Overall Isolation - network, USB, and power

[austinpop]

Rajiv,

 

Many thanks. AND I think you've done us all a great service in highlighting a key and critical set of truths about audio in general and computer audio in spades... the way things work together in a given system is a complex set of interactions and the impact of a change that produces positive results in one system MAY produce very different results in another.

 

<Snip>

 

Finally, another thing I learn again and again is recheck your setup as you evolve it over time.... what was the cat's meow a few months ago may not be needed or even be a hindrance today!

 

Greg in Mississippi

 

P.S. And if you want to sell your Baaske, drop me a PM!

 

Amen to that!

 

And I'll keep the Baaske, since I've already been meaning to isolate my router from any nasties on my incoming cable line, and the Baaske should be good for that.

[fob69]

@fob69

 

Thanks very much for your comments. You made me think about what a passive isolator like Baaske is doing, and given it's at heart a transformer, your point regarding it's ineffectiveness with high frequency noise makes sense.

 

Your other point about the Tecknet batteries is also very well taken. I tried that route because it was cheap. I must say I was (am) surprised that it sounded better than the Jameco 9V LPS wart, despite my concern that the Tecknet's regulator was cheap and potentially noisy.

 

It has always been my intention to try feeding the downstream (DAC-side) FMC from a good power source. I'm still waiting for my Teralink X1/X2 U9VA LPS to get here. If I had deeper pockets, I'd put it on an LPS-1!

 

 

Thanks a lot for your thread ! I decided three weeks ago to upgrade my system on digital side and it makes me do a big jump ahead.

 

I use now two lifepo4 batteries for FMC and streamer with wonderfull results (with 4 solders each for jack connectors). I am now integrated those batteries in a box with the loaders and a relay switching system. It is a bit of DIY job but i will post somme info on the forum when it will be finished.

 

 

I can be wrong, but if DC leakage cause noise, IMO it is better to keep going on use the word "noise", it can avoid misunderstood on what an isolation can do or not.

 

B.

[austinpop]

...

 

I use now two lifepo4 batteries for FMC and streamer with wonderfull results (with 4 solders each for jack connectors). I am now integrated those batteries in a box with the loaders and a relay switching system. It is a bit of DIY job but i will post somme info on the forum when it will be finished.

 

...

 

Yes, please do. We would be very interested.

[JohnSwenson]

Hi All,

unfortunately I haven't had much time to participate in this thread, but this is related to a LOT of what I have been doing for the last several years, some of which have made it into products you all know about.

 

I have a little bit of time right now so I'll go into a broad overview of what I have found in my wanderings through digital audio.

 

First USB.

 

There are at least three issues with USB that need to be addressed, it is rare for all three to be dealt with well in the same system, making it possible to do this is what I have spending a lot of time on.

 

The three things are:

 

timing

signal integrity

leakage loops

 

Timing should be familiar to everybody on this thread. Its is the age old issue of where the clock that feeds the DAC comes from. Early implementations were terrible, having to sync a local oscillator to the USB signal. Asynchronous mode fixed that, allowed a local oscillator in the DAC to be in charge. Unfortunately MANY implementations did this very poorly so the advantage of async was not realized fully. Fortunately things are MUCH better today, with many manufacturers finally realizing how to do this.

 

Everyone thought this would BE IT, the ultimate interface. Unfortunately it was not so, there were OTHER things involved here.

 

The first I started looking at was signal integrity of the USB bus. Exactly how this makes it through to sound coming out of the DAC is not fully known at this point. BUT it does look like increasing the signal integrity at the DAC USB chip decreases small noise voltages in the ground plane of the DAC. Devices such as the REGEN are designed to increase the signal integrity going into the DAC USB chip.

 

Some manufacturers have added isolation techniques after the USB chip, trying to block the ground plane noises from getting to the clock and DAC chips. Again unfortunately many of these implementations have not been done very well. But even the ones that ARE done well still do not seem to completely get rid of cable and source dependencies. There still has to be something else.

 

Enter leakage loops.

 

I don't have time here to go into detail on leakage loops, I have written extensively about this in recent posts. A few important points. This is caused by leakage from the AC line through capacitances in the power supply to the DC output of the supply. They have NOTHING to do with the traditional "ground loops" that happen through the safety ground (third pin) of the AC wiring, it is something different. Earthing (ground rods etc) have nothing to do with this. Leakage loops always go through at least two power supplies: AC line, PS A, DC output to circuit A, interconnect to other box, DC of circuit B to PS B back to AC line.

 

Leakage loops depend on the type and implementation of both power supplies. Leakage current is line frequency (50/60Hz) plus harmonics, plus any crud from the PS. It is primarily low frequency AC, but higher frequencies can exist. The problem from the leakage loop is the voltage noise generated when the leakage current flows through a non-zero impedance, such as the shield on an interconnect between boxes (analog or digital).

 

ALL AC mains connected power supplies have leakage currents, SMPS seem to have considerably more leakage current than most LPS. These leakage loops have always been there in audio systems (except the very earliest ones that ran off batteries!), but computers in audio have exacerbated the issue considerably due to most computer systems running exclusively from SMPS. Thus many of the ills of digital audio have actually come from the leakage current of the SMPS rather than the "noise" of the digital systems themselves.

 

There are two ways to deal with the noise: block the loop or decrease the impedance of the loop. Blocking the loop means blocking the flow of the leakage current anywhere in the loop. There are several ways to do this, a battery supplying a component prevents leakage current from an AC powered supply. Breaking the ground of an interconnect with say an optical interface breaks the loop. But beware of this, the "receiving" end of the optical interface requires power, if that comes from an AC line connected PS, you are adding in another leakage loop. It may be better than the original, but it will still be there.

 

The LPS-1 and the Intona deal with these two sides of loop breaking, the LPS-1 at the PS side and the Intona at the digital interconnect side.

