250DR Buzz

I have a Nait XS3 pre-amping to a 250 DR via a FlatCap XS - unusual setup I know but it works well and gives me a fairly clear upgrade path before I retire in three years time. However, I have suddenly - and for no apparent reason - started to suffer from the dreaded buzz, as mentioned frequently in the forums. It’s not permanent and generally from just the 250DR, but sometimes from the XS3 also. Nothing has changed in my house that could add noise, I’ve taken my whole system apart and put it back together again and installing a dedicated circuit into my house really isn’t practical. Therefore, I’m simply after suggestions as to how I can make the most of, and improve, the mains that I have - using, as best as possible, known and successfully employed products (I live in the UK).

Unfortunately it could be something from your neighbour. Cheap items using heating elements are prime suspects - hairdryers, electric blankets, electrics fires, that kind of thing. Does it happen last the same particular times?

The article below is certainly worth a read. If its new then it might be something on your circuit, or it could actually be a neighbour. See if it’s only certain times of the day, are those times consistent, is it a contact buzz, or have waves. Try and turn off all items on your ring main, or/and use an extension lead from upstairs ring down to your hifi and see if it stays.

It’s possible that an electrcal component somewhere nearby is causing interference. This may be a newly installed device, one that has recently been set to come on at certain times, or that has developed a fault. It could be in a nearby neighbour’s house.
You can test for items in your own house by selectively turning things off, or even whole mains circuits, then wait a minute or two and see if things improve. Of course if it’s coming from outside your house it gets harder to track down.

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Hairdryers would be where I’d start. When my daughter is back from Uni I can tell instantly when she using her hairdryer. Unfortunately it’s a while since I needed to use one

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Thanks for all the replies so far. It’s not my neighbours - they’re at least 300m away. Also, it’s completely random - the amps can be silent for long periods, and then the hum suddenly starts. The only new thing in my house is a new Samsung TV and it’s ‘one-connect’ box is powered from of the same double wall socket - but if it was that then you’d expect it to be permanent, and it occurs even when the TV is entirely unplugged. Equally, it is none of my other sources as disconnecting them (both as inputs and unplugging them from the mains) has no effect, so it is clearly my mains but it only started on Friday, so I don’t know what has caused the change…

Get a DC blocker and problem solved.

I guess it’s not impossible that the fault is in the amp, perhaps the transormer mounting is loose? Can you take it to a different location and see if the noise persists?
Are there any farms or industrial units nearby? Not impossible that these are pumping some interference onto the mains, even if they are some distance away.

I’m sure it’s the electrics in my 100 year-old house. A DC blocker might be an option, but which one? And what impact might that have on the musicality of my system as for every recommendation on the Forums, there is an equally vehement negative opinion!

You will get answers both ways on that - if you try one, look for one you can return, then make your own mind up

I’m a bit concerned about the One Connect Box you mention. Looking out up, it talks about “invisible” connections via the mains to your TV which set off some alarm bells. Have you tried disconnecting the box and TV from the mains to see if the problem stops?

Think he’s tried it all unplugged Richard, still same

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Hi Richard. My previous Samsung had one of these too, albeit smaller and it didn’t carry power. However the buzz was present even when the TV (and it’s box) were totally disconnected/disassembled. At the moment it’s quiet, so I’m just going to monitor it. Unfortunately, Exmoor is famed for many wonderful things, but not so much for Naim dealers. As this is probably a Naim-specific issue (I accept that ‘clean’ mains would benefit any system, but it appears from the Forums that Naim seem particularly sensitive). What I really need is a Naim expert to visit and assess my setup first-hand though that would likely just lead to a - perfectly justified - critique of my lack of racking, which is an upgrade for another day, and maybe never, if the current Mrs Gale has her way. Units I can swap without her really noticing, but the sudden appearance of a couple of HiFi racks is harder to disguise…

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When we say your neighbours, we mean anyone who is getting their supply from the same street box as you. More specifically, anyone who is one the same phase as you.

For example, my amps buzz like mad occasionally. Western Distribution explained to me it would not be caused by either of my immediate neighbours as they were on a different phase to me. It could be any one of every third house in the neighbourhood.

What people are talking about is Electromagnetic Interference being picked up from the incoming Mains Wiring itself - no transmitted through the air. Conducted - not Transmitted EMI.

One thing that can help a little is to slightly change the physical stress on the chassis and components. When it’s buzzing, see if slightly lifting one or other of the corners of the unit makes any difference. This doesn’t change the source of the issue, but might make it a little-less audible. It’s a bit of a long-shot as Naim stuff at the level is very well physically isolated.

If it’s coming from within your house it must be generated by a noisy device, so you can diagnose thus simply by switching things off while the amp is buzzing. Then you can repair or replace the rogue device. Prevention is better than cure, and possibly cheaper.

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Chris, you’re right, of course. Bizarrely, having done quite literally nothing at all, it’s presently quieter than it’s ever been - the noise floor has dropped right away on all inputs. Maybe my system is possessed. The only thing I’ve added, aside from changing the TV, is a cheap DC suppressor that Richard recommended as a potential cure for a ground loop between the Naim side of my system and my Arcam-driven multi-channel system via the AV Input on my XS3 (the common component is my Cambridge BluRay which I also use for CD/SACD via RCA). It cured that loop spectacularly - easily the best £11 I’ve spent - but I have no explanation for my present happy state of affairs.

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