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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61 replies

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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.
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.
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:-).
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.
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.
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.
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.
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:
You seem to have covered all the bases; the only one left is to see is if swapping Connects fixes this. Worth trying before moving to another streaming solution. I am not being a biased fan when I say that there really isn't any better one in the market, so that little extra effort is worth it.
There's one possibility which hasn't yet been addressed: ground float. In other words too little earthing rather than too much.

As an experiment, plug a spare RCA lead into a vacant socket on the CONNECT, then touch the shield of the plug at the other end onto something which is grounded, say a water pipe.

I encountered a persistent buzz when using a ZP80 with a headphone DAC/amp (connected by digital coax). Neither was earthed to the mains, so I butchered a spare RCA lead to ground the ZP80. Now totally silent.

CORRECTION: I grounded the headphone amp. See later post.
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Ted, on a lighter side, another cut/paste from the Naim forums:

"Stop thinking about how much you spent on your Naim amp.

Stop questioning the hum - it's there for a reason.

In life there are things better left unexplained. Knowledge is pain.

Instead of seeing the fingers, see the space between the fingers.

You need to embrace the hum. Like a mantra. Oooohuuuummm oooohuuuummm oooohuuuummm...

Have some camomile, see a therapist, get into yoga..."

End quote:-))

Ha! The power of positive thinking! Maybe I should try pouring some camomile tea into the amp to see if it soothes the hum... 🙂
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I just bought the Naim because it was the best-sounding amp I could afford. I didn't realise there was such a cult of quirkiness around the brand and its unorthodox approach to electronics! 😃
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I'd be looking for something external to tie the CONNECT's ground down.
Digressing to understand this: how come that using the 2 pin US style socket that came with the Connect cable, I don't see this problem? I thought that the 3rd pin is the one that does earth? All my Sonos kit including play units use the same 2 pin plugs.

Must've missed this post. I think the third pin on my Connect is a 'dummy' - it's just plastic to fit into UK sockets, but doesn't actually earth the unit. At least, I think that's what the hi fi man said. Sometimes I wish I'd paid more attention at school, then I'd understand these things better. 🙂
My understanding is that units that don't draw a lot of current can do without the third earthing point and still be safe in use. Connect fits into that category very comfortably. What this means to causing hum or not, I don't know.

That all well made amps - which almost all modern name brand amps are - sound the same in a controlled sound level matched blind test is something the amp makers desperately haven't wanted anyone to know for decades now - perhaps five decades.

A 60-70 wpc Marantz/Rotel/Yamaha/XYZ....will deliver the same sound quality. Just make sure that any you choose delivers the features you need and you ought to save significant money if you can get good value for the Naim in return. All you will lose is bragging rights about having a Naim...and the hum. But test for that in the shop with your Connect.
I think the third pin on my Connect is a 'dummy' - it's just plastic to fit into UK sockets, but doesn't actually earth the unit.
Well, yes. The connector into the back of the CONNECT is a 2-pin 'figure-8'.
you ought to save significant money if you can get good value for the Naim in return.
When I wrote this I thought the Naim was for close to a thousand pounds; I was shocked to later see that it sells for twice as much. For just 70 wpc of amplification.
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you ought to save significant money if you can get good value for the Naim in return.
When I wrote this I thought the Naim was for close to a thousand pounds; I was shocked to later see that it sells for twice as much. For just 70 wpc of amplification.

Thanks, Kumar. Really making me feel good about my purchase, man. :)

Nah, if it the problem can't be solved, I'll take it back to the shop and get my money back. I love the amp - far better than anything else I auditioned, and I tested a lot of amps before settling on that one. But it has to work with my existing setup, or all that quality sound isn't worth a damn.
Lol. Trust some of us here that have used high end - read expensive - HiFi kit for decades before realising we have been gulled.

Whatever you buy has certainly got to work with your set up, and it has to be reliable with after sales support available as well. Modern tech and manufacturing economies of scale means that "budget" kit can now offer that and all the sound quality that the much more expensive audiophile kit can. For a much lower price. But the high street HiFi shop is not going to tell you that. Nor will What HiFi. One has to pay the rent and and staff salaries, the other has to stand by its advertisers.

I could make a case why even a Connect Amp that functionally does what the Connect + Naim do, will serve just as well in some cases with easy to drive quality speakers and just one source other than streamed music.

I could even go beyond that and say the same thing about a Sonos play 5 pair + Sonos Sub. Or at a lower price point for a smaller space, a 1 pair + Sub. Or even either of the two minus the Sub.

Leaving all that aside, I would say that the biggest mistake you could now make is to look for and buy another streaming solution because the Naim and the Connect don't like each other.
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I'm hopeful that there's a solution to this problem out there - whether it's something that'll make the Naim and the Connect play nicely, or swapping the Naim for something else.

But on the topic of high-end gear vs budget stuff, I'm not really interested in 'name' brands or high end for the sake of high end. I fancied a step up from my Rotel - a very fine amp - and tried many things at various price points, and just fell in love with the sound of the Naim. Basically, it did what my ears wanted it to do. So it'll be a shame if it has to go back to the shop in favour of something that'll play nicely with my existing setup, but if that's how it has to be, well...
I have used a lesser Rotel model than yours for years and it still gives flawless service at my daughter's home. Excellent amp maker, Rotel, and I have not read poor reports of any of their models. I have used the legendary Quad 99/909 pre + power amps as well for many years. But the sound from them was just as it was from the Rotel because I did not need the higher sound levels that the 140 wpc 909 could deliver. The Rotel went as loud as I needed it to go without distorting, so the 909 was overkill; it could go a lot louder, cleanly, but at the same sound levels as the Rotel, I could not say which one was playing; both were excellent. After all, as the founder of Quad said decades ago - a good amp should be just straight wire with gain. All it should do is amplify the source signal without adding anything to it, or taking anything away from it. And it does not now take much to make amps that are such wires whose non straightness is small enough to not be audible. Even if it can be seen on a test instrument. If it cannot be heard, it is meaningless progress to being more straight.

But any stereo salesman that wants to sell a 2000 pound amp has been taught how to have the sound from it come across better than from functionally equal but cheaper kit; or even from other kit at the same price point. There are too many tricks of the trade to narrate here, so I will stick to the simplest and most common one practiced: louder sounds better, even when the difference is as small as 0.2dB.

The intent of this isn't to be a wet blanket; I wish you all the luck in having a Connect work minus hum with the Naim. But the intent is to convey that if it does not, and you have to get a different amp, this need not involve any sound quality compromise other than psychological. Indeed you may end up having your cake and eating it too - the Connect working fine and a lower investment in the amp.

Good luck!
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Thanks, Kumar! You've been a big help, and it's been a pleasure chatting to you. Have a great day!
Ditto; I would be interested in knowing how the hum issue gets resolved.
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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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.
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.