Sonos Connect causing ground loop buzz

  • 13 February 2018
  • 61 replies
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I've recently swapped my old Rotel RA12 amp for a new Naim Nait XS2.

Great amp, but since switching over I'm very aware of a ground loop buzz caused by my Sonos Connect. I've tried different interconnects, plugging the amp and Connect into separate power strips, even adding a ground loop isolator (which just made the buzz worse).

Bearing in mind my complete lack of technical knowledge or skill, is there an easy way to solve this issue? Someone from the shop which sold me the amp came out and fiddled with various combinations of fancy power strips, super-expensive leads and other things, but couldn't solve the problem. He did suggest, though, that the problem may be because the plug on the Connect isn't earthed.

Any suggestions on a straightforward solution?

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I don’t know if it has been mentioned yet, but I got rid of the hum by wiring up the outer of the digital output coax (of the Sonos Connect) to the Earth pin of a regular mains plug. I did it years ago when I heard about the floating earth issue, anyway, the long and short is that it works, it hasn’t harmed the connect in 4 years, and hum is gone.
Ted, I have sent you a long post via PM since the Sonos Roomba ate it up mistaking it for spam.

More entertainment on the spam subject here, if you want some laughs: https://en.community.sonos.com/new-community-feedback-229090/new-spam-6798989/index2.html#post16207785
The next purchase is some way off now, so I've got plenty of time to research, audition and try things out at home.

That is a good space to be in so what follows ought to be useful to search your way to the answers via Google.

Note that what follows is based on a personal journey to where I now am with music and audio kit - so what follows is valid and invalid in equal parts! And no audiophile and almost no HiFi shop will agree with much of the following because it cuts their margins and even reasons to exist.

First, before buying any more kit to support what you have consider this: While an excellent set up, the Naim+B&W is essentially decades old tech that has stagnated and is obsolete. Changing speakers to better ones will improve the sound, but only to the extent allowed by this tech and at a higher price. Fyi, the speakers used for this set up are known as passive speakers - ones that need an external amplifier to drive them. Adding a Connect to this set up does bring it up to date in terms of features and music access, but does not confer the other benefits of tech progress of the last decade or so.

Research and consider instead active speakers/active crossovers that represent the state of the art. These are speakers that have built in amplification, often a dedicated amplifier to the needs of each driver in the box. For instance the same box may have a 50 watt amp for the tweeter and a 200 watt amp for the woofer because of the different energy needs of the two units to deliver a given sound level. Active crossovers handle the separation of the signals between the two drive units before the signal is amplified, allowing for state of the art tech to be deployed in the process.

Not many traditional HiFi makes have active speakers in their portfolio - neither Harbeth nor Spendor does. One well known name that has been doing this for a long time is ATC. Dynaudio also now has an excellent range of active speakers. With a pair of active speakers and a NAS that contains ripped copies of all the music on now obsolete CDs, all you need to add to them is access to the NAS and to the much wider world of quality music available on the net. So if you had a pair of quality active speakers, all you would need to get the sound quality you get today in addition to the said NAS is a Connect wired to each of the two speakers. No other wires except the mains wires to all units, and no other boxes of kit.

Both makes named offer active speakers that are expensive, but no more expensive than an equivalent pair of passive speakers + the external electronics needed to drive them. But that is if you want to remain in the gentlemen's club of pipes and slippers - the wood veneer for the speakers and the fancy cabinets for the electronics. The same sound quality is obtained for less than half the price of this kit in the world of pro audio that is functional and carries an industrial look. Because the pros don't care for veneer that only damages their return on investment. This is a huge market that is a lot more competitive with names like JBL, Adam, Genelec to name just a few. As an example of a speaker pair that will give you sound that is very good indeed is the JBL LSR 308. For about 10% of the price of HiFi kit, they will do more than 80% of what that kit will do. And by paying a little more but not more than 25%, you can get the same sound quality. Industrial looks of course, there is that.

Finally on the subject of active speakers, every Sonos speaker made is of that kind. Even the little play 1, with two amplifiers for each driver. While the play 5 has as many as six amplifiers inside each box for each driver. With DSP that includes tuning of the speaker's sound to the responses of the unique room it is placed in and bass and treble controls that allow for further tweaking. The Naim on the other hand has no tone controls, so the only way to cope with room acoustic effects is to tailor these by adding stuff to the room. Or by playing around with speaker placement. Both routes do not offer the same degree of freedom to customise the sound compared to an amp that has tone controls - leave alone one with room response tuning DSP of the kind Sonos has. And of course, with Sonos play 1 units, even the Connect box becomes redundant. Except if you must have active speakers that have even more money spent on how they look, and with more power to fill larger spaces loudly than any Sonos play unit will; in such cases a Connect with a pair of these is the way to go.

