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Review and Measurements of EMO EN-60KDS Ethernet Isolator

Jinjuku

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This all just reaffirms that good sound is solid, best practices, system setup. When people start talking about EMI in a home environment I am left scratching my head over how they can just mess up what is trivial to implement.

And yeah, I like wireless.
 

jtwrace

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This all just reaffirms that good sound is solid, best practices, system setup. When people start talking about EMI in a home environment I am left scratching my head over how they can just mess up what is trivial to implement.

And yeah, I like wireless.
Most audiophiles can mess up anything. Have you visited most of their houses? :eek: No in room measurements, no room treatments but very fancy power cords.
 

jabbr

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Yes reducing interwinding capacitance is the goal to reduce leakage currents. Note that leakage frequencies are not typically 60 Hz but harmonics (this is alluded to) where impedance is less across the parasitic capacitance and why snubbing is also important. I think this might be helpful only in situations where leakage is an issue, so perhaps create that environ to test. Not that the reason SMPS gen leakage are a because of the switching and this at typically higher frequencies than mains AC.
 

Palladium

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Most audiophiles can mess up anything. Have you visited most of their houses? :eek: No in room measurements, no room treatments but very fancy power cords.

They have won't have good sound with just a fancy power cord...when they don't even have their own nuclear powerplant feeding the best zero-harmonic 60Hz power across it. :p
 

Jinjuku

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I've still yet to see the efficacy of the argument made in favor of the SQ of optical or even wireless vs wired.I've done countless computer based setups and have never heard these SQ differences.

I've STACKS of Cisco/Juniper with fiber BTW.
 

DonH56

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Yes reducing interwinding capacitance is the goal to reduce leakage currents. Note that leakage frequencies are not typically 60 Hz but harmonics (this is alluded to) where impedance is less across the parasitic capacitance and why snubbing is also important. I think this might be helpful only in situations where leakage is an issue, so perhaps create that environ to test. Not that the reason SMPS gen leakage are a because of the switching and this at typically higher frequencies than mains AC.

I think you may be confusing what is normally considered mains (AC power source) leakage with EMI/RFI... Or I am simply confused by your post, take your pick.
 

Thomas savage

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BTW, if anybody wants to complain again that we can't measure these things, should come and look at these measurements. Mere wrapping of one wire around the other is easily detectable in these measurements! It doesn't get more sensitive than this.

So if the measurements don't show any change, there is no electrical change. Period.

Let alone have it be audible.

I mean really. If Thomas flush the toilet in UK, I think I can measure the impact on Schiit DAC here. :D
After my daily music festival diet of kebab, burgers and fish and chips washed down with constant beer drinking I bet that's true.
 

jabbr

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jabbr

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I've still yet to see the efficacy of the argument made in favor of the SQ of optical or even wireless vs wired.I've done countless computer based setups and have never heard these SQ differences.

I've STACKS of Cisco/Juniper with fiber BTW.
Could be your good luck!

There is that famous EEVBlog video where he tracked down some noise on a scope to a hidden SMPS under the workbench ... these things don't always happen, but they happen. USB is weird because you have the power, ground and differential all together and I've seen nasty "ground loops". Ethernet not nearly as bad but can be improved on either by reducing interwinding/parasitic capacitance or eliminating.
 
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amirm

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I've still yet to see the efficacy of the argument made in favor of the SQ of optical or even wireless vs wired.
I plan to do some tests there. :)
 

Jinjuku

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Could be your good luck!

There is that famous EEVBlog video where he tracked down some noise on a scope to a hidden SMPS under the workbench ... these things don't always happen, but they happen. USB is weird because you have the power, ground and differential all together and I've seen nasty "ground loops". Ethernet not nearly as bad but can be improved on either by reducing interwinding/parasitic capacitance or eliminating.

Doesn't matter to me if someone runs fiber or copper. It's the same amount of work either way. Wireless is much easier.
 

jabbr

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I think you may be confusing what is normally considered mains (AC power source) leakage with EMI/RFI... Or I am simply confused by your post, take your pick.
Another comment.

Perhaps I'm confused by the use of the term "leakage" wrt AC mains. An ideal power transformer would only transmit 50/60 Hz!

50/60 Hz on output is usually called ripple and the PSRR is the relevant value.

The way I've seen and used leakage has to do with a circuit formed across the power supply via parasitic capacitance (non infinite impedance) and whose return path is the common ground.

These loops can involve multiple power supplies linked by non infinite impedance connections (cables). The reason that SMPS are more prone than LPS is precisely because the higher frequencies have less impedance.
 

jabbr

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Doesn't matter to me if someone runs fiber or copper. It's the same amount of work either way. Wireless is much easier.

I have all three at home.

Wireless is getting better year by year. Multiple video streams still do better with switched fiber/copper.

