The Switch
Contents
Once the router is running and set up so that media traffic has priority, it’s time to look at the switch.
The key points you have to keep in mind are that the switch:
- Handles vlans (otherwise setting it up on the router makes no sense)
- Generates very low noise from itself
- Insulates well between ports
- Has a clean power supply
We have in the past measured through an extraordinary number of switches in terms of noise, power supply noise, isolation and jitter. After that first, major study came numerous more in-depth studies, where we went deeper with new equipment. Think of the Wavecrest SIA-3000, Aeroflex PN9000 and the Picoscope 5000.
Jitter measurements
We have done several jitter measurements with cables and switches. That a switch has an influence, we have long been able to hear. But we can now measure it as well. Also with cables, as you can see in the tables above.
The differences between switches and power supplies to switches are greater than with cables, of course. But in both cases the differences are audible and measurable and also reproducible.
Isolators
We also tested “filters,” of course. A test of these can be found here. In this test, we put the English Electric EE1 next to some other filters. Filters also work, but be careful when connecting filters in series, as the effect can be quite variable.
Last link
What proved crucial is the last switch. The last switch determines the quality, as it directly sends the noise into the streamer and thus can affect the clock. The links before it have no, or at least much less – positive influence on playback. At least we have not been able to measure that. And hear…
And that makes sense because a switch isolates using isolation transformers. So, if all goes well, only the noise from the last switch goes to the streamer; everything before it is – if all goes well – attenuated by the islolation transformers (galvanic separation).
Now those transformers do not 100% block all noise. Our measurements show that, too. But in decent models they do a decent job. The noise from the power supply and the switch itself is much more important (and dominant), because it is thus sent directly to the streamer.
The above measurements clearly show that “stacking” does not make a whole lot of sense, just as the path before it does not have a whole lot of influence. What has influence is the noise of the switch itself as well as the power supply applied.
| Switch | Phase Noise (ps) | Allan Variance | Jitter from Allan Variance (ps) |
| Dlink stock | 5,01 | 4,90E-10 | 5,73 |
| Dlink Sbooster | 5,23 | 4,50E-10 | 5,49 |
| Dlink Dodo | 4,62 | 4,66E-10 | 5,59 |
| Netgear stock | 4,68 | 4,81E-10 | 5,68 |
| Netgear IFI | 5,48 | 4,41E-10 | 5,44 |
| Cisco stock | 5,17 | 4,99E-10 | 5,79 |
| Stack | 5,67 | 4,40E-10 | 5,43 |
| Stack tweaked | 5,31 | 4,83E-10 | 5,7 |
Now here we have picked only good switches. And yet the difference between the best and worst combination is 1ps. The Dodo is the best power supply. We could not try it on the Netgear, since it needs 12V and our Dodo provides 5V. The IFI on the Netgear does not work well. We estimated that the Dodo on the Netgear would give a result toward 4.2ps.
Thank you all for your comments!
A simple question: I use my router also as wlan base station for my non audio use. Would it be advicable to seperate these two functions, ethernet for audio and wlan for non audio, and use two routers?
Thank you, Ulrich
We never compared this setup and what it does in terms of sound quality, so hard to predict.
Nice and interesting article again. Recently I bought the Punk Faun isolator. Supply of Qobuz goes via a Silent Angel Bonn8 with Forester power supply. A longer Supra cat8+ (got it for free!) ends in the Pink Faun which in turn is plugged into a Bluesound N130. The N130 has an external PD CREATIVE power supply. Yes I know, the Bluesound is the lesser link but I am waiting for a test at Alpha Audio of the Rivo Plus. More expensive is not in the cards for the time being.
I have the iFi LAN Silencer since a few months and this one of the best improvements in my system. Today I feel like network is very important. One thing you didn’t mention if I’m right is the role of quality clocks in switches. Have you tried to measure their impact? Because someone at UpTone Audio explains really well why by reducing the jitter on the network signal they should help reducing phase noise in the streamer, I am really interested in seeing their impact.
Thank you for all this beautiful work, it is very interesting!
Firstly, fantastic research and very helpful to all.
I do have a few questions as I am still in the early stages of creating my ideal audiophile network. At present my network is fibre to premises, Ont converted to Ethernet, to link router, cat 6a shielded cable to nether gs105e switch, cat 7 Audioquest pearl shielded cable, Nordost qnet with smps, Audioquest Cinnamon to Tambaqui dac.