To summarise: well implemented active tech will deliver the same sound quality as the best passive tech at a much lower price and will deliver much better sound quality than passive tech of the same price. Except of course when the price point is so high that the law of marginal returns kicks in. And active tech will always have the advantage of drastically reducing messy cables, and have a smaller footprint by not having so many boxes of kit that need space for keeping them.

The other thing to discover, that is easily done at home with what you have on hand, is the explosion in the amount of cheap well recorded music available on the net, compared to what the largest of CD collections can provide - if you can escape the trap of thinking that just because it is so easily available and is cheap compared to buying CDs, it is not good for anything more than background listening. Over five years ago, I finished the ripping of about 1500 CDs to my NAS, and in time added about 500 more via iTunes downloaded purchases. Now, I hardly use even the 20,000 tracks filled NAS; the music services are used over 90% of the time. A no brainer that - Apple Music has some 45 million tracks, as does every other mainstream service.
I would be surprised if there is a difference, I just happen to be more of an apple music user.

For a day try this: pretend you don't have any CDs and listen to apple music as you would to a CD. Turn the volume up a little to compensate for the slightly undervolt signal output level of the Connect. Listen this way also to albums you have on CD, and see what you find on the sound quality front.
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I'm hoping to give the Connect a good workout tomorrow. To be honest, I've tended to use it more as a 'background listening' tool, so it'll be interesting to compare the quality from the various services - I mainly use Spotify and Apple Music, and very occasionally Amazon Music. Have you found much difference between them? I used Deezer for a while, but wasn't overly impressed (lots of tracks cutting off before they were finished etc).
At this time I also suggest you give Apple Music a test drive via Connect. You may need to turn up the volume control a tad to get the same sound levels as CD, but you may then be surprised at how little if any is the difference in sound quality obtained.
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I had a listen to the Spendor A4 floor standers and they were very impressive compared to the B&Ws - but, as you say, a lot depends on how they'd transfer to my own listening space. The next purchase is some way off now, so I've got plenty of time to research, audition and try things out at home.

Thanks a lot for your advice - it's been a pleasure chatting with you. I feel a bit guilty that more of it hasn't been about Sonos since we're in the Sonos forum... :)

Cheers!
I have found that not only are floor standers more expensive for just the cabinetry needed to reach down to the floor, but they often suffer from bass bloat. And if you see a Harbeth SHL 5 in the flesh, you will see that it is not the average stand mounter in size. Neither are some stand mounted Spendors I know of. Even the smaller Harbeth C7s are large speakers.

But when spending on expensive speakers like Harbeth/Spendors, let the shop earn its profit in full by allowing you to audition the speaker you like in the shop, at home in its designated listening place for a day or two before finally buying it. Because the sound that any speaker delivers is a function of how it interacts with the room. And to a lesser extent, with the amp that is driving it. The other reason for this is that speaker preferences are also subjective and only at home will you know how it will sound in the home, to be sure it ticks that box.

Doing this will allow you to make sure that the expense becomes an investment.
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I am certainly not saying that the guys at the shop indulged in any sharp practice.

And if the sound is fantastic, it is a four way win - for you, the shop owner, Naim and Sonos. Which can only be a good thing:-).


With you on that one! I'm just listening to stuff I've had for 20-30 years or more and finding new details and clarity all over the place. Crucially, the Connect sounds pretty damn fine through this system (especially without that infernal buzzing!).

The CM1s are excellent little speakers and definitely sound rejuvenated with the new arrivals, so I'll take my time and keep an ear out for anything that might be an improvement. I'll keep your advice re. hi fi shop snake oil in mind, though..!

I'll definitely put the Harbeths at the top of the audition list with the Spendors. Bearing in mind something you mentioned earlier, do you really think there's little advantage in floor-standers over stand-mounted speakers? I've always gone for stand-mounts from a budget and space perspective, so I don't have any practical experience with floor-standers.
I am certainly not saying that the guys at the shop indulged in any sharp practice.

And if the sound is fantastic, it is a four way win - for you, the shop owner, Naim and Sonos. Which can only be a good thing:-).
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The entire concept of HiFi separates where one can pick and choose the system components from different makes is not something any make is happy about, but this way of ensuring that this does not happen to them seems drastic and even unscrupulous.

That's a bit of a stretch of the old imagination, if you don't mind me saying. I already had the Naim CD player in mind way back when I started auditioning amps, and asked the guys at the shop to keep me in mind when it went ex-demo (hence bringing the price down a bit and avoiding the risk of buying a second-hand one via eBay). So there's no unscrupulousness going on - the piece of kit I was going to buy became available roughly on schedule, and managed to solve a problem which has so far baffled everyone.

