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Offline frank23  
#21 Posted : 14 March 2019 08:20:06(UTC)
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Originally Posted by: Martin Colloms Go to Quoted Post
Our perception can be astonishingly acute in respect of unwanted, vibration induced noise. Many improvements are based on effective noise suppression, and it was with some surprise that net switches were found to be strongly microphonic expressed in their digital, pure switching domain.


Originally Posted by: frank23 Go to Quoted Post

Do you mean that a sound played finds its way back in the digital signal through vibrations? That is, that the digital signal itself when decoded, shows traces of these vibrations?


Originally Posted by: Martin Colloms Go to Quoted Post

Broadly you could say that it is a form of jitter present when the digital signal is decoded to analogue. The 1,s and zeroes, are unchanged but the micro timing is. Jitter rejection is an imperfect art.


Ok, I can follow that reasoning. But since the signal itself does not change, all the noise effects (be it induced in or through the cable through vibrations or RF or otherwise) must be transferred internally through power supply lines. As there is no timing information going through the ethernet cable, because timing is fully done within the receiving device.

Somewhere within the receiving device there is a circuit that buffers the incoming stream. Up to this, is it untimed. Then it is read from the buffer and enters a timed DA circuit. Then if there is an effect, it is that the timing from this point on is influenced by noise transferred by or induced by the ethernet cable, through power supply circuits. Another option would mean that internal shielding is inadequate.

Edited by user 14 March 2019 08:22:44(UTC)  | Reason: Not specified

Offline Steveh100  
#22 Posted : 14 March 2019 09:55:01(UTC)
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My take on all this is we don't' know. It's easy to say certain elements of the design are inadequate, it's easy to blame jitter because we think we understand the effects but my belief (and you note I say belief as I don't know) is this it is more complicated and until we start the investigation we are only guessing.

Now realistically given the resources, the motivations, and the economics it's unlikely we will find the solution but we may move forward a little.
Offline frank23  
#23 Posted : 14 March 2019 10:04:22(UTC)
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Originally Posted by: Steveh100 Go to Quoted Post
but my belief (and you note I say belief as I don't know) is this it is more complicated and until we start the investigation we are only guessing.


Well, what sometimes seems, is that people think that the digital signal itself is in any way influenced by analogue noise. Sandy thinks so, he thinks his ripping device makes 100% accurate rips being bit identical to other rips, sound different than those other 100% accurate bit identical rips.

I don't think we are guessing here. There is a mechanism through which noise over an ethernet cable can influence sound, but this is a fully analogue path. It cannot be by influencing the digital signal, bits are bits in this stage, or by making changes to the timing of the digital signal as in this stage there is no timing in this digital signal.

ps. there is a sequence in the digital signal of course, but no timing.

Edited by user 14 March 2019 10:48:14(UTC)  | Reason: Not specified

Offline kengale  
#24 Posted : 15 March 2019 12:47:04(UTC)
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Originally Posted by: frank23 Go to Quoted Post
Originally Posted by: Steveh100 Go to Quoted Post
but my belief (and you note I say belief as I don't know) is this it is more complicated and until we start the investigation we are only guessing.


Well, what sometimes seems, is that people think that the digital signal itself is in any way influenced by analogue noise. Sandy thinks so, he thinks his ripping device makes 100% accurate rips being bit identical to other rips, sound different than those other 100% accurate bit identical rips.

I don't think we are guessing here. There is a mechanism through which noise over an ethernet cable can influence sound, but this is a fully analogue path. It cannot be by influencing the digital signal, bits are bits in this stage, or by making changes to the timing of the digital signal as in this stage there is no timing in this digital signal.

ps. there is a sequence in the digital signal of course, but no timing.


We're blaming the wrong thing here - the problem is with the receiving device. If it has any analogue sensitivity to the characteristics of the CAT cable then there is something seriously wrong with its design which should have been sorted out long before it was put on the market. And of course if the cable group test is carried out the results can only apply to cables used in a setup with the identical equipment identically configured - the results are likely to be completely different with any receiving device with its own particular design defects.

Offline frank23  
#25 Posted : 16 March 2019 13:51:55(UTC)
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Originally Posted by: kengale Go to Quoted Post
We're blaming the wrong thing here - the problem is with the receiving device. If it has any analogue sensitivity to the characteristics of the CAT cable then there is something seriously wrong with its design which should have been sorted out long before it was put on the market. And of course if the cable group test is carried out the results can only apply to cables used in a setup with the identical equipment identically configured - the results are likely to be completely different with any receiving device with its own particular design defects.