Before the Cinnamon I had all cable shields bonded to telegartner connectors. But I found that when I touched the qnet switch and dac I was getting a strong tingling. I tried disconnecting the shield from the cable feeding the qnet which helped a bit. I then tried the cinnamon between dac and qnet, which reduced the tingling a bit more.
With all Ethernet cables removed from the qnet there was a strong tingling when touch the dac and Qnet because of the ground difference.
All of my switches use smps so none are conn cited to ground and therefore the shields are not connected to ground.
I checked with Audioquest and their network cables the shield is on connected at the receiving end (in my case the dac end).
Is the difference in grounded(dac) and ungrounded Qnet a problem? Should my cables be shielded end to end? Should I use a switch with an earth so that the cable shields are grounded?
Any thoughts or suggestions would be greatly appreciated.
Kind regards to all. Richard W
First off, the Nordost QNet with an SMPS can be significantly improved by upgrading to an LPS (or if not possible by shunting the SMPS). Even if you’re using a Telegärtner or another type of metal connector on your network cable, it doesn’t necessarily mean it’s connected to the shield—it might be, but not always. Cat 8 spec could be an indication.
When it comes to grounding, there’s often room for improvement. However, grounding can be a complex topic. It’s worth reading up on it, particularly from manufacturers who specialize in grounding solutions for hi-fi systems.
Finally, try connecting the AudioQuest Pearl as the last cable in your setup instead of the Cinnamon. If you don’t notice an improvement, it could indicate that something else in your system needs attention. Remember, the final meter before the streamer (or DAC) is where your best gear should go. But go back and evaluate your network all the way to the router, for example also replace the standard SMPS for the Netgear as discussed by Alpha.
Sorry, my mistake, I read Audioquest Diamond. It is a pearl. Nevertheless try with much better shielded ethernet cables, especially the last one.
Hello Richard. It is certainly not wanted that you feel the current when connecting your DAC through an Ethernet cable. It sounds like a faulty Ethernet port on the DAC side.
Hello Martin,
If I remove the ethernet cable from the dac I still get a tingling (current) when touching the DAC and Qnet switch at the same time. Does this occur with the switches you have tested?
No. And since you feel the current on both devices when they are unconnected, I think you use a power distribution block in which both devices are plugged in?
If so, I’d take a hard look at that power distribution block, it seems there’s current leakage somewhere.
I also assume that the power distribution block or wall sockets are earthed.
If that’s the case, unplug everything, and plug in one device after another to figure out where the leakage is originating.
Thank you Martijn and Paul,
Yes dac and qnet both connected to Audioquest 5000 distribution unit all grounded (I checked with a socket tester).
I will check each unit separately but using multimeter the Vitus amp and dac cases do not have current. As the qnet smps does not have an earth i presume the Qnet has a floating ground and perhaps when I touch Qnet and dac the current in the Qnet is just seeking the lower ground. Also perhaps your network is earthed at some point. I am also asking Nordost with regard to shielding and grounding and will post anything useful. So far I have learnt that Valhalla and Helmsdale network cable shields are bonded both ends which blue heaven shield is bonded only at one end.
Great that you found information about connector-bonded cable shields (is it specified on the website? It’s usually not). Make sure the bonded shield is on the switch side for maximum noise reduction. I read that Blue Heaven also has solid core copper conductors, and with the shield on one side, it could be a strong contender for the best last Ethernet cable. But give it time—leave it in place for a month before making any judgment.
You already know this, but the grounding issue needs to be addressed before any auditions.
Jaap,
Thanks for all the work you did here!
First off why in some areas is Phase Noise depicted as PS? It would always be in dB.
Now from digital audio we know the better (negative) the Phase Noise is below 10Hz the less effect that jitter has on the SPDIF, I2S and other audio protocol formats.
The big question here is…. Is that the same for Ethernet and or types of Ethernet? I was heavily involved with the design of 100M Ethernet when I was designing bridges and routers back in the late 80’s early 90’s. One of the reason’s I prefer 10/100 over 1G and above is the full duplex protocol. There are so many less variables to consider. When you hit up 1G and above and the protocol becomes nibble (4bits) 1/2 duplex then there is so much more going on and Phase Noise and Jitter may not account for as much as how the receiver processes each bit.
Thought?
Thanks,
Gordon
Enhancing Streaming Audio with Optimized Switches
Alpha Audio’s recent reference to their article as an “absolute and ultimate guide” to streaming audio networks is ambitious and reflects the team’s dedication to this topic. Their detailed work, particularly on the role of the final switch and the impact of a high-quality linear power supply (LPS), offers valuable insights to the community. However, it’s important to recognize that there is still more to explore before reaching an “absolute” or “ultimate” understanding of streaming audio network optimization.