 

The OTHER way to deal with leakage loop noise is by decreasing the impedance of the loop. One interesting way to do this is on the AC mains side of things. Remember this IS part of the loop. Many audiophile have special "power conditioning" devices designed to "lower noise on the AC line". Unfortunately the implementation of these devices can greatly INCRESE impedance between devices plugged into them! They do decrease the noise between neutral and hot, but increase the impedance between devices, thus increasing the noise generated by leakage loops. My experience has been that in many cases the leakage loop noise increase wreaks more havoc than any advantage from decreased neutral to hot noise.

 

Thus my recommendation is to get rid of the expensive filters and instead use a simple power strip that has nothing between outlets other than thick wire. EVERYTHING goes into this strip. This will dramatically decrease leakage loop noise simply by decreasing the impedance on the AC mains side of the loop.

 

So in order to get the best from USB you need an async implementation done right, good signal integrity at the DAC and some means of blocking the leakage currents from the computer's power supply from getting into the rest of the system. It takes all three to really get the best from USB.

 

Note there was nothing in here about "the noise from all that digital stuff going over the wire to the DAC". My research seems to show that this doesn't happen very much, the leakage current from the power supply is FAR more important to great sound.

 

Now that we have covered USB, lets briefly touch on Ethernet. It seems like the same things affect SQ. You still need the main timing control to be in the DAC, signal integrity matters and leakage currents are very important.

 

Fortunately Ethernet is inherently galvanically isolated if you are using UTP. BUT if you are using STP (shielded) with connectors that connect the shield you are right back in the leakage current mess.

 

At this point in time I am not sure what the passive isolators are doing. They are high frequency transformers which usually have almost no response at the frequencies usually associated with leakage currents. They might be changing signal integrity in a good way, I have never looked at one on a scope so I don't know. One possibility is that the power supplies frequently supplied with network equipment (routers, switches) are some of the worst I have ever seen with some pretty strong high frequency components to their leakage current. These isolators may have better rejection at these frequencies than the ones commonly used in equipment.

 

The Optical system completely block any leakage current of course, but you can get some back from the power supply feeding the downstream side of the optical system. The signal integrity of the downstream side is also very important and is also usually dependent on the quality of the power feeding it. An LPS-1 will do well for both purposes on the downstream side of the optical system.

 

BTW the speed of signaling on gigabit Ethernet is much less than high speed USB. Both 100 megabit and 1 gigabit use the SAME rate of 125 mega symbols per second. High speed USB is 480 mega symbols per second. HUH? 100 and 1000 are the same? 1000 uses four pairs at the same time, 100 uses just one pair, AND 100 uses 3 voltage levels (high low and in the middle) but 1000 uses 5 voltage levels. The result is one bit per symbol vs two. So bandwidth of transformers needs to be exactly the same for 100Mb and gigabit, just a lot more of them for gigabit.

 

I guess that is enough for now, and I didn't even talk about vibration isolation.

 

John S.

[austinpop]

John,

 

We love your occasional lecture series on isolation. Thanks for this last essay. Fascinating stuff!

 

<Snip>

 

The Optical system completely block any leakage current of course, but you can get some back from the power supply feeding the downstream side of the optical system. The signal integrity of the downstream side is also very important and is also usually dependent on the quality of the power feeding it. An LPS-1 will do well for both purposes on the downstream side of the optical system.

 

<Snip>

 

Dammit - now you just sold me another LPS-1!

 

I guess that is enough for now, and I didn't even talk about vibration isolation.

 

I admit that is the next frontier for me. It's also the hardest one to explain causality - i.e. why does "The Amazing Vibrapod 2000" improve SQ.

 

It would be fascinating to hear your views.

[Peter C]

John, thanks for the education, which I find extremely valuable. I have two UpTone products...JS-2 with linear fan controller and Regen. I also use these products on power supplies to Amp, DAC, AV Processor, etc....

https://www.arraysolutions.com/Array-Solutions/ac-7a

 

I have had them for a long time, and back then they seemed to make a positive difference, and have not tried removing them. Do you have any advice for us on whether these should theoretically be a positive or a negative and how they should impact on the system. Thanks for your expertise and advice.

 

Regards Peter

[Superdad]

Hey folks,

 

System Details:

 

Playback chain:

Synology DS213 NAS running MinimServer <- wired Gb network -> FMC (TP-Link MC200CM) <- MM fiber -> FMC <- Blue Jeans Cat 6a -> Auralic Aries Mini <- Curious 0.2m USB -> Intona Industrial <- Vbus2 -> <- Curious 0.2m USB -> W4S Recovery <- Cardas Clear USB -> Ayre Codex <- Ayre Signature XLR -> Cavalli Liquid Gold <- Moon Black Dragon balanced -> HD800 headphones

Power supplies: Tecknet PowerZen G3 5V batteries for FMCs, Auralic 16V/1A LPS, stock 9V/1A SMPS for RUR

Power Cables: PS Audio AC-12 (wall to P5), Pangea AC-9SE MkII (Cavalli Amp), AC-14XL (Codex), AC-14SE MkII (Auralic LPS)

Power Source: PS Audio P5 PerfectWave Regenerator

On order awaiting evaluation: ​Utpone LPS-1, Teradak 9V/1A LPS, Baaske MI-1005 ethernet isolator

 

 

Rajiv in Austin

 

Hi Rajiv:

 

I read your system chain carefully, and there is ZERO doubt in my mind that the single biggest weakness in your chain is that you are powering the W4S Recovery--AFTER the GI of the Intona--with a PS that is reintroducing your DAC to major leakage currents. All that effort you have put in upstream--with the FMCs, the Intona, etc.--is almost completely overshadowed by how you are powering your Recovery just before the DAC. I agree that the Intona, with just average signal integrity, benefits from a REGEN/Recovery, but because of the leakage issue, it up until now it has been a mixed bag to put a device after the galvanic isolation of the Intona.

