I got my XPS (DR) however.........

Steve GTX posted:

HH,

Having re read my earlier reply, I quite understand why you asked.

You do know that this is all your fault, after all, it is your plan I've been following .

Ah good; as you have seen your post implied that. But of course, owning a 272/250 you are a top man who would never make such an error. 

As to a dedicated line, do it. It takes all the rubbish from other stuff off the mains and will improve sound quality. We run our wire round the outside of the house buried under the flower bed, using 10mm2 steel walled armoured cable. You should get a separate small consumer unit installed. We have no hum at all.

Regarding a stand, have the 272 at the top with the XPS below, and it's important that the Burndy doesn't touch the wall, floor or other wires. Make sure you arrange it into the right shape before plugging in, so that there is no strain on the connections. 

In general, a dedicated mains supply won't silence mechanical transformer hum.  The hum arises for one of two reasons:

A  (Rarely) because the transformer is just a noisy one.
B  (More often) because the mains supply is asymmetric (positive 1/2 cycle isn't equal to negative 1/2 cycle).  Reducing the wire resistance won't affect this.  If a dedicated supply does reduce the problem then you're causing the problem inside your own home, so fix the problem where it's being caused!

Hi Steve,

A thread that may help in some but not all situations:

Search for " Suffering from those transformer hum blues?"

It may help. It did and still does for me.

Best regards, FT

Since you have an isotek why not try it? even though people here seem to know it is bad, probably without having tried one, because they are bad so no need trying out what you already know does not work.

The thing is - there is no practical method of getting rid of a transformer hum.

By practical I mean one with decent return on costs / effort ratio.

All my power supplies hum, my CDX2 hums, even my NDX hums - but never at the same time

Adam Zielinski posted:

The thing is - there is no practical method of getting rid of a transformer hum.

By practical I mean one with decent return on costs / effort ratio.
...

That depends...

If you already have a radial circuit, get an electrician to install a balanced isolation transformer wired CTE.

If you have skill with a soldering iron, build a 'DC blocking filter'.

Otherwise the cost is of the order of £1000(GBP) up.

I will have a chat with my electricians. Despite having dedicated mains spurs I still get transformer hums. Most likely an asymetric sine wave - just my guess now. 

Let's see what I can come up with.

Adam

I use two Isol-8 axis blocks in my system and these cured DC-induced transformer hum for me. Before I had them the Supercap and the XPS I had  used to drown out quiet musical passages. To be quite honest I've not detected a drop of in SQ and if there has been a slight change for the worse, these ears can't hear it and it's more than compensated with all that transformer hum banished .

As usual best remedy is to try the solution yourself. I find there's a lot of folklore out there, some based on fact, some just passed around rather than directly experienced. That's the scientist in me speaking!

Adam Zielinski posted:

The thing is - there is no practical method of getting rid of a transformer hum.

By practical I mean one with decent return on costs / effort ratio.

All my power supplies hum, my CDX2 hums, even my NDX hums - but never at the same time

Hi Adam

You might like to check the thread in the post that is two above yours.  

Huge's post below yours suggests a very similar train of thought.

Best regards, FT

Hi FT

Certainly - I remember that post well. I already had an interesting discussion with my electricians on that.

But it would seem we have not yet found a foolproof solution for my system. The current thinking is that my gear is hooked up to a different phase than the rest of the equipment which isolates it well from fridges, hairdryers etc. But that phase seems to be picking up interference from other building equipment in the basement (water pump, heating pump...).

Adam

My xpsdr hummed so much I sold it!

liam posted:

My xpsdr hummed so much I sold it!

Well that is certainly a pedestrian solution - you should have rewired your entire house or failing that, bought a different one.

Have you no commitment to sonic excellence?

Brexit Schmexit - I think we need to focus on bigger issues...

(Disclaimer - the above statements are pure hyperbole for comic purposes, and are not meant to be taken in any other spirit.)

I've owned 3 Hicap DR's. One hummed and two didn't.

G

GraemeH posted:

I've owned 3 Hicap DR's. One hummed and two didn't.

...... but did they tap their feet instead? 

Weather or not a Naim box is going to hum does seem to be a bit hit-and-miss, and I can only assume this is the result of variation in hand assembled products. To help eliminate any external factors, you can try turning off all other appliances in your house, by unplugging them, or turning off whole circuits at the consumer unit. Turn things back on one by one to see if there are any individual culprits. These might include fridges, some light fittings, anything with a SMPS. There's a good chance this will not solve your problem, but it's worth checking anyway in case you have any rogue appliances.

Putting your HiFi on a dedicated circuit may also not solve your problem, but for many people it's a good sound quality upgrade at relatively low cost, so well worth doing in my opinion, even if the hum persists.

For some reason my entire system hums when I play this:

DrMark posted:

For some reason my entire system hums when I play this:

My kit wasn't humming at all until I played this. @#$%$!!!! I hope is not something permanent from now on.

I'm sorry Erich - I feel bad for giving you the hum virus.

Before you go spending too much money try this experiment:

 unplug everything in the house that you remotely suspect / all smps but also refrigerator etc.

does it still hum?

Thank you Guys,

I've spent ages exploring the forum threads on this topic and I'm really surprised how many people have experienced mains (Naim's) hum . 

The feedback is really appreciated - apart from the Puccini - I just can't get it out of my head.............or is that Kylie?.

I'm taking a break for a couple of weeks and will return to this issue (problem) then. 

Should I leave the kit switched on or off?

Steve

Just a question my 250 DR does have a transformer buzz is it ok to leave on all the time?

Ricto

Ricto posted:

Just a question my 250 DR does have a transformer buzz is it ok to leave on all the time?

Ricto

Yes.

An interesting thread for me as XPS is the next step for my 272/250. In fact I am hopeful that one day I will have two with the other one powering the CdX2.

Have those further up the road found hum problems when you have two PS's? Secondly, on a five shelf full fat Fraim would I best have the CD player on top and Ps below then 272 with Ps and finally 250 on the bottom? Yes I know another Fraim would be better but no room for that, let alone the cash!

i currently do not have a dedicated mains supply which I know would be better but practical considerations make it difficult to install. The good news is that I currently have no hum

I am having a dedicated supply installed as part of an extension. Still a month or so from completion  - so will be interested to hear the result SQ and hum wise. As it happens my experience is that the DR models (SC, XPS and 250 in my case) have all been less prone to hum than their predecessors. Still had their moments though. Worst identifiable offender was my wife's hairdryer by a country mile. Other moments seemed to be unconnected to appliances such as fridge, boiler, etc. use / switch cycles.

Steve gtx....Why don't you try the xppsdr in a family members house or friends homes and see if it hums? that way you may eliminate the cause of the hum, " before anyone else asks " once tried don't forget to bring it back home and connect to your nac n272,

This may eliminate the need for a dedicated power supply...although no harm in having one anyway, or simply ask Naim for another as yours isn't fit for purpose, sorry Naim but if as you say you quality match components then one xppsdr shouldn't be any different to another, ( as graemeh pointed out ) or should it? 

Does your local dealer have a dedicated spur, does it buzz on his/her premises 

Just a thought