Or non crowing capons😉
When you can hear the cow mooing at the listening position 3m away, it’s useful to know
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Just a reminder to all, this thread is not a continuation of the other closed thread. This is not a, “let’s whine about a problem” thread. This is a data collection thread to find (or not) anything of potential use to users and/or Naim (if they care).
We just need votes and any first hand observations about the nature of this if anything interesting was experienced. No axe grinding please.
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Interesting and if that’s the case then Naim have really made a mistake in pursuing the use of such devices then. I would hope that they have fully analysed and tested all this, which I assume they have. It would be interesting to see something from @110dB in response to your post.
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I remember , and I read that relatively often, that some guys have bought a Naim component that was humming too much , returned it, and got a replacement for the same component that was not humming.
It’s a bit a lottery sometimes.
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I have owned all kinds of hi-fi brands, to name a few: Linn, Denon, Bluesound, Ayon, McIntosh … etc, never a humming device, only now with Naim Atom …
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Hard to post a link using an iPhone but there’s a long thread about our various efforts to stop the humming on the old forum. It’s all in there. I can no longer remember how to access the old forum.
We started with a measured 242v output at the wall socket. This silenced all but the 555PS, which was still humming but much more quietly. After a call to Naim Tech Support to confirm that 230V would be okay, we changed output tap on the BPS to deliver 230V and all was quiet. No downsides at all.
Hope this helps, BF
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Thanks, yes I remember reading that now
I don’t think there’s a need. There sre always trade offs with any design. As ststed, toroids are favored by most (not all) hifi manufacturers but they generally don’t have issues. Naim tested (so I hear) just about every linear transformer on the market and selected what they felt was sonically the best. Simple as that.
The really early power amps from Naim actually had EI cores if you can believe. Given the form factor, you’d never fit a high current EI in a modern Naim case anyway.
Any, my post isn’t explaining why EI are superior. It’s explaining the design tradeoffs of each… not to mention EI are cheaper too. I’m sure that’s the primary reason for most of their implementations.
That is a big assumption - I’m not sure on what it is based? Whilst the only piece of Naim gear I had, an ND5XS, never emitted a noticeable hum, I had a Musical Fidelity P270 power amp for a few years, which from time to time would hum merrily away, sometimes cutting in or out quite abruptly, or changing volume level of hum. My MF P170 that I used before it also hummed from time to time, though not as loudly. My guess is that it is not uncommon with torroidal transformers, and possibly, though the two with which I have experienced it is far too small a sample for any conclusive indication, the bigger the transformer the more noticeable the hum may be. The MF amps were both dual-mono, with twin transformers - and those in the P270 were not exactly small:
All assumptions always are. They’re based in incomplete visible data and often proved wrong.
Two things:
- I chose the wordword “most” as opposed to all very deliberately.
- The assumption is based on a couple superficial observations. First, although my boss mentioned humming once, in the years I was in retail, I never experienced it once nor heard from any customer about it - and they raised all sorts of issues. Second, Naim seems to crop up in relation to humming more often in other forums too. So while hearing your toaster hum while standing 40cm away on a quiet 7am might be common, I feel (assume - perhaps wrongly) that the problem of a noticeable hum from the hifi in the listening position is very rare.
I’ve no doubt the odd bits from maker X crop up. The question is how often? That’s probably another poll and of less interest.
I’ve had valve amps with electronic hum now and then through the years. But Naim is the only brand I’ve owned with mechanical hum.
Whenever my naim torids are noisy, so are the ones in my MF power amp ( they are 1300va each side). They come out in sympathy.
I wonder if the good performance of the old H&F transformers is also partly down to them being wound for 240V rather than 230? Certainly my mains sits at about 242V and I very very rarely hear any hum. Even then you have to be about a foot from the boxes to hear it!
Maybe Naim and MF share this trait.
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My MF Nu Vista 300 has been somewhat tweaked by their ex service manager who lives South of London. The transformers were specially wound for my amp. A pair at 1300va each. Originals were 600va. Intresting the cost of each was £130. Originals cost £13 each.
I think the noise is simply a function of toroids and less than clean ( dc-off set?) mains.
We’re all drinking from a dirty well; asking how full it is doesn’t, I feel, address the core (ahem) issue.
Mechanical vibration can be induced in toroidal transformers when the supply voltage has asymmetric distortion in the sine wave. The asymmetry is a result of a phase difference between the voltage and current caused by appliances with poor power factor (PF) due to high and/or uncorrected reactive power. All inductive loads (induction motors, lighting ballasts, welding sets, induction furnaces, most things on a farm) do this but some are corrected more than others. It’s noticeable with Naim because the transformers are so darn big and it’s probably more noticeable when demand is high relative to supply (partly because more uncorrected inductive loads are in use) and maybe there is some correlation with supply voltage but to solve it completely you would need to change or modify everyone else’s appliances!
It’s less of an issue now but back in the days of CRT TVs we’d routinely tighten the bolts coupling the transformer to the case of any Naim supply or power-amp we had cause to open and quite often vibration had caused them to become slightly loose. The guns of a CRT are driven by flyback transformers (coupled inductor with a gapped core) and all are in sync with the local transmitter. Ugh.
Having generally become known that all electronics, even semiconductor, are microphonic I understand the concern over mechanical vibration but in my experience Naim equipment is so far ahead of the competition it will still beat the socks off anything else, even with a buzzing transformer.
My 250DR hummed noticeably. Nothing else did prior to or thereafter. An Airlink balanced power supply transformer got rid of it, but it was a nuisance to have to install one to deal with it.
Didn’t have any hum for years until recently. I can’t say it bothers me when listening to music but when I’m sitting in the living room reading or watching TV it eventually gets on my nerves until I turn it off.
Always said I would never put up with a buzzing amp so at this point seriously looking to sell and move on.
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If you like the amp, try fixing the problem (identifying and eliminating the root cause if an item or items of domestic equipment, and if none then trying a DC blocker, after first checking your mains is within voltage spec). If the amp doesn’t wow you, then indeed why bother?
As nothing has changed around here I can’t see what could be causing the buzz other than the amp itself. From what I’ve heard DC blockers can have a negative effect on dynamics, don’t want to spend money for something that might end up in a drawer. For now I’ll just put up with it as is, if I find another amp that sounds better at a reasonable price then I’ll probably cut my losses and move on. Montreal AudioFest a month from now will be a good chance to check out options.