Naim vs Mains power

Hi new to this forum hoping you can help, I’m sure this has been spoken about many times. I have had Naim kit for a few years now, but since moving to a new build house I notice at certain times of the day my kit gets quite warm and my amp hums (more than normal). I have NAC282, 300DR, CD5Si, Hi-Cap DR, NDX plus Linn TT. From the wall power socket I have a Matrix Power block and Naim Powerline plugged from this into mains. Recently they all have got quite warm, where as previously only the NDX was slightly warm. Naim amps do sometimes hum I know, but occasionally I have had the transformer hum louder. I wondered if anyone can recommend a good mains solution that doesn’t involve a separate spur etc - a plug in version that will work? Thanks for any input

You must root cause the hum first. Taking medicine without a diagnosis probably won’t help much.

The main causes of hum in order (from experience) are:

  • Overvoltage. Significant deviation over the nominal voltage is prone to make a transformer hum. Not an easy fix. If a power company cannot address this, a variac may be required on the circuit.
  • DC offset. A lot is made of this by audiophiles but not quite as common as stated. If DC offset exists on the AC mains, then a DC blocker can be used. Effective ones would be balanced isolating transformers, but you can get smaller blockers that can go on the rack.
  • Defective transformer winding. I think we can rule this out since the problem didn’t exist before the move and varies according to time of day.

A multimter rated for mains current can be used to detect the first two.


It sounds like you have some issues with your mains quality. The first thing you can do quite easily is to find out if it’s coming from within your house, caused by other mains appliances, or elsewhere. Turn off everything except the HiFi and see if that helps. If not it could be a mains supply issue from outside the building which is more difficult to correct. Then start to turn appliances on and see if you can identify any culprits. These may include LED or fluorescent lighting, fridges, boilers, hairdriers, network equipment etc.
I would suggest that trying to identify and deal with the problem at source is better that spending money on fancy boxes that claim to correct these issues.


Thanks for your help will look into it

Will do, makes sense - as a new build there are more houses going up so I guess that could interfere with the supply? I do have LED lights too thanks for the advice

Get a DC blocker. Done.

If you want some more info on this, read topic below

Does that resolve over voltage too?


I know. So it’s not job done? :thinking:

Knowing where the OP is would help - different countries have different mains setups with different solutions…

My estimate based on all related topics on this forum is it is 99% sure it solves the posters issue.

“Recently they all have got quite warm, where as previously only the NDX was slightly warm”

The above is not quite right and isn’t likely to be DC offset. Other posts have suggested getting the mains voltage checked. Naim PSUs are normally stone cold, my HiCaps were, my Supercap and XPs DR are also cold.

NDX does run slightly warmer than ambient, mine runs about 16’C above ambient after an idle overnight rest, when running with iRadio or streaming its 18 to 20’C above ambient.

It would be very useful to know the OP new house actual voltage number.

The NDX yes, computers do that, but PSes getting warm seems odd

Heat being caused by friction, I’d expect heat and hum to go hand in hand.

My NDX was always very warm but everything else fairly cool.

In any case, checking mains with a multimeter when the problem manifests is a 2 minute task.

In principle sure, physics and all, but I suppose it would have to hum a lot to make it as warm as a streamer

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