If everyone used fiber, 30% less power usage but most importantly -- audiophile Ethernet cables prob wouldn't exist
 
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Perhaps I'm confused by the use of the term "leakage" wrt AC mains. An ideal power transformer would only transmit 50/60 Hz!
Why? AC mains has harmonic distortion and those harmonics would also go across the transformer.
 

Jinjuku

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If everyone used fiber, 30% less power usage but most importantly -- audiophile Ethernet cables prob wouldn't exist

This isn't the Comedy Vault. Take your stand up routine elsewhere :)
 

DonH56

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Another comment.

Perhaps I'm confused by the use of the term "leakage" wrt AC mains. An ideal power transformer would only transmit 50/60 Hz!

50/60 Hz on output is usually called ripple and the PSRR is the relevant value.

The way I've seen and used leakage has to do with a circuit formed across the power supply via parasitic capacitance (non infinite impedance) and whose return path is the common ground.

These loops can involve multiple power supplies linked by non infinite impedance connections (cables). The reason that SMPS are more prone than LPS is precisely because the higher frequencies have less impedance.

Unfortunately I don't have time for a thorough debate... I'll comment on my perception which clearly is not the same as yours. Not worth a debate to me as my context and career is not this sort of thing.

An ideal transformer would transmit any AC signal of any frequency above DC. If it only transmitted 50/60 Hz that would be a filter, or a transformer with a filter, or perhaps the closest to your definition would be a resonant transformer circuit like the old SOLA units. That does not match what I learned, maybe different schools, or I'm just too old and out of date. Take your pick. But my son's recent college class used the same definition that I use for an ideal transformer.

Ripple can be 60 Hz for a linear supply in the USA, but is also used to define noise ripple for a SMPS. At least in the data sheets and spec I have. Again maybe just a difference in work location or whatever.

PSRR is defined differently in different datasheets, something that has always vexed me. Commonly it refers to DC or very LF AC rejection. OTOH some systems I designed chips for required PSRR be spec'd broadband, well into the RF/mW/mmW region. Ditto CMRR. I always look to see how it is tested in an audio product's datasheet.

To me, in this context (e.g. commercial product power supplies and audio), leakage usually implies DC or LF AC signals, not broadband coupling, though the term "leakage" could certainly imply wideband signal coupling. Signal leakage is a term used in RF mixers to describe LO leakage into the RF and IF ports, for example. Note there are technically capacitive, inductive, and resistive/conductance leakage paths.

I am not sure what you mean in your last statement, sorry. I have not observed SMPS to be more sensitive to leakage, rather the opposite, but they generally generate higher frequency harmonics in higher amplitude than linear supplies. The impedance of traces, decoupling capacitors, vias etc. goes up with frequency, typically leading to higher voltage noise, is that what you are saying?

A little dim today - Don
 
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jabbr

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Why? AC mains has harmonic distortion and those harmonics would also go across the transformer.

Yeah OK I could have said that better. When we talk about "leakage current" this is not the amount of 50/60 Hz signal that crosses across the isolation transformer -- a power isolation transformer wouldn't work if it didn't pass AC mains.

The AC mains circuit does not involve current to the protective earth ground. The AC mains circuit is completed by the +/-. Leakage current refers to leakage to the protective ground. An isolation transformer intends to block this -- to minimize the current that travels through the protective ground. Why? The DUT of this thread is intended for medical applications. Consider an electrode attached to a sick patient attached to an Ethernet connected device. Consider the patient grabbing a metal guard rail, completing a circuit. Might shock the heart the wrong way. Now consider an electrode in the heart itself ... might not want too much current.

Leakage currents are specified in uA for medical devices. The power supplies could easily have mA range 50/60 Hz ripple.
The impedance is inversely proportional to the frequency and capacitance, so at a given degree of parasitic capacitance, more current will flow the higher the frequency of the leakage signal.

Now you might think: well if I just ground the device really well, the impedance through the patient will be higher and ... again except that doesn't necessarily work for high frequency currents... too much to get into here, but that's why these standards exist, and leakage current and ways to measure leakage current are defined in standards (the DUT is intended for medical applications)
 

jhaider

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Conclusion:
The use of Ethernet isolators is for life safety and belts and suspenders at that. There is no reason to use them with computer audio or data for that matter.

Use that money to buy pizza and ice cream and you will be happier for it. :)

If I understand you correctly, these things are obviously pointless as sound quality "tweaks," just like most or all just things. But, it might provide some margin of protection for gear in highly networked homes. For example if installed before the POE injectors for outdoor cameras. Is that right?

After my daily music festival diet of kebab, burgers and fish and chips washed down with constant beer drinking I bet that's true.

You guys have better music festival food than we do.
 
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