Well, I don't think on this audio level any device is without any sensitivity to anything. I mean, lets say the receiving device would be fully independent with it own power supply and power cord, and would be optically (non galvanically) connected. Even plugging in a device next to another can affect the sound. Let alone if this receiving device shares a cabinet, and parts of the power supply.

So I accept there can be an influence on the sound from the noise that the CAT carries or picks up. But yes, as @Pete and @Kengale said, this influence will vary from one device to another. And the effect is fully analogue, and not in any way digital.

So when comparing CAT cables, an interesting thing would be to assess the effects with different sending and receiving devices. Any detected consistency there might be valuable.
Offline Martin Colloms  
#26 Posted : 16 March 2019 14:18:58(UTC)
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NETWORK AUDIO DATA

While I will report in greater detail, and note my earlier article on network susceptibility
to these effects ( Audio Networking April -June 2018 ) here more specifically network switches ,

there does not seem to be any part of an audio network , plugs, wired/optical, cable length, cable type,
anti- vibration supports, mains supplies, cable decoupling, network switch damping,linear and S/M supplies
which does not affect the sound quality, even for costly very well re-clocked, jitter cancelled destinations.

I took networks for granted, data packets perfectly clocked-in clocked-out, must be OK? ....No!

Whilst on this digital data subject, note that HDD and SSD may be differentiated by ear from the reproduced music quality. ( UNitiCore review )

Note that SPDIF cables/ interfaces are audible no matter how extreme the re-clocking. Splitting out the sub codes, and separating the clock from the data helps immensely but the cables/connections still matter.

Blaming the streamer is pointless. The better the streamer the more revealing it is of low level interferences because it is more transparent.

Net switch chips are often microphonic, damping then produces a clearer sound , crystal locked or not.

There is more to do here............

Martin Colloms
Offline BMP  
#27 Posted : 18 March 2019 16:17:48(UTC)
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As a non electronics expert can somebody please explain to me the difference between analogue and digital cables. I was under the impression that digital signals sent down ANY cable were digital only in that the analogue signal carrying them was a simple square wave form with the wave representing a one and its absence a zero. Unless I have this totally wrong and that is quite possible, then its seems to me that ALL signals are analogue.

Please clarify,

Brian PinderCrying Confused
Offline Togil  
#28 Posted : 18 March 2019 18:47:10(UTC)
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Yes they are analogue, just as numbers written down on on a piece of paper or in a book are "analogue" but their meaning is independent of the means of presenting them.
Hans
Offline frank23  
#29 Posted : 18 March 2019 21:55:14(UTC)
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Maybe a bad analogy. But lets say I wanted to transfer "this text". And the text formatting represents noise.

So it starts clean as "this text". It could be transported as "this text" through cable A, or could transported as "this text" through cable B. But the receiver still knows it is "this text" that it has to deduct from the signal, not looking at the formatting caused by noise picked up underway.

So a digital signal can be fully restored to the original input text, independent of the noise encountered en-route. As long as the noise is not so bad that it can't be read anymore of course. Then you'd get dropouts.

As I said, SPDIF is different, as there is a master-slave relation in the timing, and "this text" through cable A, could really sound different from "this text" through cable B.

Edited by user 18 March 2019 21:56:42(UTC)  | Reason: Not specified

Offline Martin Colloms  
#30 Posted : 19 March 2019 08:47:09(UTC)
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Observed 'digital' cable sound differences are not just electrical, e.g. jitter.

A cable approximates to a mechanical rod, coupling vibration from one unit to another, and to and from the the surfaces it may be resting on.

Such resulting microphony subtly alters sound quality, and jitter need not be the reason in every case.

Martin Colloms
Offline frank23  
#31 Posted : 19 March 2019 14:40:39(UTC)
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Originally Posted by: Martin Colloms Go to Quoted Post
Such resulting microphony subtly alters sound quality, and jitter need not be the reason in every case.


In ethernet transport there is no timing related to the audio information, so there cannot be jitter. There is just noise on the digital signal. And in the receiving end, this noise may influence all kinds of processes, resulting in influencing the final analogue output signal.
Offline Martin Colloms  
#32 Posted : 19 March 2019 18:58:51(UTC)
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it is ' all those kinds of processes' that we need to get a grip on.

we had thought that data was data on a network, now many tests are showing that other factors still get in the way of perfection.

Meanwhile I am enjoying running in an ARC REF 160 M combo for an upcoming review. It is interesting comparing triode mode with ultra -linear.
With the Magico S5 II I find triode mode with the 4ohm tap optimal. The Wilson Sasha DAW is soon to arrive for review and it will be interesting to see which monoblock settings will suit them.