And it all sounds fantastic.
Given that budget is always a constraint, this raises the question of whether one would better off in the sound quality stakes with an equivalent/higher power delivery amp and even a CDP if one has to still have that, from a lower price point, and divert the savings to a better, more expensive speaker where there is a somewhat better chance of the "pay more, get more" rule applying. Using commodity interconnects and speaker wire of course:-).
Given the references you located on the Naim forum... hmm indeed!
Hmm...so if one did not even need any CDP because one had ripped all CDs to a NAS accessible via a Connect, but wanted only Naim amplification?
Maybe the other sources Ted tried were also themselves well grounded, as the CDP appears to be. It's not inconceivable that the circuit ground in the amp floats free of the chassis, and hence the mains earth.
But if the amp is not well grounded, it is a mystery why only the Connect as an input was causing the hum and not any other input source when attached to the same socket via the same interconnects. So said Ted.
I've been waiting for ages for the Naim CD player the shop uses for demos to become ex-demo. They boxed it up for me to borrow to test at home - and, lo and behold!, the buzz was gone. Completely gone.
So maybe my initial comment about a shortage of earthing was near the mark. It's somewhat worrying though, since it suggests the amp is not well grounded via its mains lead.
Good for you. Though I note that this means that Naim is doing all in their power to sell more Naim kit. The entire concept of HiFi separates where one can pick and choose the system components from different makes is not something any make is happy about, but this way of ensuring that this does not happen to them seems drastic and even unscrupulous.
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My friendly neighbourhood hifi shop stocks Harbeth, so I'll definitely take a look.

Surprisingly quick update/resolution to the buzzing amp problem. Today I popped in to see if the guys at the shop had any ideas for solving the problem. One guy suggested that testing a component with a fully earthed plug (my Rotel RCD12 has a dummy earth pin) might be worth trying, to see if it helped.

I've been waiting for ages for the Naim CD player the shop uses for demos to become ex-demo. They boxed it up for me to borrow to test at home - and, lo and behold!, the buzz was gone. Completely gone.

So, long story short, a very good deal has been made and my Rotel is being traded in for the Naim CD5XS. They're even being extremely reasonable about paying the not-too-terrifying cost over a couple of instalments.

So the buzz is gone, the Naim amp and CD player are in place, and the Sonos Connect sounds terrific and buzz-free.

Now I just need to get my mitts on those Harbeths....

🙂
I had used Spendor stand mounted speakers for some years, but I found the Harbeth C7 to be in a different league on the first listen. The SHL5s were too rich for my budget, but you may have an opportunity there with a Naim transaction that comes to mind:-).

You will need new stands for either of the two Harbeths; they are taller than most stand mounts, the SHL 5 is half a floor stander in its height and with their tweeters needing to be at ear levels, that pretty much dictates custom stands that achieve this.

By the way, Harbeth has a excellent user forum as part of their website. Alan Shaw, the owner, is an active participant. For years now he has also actively promoted a amplifier agnostic approach of the kind I have spoken about, and an objective, sensible approach to all things audio - with the sole exception of his expensive speakers! He pays for the forum, so one can excuse that little foible. Worth a look around in what is called the Harbeth User Group on the Harbeth site to get insights into home audio fundamentals, even if you buy/own a different speaker. Be warned that the place has a bit of Harbeth cult feel to it, though. Since you are in the UK - presumably - even a visit to his factory to meet him and take a look might be a good idea.
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I had Harbeths once, and they are worth a serious audition. The C7 or the SHL5. Both stand mounted, but the latter can go head to head with floor standers.

I have found that much of the premium that is paid for floor standers is for expensive cabinetry.


Worth a look - thanks for the tip re. Harbeths. I was able to audition the Spendors against a pair of CM1s and they really were outstanding. Mind you, I haven't tested any stand-mounted Spendors yet - I might hang on to my speaker stands yet...
I had Harbeths once, and they are worth a serious audition. The C7 or the SHL5. Both stand mounted, but the latter can go head to head with floor standers.

I have found that much of the premium that is paid for floor standers is for expensive cabinetry.
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Lol. If you use chamomile tea, you should be ok:-))
Curious though - what speakers are you using with the Naim? Nothing to do with the hum, just to have a better handle on the sound signature you are getting, having used many makes in my audiophile past life.


B&W CM1s, which have survived a few changes of setup. But I may be upgrading those in future too - I have my eye on some floor-standing Spendors.
Lol. If you use chamomile tea, you should be ok:-))
Curious though - what speakers are you using with the Naim? Nothing to do with the hum, just to have a better handle on the sound signature you are getting, having used many makes in my audiophile past life.
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Ditto; I would be interested in knowing how the hum issue gets resolved.

I'll update this thread whenever there's a resolution. If there's no update, you can assume I've electrocuted myself.