For example, Alpha Audio acknowledges better sound quality when streams are separated via VLANs on the router, yet they dismiss the possibility of hearing upstream improvements beyond the last switch. Additionally, their tests focus primarily on standard switches, which—while effective when paired with an excellent LPS—cannot match the intentional noise management and design benefits of audiophile-grade switches. By omitting these, the guide misses an opportunity to address the broader potential for network optimization.
True progress lies in addressing noise at every stage of the network, including routers, intermediate switches, power supplies, and cables. Many audiophiles report audible improvements in these areas, even when measurable differences are elusive. Alpha Audio’s current approach, while thoughtful, risks oversimplifying the nuanced interplay of components within a high-performance network.
Lastly, breaking the noise chain between the switch and streamer is crucial for maximizing sound quality. High-quality Ethernet cables, designed with proper shielding and grounding strategies, play an essential role in this process, preventing noise propagation and enhancing the clarity of the audio signal.
Alpha Audio has done commendable work in pushing the conversation forward, but there remains significant room to expand the scope of exploration. By embracing these additional factors, they could further solidify their leadership in streaming audio network optimization.
Thanks for this article. Very timely for me, as I’m about to add a separate streamer, something beyond an SSD plugged into an Oppo.
Is this article available as a PDF? Other than convenience, trying to print page by page is hindered by the Alpha–Audio banner at the top of each page, sometimes blocking text. Thanks,
You need to compare the sound quality when using WiFi instead of cabling (whether with fiber or not).
The WiFi radio in streamers are often not shielded well enough, known exception is Auralic, and introduce more problems than they potentially solve.
Very interesting – however I cannot help wondering what exactly the or rather where the benefits to the sound arise. Is it due to the media conversion or the galvanic separation?
Would be interesting to compare to a streamer/dac with galvanic separation.
To me one fundamental flaw with Ethernet is that was based on a collision system where random timers on the network adapters sends the signal with varying timing to avoid collision. Yes, now we have switches so no collision but there is no timing signal in Ethernet and never will be. So, the way the signal is assembled and buffered is what determines the sound quality.
This is also why when you stream Apple Music using Apple lossless then there is a 2 second delay to allow for a buffer to be compensating for network errors and delay. As far as I know it is the only protocol with built in buffer. Yes, you can add it to all forms of streams but Apple included it from the start.
Anyway, just my question and observation.
“…however I cannot help wondering what exactly the or rather where the benefits to the sound arise.” and “So, the way the signal is assembled and buffered is what determines the sound quality.”:
It seems there is no really perfect buffer for digital streams. There’s all sorts of re-clocking, super-femto whatsoever clocks, PLLs, … but in the end none of these things seems to be able to reduce slight and cyclic variations (aka jitter) in data timing at the DAC to exactly zero.
Put another way: everything that influences the quality of the digital stream in from of the final DAC stage has potentially influence on sound quality.
At least that’s my layman’s understanding, or should I say… belief! 😉
You guys are working hard! Amazing work in this area and a great help for the community!
We have recently discussed this, and i am sure you are going to get simial question from others, so i am thinking it might be good for you to explain your thoughts on this a bit deeper.
I am not the only one that is reporting rather big impact also when doing changes prior to the switch. In fact, in my own experience that was a big wake-up call for me where i realized the scale of this problem, even more. This of course gets more noticeable the lower noise floor you have later in the signal chain (in my experience and that also makes sense in my head)
In my case, i used to have the GS105 switch + Ifi Ipower X with a wireworld (the red one) cable to my streamer. Then later i also implemented a Ifi Ipower X on my router and a used long AQ Vodka cable between my switch and router. I put the more expensive cable there since it happened to be longer (5 meters) and i needed the length there.
It was a very big and instant improvement, that was impossible to unhear.
Now, since you don´t have the same view on this (in general at least) and can´t go back and test this again, since my setup now is different, i have given this some thought to try to understand why i had this experience.
1. First of all, i live in an apartment with 20-30 WiFi connections coming up on my phone. I know WiFi radiation has an impact on the cables, but could this explain this big difference?
2. My router (and switch) was only physically connected to the switch->streamer, meaning that it was not contaminated by anything else, if that matters? (i have a feeling many have some sort of NAS or similar there…?)