 

I also see you have an UltraCap LPS-1 on order. I don't know what you were planning on powering with it, but I can with near 100% certainty that the best possible use in your above chain will be to power your Recovery with it. In fact, I am pretty darn sure your are going to need adult diapers for when you do. As John and I have been explaining, the impact of the LPS-1 is not so much because it is a really quiet, extremely low impedance LPS (though that helps a lot and puts it above batteries). It is because it breaks the "leakage loop." Your chain already has so much good isolation upstream, thus eliminating that re-entry point at the Recovery with the LPS-1 is going to make all your efforts come together.

 

The above is absolutely what accounts for the totally outsized experiences people are having with the LPS-1. It is a good little supply, but it is like a lever (leveraging a lot with a little force) because of the problem it solves. That is what John and I find so much fun and satisfaction in: Doing something simple (okay the LPS-1 design itself is FAR from simple) to help folks obtain the full musical potential of their systems.

 

Sorry folks, I really did not start out this post intending to sound like a commercial. I just can't wait for you report once you "fix the problem" that I see. Oh good, I just checked and saw that you just made it into the batch of orders we have promised to ship by November 18th. So neither of us will have to wait too long for your reaction.

 

--Alex C.

[austinpop]

Hi Rajiv:

 

I read your system chain carefully, and there is ZERO doubt in my mind that the single biggest weakness in your chain is that you are powering the W4S Recovery--AFTER the GI of the Intona--with a PS that is reintroducing your DAC to major leakage currents. All that effort you have put in upstream--with the FMCs, the Intona, etc.--is almost completely overshadowed by how you are powering your Recovery just before the DAC. I agree that the Intona, with just average signal integrity, benefits from a REGEN/Recovery, but because of the leakage issue, it up until now it has been a mixed bag to put a device after the galvanic isolation of the Intona.

 

I also see you have an UltraCap LPS-1 on order. I don't know what you were planning on powering with it, but I can with near 100% certainty that the best possible use in your above chain will be to power your Recovery with it. In fact, I am pretty darn sure your are going to need adult diapers for when you do. As John and I have been explaining, the impact of the LPS-1 is not so much because it is a really quiet, extremely low impedance LPS (though that helps a lot and puts it above batteries). It is because it breaks the "leakage loop." Your chain already has so much good isolation upstream, thus eliminating that re-entry point at the Recovery with the LPS-1 is going to make all your efforts come together.

 

The above is absolutely what accounts for the totally outsized experiences people are having with the LPS-1. It is a good little supply, but it is like a lever (leveraging a lot with a little force) because of the problem it solves. That is what John and I find so much fun and satisfaction in: Doing something simple (okay the LPS-1 design itself is FAR from simple) to help folks obtain the full musical potential of their systems.

 

Sorry folks, I really did not start out this post intending to sound like a commercial. I just can't wait for you report once you "fix the problem" that I see. Oh good, I just checked and saw that you just made it into the batch of orders we have promised to ship by November 18th. So neither of us will have to wait too long for your reaction.

 

--Alex C.

 

Alex [emoji51]

 

I am already convinced of everything you wrote. It is EXACTLY my plan to use the LPS-1 power the RUR

 

My - meant to be humorous - reaction was to John's point about powering the downstream FMC with an LPS-1 too.

 

I have a niggling theory that the Intona/RUR/LPS-1 trifecta may - and I stress may - render any network isolation upstream of the USB chain moot. As I mentioned, I am already seeing less difference between with and without network isolation.

 

I will reserve judgement of that until after my LPS-1 (and diapers) are here.

 

As I keep learning, optimizations are system-wide, and their benefits, while cumulative, are not necessarily additive.

 

 

Sent from my iPhone using Computer Audiophile

[austinpop]

... there is ZERO doubt in my mind that the single biggest weakness in your chain is that you are powering the W4S Recovery--AFTER the GI of the Intona--with a PS that is reintroducing your DAC to major leakage currents.

 

In my defense, it was never my intent to neglect this aspect of my system. My cunning plan was to get an el cheapo LPS as an intermediate step, that could initially power the RUR, and continue its duties when the LPS-1 gets here to power the downstream FMC.

 

Sadly my el cheapo appears, after a month in transit, to be lost at sea, so I need to figure out if there's a faster way to get one than the slow boat from China or Hong Kong.

 

Ah, first world problem!

 

 

Sent from my iPhone using Computer Audiophile

[fob69]

Hi John,

 

Note there was nothing in here about "the noise from all that digital stuff going over the wire to the DAC". My research seems to show that this doesn't happen very much, the leakage current from the power supply is FAR more important to great sound.

 

Now that we have covered USB, lets briefly touch on Ethernet. It seems like the same things affect SQ. You still need the main timing control to be in the DAC, signal integrity matters and leakage currents are very important.

 

Fortunately Ethernet is inherently galvanically isolated if you are using UTP. BUT if you are using STP (shielded) with connectors that connect the shield you are right back in the leakage current mess.

 

At this point in time I am not sure what the passive isolators are doing. They are high frequency transformers which usually have almost no response at the frequencies usually associated with leakage currents. They might be changing signal integrity in a good way, I have never looked at one on a scope so I don't know. One possibility is that the power supplies frequently supplied with network equipment (routers, switches) are some of the worst I have ever seen with some pretty strong high frequency components to their leakage current. These isolators may have better rejection at these frequencies than the ones commonly used in equipment.

 

The Optical system completely block any leakage current of course, but you can get some back from the power supply feeding the downstream side of the optical system. The signal integrity of the downstream side is also very important and is also usually dependent on the quality of the power feeding it. An LPS-1 will do well for both purposes on the downstream side of the optical system.

 

BTW the speed of signaling on gigabit Ethernet is much less than high speed USB. Both 100 megabit and 1 gigabit use the SAME rate of 125 mega symbols per second. High speed USB is 480 mega symbols per second. HUH? 100 and 1000 are the same? 1000 uses four pairs at the same time, 100 uses just one pair, AND 100 uses 3 voltage levels (high low and in the middle) but 1000 uses 5 voltage levels. The result is one bit per symbol vs two. So bandwidth of transformers needs to be exactly the same for 100Mb and gigabit, just a lot more of them for gigabit.

