Ethernet Cables - which are the most important?

[plissken]

Interesting information and exactly the nuggets I look for from you :~)

 

Do you know why the medical world uses Ethernet isolators like the Baaske units?

 

Mansr provided the best answer in the 5 kilo Volt protection.

 

How many GE, Siemons, Teledyne Ethernet capable devices that are built for hospital use require such an isolation device?

 

Also from the Baaske Page: " If PCs or other electrical devices are connected to an Ethernet network in the patient's environment inadmissible leakage currents can appear from other devices that are also connected to network."

 

So it has better magnetic transformers. I'm certainly not arguing against such a device.

 

Are we now debating a $350 Ethernet cable will provide said isolation vs a $12 cable? That is the point to be made.

[The Computer Audiophile]

Mansr provided the best answer in the 5 kilo Volt protection.

 

How many GE, Siemons, Teledyne Ethernet capable devices that are built for hospital use require such an isolation device?

 

Also from the Baaske Page: " If PCs or other electrical devices are connected to an Ethernet network in the patient's environment inadmissible leakage currents can appear from other devices that are also connected to network."

 

So it has better magnetic transformers. I'm certainly not arguing against such a device.

 

Are we now debating a $350 Ethernet cable will provide said isolation vs a $12 cable? That is the point to be made.

 

I'm only looking for answers and trying to square information. It seems that arguments against expensive Ethernet cables go down the path that they are immune from noise by design, so I'm trying to figure out the need to use further isolators in different environments etc...

[lmitche]

Interesting information and exactly the nuggets I look for from you :~)

 

Do you know why the medical world uses Ethernet isolators like the Baaske units?

Hi Chris,

 

In the link below is an explanation that includes an introduction to the global hospital safety standards about galvanic isolation called IEC*60601-1.

 

https://en.m.wikipedia.org/wiki/Network_isolator

 

Remember hospitals can be messy, wet environments, usually even more so then our music rooms.

[mansr]

I'm only looking for answers and trying to square information. It seems that arguments against expensive Ethernet cables go down the path that they are immune from noise by design, so I'm trying to figure out the need to use further isolators in different environments etc...

The medical isolators are not noise filters. They are safety devices to prevent electrocution in case a malfunction elsewhere sends a high voltage down the network cable. Under normal circumstances they perform no function, much like a fuse or a GFCI.

[jabbr]

How much leakage current passes through an Ethernet transformer?

 

Leakage currents depend on the parallel/parasitic capacitance across a transformer i.e. Interwinding capacitance -- so yes those dinky little transformers will have leakage current.

[The Computer Audiophile]

The medical isolators are not noise filters. They are safety devices to prevent electrocution in case a malfunction elsewhere sends a high voltage down the network cable. Under normal circumstances they perform no function, much like a fuse or a GFCI.

 

Great information.

 

In my testing the Baaske units do slow down the data transmission just a bit. But that's another story.

[jabbr]

Mansr provided the best answer in the 5 kilo Volt protection.

 

How many GE, Siemons, Teledyne Ethernet capable devices that are built for hospital use require such an isolation device?

 

Also from the Baaske Page: " If PCs or other electrical devices are connected to an Ethernet network in the patient's environment inadmissible leakage currents can appear from other devices that are also connected to network."

 

So it has better magnetic transformers. I'm certainly not arguing against such a device.

 

Are we now debating a $350 Ethernet cable will provide said isolation vs a $12 cable? That is the point to be made.

 

More than just the 5kV protection, also decrease parasitic capacitance (actually place a lower capacitance value in series) -- better magnetic transformer means precisely that.

 

I agree that $350 or whatever price copper Ethernet cable can't do that whatever else it may or may not do. Fiberoptic Ethernet obviously solves this issue-- and cables are cheap

[The Computer Audiophile]

Some interesting comments about Ethernet noise and cables etc ...

 

[jabbr]

The medical isolators are not noise filters. They are safety devices to prevent electrocution in case a malfunction elsewhere sends a high voltage down the network cable. Under normal circumstances they perform no function, much like a fuse or a GFCI.

 

Leakage currents need not be high voltages particularly if an electrode is connected to the heart. The medical isolators work all the time because commodity power supplies create leakage.

[plissken]

Some interesting comments about Ethernet noise and cables etc ...

 

 

I have my technical license for HAM radio. You have to read carefully what they are saying in that thread.

 

Their radio equipment is being interfered with due to noisy PSU's etc... If there is noise introduced by the power supply on a switch it will show up on Ethernet cable. They are complaining about noise swamping their VHF band. That would be switching speed of the power supply.

