Naim Transformer hum (or not) to AC mains type poll

The objective here is to determine:

  • What proportion of members actually have had this problem.
  • What the distribution is on AC regions from 100v up to 250v.

The hypothesis going in is that while hum is a frequent topic, most users don’t have the problem. Of those that do, it is more an issue in the >200v AC regions. The poll is not truly accurate as it samples only forum members who participate and not the wider user community.

You may make up to two selections to reflect different living experiences.

Have you ever had a problem with Naim transformer hum?
This is defined as audible from the listening position with no music playing.
Voltage is defined as what you understand your nominal voltage to be in your country or region. Not what is measured from your outlet (which may vary).

  • No : My voltage is 250v (or higher)
  • No: My voltage is 240v
  • No: My voltage is 230v
  • No: My voltage is 220v
  • No: My voltage is 125v
  • No: My voltage is 120v
  • No: My voltage is 115v
  • No: My voltage is 110v
  • No: My voltage is 100v
  • Yes: My voltage is 250v (or higher)
  • Yes: My voltage is 240v
  • Yes: My voltage is 230v
  • Yes: My voltage is 220v
  • Yes: My voltage is 125v
  • Yes: My voltage is 120v
  • Yes: My voltage is 115v
  • Yes: My voltage is 110v
  • Yes: My voltage is 100v

0 voters


I’m guessing you want measured voltage, not nominal? Of so that perhaps needs making clear.

Actually nominal. Measured voltage correlation would be a factor of post correlation. For example if most problems happen in the 240v range, then it might be looking at whether measured voltage shows a common similarity like over voltage.

I will put in a note to clarify. I do not expect anyone to measure their voltage.

Good initiative.
FYI, the 230V nominal voltage for UK and the EU is a diplomatic fudge.

Many EU countries ran (and still run ) on nominal 220V, while the UK was and is 240V. However, it was agreed to establish a European standard of 230V. This new 230V was agreed with limits wide enough to ensure that no country had to actually change their electricity distribution networks.

Hence, France for example still runs at a nominal 220V while the UK is still at 240V but we all call it 230V.

This diplomatic anomaly will influence the poll results. Some UK Naim owners will say 230V, while others (like myself) will select 240V. Equally, some E.g. German or French owners may select either 220V or 230V.

You may need to combine certain response groups once the votes come in.

Best regards, BF

Absolutely. Once there is a significant number of responses, I will churn the numbers into something meaningful. And it will need some volume of responses to be meaningful. A known constraint is that some people may not know what their voltage is within as much as 20v for the reasons you state above.

On the other hand, the world is big and many countries have more clearly stated voltages that match what their power company is (attempting) to deliver, I don’t want to get too bogged down with getting people to measure or think about their power versus some EU agreement on stated power. If people respond with what they think they are on, and enough respond, it will be good enough.

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In the text, but not the heading, you mention Naim. Are non-naim hifi products with toroidal transformer hum also of interest?

No. This is specific to Naim

I’m in the No 120v camp.

Sorry but this is a pointless exercise.
It’s the voltage to the property that is imporartant.
As for voltage regions …. let’s keep it simple, the whole of EU incl UK is nominal 230v 50Hz, there are no 240 or 250 areas, ditto 210 & 220, but that is what individual areas & properties may be getting.

The world is bigger than Europe Mike.

And you are free to think this is pointless. Many might. Personally I think if there is a correlation after a significant number of votes that shows (hypothetically 90% of the problem is for uses on 240v then I think that would be very useful to engineers if they cared to do anything with that data.

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I voted yes but it only became audible from across the room when a hair dryer was in use in the house.
Non of my DR boxes hum.
A CD5x used to hum when first bought new but the hum reduced after some months.
My ex dem non-DR 555ps hummed, it turned out it had a blown regulator on a line not used by my CDX2 and it was only discovered when it failed to power up my ND555. It hasn’t hummed since being DRed.
Now on 220V and no humming from anything, not even my completely non-DR 250-2/Hicap/282/CDX2 second system the last time I fired it up about a year ago.

Personally I think more useful would be what the actual the voltage is (at the time of humming if intermittent), and what the equipment rating is.

Maybe better if it’s linked to Naim market share vs population size, I am sure it is predominantly European by some considerable margin.
NB there is no 240v region

Nominal but the UK is still 240 whenever I measured it and France is 220 so call 230 with a 10% tolerance and you had EU harmonisation with no tears until the UK spat the dummy.

While I agree, from a survey perspective I think it raises the bar too high to expect everyone to measure. You’d be surprised just how many people aren’t ever going to do that.

I have polled as ‘Yes’, but it is marginal and not intrusive as such.
I don’t really regard it as a problem, although that could change if it gets more prominent :man_shrugging:t2:

Thanks for taking time to do this FZ and do think the outcome should be of interest to Naim.
Edit: more details provided UK based (so nominal 230V) and on average 248V incoming causing “hum”.

Exactly my point.
FZ wants to know the regions classified (nominal) voltage.
All of EU & nearby countries are nominal 230v.
What good is recording that when the actual recieved voltage is different & does have such an effect on traffo hum.
I’m UK, nominal voltage 230, I used to get 250v & at times higher, that gave me audible traffo hum. Now its been reduced to 240v & my traffo hum is all but gone.

No, I wouldn’t!

I’ve actually had 3 humming items (2 x Supernait 3, 1 x HiCap), the 2 Supernaits were returned to my dealer/Naim and eventually I got a good one - so it is not just an electricity supply issue! As a true representation however maybe I should be able to cast 3 votes!?

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