Very good AES presentation on inter connects and ground loops.

Tony,

I stared this thread as there is a lot of incorrect perceptions on the subject.

I agree SE was never the best answer, but he is talking about the physics, not if you need it.  My point is, SE is probably just fine for a home system. Listen to see if it is, don't assume what is needed for 100 foot studio runs is also needed for 3 feet.  Fix real problems you find in your system with the help of information from the actual field experts rather than the fad of what You-Tubers and audio parlors can sell you.  

Yes, we have electrical building codes for a reason. Follow them. Yes, a lot of old equipment did not have safety grounds and the leakage could give you a tingle. Easy to fix. I like the JDS answer to use AC wall wart transformers.  No ground loop and zero risk of fault to mains. Any competent mains powered unit will deal with ground isolation internally. It is not hard or expensive. Even I can. No excuse. 

I only had one piece of equipment that had line induced issues. A Parasound amp so I dumped it as being incompetently designed. It also sounded like garbage. Not like the old 1200's. I do run a DC blocker as it filters DC added within my house by cheap devices not supplied by the power company.   Real problem. Real fix. 

One  store I visit does play all kinds of games moving speakers within 1/4 inch.  So what! I move my head more than that. If you have to hold your head that still, it is a useless system. ( Kef Meta's?)   On the other hand the big store here has the wall of speakers driven through switching and a mid-range class D amp which are almost useless other than to eliminate the worst of the bad. They will take a pair down to a better room to their credit but that leaves you with no comparison and within seconds your brain remaps so still not a very valid audition. End result is, you can pick something to take home over the weekend and give areal listen. 

R2R, I think you mean Reel to Reel low generation dups onto quarter track a few studios issued? All analog. ( In todays jargon, it is assumed to be a ladder DAC)  Yea they were good but I only had a couple. Way out of my price range and were only available mail order. I had a 10 inch Teac. Like vinyl, they degraded with every play.  I went for the direct-to-disk live performance route where I could afford them.  And don't tell me MoodyBlues analog mastering quality is HALF of Redbook.  Things got better with the second generation SONY digital mastering ,16 bit, then 18 and on. Yea, my CATs CD was mastered in 14 bits. Most early Deuchas Gramaphone was. No wonder the best vinyl sounded better.  40 years later,  newest studio work can be very very good. Unfortunately most of my music collection predates digital recording and was re-mastered and processed digitally for CD release. 

If your "audiophile Ethernet" sounds better to you, have fun.  It is your perception in your system that matters to you.  I  am not a fan of made up problems that may exist in theory, but not in the real world. If network noise is causing you a problem, you need to find the faulty devices.  We don't need audiophile grade switches for 10G, live fire, nuclear, life threat, and can bounce 100% reliable data around the world on the Sonnet ring and satellites.  If you can't within your house, you got a problem. If you can identify the demo of a DAC being lackluster due to Ethernet noise, you should get some University to study your clairvoyance.  I am not saying you did not hear a lack-luster DAC. You heard it, I did not. I suggest your reasoning is less than a guess.  It could well be you are not used to a clean reproduction from a really good DAC?   Or maybe it was Cambridge/Rotel/Arcam amp with half the power supply reserves needed not the DAC?  Was the stream actually high quality? Most is not. 

Setup, room, treatments, yea, duh!  Differences almost as large as the speakers. 

You missed my point on if high end gear is effected by noise; digital, ground loops, power, then yes, I blame the OEM.  NO excuse.  Apples will start rotting as that is the environment they live in, just as dirty power is the environment.  We understand the environment of apples and learned to pick them before they fall off. Just as decent engineers know how to handle system noise. 

If you play vinyl, then isolating your player in a sealed box does wonders. Put your RIAA preamp in the base of the table close to the arm and you won't have any RFI exposure. That way you can maintain the balanced signal from the cartridge until you have provided enough gain that a couple feet of coax is fine. 