 

It's nothing in the audible band.

 

It's even pointed out to start using linear supplies. Which is what is powering my 2.0 setup. If people want to get the most out of their hard wired consumer Router / Switch start powering them with a linear supply or better yet a -60/0/+60 linear supply.

 

Or start using wireless.

[plissken]

More than just the 5kV protection, also decrease parasitic capacitance (actually place a lower capacitance value in series) -- better magnetic transformer means precisely that.

 

I agree that $350 or whatever price copper Ethernet cable can't do that whatever else it may or may not do. Fiberoptic Ethernet obviously solves this issue-- and cables are cheap

 

I think you are closest to getting the point I'm attempting to make:

 

If GE/Siemons/Teledyne/ etc don't require a device like the Baaske, it's because they have taken greater care to the physical implementation of their network connection.

 

Which leads me to the obvious point: Why aren't manufacturers of supposed high end audio devices doing the same?

[plissken]

Leakage currents need not be high voltages particularly if an electrode is connected to the heart. The medical isolators work all the time because commodity power supplies create leakage.

 

nobody is submitting results for FDA testing where someone might get killed. This is audio. There are no emergencies here.

 

Just sayin'

[infonut]

 

Are we now debating a $350 Ethernet cable will provide said isolation vs a $12 cable? That is the point to be made.

Is it possible that the improvement in sound quality that some say they hear is not due to improvements made to the ethernet signal, but instead due to reducing the noise emitted from the ethernet cable into the other parts of the system?

 

If the ethernet cable is inducing noise in other cables or audio circuitry, then a cable with a properly grounded shield and twisted pair ethernet signal wires should reduce the amount of noise induced in other parts of the system.

 

Have people who have heard improvements with expensive ethernet cables experimented with different cable routing and positioning?

[plissken]

Is it possible that the improvement in sound quality that some say they hear is not due to improvements made to the ethernet signal, but instead due to reducing the noise emitted from the ethernet cable into the other parts of the system?

 

If the ethernet cable is inducing noise in other cables or audio circuitry, then a cable with a properly grounded shield and twisted pair ethernet signal wires should reduce the amount of noise induced in other parts of the system.

 

Have people who have heard improvements with expensive ethernet cables experimented with different cable routing and positioning?

 

Ethernet signaling isn't a net radiator of RFI outside of bundling a bunch up together.

 

With Ethernet being a 100 or 250Mhz fixed frequency signaling architecture the short answer is no. The frequency is so high and so low power that its a audio non-issue.

 

If we follow this down the path of CAT5/6/6A what you will see are primarily three concerns:

 

1. Interpair scew and crosstalk. In CAT6x applications the interpair winding is so critical that two approaches are made:

A. X-spline in the cable to ensure proper separation distance of the pairs

B. Foil wrapped pairs to further reduce vampire loading between pairs

 

2. Inter-cable vampire load. Screens placed around the entire cable assembly to prevent cross talk when you have a large bundle in a horizontal run.

 

3. Shield, usually tied to chassis ground, that is meant for industrial applications.

 

* There is also armored Ethernet that provides -20dB of attenuation reduction.

 

The interesting thing is, using the AQ Vodka cable as an example, is that it doesn't have some of this. Primarily the X spline. Also take a look at the extremely poor termination. These cables will be bested by injected molded, machine crimped, $10 CAT6A in 10GB applications.

 

AQ is selling a non compliant cable for a helluva lot off money.

 

Gallery: We tear apart a $340 audiophile Ethernet cable and look inside | Ars Technica

[scan80269]

Ethernet signaling isn't a net radiator of RFI outside of bundling a bunch up together.

 

With Ethernet being a 100 or 250Mhz fixed frequency signaling architecture the short answer is no. The frequency is so high and so low power that its a audio non-issue.

 

If we follow this down the path of CAT5/6/6A what you will see are primarily three concerns:

 

1. Interpair scew and crosstalk. In CAT6x applications the interpair winding is so critical that two approaches are made:

A. X-spline in the cable to ensure proper separation distance of the pairs

B. Foil wrapped pairs to further reduce vampire loading between pairs

 

2. Inter-cable vampire load. Screens placed around the entire cable assembly to prevent cross talk when you have a large bundle in a horizontal run.

 

3. Shield, usually tied to chassis ground, that is meant for industrial applications.

 

* There is also armored Ethernet that provides -20dB of attenuation reduction.