 

I guess that is enough for now, and I didn't even talk about vibration isolation.

 

 

With Ethernet TCP/IP transfert there is NO SIGNAL INTEGRITY TO MANAGE. This integrity can ONLY BE PERFECT. And with optical bridge you don't have to manage anything on upstream side of optical system (except that a bad supply can affect the audio system the same way that any other supply of you home equipment).

 

Considering that ethernet is already isolated from DC, and that ALL ethernet isolator are ALL blocking high voltage and low frequencies at a higher voltage level (result no leakage at all on the way you describe it), and if there would be not so much noise coming from network, there would be no sound difference with ethernet isolator or not, and between no ethernet isolator / isolator and a optical bridge. The fact is that there is a BIG impact on SQ.

 

Ethernet symbol rate is the same for 100M / 1G ethernet and it is about TEN TIMES the rate of a high speed USB transfert (192mhz for ethernet Vs 24mhz for USB). Here are all digital transfert clocking frequencies : https://en.wikipedia.org/wiki/Crystal_oscillator_frequencies.

 

B.

[scan80269]

Hi John,

 

 

 

 

With Ethernet TCP/IP transfert there is NO SIGNAL INTEGRITY TO MANAGE. This integrity can ONLY BE PERFECT. And with optical bridge you don't have to manage anything on upstream side of optical system (except that a bad supply can affect the audio system the same way that any other supply of you home equipment).

 

Considering that ethernet is already isolated from DC, and that ALL ethernet isolator are ALL blocking high voltage and low frequencies at a higher voltage level (result no leakage at all on the way you describe it), and if there would be not so much noise coming from network, there would be no sound difference with ethernet isolator or not, and between no ethernet isolator / isolator and a optical bridge. The fact is that there is a BIG impact on SQ.

 

Ethernet symbol rate is the same for 100M / 1G ethernet and it is about TEN TIMES the rate of a high speed USB transfert (192mhz for ethernet Vs 24mhz for USB). Here are all digital transfert clocking frequencies : https://en.wikipedia.org/wiki/Crystal_oscillator_frequencies.

 

B.

 

I don't think Ethernet signal integrity is always perfect. There are plenty of cheaply made Ethernet cables that are not spec-compliant that distort the signal waveform (in several ways: differential impedance variation, intra-pair skew, etc.) by the time it reaches the far end of the cable. Ethernet is full duplex so signal integrity degradation can occur in both directions over a single cable. Maintaining signal integrity for high speed differential signals has always been an engineering challenge, especially as the symbol rates keep getting pushed higher as technology advances.

 

As John said, the leakage currents affecting sound quality are not DC, but rather AC. The pulse transformers used in Ethernet block DC, but AC noise at a certain frequency range can jump through the transformer (via capacitive coupling) and run down the cable. The Ethernet isolators affect SQ not because of their DC blocking capability but rather their ability to attenuate AC noise to some degree.

 

Regarding symbol rates you seem to be confusing reference clock frequencies with symbol rates. Ethernet symbol rate is NOT ten times that of High-Speed USB. As John has explained, gigabit Ethernet uses 4 lanes (differential pairs) at 125 mega symbols per second and 2 bits per symbol: 125M * 4 * 2 = 1000Mbits or gigabit. USB 2.0 High speed uses only one (mostly) differential pair (just D+/D-) running at 480Mbits/sec based on a 24MHz reference clock PLL-multiplied by 20 times. This means the per-lane bit rate running down an Ethernet cable at gigabit speed is lower than for USB 2.0 High-Speed. Hope this helps!

[fob69]

I don't think Ethernet signal integrity is always perfect. There are plenty of cheaply made Ethernet cables that are not spec-compliant that distort the signal waveform (in several ways: differential impedance variation, intra-pair skew, etc.) by the time it reaches the far end of the cable. Ethernet is full duplex so signal integrity degradation can occur in both directions over a single cable. Maintaining signal integrity for high speed differential signals has always been an engineering challenge, especially as the symbol rates keep getting pushed higher as technology advances.

 

I did not said that signal integrity on ethernet is perfect. I said that YOU DON'T HAVE TO CARE ABOUT IT because data transmission through TCP/IP protocol is PERFECT. If there is a mistake the data is resent (this is not the case for digital audio signal, the receiver can have a error control, but data are not resent). It it wasn't like this there would be no computer network technology.

The only problem could be that the signal transmit is so bad that you have no data at all. If data are transmitted, and even if there are errors (and resent data), bit rate will be close to ethernet nominal bit rate (it works or not).

 

 

As John said, the leakage currents affecting sound quality are not DC, but rather AC. The pulse transformers used in Ethernet block DC, but AC noise at a certain frequency range can jump through the transformer (via capacitive coupling) and run down the cable. The Ethernet isolators affect SQ not because of their DC blocking capability but rather their ability to attenuate AC noise to some degree.

 

Regarding symbol rates you seem to be confusing reference clock frequencies with symbol rates. Ethernet symbol rate is NOT ten times that of High-Speed USB. As John has explained, gigabit Ethernet uses 4 lanes (differential pairs) at 125 mega symbols per second and 2 bits per symbol: 125M * 4 * 2 = 1000Mbits or gigabit. USB 2.0 High speed uses only one (mostly) differential pair (just D+/D-) running at 480Mbits/sec based on a 24MHz reference clock PLL-multiplied by 20 times. This means the per-lane bit rate running down an Ethernet cable at gigabit speed is lower than for USB 2.0 High-Speed. Hope this helps!

 

 

I don't see why the noise generated by : EMF, AC input (CPL of the neighbors) and switching supply from your shaver, devices themselves, DC leakage (and i don't know which noise frequency and voltage we are talking about for this last case), would affect the sound, and not the incoming noise from the network (and my hears tell me it strongly does). IMO there are business concerns behind this strange point of view, and the switching of "noise" word with "leakage" word.

