It’s no different to receiving a parcel from a delivery company. And presumably you wouldn’t knock on a random neighbours door 
Meanwhile we have bunches of blokes hugging, kissing and spitting on the floor. Oh and kicking a ball about too. What does Twitty Whitty say about this?
HH has done some sterling voluntary work assisting with dealing with Covid, which is not a lonely position unlike some people’s positions on here.
Let’s remember this is OP’s first entry, we wouldn’t want them to think this is what usually happens on all topics. Please let’s stick to the subject going forward - Many Thanks
@Magnolia you mentioned that all was fine then poof, Hum! Do you know or remember anything that might have proceeded this? Bad weather, power going out then back on, new computer in the house or anything new or anything that’s changed? New neighbors that are running Ham Radio, something on a timer? Grow lights? Xmas lights?
My experience is that electronic devices either fail rather quickly or work and stay that way. Rare that something fails almost a year in without something external causing it.
Naim gear can produce hum as normal, but that loud is not normal. Whatever the cause is, outside or not, this is not normal and I believe your unit should be checked by Naim.
I have only the very best experience with Naim aftersale services and really hope everything will be ok in your case too.
What’s the reason behind humming transformers in cases they do have clean AC? I have had multiple Naim products attached after a DC Blocker and some transformers are totally silent when others hum quite a lot. Could it be that they are a bit loose? I had a tube amp humming which was completely removed by tighten the bolts to it.
A loosened retaining bolt could possibly cause an issue, yes. However, it’s usually issues such as DC on the mains that cause toroidal transformers to sometimes hum. It would appear after studying the issue over many years that the higher quality of transformer, the more propensity to hum, but all are individual in this respect, so you could have one that will hum with one scenario and another essentially the same that doesn’t. Change the scenario and the hum may flip to the other. Naim and Nuvotem have done a lot of work on the issue over the years, and continue to do so. It’s why the transformers are so rigorously tested for hum levels both at Nuvotem and at the Naim factory, with many not making the grade for production (hum level too high), but you can’t replicate every solution scenario, sadly. Of course, bear in mind that with a mains supply working properly without any issues, they will not hum at all.
It’s relatively easy to make toroids that won’t hum when faced with mains problems by using lower grade steel (they’d be much cheaper too), but the problem is that they just don’t perform as well. For Naim, performance is the last thing that should ever be compromised, so…
But like in my case. I have a 300PS and a XPSDR on the same connection after my DC Blocker. The 300PS is like totally silent and the XPSDR hums. They get same AC distributed to them still they behave different. So it could be that the 300PS transformer is lower grade than the one in XPSDR or windings are different or so meaning the tiny bit of DC that still might get through is amplified by the XPSDR in greater extent. What I’m after is, can a transformer within it’s specifications and without issues and clean AC and all this still hum by the way it is built? No Naim transformer would hum even the slightest if you had pure clean AC to it?
I will try to run the DC blocker to the XPSDR only to see if any difference.
While it’s nice to get supportive comments, as I’ve said my suggestion was not a good one. The situation out there is truly frightening and the NHS is getting to breaking point. The rules may permit various things but the right thing to do is to go out as little as possible and see as few people as possible. I’ll be at the vaccination centre later and we’ll be doing over 600 more over 80s today. They are so pleased to be getting their vaccinations and many have not been outside since last March and are very frightened of something many of them do not understand. So we must all do everything in our powers to keep them, and everyone else safe. There are plenty of steps that the OP can take to resolve the hum that do not involve having unnecessary contacts.
So on that note, how’s it going @Magnolia? Have you tried turning everything else in the house off yet? Have you found the culprit?
The transformer in the ND5 isn’t large and it’s usually the big ones that hum; is it definitely the transformer?
No, if you re-read my post you’ll understand that each transformer may react slightly differently to all the many variations of main pollution.
If no mains pollution, then no transformer buzz.
I believe it is an increasing problem for Naim and others with similar design philosophy in that the average home get more and more DC on the grid due to dimmers, LEDs, motors for all kinds of machines helping you out and to come charging stations for electric cars and for sure more stuff contaminating the grid. Would be awesome if Naim could help their customers releasing a top of the line product cleaning this dirt up because IMO it is much to ask for when telling the average user to get a dedicated line to their hifi system and many rents their living and are not allowed doing so. Just a thought.
This may not help.
We get regular drop outs for our Mu-so in the kitchen, but only in the morning!
Today this happened and I noticed that it coincides with when the microwave is running. They are 10 feet or more apart. It always happens when my wife is microwaving her porridge she tells me.
So HH suggestion of turning everything off is a good idea. It’s how I discovered our washing machine was tripping the electrics when the heater element was functioning…or rather not.