 

The interesting thing is, using the AQ Vodka cable as an example, is that it doesn't have some of this. Primarily the X spline. Also take a look at the extremely poor termination. These cables will be bested by injected molded, machine crimped, $10 CAT6A in 10GB applications.

 

AQ is selling a non compliant cable for a helluva lot off money.

 

Gallery: We tear apart a $340 audiophile Ethernet cable and look inside | Ars Technica

Would you say Blue Jeans Cable with bonded-pair Belden cable stock in their Cat5e, Cat6 & Cat6a cables are good enough to address intra-pair skew?

 

Someone has mentioned that BJC recommends Cat6 over Cat6a for audio use, so I wonder what would be the reasoning behind this. Cat6a should have less inter-pair crosstalk than Cat6 UTP.

[Jud]

I have my technical license for HAM radio. You have to read carefully what they are saying in that thread.

 

Their radio equipment is being interfered with due to noisy PSU's etc... If there is noise introduced by the power supply on a switch it will show up on Ethernet cable. They are complaining about noise swamping their VHF band. That would be switching speed of the power supply.

 

It's nothing in the audible band.

 

It's even pointed out to start using linear supplies. Which is what is powering my 2.0 setup. If people want to get the most out of their hard wired consumer Router / Switch start powering them with a linear supply or better yet a -60/0/+60 linear supply.

 

Or start using wireless.

 

I don't know if you wanted to go down this particular rabbit hole, but are there some economical power supplies you might recommend?

 

 

Sent from my iPhone using Computer Audiophile

[Ralf11]

@Ralf11: yeah that's about right, although pure tones are limited to 20kHz (at best) the timing of pulse differentiation can be >20kHz components IIRC

 

 

Sent from my iPhone using Tapatalk

 

Do you have a cite for the pulse info? I'd like to read more about this.

[plissken]

Would you say Blue Jeans Cable with bonded-pair Belden cable stock in their Cat5e, Cat6 & Cat6a cables are good enough to address intra-pair skew?

 

Someone has mentioned that BJC recommends Cat6 over Cat6a for audio use, so I wonder what would be the reasoning behind this. Cat6a should have less inter-pair crosstalk than Cat6 UTP.

 

There are some videos on Youtube where Belden reps are at audio shows talking about different cable types. You can only minimize skew and I believe Belden has the best numbers on this as their process is proprietary. They also use it on their HDMI stock which also, if I remember correctly, nets them the inter-skew performance crown on HDMI as well.

[jabbr]

Do you have a cite for the pulse info? I'd like to read more about this.

 

Start with: https://www.ncbi.nlm.nih.gov/pubmed/25166166, there are also several articles on ultrasonic bone conduction, also: https://www.ncbi.nlm.nih.gov/pubmed/26022837

[jabbr]

Would you say Blue Jeans Cable with bonded-pair Belden cable stock in their Cat5e, Cat6 & Cat6a cables are good enough to address intra-pair skew?

Someone has mentioned that BJC recommends Cat6 over Cat6a for audio use, so I wonder what would be the reasoning behind this. Cat6a should have less inter-pair crosstalk than Cat6 UTP.

 

Belden Mediatwist is as good as you need regarding intrapair skew because the pairs are bonded. For Ethernet, this will show up in the eye plot. Regarding "audio", Belden means "analog audio", not Ethernet: The Strange World of Cat 5e and Cat 6

[plissken]

I don't know if you wanted to go down this particular rabbit hole, but are there some economical power supplies you might recommend?

 

 

Sent from my iPhone using Computer Audiophile

 

Here is what I can tell you from experimentation:

 

I took an audio card that can drive either balanced or SE connections. In balanced mode I took TRS and floated the shield at the output.

 

With a 330 watt SMPS you could hear the mouse movement and HDD access as a quick series of rapid, soft, click like pulses.

 

Next up mapping a network drive letter and pulling over SMB cut the file access noise out as far as pulling a file.

 

Next up an SSD cut the HDD noise out.

 

Next up a Tripplite 12VDC, 7 amp with DC to DC atx converter cut all of it out almost to the point of beyond perception.

 

Next up re-attaching shield and having a properly balanced cable returned the system back to it's optimal noise floor regardless of SMPS or linear regulated power supply.

 

Purchase properly designed gear. We are talking a $200 PCIe sound card. If they can get it right then I expect multi-thousands of dollars of DAC to get it right.

 

Measurements were taken mono at the speaker with a Dayton Omni-mic V2 so I had the transfer function of the entire system accounted for.

