Hey !
I bought an amplifier on ebay, model from 2008, is it normal to hear a working transformer?
The sound does not come from the speakers, but directly from the device, it is a characteristic “humming”, audible from a distance of 1 meter?
Can this be remedied somehow?
Regards
The toroidal transformer may hum a bit depending on how dirty your mains electricity supply might be. DC on the mains in particular can cause it to hum - it’s nothing to worry about in particular, although if it gets really loud and you can hear it from your listening position it could be a bit annoying. Best try to track down the source of the problem (items with heating elements, faulty fridges etc… can be the main cause). Plenty of threads here on the subject.
I went the easy way adding DC blocker. Many threads on it here. Starting with Ifi DC blocker (from what I know) in price. I use Supra DC Blocker myself today and will end of this month get me an Isotek Evo3 Syncro Uni for evaluation. There are more alternatives but this gives you a starting point in doing some research 
To me the downside having three boxes humming and get saturated transformers is a bigger compromise than tiny bit on the audio performance. I’ve always felt my system performed bit better with DC blocker but all systems and conditions are different so give it a trial.
Welcome to Naim & the forum Proksior,
I too have SuperNait, and the transformer hums.
Above posts from Richard & Slamdam is good advice.
In my case it was not all DC offset distortion as the background hum was a constant never changing tone & volume, however it did change tone & volume when the hairdryer and the now long departed electric blanket were on; both used half wave rectification for speed & heat control.
Whatever, I designed & built my own DC block filter, that fixed the half wave rectifier distortion but did not eliminate the background hum although it did reduce it to just about audible in a silent room.
The unexpected upside was it bought an improvement in SQ, so it was a keeper.
Since then the UK national grid have been reducing voltage, mine has gone from aprx (+/-) 250v to 240v and this has lowered hum volume even more.
So, apart from trying a DC filter, if you can check your power voltage it would be nice to know.
If you are in UK and have 240 to 250v it might be a factor, however if you are outside UK the voltage is typically 230v or less, maybe the DC filter will be more helpful.
You may want to consider a service, it’s at least worth checking if Naim have done so in it’s lifetime. Your local dealer can check that on your behalf. You would ordinarily anticipate a service on a NAIT every 10 years or so.
There’s nothing wrong with a bit of transformer hum that a sharp clockwise rotation of the volume control won’t sort out/kill off.
This statement is as verifiably true as you want it to be!
Thanks for the answer Richard
Thanks for the answer, I used a DC blocker from a local Polish electronics manufacturer, no results, the hum of the transformer did not decrease, I found good information about the DC blocker Supra, can you confirm that the “humming” decreased or stopped?
Regards
Thanks for the answer, I live in Poland, here the mains voltage is 220/230 v, I used DC Blocker, no results, the amplifier works in close proximity to a fridge, toaster, coffee maker, cooker.
I had the Alchemist amplifier before, there were no problems, but there is nothing to hide, it didn’t sound that good
Regards
Richard, can you suggest a DC blocker from a specific company?
I can’t as I have no good experience - always better to try to nix the problem at source. However, others here have some good experience where there was nothing else that could be done.
1 Like
If you use a DC blocker already with zero effect I would be surprised if another brand/design suddenly would kill the hum. Some naim transformers do hum even with a DC blocker in my experience. No idea if that is defect, tolerance issues or other noise on the grid which is not eliminated by a DC blocker. I can just say they all behave bit different but in my case a DC blocker have removed hum completely or to a level which I cannot hear it other than if I’m close to the box.
It’s a fair point made regards variability. I had a noisy HiCap DR at one point that was very sensitive, and later the same product but a replacement and that was practically silent, in the same system powered off the same wall socket!
If you can measure resistance to earth also. don’t under estimate the importance of the influence of the mains supply and grounding in system performance.
Many owners will put their systems on seperate circuits and so forth. I’m fortunate here to have TT earthing but some arrangements can be negatively impacted by your neighbours or local supply. Worth an electrician checking and measuring such things anyway.
How much you want to invest in a SN1 hum is debatable of course, a service if one is needed, may also help.
Have you checked if the the mains cable is in phase ?
Turn the mains plug around and see if it change, the transformer works better if it will be fed with the right phase.
It’s also very important to have the phase correct for a musical sound.
May I know which one are you using?
Supra DC blocker today. Have an Isotek on order for comparison. But sometimes when the heater for water turns on I can still hear some hum from the transformer if not playing music. But most of the time it is near total silence. Will see if the Isotek could be even bit better since it cost twice as much as the Supra.
Transformer hum is a recurrent issue with Naim products - this forum has masses of info and discussions about this.
My personal experience has been that my SN3- new in 2021- has got progressively noisier such that the hum is audible 6m away in a quiet room and it’s driven me nuts!
I have tried every remedy suggested including 2 different dc blockers- at different price points £110 and £750- no joy.
SN3 is going back to Salisbury-
Hopefully will come back quieter…
My dread is that they say the hum is “within limits” in which case the amp will have to go😢
3 Likes
One more thing to try: what happens when you lift the amp or put it on e.g a towel? Sometimes then hum gets ‘amplified’ by the stand / cupboard it’s placed on.
2 Likes
Try turning off other electrical appliances that may be causing the amp to hum. Sometimes this enables you to identify a cause, often a fridge or central heating boiler. Occasionally this helps, but not always. Even if your mains supply is very clean, some Naim transformers always hum.
1 Like
Until I had a hifi specific radial installed I used to get a spike through my speakers whenever the freezer kicked in, hum as well.