I don't think you can expect manufacturers to anticipate every possible scenario for noisy power, noisy environment, vibrations, RFI, EFI, etc.  The costs would be very high for those components.  Should everyone pay for those features if they do not need them?  They design to standards and our homes must conform to certain standards.  The same for the modem and router.  Beyond that, it is up to us- the hobbyist to either accept the performance as is or experiment and find ways to enhance the sound.  That goes from what is most obvious and accepted such as isolating your turntable from mechanical vibrations to the more controversial audio grade Ethernet switch and silver plated Ethernet cables.  Results vary from user to user which should be no surprise.  A DAC or music server may already have adequate isolation or perhaps its performance is of such a low level that a difference cannot be detected.  

I have an 8 meter run of balanced cables from my preamp to my amps.  My shorter runs are also balanced connectors.  Nowhere here was it mentioned that the output of DACs and preamps is higher for balanced out than for SE.  I consider that another benefit.  I also like the connectors much better than RCAs.  Some electronics may have XLRs but not be a true balanced design.  In that case figure no electrical advantage over SE.  

For high end ,YES I DO expect them to deal with the environmental issues. That is what you pay the high price for.  For commodity grade, sure as people make decisions on features and price so every corner must be cut. 

Yes, the balanced lines have higher voltage REFERENCE which makes any interference relative lower by a few DB.  But, that is only because there is a pseudo standard for the professional industry ( many OEMS do not comply to anyway). Just as some pre-amps have much higher maximum output voltage.  I think my old Nak did about 9V se. All three of my preamps have two gain ranges. On the flip side, I run about 70 feet of coax to my antenna and it carries microvolts just fine. Note that amps do not all have the same front end overload or the same gain. THX has sort of pushed for a voluntary gain standard so at least multiple amps in a system can match levels.    Lack of standards was one of the key points the presentation mentioned and why the committee exists. And some standards are not standards. HDMI for example.  Like the old saying :" I love standards as there are so many to choose from" 

8 meter? I sure would also go balanced. That is what it was designed for. Did that in my last house where my pre was across the room from the amps and speakers.  My desk dac has 6 inches of coax to the pre and 2 feet to the amp. Noise is not an issue. Balanced connections would be useless feature not providing any advantage.  Don't tell me a $5000 DAC can't afford an optical isolator on the USB when my $99 Schitt can!  Power line RF? Bought a pack of 30 ferrites for about $12.  No excuse. 

Another place where balanced does make sense is with amps like the Purify where the amp architecture is balanced  by design, not by input add on. Like I said, look at your reality, not the marketing one. If I could stand a class D, I might have a March and would do balanced DAC and pre.  I can't, so I don't. 

@tvrgeek

HDMI on the other hand is a disaster and who ever designed the plug needs a dope-slap.

Thanks for posting the article. I’m lucky to not have line noise problems right now, but I have had them in the past, tried everything to no avail, and now have some understanding of why I failed to fix it.

I’m using a computer with HDMI output going into a cheap Denon receiver. I’m not having any issues with power noise coming through the system. This may be the quietest setup I've ever had. Usually I can hear a little buzz if I put my ear right up to the speaker, but now it’s dead silent, other than the amplifier’s own hiss if I turn it up. However, I switched out to a different used receiver to test out and am now getting what sounds like CB radio coming through once in a while. What’s really strange is that it came through the right rear speaker, so I figured it was a problem with that amp channel. Last night it came through the left rear speaker. Scared the crap out of me. I thought my system had become demon possessed. The voices are distorted and weird sounding. I can’t make out what they’re saying.

Cutting open several HDMI cables, as I was having issues with POD and ARC, I found on several the shield drain was not connected and some the foil had the insulated side ( mylar) against the drain making it totally ineffective.  Bought a Belden cable and no more problems.  Belden, Belken, or for a few bucks BlueJean. No magic, just made correctly. Connector is junk. Not secure, prone to falling out and can't support the weight of a correctly made cable.  I wish it was a DB-25

Many years ago I had long speaker runs and someone in the park had a "foot warmer" in their truck.  For the younger crowd, it was a modified Lafayette 1000W amplifier on CB which was limited to 2.5W non-side band.   Picked it up, feedback loop amplified it and fried a tweeter.   I went to Kimber cable leads and when I tracked him down, a pin through his coax took care of the root of the problem. 

If your speaker leads are not twisted, you might try that. 

Of all the "cheap" audio gear, I have always found Denon to be on top of the category.  They have even at various times made some truly high end. 🙂