3. My router and switch was on the same power line. My HiFi setup was on a separate power line, if that matters.
I should say that i do understand that the Vodka cable is rather expensive and maybe that money is better served somewhere else! But still, the logic seem to be there (for me at least), and maybe there are cheaper ethernet cables that do a similar job?
I hope i don´t come across as complaining since i really just would like to understand why your findings are very different than mine (and many others on HiFi forums, it seems).
… I noticed that my NetGear Switch (GS108Ev4) influences the sound depending on the connection speed. Read: When I manually set it to 100Mbit/s, it sounds worse. The default 1Gb/s sounds better.
Then I also noticed that an older long Ethernet cable I used up till recently seems bad / of worse quality, since it only allowed other components to connect with 100Mb/s instead of 1Gb/s.
Maybe the long ethernet cable that you used before the AQ Vodka influenced the connect speed into the switch? Even if not, after learning about all these funny effects of noise and so on I am not surprised at all, any more. Hearing is believing. 😉
Tobias,
In your case the Vodka cable replacing the Wireworld cable is implementing a proper CAT7 twisted pair design instead of the parallel twinax geometry of the Wireworld cable. Esspecially on a medium/long lenght of 5 meter, I’m not surprised that is yielded better results. Purely based on this I wouldn’t question the conclusion of Alpha that the biggest impact on network optimization is in the last few inches (last switch and ethernet cable).
However, as the genius Alpha guys also mentioned, tuning your network end-to-end does make a certain amount of sense. Maybe the 80/20 rule is applicable. But even if optimizing the first 80% of your network section only yields just 10% quality improvement, in a well balanced high quality hifi set that might.judt be the cherry on the cake.
Things to consider:
1) upgrading/tweaking your router yields minimal benefits. Setting up vlans and splitting your domestic network also physically from you audio network does.
2) Decoupling your router and switches with dampers/absorption platforms to minimize vibrations will give improvements
3) same as your point 3, power lines doesn’t have to be exactly the same, as long as you also apply the right polarity, same as with your hifi rig. In the end it is all modulated power,, so ensure you use the same polarity end to end.
4) using good quality ethernet cable early in the network does help a bit. I shifted all my obsolete LAN cables after upgrades ‘upstream’ and it at least didn’t hurt anything. Even upgraded the coax cable between router and 1st switch for a nice design assembled by Peacock Audio. May be confirmation bias to justify the 150 euro’s spend, but I did sense some more blackness and piece (of mind?).
5) apply a proper shielded twisted pair ethernet cable between tonyour audio switch. I chose Audioquest Carbon.
Still the biggest improvement, as concluded by Alpha Audio as well, is your last switch and cable to the streamer. I’m still surprised how much impact that makes. Three years ago I found spending serious money on that questionable, to say the least. Yesterday I tried a 3.5k power cable on my switch alone, and I was blown away with what I heard. Quickly disconnected it, to prevent an unsuppressable itch…. 😉
I agree that the biggest difference is the last switch (ps) and cable, no question about that!
I didn´t replace the Wireworld with the Vodka on the 5 meter from my router. There i replaced a Supra cable. The Wireworld was still my last cable.
I just try to understand why it had such a profound impact in my setup, to implement the Vodka and PS from the router and not noticed at all by Alpha Audio. But there are many variables of course so I also understand and respect that they have to draw the line somewhere on what they can investigate in this area…
To support my theory logically, if that cheap switch is so good at stopping the noise prior why can´t we stop this noise in the streamer, or in the DAC step? In my experience you can take the noise reduction much further if you make sure to feed that switch with a less polluted signal.
This lead me to a completely different solution actually since i noticed that you ideally don´t want Power Supplies at all in the network signal. It is possible to reduce the number of PS to one if thinking very differently.
Tobias, Sorry I didn’t understand your setup or made wrong assumptions. Tried to figure out where the differences you heard could originate from.
piece (of mind?) = peace (of mind?)
and excuse some other typos.
Would be nice if the platform allows editing messages to correct it.
As mentioned I tried a different (and rather expensive) power cable on my switch. After some more testing I found the power cable on the switch actually had a bigger impact compared to the streamer (MU2). The difference was of a magnitude that I am actually considering biting the bullet and get an order out.
A mouth full: Synergistic Research Atmosphere L3 Euphoria power cable
Even forgot and ‘SX’ in the above. What I don’t get, is that I experienced the same improvements regardless streaming Qobuz over the internet/ethernet compared to ripped files stored on the MU2’s internal SSD. One would assume with local files in an all-in-one like the MU2, that the network switch handles only Roon metadata. Can you explain why that could be?