 

B.

[agladstone]

After reading this entire thread, I've decided I should try something to address the potential that my router and cable modem may be adding noise into my system.

Questions:

1. Would a passive network/ Ethernet isolation device theoretically do the same general thing within my system? ( after reading the thread, I've gathered that the FOMC/ optical isolation route would only work if using either battery PS or expensive LPS on both sides, so with a passive network isolator, it seems that would eliminate the need/ cost for adding 2 additional LPS into my system).

2. With a passive network isolator, where do I want to insert it within the chain?

(I have an Aurender N100H, Most of my listening is from DSD and FLAC files stored locally on Aurender internal HD, but I also have wired Ethernet coming in for Tidal and to manage / burn files into HD).

3. Within my system / rack I have:

Cable modem > Router w/ 8 ports (using provided SMPS) - all 8 ports out feeding other equipment in my system (Apple TV, Integra HT Pre/Pro, Cable Box, Smart TV, a 5 port switch (also with provided SMPS), OPPO 105).

- would I need to isolate each of the devices in my system with Ethernet connection to gain benefit? Would I also want to isolate the Ethernet going from cable modem into router?

4. Do these passive isolation devices do anything to affect signal or speed (all gigabit with Cat 7 cables from cables to go - they do have metal shielding on both connection ends)?

FYI - I have the Cable modem, wireless router and fan (my rack has fan system for heat) SMPS all going into seperate furman power conditioner on a separate AC line).

I have my DAC AND W4S both being powered by 1 HDPlex 100 LPS ( should I get a separate LPS for the RUR)?

The rest of my equipment in rack going into a furman elite 20i conditioner into a second dedicated 20AMP AC line. My amplifier going direct into a 3rd dedicated 20AMP AC line. My subwoofers going into a 4th dedicated 20AMP AC line and both through a third furman elite 20i power conditioner.

Last, one of the Ethernet cables coming out of the wireless routers 8 ports goes into a desktop computer, that computer and printer, etc all going into a 5th Non dedicated AC line and through a industrial surge protector / line conditioner.

Sorry for all the specific details of Ethernet / power supplies in the room, but since they are all somehow physically connected together, I think that's important information if I'm going to actually figure out how to isolate USB, power, and Ethernet / Network "noise".

Thanks in advance for any help / suggestions!!!

[Indydan]

Hi Rajiv:

 

I read your system chain carefully, and there is ZERO doubt in my mind that the single biggest weakness in your chain is that you are powering the W4S Recovery--AFTER the GI of the Intona--with a PS that is reintroducing your DAC to major leakage currents. All that effort you have put in upstream--with the FMCs, the Intona, etc.--is almost completely overshadowed by how you are powering your Recovery just before the DAC. I agree that the Intona, with just average signal integrity, benefits from a REGEN/Recovery, but because of the leakage issue, it up until now it has been a mixed bag to put a device after the galvanic isolation of the Intona.

 

I also see you have an UltraCap LPS-1 on order. I don't know what you were planning on powering with it, but I can with near 100% certainty that the best possible use in your above chain will be to power your Recovery with it. In fact, I am pretty darn sure your are going to need adult diapers for when you do. As John and I have been explaining, the impact of the LPS-1 is not so much because it is a really quiet, extremely low impedance LPS (though that helps a lot and puts it above batteries). It is because it breaks the "leakage loop." Your chain already has so much good isolation upstream, thus eliminating that re-entry point at the Recovery with the LPS-1 is going to make all your efforts come together.

 

The above is absolutely what accounts for the totally outsized experiences people are having with the LPS-1. It is a good little supply, but it is like a lever (leveraging a lot with a little force) because of the problem it solves. That is what John and I find so much fun and satisfaction in: Doing something simple (okay the LPS-1 design itself is FAR from simple) to help folks obtain the full musical potential of their systems.

 

Sorry folks, I really did not start out this post intending to sound like a commercial. I just can't wait for you report once you "fix the problem" that I see. Oh good, I just checked and saw that you just made it into the batch of orders we have promised to ship by November 18th. So neither of us will have to wait too long for your reaction.

 

--Alex C.

 

Great explanation Alex. I understand what you are saying. But, if one adds up the price of the Intona, Recovery and LPS-1, and the computer that acts as a server, that is a good amount of money. I understand if someone already has 3 out of the 4 devices, might as well go all in and get the 4th.

 

If someone is starting out, maybe a dedicated server would be a viable alternative.

[scan80269]

I did not said that signal integrity on ethernet is perfect. I said that YOU DON'T HAVE TO CARE ABOUT IT because data transmission through TCP/IP protocol is PERFECT. If there is a mistake the data is resent (this is not the case for digital audio signal, the receiver can have a error control, but data are not resent). It it wasn't like this there would be no computer network technology.

The only problem could be that the signal transmit is so bad that you have no data at all. If data are transmitted, and even if there are errors (and resent data), bit rate will be close to ethernet nominal bit rate (it works or not).

 

I don't see why the noise generated by : EMF, AC input (CPL of the neighbors) and switching supply from your shaver, devices themselves, DC leakage (and i don't know which noise frequency and voltage we are talking about for this last case), would affect the sound, and not the incoming noise from the network (and my hears tell me it strongly does). IMO there are business concerns behind this strange point of view, and the switching of "noise" word with "leakage" word.

 

B.

 

I agree that error-free transmission of Ethernet is worry-free for normal networking like you said. However, for audio SQ, things are not quite so simple. We are collectively still in the early stages of understanding how noise in the digital world can impact SQ of digital audio playback. One thing I've learned is that the DAC is among the most sensitive to being contaminated by noise and yielding less-than-ideal SQ at the analog outputs. Noise (something other than the intended audio signal itself) present on the power and ground rails of the DAC chip will translate into a form of jitter that will be reflected negatively in the analog output signal.

