Review and Measurements of EMO EN-60KDS Ethernet Isolator

[amirm]

This is a review measurement of an Ethernet isolator cable (passive) which is sold to medical industry. Ethernet is normally an isolated interface with transformers at both end. Addition of this is likely for high voltage surges and such.

I was loaned one of these to test. As you see, it is a simple, in-line cable: http://www.emosystems.com/product/en-60kds/

The unit retails for $204 in US and about 153 euros.

Searching on CA forum, seems like folks advocate its use to get rid of leakage noise. So I used the Sonore microRendu networked audio adapter which seems to be pretty sensitive to AC mains leakage. To make sure it didn't contribute any, I used my lap supply to power the microRendu.

The Ethernet connection is from my local lab switch which in turn connects to another larger switch in basement equipment closet. The cable from switch is about 6 feet. The isolator was placed at the end of the cable and terminating into microRendu.

Here are the measurement results:

As we see, there is no change other than run to run variations.

Running another pass at low frequencies up to 1 Khz, we get this zoomed in response:

As we see once again, there is no change.

Not shown but I also zoomed in around the main 12 Khz tone and found no difference either.

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.

Edit: further testing with ethernet cable wrapped around mains cable to force induction of mains, some difference was found. See: http://www.audiosciencereview.com/f...o-en-60kds-ethernet-isolator.1869/#post-48753

 

[Mivera]

I agree with this one. That's why we use fiber. Hard to polish a turd.

 

[Jinjuku]

I've tried telling people that the device only shows it's colors if you happen to experience a high voltage spike. I have one on my line from the cable modem to my core switch to protect my equipment from lightning strike.

Ask me how I came to that decision

As always I advocate wireless.

 

[Sal1950]

I've tried telling people that the device only shows it's colors if you happen to experience a high voltage spike. I have one on my line from the cable modem to my core switch to protect my equipment from lightning strike.

Ask me how I came to that decision

As always I advocate wireless.

Not being very bright myself, I see lightning jumping thousands of feet out of the sky.
Then I always ask how any device such as these are really any protecting against a hit?

 

[Jinjuku]

Not being very bright myself, I see lightning jumping thousands of feet out of the sky.
Then I always ask how any device such as these are really any protecting against a hit?

Not all hits are direct... We had lighting strike a neighbor's tree about 30 meters away. If I had something plugged into an ethernet port I lost that port.

 

[amirm]

Then I always ask how any device such as these are really any protecting against a hit?

If a real lightning strikes, any device like this will fold like a blade of grass in front of a semi truck passing over it .

As Jinjuku said, it is for secondary effect where the strength is much reduced but still powerful enough to want to find a way from outside of your home to the rest of your electronics.

The best defense for such surges is to put an SPD (surge protection device) right at service entrance where you can shunt that energy to ground with low impedance.

 

[Sal1950]

Not all hits are direct... We had lighting strike a neighbor's tree about 30 meters away. If I had something plugged into an ethernet port I lost that port.

If a real lightning strikes, any device like this will fold like a blade of grass in front of a semi truck passing over it .

As Jinjuku said, it is for secondary effect where the strength is much reduced but still powerful enough to want to find a way from outside of your home to the rest of your electronics.

The best defense for such surges is to put an SPD (surge protection device) right at service entrance where you can shunt that energy to ground with low impedance.

Yes I realize that, the post was more tongue in cheek than anything.
But I do wonder how limited the usefulness of many of these devices really is?
$200 bucks is a lot to spend for something that will only be effective in a very tiny percentages of cases.
If you could use a time machine to recreate the same strike I wonder if that cable would have prevented the damage Jinuku experienced, but we'll never know IAC.
I also recently lost a D-Link 524 wireless router after a big storm here. I use it to broadcast wireless with a long distance outboard antenna to folks in the immediate vicinity.
But I replace them for around $30 on ebay.
Remember, I'm the Audio Cheapskate. LOL

 

[Blumlein 88]

Neighbors on a bit of hill a couple years ago had lightning hit an oak tree, split the tree, jump to the windshield of their car 10 feet from the tree, slightly melt the tires, hop from the bumper to the electrical entrance where it fried two desktop PCs, a TV and a couple other items plus their modems. They asked me to look at their computers, but it was a total loss on those. Made me wonder when people tell you to get in a car during a storm as the rubber tires insulate it. The car still ran though. Just needed tires and a windshield.