[mansr]

Belden Mediatwist is as good as you need regarding intrapair skew because the pairs are bonded. For Ethernet, this will show up in the eye plot. Regarding "audio", Belden means "analog audio", not Ethernet: The Strange World of Cat 5e and Cat 6

Intrapair skew can be a problem for high speeds over long distances. For gigabit over typical domestic distances any Cat 5e is plenty. No matter what the circumstances, if the link works reliably, the skew is within whatever limits the receiver tolerates, and reducing it further won't improve a thing.

[JohnSwenson]

Too much stuff to quote individual posts.

 

First off, Ethernet PHYs

I have worked in the semiconductor field for 33 years, during that time I have worked on over 50 PHYs for many different standards including many Ethernet PHYs. As a matter of fact there is a good probability that your computer has a PHY I worked on. I know a little bit about the subject.

 

Ethernet PHYs DO draw different amounts of current depending on the signal integrity of the signal being fed into the receiver. There is a LOT of both analog and digital circuitry trying to extract the bits out of that noisy piece of wire. When these circuits are running full bore (to extract bits from very noisy wires) they use a LOT of power. Part of my job has been to design power networks in the chip that can try and deliver clean power to those analog circuits. The advent of battery powered devices has put a premium on low power consumption of every chip in a device, so the PHYs are very carefully designed to use just the bare minimum of circuitry necessary to extract the bits. The result is the power varies radically with the signal integrity of the received signal.

 

When testing these PHYs we actually use a $700 cable to give the PHY the best signal integrity possible in order to find the baseline low power usage. These $700 cables use very expensive materials and extremely high precision geometry to have the least possible degradation on the signal. We then test with all kinds of more "normal" cables and lengths to see what happens in the real world.

 

What happens is that the BER stays almost the same, the chip is doing its job right and adjusting its internal circuitry to handle increasing signal degradation, which causes increased power draw and noise on power supplies and ground planes. At some point the BER skyrockets, it is interesting that what usually causes this is the PLLs that generate the timing for the PHY start outputing too much jitter as the noise on the PS and planes increases. One solution is to include an internal linear regulator on chip for the PLLs, which works, but increases the power dissipation of the chip. The customers don't like this.

 

The result of this modern heavy focus on power consumption HAS produced Ethernet PHYs which produce significantly varying power consumption depending on small changes in signal integrity.

 

On the issue of EMI coming from the cable to other parts of the system.

It is not so much the 125MHz symbol rate, but the PACKET rate that matters. In audio over Ethernet the packet rate frequently winds up right smack dab in the middle of the audio band where the human ear is quite sensitive. It is possible for the 125MHz to wind up getting into analog systems and going through non-linear parts of the circuit which can lead to small amounts of the packet frequency winding up in the audio signal. It probably is pretty low intensity and systems will vary radically on how sensitive they are to this, but I don't think it is wise to completely discount it.

 

On leakage currents and Ethernet cabling, I have no idea what is going on there. I have had no time to do any testing and won't for a long time. My lab is going to be packed up and in storage for many months so I won't be able to do any testing on this subject. I don't know enough about this subject at this time to make any comment on it.

 

On expensive Ethernet cables from audio cable makers, I'm fairly skeptical that they know what they are doing. I DO know what it takes to make a REALLY good cable, and what I have seen from the audio cable companies does not even come close to this. If these cables wind up sounding better I think it is much more likely to be an accident than any form of exceptional cable construction. And BTW making a cable with VERY low signal degradation DOES cost a lot of money, maybe the companies that make these should look into the audiophile market!

 

Someone asked the question about integrated PHYs, it's probably about 50/50 right now. A fair number of processors these days come with Ethernet MACs built in, so they just need a PHY on the outside. Other processors use a combo MAC/PHY chip. Then there are hybrid motherboards, the processor has a builtin MAC, so just a PHY is needed, but if the motherboard wants a second (or third) Ethernet port they use a combo chip. The motherboard of the computer I am typing on right now does this.

 

Well I guess that is about it for now.

 

John S.

[plissken]

On the issue of EMI coming from the cable to other parts of the system.

It is not so much the 125MHz symbol rate, but the PACKET rate that matters. In audio over Ethernet the packet rate frequently winds up right smack dab in the middle of the audio band where the human ear is quite sensitive.

 

Which optical isolation isn't going to prevent?

