Humming Naim gear versus alternatives

Huge posted:

Then the hairdryer is using the mains inappropriately - get her a better one that uses two heating coils instead of using a diode.

An audiophile hairdryer. Perhaps Naim should make one?

Adrian_P posted:

Adam, I like your thinking but I think the hairdryer is here to stay. However, the buzzing issue I have is not when the hairdryer is in use (when it is much worse as expected but it doesn't happen that often, thankfully). I can live with that, but it's the constant buzzing at all other times which is quite intrusive.

I was kiddin' of course.

I wrote a post recently, trying to summarise power supply issues. Whilst not entirely 'up your alley' see if you can pick up some useful tips form other members.

https://forums.naimaudio.com/topic/powerrrrrrr

Despite having a dedicated mains spur, my Naims hum at different intervals. I've detected a certain pattern to it though. Evenings when it's cold. A central heating pump, located in the basement of our old building kicks in as needed. When it's working, I get a slight 'buzz' from my Naim power supply and from a REL subwoofer. As my audio spur is on a different phase than the rest of the flat, I'm getting that interference in my system. But I'm immune to common domestic pollutants - fridges, hairdryers, etc, etc.

Apart from that - all is dead quiet. I don't even have hiss from the tweeters.

Thanks, Adam, I will investigate.

I don't have a dedicated spur and the wiring in my 1902 house is at least 20 years old. I've tried turning off all the usual suspects including the fridge/freezer but nothing has made a difference to the Supercap DR. What surprises me is how much worse the Supercap DR is than the other supplies.

I'm not an electrician, but it seems you are getting external interference or you have unstable voltage.

In my set up, when it hums occasionally, it's the 555PS that is a main culprit - SuperCap DR is dead quiet.

I might be repeating myself,  but no harm:  If you have power with asymmetric wave distortion (DC Off-set) then the hum/buzz from the transformer will change in tone & volume at different times,  if its constant & unchanging,  its a noisy transformer.

Mike,  I think another test is required to be certain that you can blame the individual transformer itself.  I believe you should move the transformer to another location where it's known that there's no waveform distortion.

For instance, I believe that an asymmetry in demand on one or two phases of the three phase supply cause a loss of  3-way balance and can result in distortion on the remaining phase(s), when the asymmetric currents interact with the earth potential, causing distortion in the remaining L-N waveforms.  This effect can be near constant where there is a 24x7 effect causing this (e.g. planning causing mass changes in housing or light industry).  In many cases the effect is constant, just varying in magnitude through the day, so it will be difficult for human perception to clearly identify the variance.

I will get my electricians to check my dedicated mains spurs as I'm curious now and will report back with their findings. May be beneficial for other forum members.
They are due at my place this week anyway, for some minor work.

Adam

Kuma, I don't think it's the topology.  Just like another Tx maker, Nuvotem are more than capable of making a relatively hum-free toroidal transformer. They have supplied many such samples to Naim for testing over the years. But there's a catch...  None of them sound as good as the ones that are currently made for them by Nuvotem (and are prone to hum given the right set of circumstances from polluted mains).  And Naim have tried many, many samples, from just about everyone who winds their own toroidal transformers.  Same thing.  None got anywhere near. Of course, the 60,000 dollar question is, "is the difference in performance worth the possibility of hum?"  Naim being such a no-compromise, performance-is-all kind of company, I reckon we have their answer.  For now...

When I ordered my SuperNait 2 I asked the Naim dealer to request the quietest one on the production shelf. It arrived and was quiet and not audible from my listening distance so I was a happy bunny, and it sounded superb.

My mains aren't that bad I guess, but I could realize that the amps were on, whereas with 3 LK 280's I really had to try hard to detect if the amps were on.

Of course, this was in silent no music mode!

When I introduced my 282/HCDR/3 x 250.2's to the Fraimlite, and addressed the IC's properly, amps are barely noticeable. Albeit, not quite LK 280 level of quietness.

Just curious, is humming a thing of the past, with the new Dred Amps?

Allante93!

Can Naim recommend or someone suggest a product available in the uk to remove the DC offset which doesn't cost a fortune or affect the sound quality and dynamics? I have one Naim component that buzzes loudly at different times. If sitting 10 feet away and it starts buzzing it's really distracting if watching tv for example. I currently have to switch off the component when I'm not listening to my system as SWMBO complains when it buzzes excessively which obviously isn't ideal. I have an energy meter which displays how much electricity I'm using and the reading on the display doesn't change when the excessive buzzing occurs, so I know the interference is external to the house supply and therefore there is nothing I can do about the polluted incoming mains supply.

From personal experience the Isol8 Axis extension does the trick . Circa £500 as I recall and to these ears no impact on SQ.  perhaps you could borrow one to try? Perhaps best to trust your own ears at the end of the day - that's if DC on the mains is your problem.

It could be the main. When I was in London, my HICAP hummed very badly, especially at night/evening, but when I moved to the US, the same HICAP did not hum any more. Of course, the only change was from 220 V to 115 V.