 

By the way, did you know that the so-called asynchronous mode of USB Audio 2.0 that's used by practically every modern USB DAC is based on the isochronous transfer mode of USB 2.0 which does not have an error detection and packet resend mechanism for the audio stream? Only the "bulk transfer" mode of USB 2.0 has CRC verification of USB packets and a resend mechanism, which is used by USB devices like flash/thumb drives to ensure correct data written to/read from the drive, but this is NOT the USB transfer mode in use when the PC/renderer streams audio to the DAC over a USB cable. There is no USB packet resend, since the timing and regularity of USB data transfer is much more important than the data accuracy. In USB "isochronous mode with asynchronous feedback", the USB receiver (DAC) has the ability to pace the sender by sending "speed up" or "slow down" instructions periodically back to the sender, mainly to avoid receiver data buffer underrun or overrun situations which will interrupt the audio. This USB isochronous transfer mode is completely opposite to the USB storage case (bulk transfer mode), where data integrity far outweighs data transfer pace. So you can see that even an uncorrected transmission link (like USB isochronous) is not synonymous with poor SQ, and USB bulk mode with its error-free transmission is by itself not synonymous with good SQ either.

 

As John has explained in the past, we care about digital noise (AC) in the digital audio world precisely because it can cause the SQ to be poor. Leakage is simply a description of the how the unwanted noise can be coupled to the sensitive devices in the audio chain (e.g. DAC) that will crap out the sound. It's understandable that you find this point of view strange, but these recent learnings are based on solid engineering principles, so solutions that tackle the issue using various techniques can yield SQ benefits (to various degrees of effectiveness). Ultimately, it is what our ears tell us that matters. If audio products do not deliver at least some minimal SQ improvement, it will ultimately not sell well and disappear from the market. The popular ones are those that yield audible sonic improvements as reported by hundreds or thousands of listening users.

 

One of my recent learnings is how signal integrity (among other things) of audio transmission can directly impact the SQ. For example, the UpTone REGEN exists to deliver "as good as it gets" USB signal integrity into a DAC with USB input. The theory is that good USB signal integrity makes the USB receiver within the DAC work less hard to recover the packetized data, thus generate less digital noise to contaminate the DAC section within the same device. I suspect a similar situation exists for Ethernet, where the Ethernet PHY at the receiving end will generate more switching noise to recover the data packets if the incoming Ethernet signal integrity is poor. Products like Sonore microRendu are carefully designed to isolate Ethernet noise from reaching the USB side. I have listened to the microRendu in NAA mode where it fulfills a critical role in driving the DAC over USB, while also receiving from Ethernet, and I'm not too surprised that the microRendu can benefit from things like clean power input and Ethernet isolation. AC noise flying around a digital audio system is not trivial to attenuate, and the products that address the issue effectively will yield tangible SQ benefits.

 

Overall, the learnings of how digital audio playback can be far from ideal in SQ are fairly recent. It took the industry some 3 decades (since the Compact Disk launch in early 80's) for digital audio to reach a point of equaling and surpassing the best analog playback, but we still have much to learn and possibilities of further improvements are endless.

 

I'd like to chime in to thank John S. for his amazing insights. He has shared so much more with the CA community than what I believe we may deserve to know as a user/enthusiast group.

[mmerrill99]

I did not said that signal integrity on ethernet is perfect. I said that YOU DON'T HAVE TO CARE ABOUT IT because data transmission through TCP/IP protocol is PERFECT. If there is a mistake the data is resent (this is not the case for digital audio signal, the receiver can have a error control, but data are not resent). It it wasn't like this there would be no computer network technology.

The only problem could be that the signal transmit is so bad that you have no data at all. If data are transmitted, and even if there are errors (and resent data), bit rate will be close to ethernet nominal bit rate (it works or not).

I think you missed the subtlety of what John said "The first I started looking at was signal integrity of the USB bus. Exactly how this makes it through to sound coming out of the DAC is not fully known at this point. BUT it does look like increasing the signal integrity at the DAC USB chip decreases small noise voltages in the ground plane of the DAC. "

He's not talking about signal integrity with the usual concerns of engineers i.e "it's only of concern if it affects bit delivery", I believe he's talking about the fact that better formed USB (or by implication ethernet) signal seems to provide an improvement in sound quality. He postulates that this improvement is a result of a "decrease in small noise voltages on the ground plane of the DAC".

 

I don't see why the noise generated by : EMF, AC input (CPL of the neighbors) and switching supply from your shaver, devices themselves, DC leakage (and i don't know which noise frequency and voltage we are talking about for this last case), would affect the sound, and not the incoming noise from the network (and my hears tell me it strongly does). IMO there are business concerns behind this strange point of view, and the switching of "noise" word with "leakage" word.

 

B.

I'm not sure I understand you - you seem to be saying that leakage current is not a concern but noise on the network is? Is leakage current noise not transferred through device to device connections such as USB cables or ethernet cables?

 

BTW, John, thanks for giving your thoughts on the whole leakage current issue

[scan80269]

I think you missed the subtlety of what John said "The first I started looking at was signal integrity of the USB bus. Exactly how this makes it through to sound coming out of the DAC is not fully known at this point. BUT it does look like increasing the signal integrity at the DAC USB chip decreases small noise voltages in the ground plane of the DAC. "

He's not talking about signal integrity with the usual concerns of engineers i.e "it's only of concern if it affects bit delivery", I believe he's talking about the fact that better formed USB (or by implication ethernet) signal seems to provide an improvement in sound quality. He postulates that this improvement is a result of a "decrease in small noise voltages on the ground plane of the DAC".

 

I believe I have the same understanding of John's statements as you. From the point of a USB PHY receiving a USB signal coming over a cable, the signal has an analog waveform, which may be close to square wave with fast rise/fall times (depending on the signal slew rate as driven by the transmitter/driver at the sender) but strictly speaking an analog waveform nevertheless. The more distorted this incoming signal waveform, the more work the USB PHY logic has to do in real time to correctly retrieve the data payload carried within the USB packets. More work by the PHY logic means more digital switching noise dumped by the chip onto the power and ground rails it sits on.