Martin Colloms
Offline hkyria  
#33 Posted : 30 March 2019 23:36:08(UTC)
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Martin,

I would nominate the following network switches are included in your upcoming group test:

Cisco Catalyst 2960G Model# WS-C2960G-8TC-L (Gigabit blue model - £60 used)
Cisco Catalyst 2960CG Series Model# WS-C2960CG-8TC-L (Gigabit white model - £150 used)
Cisco SG110D-08 8 Port Gigabit Desktop Switch (£40 new)

The Cisco Catalyst 2960G Model# WS-C2960G-8TC-L (Blue model) is my current reference switch. I have also tried the later white model but in my system preferred the older blue model. I’m using Meicord Opal audiophile CAT cables.

I have just purchased the Cisco SG110D-08 8 Port Gigabit Desktop Switch (£40 new) and straight out of the box when powered by a Netgear linear power supply and although it sounds completely different to the 2960G, it is sounding extremely promising with only 5 hours of use. What prompted me to try out this inexpensive switch, is that it is one of the Cisco models which have been chosen by Clone Audio to enhance and would expect that during their search to find a worthwhile stock model to improve, a manufacturer would test many widely available switches on the market before choosing a model to invest their time and research on improving and therefore this model could be one of the better switches available in its stock form and maybe worth trying out.

Do you now have a shortlist of cables and switches you plan to include in your group test?
Offline Togil  
#34 Posted : 31 March 2019 15:32:09(UTC)
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Also if testing switches can we compare them to setups where no switch is needed, eg Melco or Innuos servers which have direct ethernet transmission to Dlna renderers.
Hans
thanks 1 user thanked Togil for this useful post.
frank23 on 31/03/2019(UTC)
Offline frank23  
#35 Posted : 31 March 2019 21:04:13(UTC)
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Originally Posted by: Togil Go to Quoted Post

Also if testing switches can we compare them to setups where no switch is needed, eg Melco or Innuos servers which have direct ethernet transmission to Dlna renderers.


Besides, if the IP adresses are hard configured instead of with DHCP, you can go without a switch also, so a switch is not always needed.

https://www.makeuseof.co...cal-area-network-router/
Offline phil page  
#36 Posted : 01 April 2019 04:46:17(UTC)
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I have an Innuos server; direct ethernet transmission to my streamer (Naim NDS or ND555) is far superior to transmission via network and switches.
Phil
Offline Martin Colloms  
#37 Posted : 03 April 2019 10:33:32(UTC)
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re cable sound


Mains cables are particularly rigid longitudinally and readily couple vibration from and to equipment.

The room when energised acoustically vibrates , floor and walls , and the latter may couple this vibration via the mains cable to the audio unit. It is possible to construct a safe mains cable which includes mechanical decoupling, which is readily audible.


The weave, wind and tension in a cable may also be contrived to reduce transmission of microphony induced vibration.

Martin Colloms
Offline Yeti  
#38 Posted : 22 April 2019 07:23:28(UTC)
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In case you haven’t been wading through it. There’s been a bit of discussion of CAT cables on the Naim forum in the ND555 impressions thread. Starting with a comparison of “bog standard” 5e, 6 and 7, of which 5e came out on top it then picked up AudioQuest Cinnamon, Vodka and Diamond cables with True Signal Audio entering the fray. There was also an observation that following the manufactures direction markers is not always the preferred orientation. A lot of this was with a direct connection from a Melco however.
Offline Chag  
#39 Posted : 27 April 2019 15:26:57(UTC)
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We all have been looking for the better Ethernet cables, last meter or not, we are now hunting for the best switches and power supplies, but very little has been written or even posted on routers. I would be very interested in a short list for that matter.

Chag -

Edited by user 27 April 2019 15:29:45(UTC)  | Reason: Not specified

Offline frank23  
#40 Posted : 27 April 2019 18:09:42(UTC)
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I have to say it again. Digital wise, there are no "better" routers, or "better" cables in this ethernet domain. They work or they don't. Ethernet is not like SPDIF.

The only thing that counts is the amount of noise that they generate or transport to the audio device. This is analogue noise, maybe caused by digital signals, but this noise does not affect the content of the digital signal that is transported over the ethernet connection. The way the receiving device handles this analogue noise is what causes differences in sound. The digital signal is not affected, nor is the timing, as this ethernet signal does not have timing.

The timer in the receiving device could be influenced by the noise on the ethernet cable of course, but this is due to the way the receiving device handles this noise.

Edited by user 27 April 2019 18:12:19(UTC)  | Reason: Not specified

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