 

It is possible for the 125MHz to wind up getting into analog systems and going through non-linear parts of the circuit which can lead to small amounts of the packet frequency winding up in the audio signal. It probably is pretty low intensity and systems will vary radically on how sensitive they are to this, but I don't think it is wise to completely discount it.

 

With all the permutations of audio equipment shouldn't a reasonably well designed DAC reject all this. I know in my test, that I posted about in this thread, that my $200 PCIe sound card took care of all the hash going on with a SMPS supply and it also decreased rather significantly with a $70 Tripplite linear supply.

 

On expensive Ethernet cables from audio cable makers, I'm fairly skeptical that they know what they are doing. I DO know what it takes to make a REALLY good cable, and what I have seen from the audio cable companies does not even come close to this.

 

What would be your go to cable? or what do you currently use.

[mansr]

Too much stuff to quote individual posts.

 

First off, Ethernet PHYs

I have worked in the semiconductor field for 33 years, during that time I have worked on over 50 PHYs for many different standards including many Ethernet PHYs. As a matter of fact there is a good probability that your computer has a PHY I worked on. I know a little bit about the subject.

 

Ethernet PHYs DO draw different amounts of current depending on the signal integrity of the signal being fed into the receiver. There is a LOT of both analog and digital circuitry trying to extract the bits out of that noisy piece of wire. When these circuits are running full bore (to extract bits from very noisy wires) they use a LOT of power. Part of my job has been to design power networks in the chip that can try and deliver clean power to those analog circuits. The advent of battery powered devices has put a premium on low power consumption of every chip in a device, so the PHYs are very carefully designed to use just the bare minimum of circuitry necessary to extract the bits. The result is the power varies radically with the signal integrity of the received signal.

 

When testing these PHYs we actually use a $700 cable to give the PHY the best signal integrity possible in order to find the baseline low power usage. These $700 cables use very expensive materials and extremely high precision geometry to have the least possible degradation on the signal. We then test with all kinds of more "normal" cables and lengths to see what happens in the real world.

 

What happens is that the BER stays almost the same, the chip is doing its job right and adjusting its internal circuitry to handle increasing signal degradation, which causes increased power draw and noise on power supplies and ground planes. At some point the BER skyrockets, it is interesting that what usually causes this is the PLLs that generate the timing for the PHY start outputing too much jitter as the noise on the PS and planes increases. One solution is to include an internal linear regulator on chip for the PLLs, which works, but increases the power dissipation of the chip. The customers don't like this.

 

The result of this modern heavy focus on power consumption HAS produced Ethernet PHYs which produce significantly varying power consumption depending on small changes in signal integrity.

 

On the issue of EMI coming from the cable to other parts of the system.

It is not so much the 125MHz symbol rate, but the PACKET rate that matters. In audio over Ethernet the packet rate frequently winds up right smack dab in the middle of the audio band where the human ear is quite sensitive. It is possible for the 125MHz to wind up getting into analog systems and going through non-linear parts of the circuit which can lead to small amounts of the packet frequency winding up in the audio signal. It probably is pretty low intensity and systems will vary radically on how sensitive they are to this, but I don't think it is wise to completely discount it.

 

On leakage currents and Ethernet cabling, I have no idea what is going on there. I have had no time to do any testing and won't for a long time. My lab is going to be packed up and in storage for many months so I won't be able to do any testing on this subject. I don't know enough about this subject at this time to make any comment on it.

 

On expensive Ethernet cables from audio cable makers, I'm fairly skeptical that they know what they are doing. I DO know what it takes to make a REALLY good cable, and what I have seen from the audio cable companies does not even come close to this. If these cables wind up sounding better I think it is much more likely to be an accident than any form of exceptional cable construction. And BTW making a cable with VERY low signal degradation DOES cost a lot of money, maybe the companies that make these should look into the audiophile market!

 

Someone asked the question about integrated PHYs, it's probably about 50/50 right now. A fair number of processors these days come with Ethernet MACs built in, so they just need a PHY on the outside. Other processors use a combo MAC/PHY chip. Then there are hybrid motherboards, the processor has a builtin MAC, so just a PHY is needed, but if the motherboard wants a second (or third) Ethernet port they use a combo chip. The motherboard of the computer I am typing on right now does this.

 

Well I guess that is about it for now.

 

John S.

Thanks for that. Now could you please clarify a couple of things?

 

1. How big a difference in PHY power draw would be expected between a regular Cat 5e cable and the best money can buy in a normal domestic environment?

 

2. How much do typical PHY power fluctuations actually affect the DAC circuitry in a competent design?