is an audible difference with EtherRegen, then you have conquered the impossible!Now, I am not beyond paying more for something if it looks better, feels better, etc. Unless you have an upset stomach and like to use the EtherRegen as a hot water bottle replacement (don't laugh, I have done that with my laptop!), there is no such benefit. Even if there were, I would not pay $640 for it. $100 maybe. But $640?Needless to say,It seems to be designed by people who a) don't understand the architecture of streaming audio and hardware and b) didn't bother make measurements of said flaws before going to fix them. A problem was imagined, and then supposedly fixed.--------As always, questions, comments, corrections, etc. are welcome.Having someone over in person on Friday to make measurements. Thought I should get some food to be polite but am too cheap to spend my money on it. So would youa few dollars? Remember, I have expensive taste in foot so be generous: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/