 

Another thing that makes me believe Ethernet cables can carry AC noise is that the unshielded twisted pairs in cables like CAT5e/CAT6 can act as antennas and pick up noise from the air and carry it to the Ethernet receiver. Having a long run of Ethernet cable in proximity to other cables like AC power, USB, etc. will make things worse by increased noise coupling to the Ethernet twisted pairs. Differential transmission is supposed to have a high degree of common mode noise rejection, but the attenuation is likely not totally perfect so a bit of common mode noise may still make it through. It likely depends on how much common mode noise rejection the Ethernet receiver can manage.

 

What we may not adequately understand yet is essentially how much (or little) noise is enough to cause audible SQ degradation. This is why the collective listening evaluations of audio tweaking devices by the CA community is so valuable.

[One and a half]

The isolation transformer on the AC does a great job of hitting the common mode noise on the head, but it raises another problem!

 

The leaks to earth/ground are not seen by the upstream GFCI/RCD, so another GFCI is required on the output of the isoaltion transformer. A picture speaks a thousand words.

 

 

 

The 6A current is just another load on the first GFCI and it's balanced, so it won't trip

 

Found this great pdf from NEMA about how GFCIs work. They are 'usually' passive devices, that is, they don't create more noise!

NEMA-GFCI-2012-Field-Representative-Presentation.pdf

[scan80269]

After reading this entire thread, I've decided I should try something to address the potential that my router and cable modem may be adding noise into my system.

Questions:

1. Would a passive network/ Ethernet isolation device theoretically do the same general thing within my system? ( after reading the thread, I've gathered that the FOMC/ optical isolation route would only work if using either battery PS or expensive LPS on both sides, so with a passive network isolator, it seems that would eliminate the need/ cost for adding 2 additional LPS into my system).

2. With a passive network isolator, where do I want to insert it within the chain?

(I have an Aurender N100H, Most of my listening is from DSD and FLAC files stored locally on Aurender internal HD, but I also have wired Ethernet coming in for Tidal and to manage / burn files into HD).

3. Within my system / rack I have:

Cable modem > Router w/ 8 ports (using provided SMPS) - all 8 ports out feeding other equipment in my system (Apple TV, Integra HT Pre/Pro, Cable Box, Smart TV, a 5 port switch (also with provided SMPS), OPPO 105).

- would I need to isolate each of the devices in my system with Ethernet connection to gain benefit? Would I also want to isolate the Ethernet going from cable modem into router?

4. Do these passive isolation devices do anything to affect signal or speed (all gigabit with Cat 7 cables from cables to go - they do have metal shielding on both connection ends)?

FYI - I have the Cable modem, wireless router and fan (my rack has fan system for heat) SMPS all going into seperate furman power conditioner on a separate AC line).

I have my DAC AND W4S both being powered by 1 HDPlex 100 LPS ( should I get a separate LPS for the RUR)?

The rest of my equipment in rack going into a furman elite 20i conditioner into a second dedicated 20AMP AC line. My amplifier going direct into a 3rd dedicated 20AMP AC line. My subwoofers going into a 4th dedicated 20AMP AC line and both through a third furman elite 20i power conditioner.

Last, one of the Ethernet cables coming out of the wireless routers 8 ports goes into a desktop computer, that computer and printer, etc all going into a 5th Non dedicated AC line and through a industrial surge protector / line conditioner.

Sorry for all the specific details of Ethernet / power supplies in the room, but since they are all somehow physically connected together, I think that's important information if I'm going to actually figure out how to isolate USB, power, and Ethernet / Network "noise".

Thanks in advance for any help / suggestions!!!

 

You may want to have a look at this webpage by EMO Systems on audio applications for their Ethernet isolators like EN-70HD:

 

Audio Applications ·

 

There are two main areas where such an isolator can help: (1) between broadband modem Ethernet out and router Ethernet in (WAN port) [assuming modem and router are separate devices linked by Ethernet], (2) between audio player (PC, etc.) Ethernet out and DAC/NAA, etc. Ethernet in. If you have only one Ethernet isolator, I suggest you try both options and listen to which one delivers better sound. It may be necessary to give each setup some break-in time before the sounds becomes optimal for that specific setup.

 

I have confirmed that the EN-70HD has no DC continuity between the metallic casing of the two RJ-45 receptacles. Not knowing how each Ethernet using device handles the grounding of the RJ-45 metallic casing, it is difficult to give a general recommendation on type of Ethernet cable to use, but overall I would try to avoid using CAT7 or any other type of shielded twisted pair cabling for audio purposes. One reason is while an Ethernet isolator will DC isolate between the RJ-45 casing on both ends, there is still a possibility of AC coupling occurring to some extent, which can lead to noise currents on the CAT7 cable shield being propagated through the isolator, thus limiting or negating its effectiveness for audio purposes. I don't know how significant an issue this may be, but by avoiding shielded Ethernet cables at least the potential of shield noise propagation can be eliminated.

 

Ethernet isolators should not affect the speed of the Ethernet data, as the transformers inside are designed to handle the target bitrates. For example, both the EMO Systems EN-70HD and the Baaske MI-1005 are designed to fully support gigabit Ethernet speeds. Signal integrity, however, may be different after the differential signals pass through their transformers. A well-designed transformer can act as a low-pass filter to attenuate unwanted noise, though the inherent capacitive coupling between transformer primary and secondary windings will always allow some frequency content of noise to propagate through the transformer. In electronics it's always a challenge to separate the noise from the signal.

 

I have used EN-70HD and MI-1005 isolators in my audio system for only a short time, but have not experienced any throughput degradation, appearance of stuttering, etc. with an isolator inserted between my microRendu and gigabit Ethernet switch. I also have an isolator between my cable modem and wireless router, but have not noticed any degradation in Ethernet performance either. I've been using a short 1-foot CAT6 UTP cable for each isolator inserted. I may order some super short CAT6a UTP cables from Blue Jeans Cables, as they test each cable they build for spec compliance, and I've read a lot of good comments on them.