I saw lightning hit a tree at the corner of my property once. The tree touched a metal fence and enough of it went 150 ft up the fence to jump to my nearby power meter and fry quite a few things. I expect most of the current went to ground. Fortunately I had turned off and unplugged all my important electronics. I had a surge protector on my microwave oven which did its job. It was blown to an open circuit and partly melted and the microwave still works. So those things can protect some times.

 

[DonH56]

Lightning traveling a mile or more through the air will easily jump a car's tires; the safety afforded is due to it being a Faraday cage'ish that channels the energy around the occupants. Wouldn't bet my life on it, though.

We've had a number of close strikes (as in 25 - 100 yards) and have been OK so far (knock on wood). We do have whole-house surge and lightning protection, and after a nearby strike took out the cable, they installed an arrestor on that as well. Still, nothing is going to do much for ya' if it's a direct strike. We have tall trees around and no lightning spikes or ground feed on the house; just as soon the trees took the hit as make the house the best ground conductor in the area.

 

[Jinjuku]

Had a friend have direct strikes on two separate houses. One blew him out of his chair while typing.

The insurance company actually asked what he was doing going forward to avoid getting struck a 3rd time

 

[Sal1950]

So during a lightning storm, do you think you'd be safer inside a below ground swimming pool, of standing up on the deck next to it?

 

[jabbr]

All copper Ethernet connections have little transformers. The need for additional isolation is to prevent reduce leakage current, typically for medical applications. If there are situations where leakage currents are relevant to audio, these isos might help. Of course there's also zero leakage across either fiber optic Ethernet or wireless.

 

[amirm]

OK, in further prompting by the company, I tried to create a situation where 60 Hz mains is accentuated. To do that, I wrapped my Ethernet cable around the AC cable of my soldering iron about three times. Here are the results across two DACs:

iFi iDAC2:

Ah, now we are getting some place. As you see in yellow, I did manage to induce 60 Hz mains into the Ethernet cable. And unlike what folks expect, it happily went through Sonore microRendu to the DAC.

Addition of EMO isolator though (in red) nice eliminated that.

Next I tried our scrappy Schiit Modi 2 which is highly sensitive to power issues:

Here I am unzoomed so you can see the spectrum past our 12 Khz J-test signal.

We see a yellow spike again showing mains related harmonics bleeding through (third harmonic at 180 Hz).

Adding the isolator nicely removed that. It also reduced the level of sideband jitters at 11.760 Khz. That is at 240 Hz or fourth harmonic of mains. In other words, the clock jitter in Modi 2 there is partially created by mains harmonics.

So there is real function there.

But please pay attention to scales. We are talking amplitudes of -128 dbFS! This is stunningly small amount. No way this is an audible concern but if you are after electronic hygiene, and you know you have this kind of mains leakage, I guess you can go this route.

Note that by standard practice, low-voltage lines like ethernet should be placed 12 inches away from mains wiring. Now you see why. Twisted or not, mains energy does leak into the cable (but again, not at a sonic or functionality level).

 

[amirm]

Just a few words about functionality of this device.

1. As noted, Ethernet already has isolation transformers. The reason it can still leak is because the transformer is not ideal. It has some capacitance and that allows forward conduction of mains frequencies. The EMO has a higher quality transformer in it with less capacitance. Hence the reason it doesn't leak as much. A good transformer in the device would have done the same thing.

2. Secondary, it has clamping diodes to clip surges. There is very little space in there so the energy it can shunt will be quite small. But it is there as a secondary measure of sorts.

My testing shows that #1 is true at least in the case of Sonore microRendu (so much for these devices being higher quality than computers in this regard). Its Ethernet input transformer did let some 60 Hz mains harmonics through which the addition of EMO eliminated. But maybe it is the combination of both that allowed that. Hard to say.

 

[Speedskater]

wrappated ?

 

[jtwrace]

Thanks for the further testing! At least they do what they say and offer surge protection.

 

[amirm]

wrappated ?

Yes, like this:

But was not in that position (was on the side of the supply which was too messy for pictures ).

Red is the Ethernet cable, black is mains.

 

[amirm]

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.

 

[jtwrace]

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.

I think that data set proves that the devil is in the details with proper wiring. Further, it shows that a device like this is actually useful in the typical rats nest environment if you're into certainty.

 

[RayDunzl]

But please pay attention to scales. We are talking amplitudes of -128 dbFS! This is stunningly small amount.

-128dB = 792.6 billionths of a volt, assuming a reference signal level of 2 volts.

http://www.sengpielaudio.com/calculator-amplification.htm