I have a xs2 which hummed from new , reading the instructions i think it mentions humming. I found it extremely  irritating and lived with it for about a year,always thinking i would change to another brand to eliminate the hum, which at times could be heard above quiet pieces of music. I persevered and investigated dc blockers. Bought an ex dem Isol8 Axis , problem solved. The xs2 still hums but quietly and consistently.  I would happily reccomend the isol8. My sanity and listening pleasure has returned.

The hum from my Naim gear has always been an irritant to me, but the SQ has always overcome this drag such that I've tolerated it. That was until I moved to a newly renovated home a few years ago (with dedicated spur) , whereupon the humming level went through the roof! I tried Isol-8 boxes, but it made zero difference. I tried everything I could think of in fact, all to no avail. The buzzing was so loud that it could be heard from way outside the listening room. In the end I was forced to resort to a radical solution. One that for logistical reasons I guess is sadly not available to everyone.

i was fortunate that the layout of my rooms enabled me to shift all the transformer-carrying boxes into a cupboard in the kitchen which just happened to be perfectly positioned to allow me mount the 'brawn' stack back to back with the 'brain' stack, but with a wall between them. By cutting a couple of letter box holes to allow cable connections through, the hum issue is now a thing of the past for my system.

The downside is that any thought of ideal cable dressing is out of the question as the Burndies in particular are at maximum stretch to make the journey between the 2 rooms, but the sonic benefit of no hum is truly liberating.

A few folk on this thread have observed that the hum only bothers them when music isn't playing, but I think that even though you can no longer pick out the humming sound from the music, it remains there as a 'pollutant' and continues to make a very unmusical contribution to the sonic noise floor (as distinct of course from the electrical noise floor of the HiFi).

As stated earlier, i appreciate that such a solution isn't universally an option, so I also think Naim should, for our good and their own, be doing more about this serious issue. I can accept that only this type of transformer has the right musical effect, but it should surely be possible to somehow mask or damp the vibration/hum more effectively?

My Superuniti doesn't hum at all, is it normal?

Chrissw19 posted:

My Superuniti doesn't hum at all, is it normal?

No - you should return it immediately and demand a humming one 

Chrissw19 posted:

My Superuniti doesn't hum at all, is it normal?

I think your SU is OK but you have the wrong kind of electricity.

Perhaps Edison was right after all - you don't get transformer hum if you use a DC supply.  

Chrissw19 posted:

My Superuniti doesn't hum at all, is it normal?

My Superuniti hums, but my 200DR doesn't. My guess is that if you got 10 Superunitis and tried them all on the same supply, you'd get 10 different levels of hum.

Of course, they only hum because they don't know the words. I suppose thry might try whistling?

wanderer posted:

Of course, they only hum because they don't know the words. I suppose thry might try whistling?

Oh - I get it now. So when there is no music, they continue to hum because they love playing music so much.... Clever 

Huge posted:

Joe, I like it!  Nice extension of the analogy.

The first group though are the only ones who can also still get on with life relatively unhindered by the rain.

I'd add that the first group remains outside to embrace the light of day. The other two groups remain indoors, safe and sheltered, but perhaps in relative darkness.

I think the larger issue here involves expectations. Many folks rightly assume that expensive gear will perform without caveats when they plunk down hard-earned money. To get an upgrade home and be disillusioned by hum or buzz has to be a let down. Perhaps no one is to blame and it's the physics of a particular domestic power situation. Maybe it's only a small percentage that experience hum, yet it is a consistent topic here.

OTOH - it has been seen on this thread that gear from other makers placed in the same domestic situation did not result in hum. No additional gadgets needed, no concerns for coloration.

joerand posted:

Huge posted:

Joe, I like it!  Nice extension of the analogy.

The first group though are the only ones who can also still get on with life relatively unhindered by the rain.

I'd add that the first group remains outside to embrace the light of day. The other two groups remain indoors, safe and sheltered, but perhaps in relative darkness.

I think the larger issue here involves expectations. Many folks rightly assume that expensive gear will perform without caveats when they plunk down hard-earned money. To get an upgrade home and be disillusioned by hum or buzz has to be a let down. Perhaps no one is to blame and it's the physics of a particular domestic power situation. Maybe it's only a small percentage that experience hum, yet it is a consistent topic here.

OTOH - it has been seen on this thread that gear from other makers placed in the same domestic situation did not result in hum. No additional gadgets needed, no concerns for coloration.

I do think you're absolutely right about the expectations thing - I believe that drives to the very heart of the issue.

About other manufacturer's equipment not humming, I also think that in the vast majority of cases that's so.  On the "no concerns for colouration" that's also true, but the salient point here is the word 'concerns'.

Naim have shown time and time again that transformer designs of the type they use (they have used two different suppliers to my knowledge), consistently result in lower colouration of the sound when the mains supply is a good quality sine wave.  So Naim make sure that the sound isn't compromised for the majority, just to cater for the few who have mains problems.  Other manufacturers use a technique where everyone gets the same higher level of colouration from their equipment irrespective of the quality of the mains supply; good for the few, but compromising the majority.  As they always perform the same the neither the majority (where the SQ is compromised) nor the few (for whom the sound is optimised) express any concerns.  It's the psychology of comparison.

Adam Zielinski posted:

Chrissw19 posted:

My Superuniti doesn't hum at all, is it normal?

No - you should return it immediately and demand a humming one 

Sensible advice from Adam.