 

The best way to determine whether an Ethernet isolator(s) can improve SQ is to just try one at various locations within your audio setup. Control experiments should be relatively easy with one isolator inserted into a specific point at a time. Use your ears to determine what works best in your setup.

 

Regarding the powering of your DAC and W4S RUR by the same HDPlex 100W LPS, you may want to experiment with separate power supplies, as your setup is possibly conducive to a loop being created for noise to propagate. I'm not familiar with the internal design of the HDPlex 100W, but I suspect its various output rails are not fully DC isolated from each other. With the principle of trying to break as many leakage loops as possible, you may want to try powering the W4S RUR a dedicated clean LPS (leaving the HDPlex to feed just your DAC), and listen to how the sound changes.

[agladstone]

scan80269:

Thank you for your input and advice!!

Based on your recommendations:

I will buy a few Ethernet Network Isolators and insert one between cable modem and wireless router and one between router and Aurender N100H, the third between router and Apple TV.

I've also decided, I really have no need to have Ethernet wired connections to my Integra Pre/Pro, OPPO 105, and my TV ( I really only use the Ethernet connections for my Aurender (Tidal/Network) and Apple TV), so I will just remove them.

Also, I will buy another HD Plex for the W4S RUR (seems decent for the money, the Uptone LPS-1 is probably much better, but it's much more expensive). Lastly, I'll order several cat6a cables from Bluejeans to replace my Cat 7's for everything in my audio system.

I'll report back in time with my results!!

Thanks! ( anyone else, please feel free to chime in)

[scan80269]

scan80269:

Thank you for your input and advice!!

Based on your recommendations:

I will buy a few Ethernet Network Isolators and insert one between cable modem and wireless router and one between router and Aurender N100H, the third between router and Apple TV.

I've also decided, I really have no need to have Ethernet wired connections to my Integra Pre/Pro, OPPO 105, and my TV ( I really only use the Ethernet connections for my Aurender (Tidal/Network) and Apple TV), so I will just remove them.

Also, I will buy another HD Plex for the W4S RUR (seems decent for the money, the Uptone LPS-1 is probably much better, but it's much more expensive). Lastly, I'll order several cat6a cables from Bluejeans to replace my Cat 7's for everything in my audio system.

I'll report back in time with my results!!

Thanks! ( anyone else, please feel free to chime in)

 

I just checked the price of Uptone LPS-1 and HDPlex 100W LPS on their respective websites, and both are listed at $395. Given this same price, I'd recommend the LPS-1 over the HDPlex, mainly because of the leakage current cutoff capability of the LPS-1 design. Also, the W4S RUR has relatively low power consumption, so using a 100W LPS to power it is overkill. I hooked up my LPS-1 (set to 7V) to my W4S RUR (rev B) a few days ago. This worked well and sounded great, and the LPS-1 didn't even feel any warmer than when it was just left on powering nothing at its output.

 

One catch regarding the LPS-1: if you don't already have an order in the queue with UpTone, you'll be waiting till December to receive one, though I'd say even that kind of wait is worth it.

[scan80269]

Quick correction: The DC continuity check I did was actually with a Baaske MI-1005 Ethernet isolator, not a EMO Systems EN-70HD. The EN-70HD does not have a metal casing for either of its RJ-45 jacks, but the MI-1005 does.

 

Based on this, I would guess that the EN-70HD is less likely to propagate noise on the Ethernet cable shield (CAT7 F/FTP, etc.) than the MI-1005. The physical spacing between the metal parts of cable plugs attached to an EN-70HD is considerable, so stray capacitive coupling is unlikely. However, I have no means of actually measuring any noise conducted by the cable shield.

 

Again, the use of unshielded Ethernet cables should render this shield noise propagation issue moot.

[Indydan]

Hi Rajiv:

 

I read your system chain carefully, and there is ZERO doubt in my mind that the single biggest weakness in your chain is that you are powering the W4S Recovery--AFTER the GI of the Intona--with a PS that is reintroducing your DAC to major leakage currents. All that effort you have put in upstream--with the FMCs, the Intona, etc.--is almost completely overshadowed by how you are powering your Recovery just before the DAC. I agree that the Intona, with just average signal integrity, benefits from a REGEN/Recovery, but because of the leakage issue, it up until now it has been a mixed bag to put a device after the galvanic isolation of the Intona.

 

----------------------------------------------------------------------------------------------

 

I am curious if Alex or someone else can explain the quality differences of the different clocks and the signal integrity they produce. I believe the clocks in the Regen and W4S Recovery are very high quality crystal clocks, but the clock in the Intona is of a lesser quality. What about the clock in a typical Mac mini or laptop? Certainly the clock in the Intona, although not the very best, is still much better than the clock in a typical Mac or PC?

 

On a scale of 1 to 10, with a Mac clock being at 1, and the clocks in the Regen and W4S Recovery at 10, where would the Intona clock be on the scale?

 

I have tried to find detailed information on the web about this, but without success.

[austinpop]

Great explanation Alex. I understand what you are saying. But, if one adds up the price of the Intona, Recovery and LPS-1, and the computer that acts as a server, that is a good amount of money. I understand if someone already has 3 out of the 4 devices, might as well go all in and get the 4th.

 

If someone is starting out, maybe a dedicated server would be a viable alternative.

 

Great point. If you'd told me a year ago that my playback chain would look like what it is now, I'd have thought you crazy! A lot of convoluted configurations you see in these threads with people like me, who are well into this isolation and tweaking journey, is a result of incremental evolution.

 

I might make different choices if I were starting over.

[agladstone]

Thanks again! I thought the LPS-1 was $1,000 (don't know why), I agree for same price I should try the LPS-1.

I need to check which version of the RUR I have, I may have the first version, if I do, it may require 9V??