My Nd5XS2 is two months old and has also developed a hum that is intermittent. I shall be taking it up with my dealer next month.
Microwaves interfering with Bluetooth and wifi is one thing, and you are right that Slamdam’s suggestion would not help for this. But in many cases there is simple, accepted and established solution for this: wired ethernet. And maybe a new microwave 
It’s certainly more difficult with mains.
And regarding mains pollution, I agree with Slamdam that it is a bit much to ask. In my case, I am blessed with little trouble despite an XPS2, a 300PS, a Supercap and a 555PS. God bless the sparky who did the installations in my rented apartment: He put one power socket out of several in the “multimedia” area into a nearly separate circuit, just shared with living room ceiling lights.
However, some days in the evening I get a transformer hum for an hour or two. I already turned absolutely everything off in the apartment, no change. So seems to come from a neighbor in the building or from outside. Not much more I can do than was already done, and if Naim had a classic-size unit (or two) to get rid of all this nonsense, it would be fabulous for many
In my XPS DR, transformer is humming since the beginning. I get used to it but I’m wondering if this can cause any damages?
A hum from the transformer at low level is normal… and as certain conditions in the mains, such as symmetry (so called DC on the mains) due to external types of mains loading effects, the transformer can saturate and it then creates a mechanical noise. Efficient toroidal transformers are more prone to saturating, a buzzing hum, that sometimes varies on and off, and may even ramp up or down, isa sign of mains asymmetry.
Now some transformers can be out of tolerance with the degree of mechanical noise they create… so if one device it’s significantly louder than other Naim devices, then I would take up with your dealer and or Naim.
Yes it’s true the cause can be in your house, or even your neighbourhood, (consumers sharing your phase from your substation or distribution transformer) but your device should not be disproportionately loud… certainly compared to other Naim components with similar size transformers.
Local causes can include hair dryers, tumble dryers, washing machines, dish washers, laser printer heaters, … so it is also worth seeing if the humming coincides with any device being activated.
It is worthwhile trying to find this, as even when the loud humming transformer is resolved, a saturating transformer creates electrical noise in the mains and in the device, so ultimately may marginally effect SQ. This is a downside to efficient linear power supplies.
Ultimately if the issue is down to challenging local mains conditions and your Naim device is within specification, then there are commercial DC mains removers available, and a few on the forum use them. Views are positive, and some even report improved SQ performance as well banishing most if not all the intermittent hum, which technically certainly makes sense.
I have had a fair number of Naim boxes over the years and the only one that hummed significantly was the XPS, to the extent that my wife, who is usually very tolerant of my hifi mania, complained about it. At one point it got sent off to be DR’d and I hoped that on return, it might be quieter, but no such luck. I should probably have asked Naim to have a look at it.
Roger
XPs has a really huge transformer, maybe that’s one of the reasons why it hum. 
UPDATE: the ND5XS2 is a machine designed to make humming noise. It does this very well. There is no way I will keep a machine that hums so incredibly loudly at 3 meters away. I could have have a construction crew banging around in my living room for the same result.
Checked, once again, with my dealer (whose identity is just begging to be revealed) and he ONCE AGAIN claimed that it is typically impossible for a Naim equipment to be found faulty and that the problem is mine, mine alone, at my house on my electrical network. The “humming machine” is under warranty still but I suppose that is of no significance because this is all my fault.
As a result, being so thoroughly DISGUSTED with Naim in general, I will sell at a massive loss an SN2, a HiCap, a HiLine, and a humming machine otherwise known as an ND5 XS2. Just tired of the headaches and heartbreak associated with making simple attempts to listen to music on Naim equipment. It’s just not worth it.
FYI, ripping the humming machine out and plugging in around the house yields same humming results. Plugging in at my son’s home yields same results. My dealer would insist that I’ve screwed up the electrical network at my son’s home as well as it is impossible to find flaw with Naim equipment.
Lastly, for a bit of humour, I replaced the humming machine with a 10 year old Squeezebox Touch feeding a 200£ Maverick Audio D2 DAC. Nothing hums and it sounds, quite frankly, exactly the same as a 2000£ black box with a green Naim logo. HOW HILARIOUS IS THAT?
Clearly, the overblown, overrated, overpriced and overhyped Naim “mystique” has been debunked and discredited at my home. Done with Naim. Forever and ever, amen.
I can confidently guarantee that that not one of you would tolerate such a massive hum in your system at your home. Generally speaking, this is not why we invest in high fidelity.
Hopefully, I won’t lose too much money unloading this stuff on the second-hand market.
Brgds.
