Now it's the turn of the ND5 to Hum

Hi Meerkat,

Mine did 'til I installed a DC blocking filter on the mains supply - I probably have some mains waveform asymmetry where I live.

Can't say that I've noticed it before, but then I wasn't able to stick my head between the shelves to hear it!  As it's now on the top shelf, I can put my ear to it! 

Huge...I hope it's not that piece of 8mm glass, and 10mm dome nuts, that's causing the hum! If it is, I'll blame you! 

Hmm, fair enough...

[walks away with glazed expression]

[comes back]

Listening very closely, mine still hums a little - only detectable up to about 150mm; same for my Nait XS-2.

Hi Meerkat, .............  re 'As it's now on the top shelf, I can put my ear to it!'  

I think it begs the question can you hear it at the listening position when no music is playing.  

Then I would add that all transformers hum - period,  some are practically silent,  some (as we all know), are not,  so from how far away can you hear this hum when the room is silent.   

Have you tried moving the boxes ever-so-slightly on the shelves?  do they rock - even a minute amount - on their 4 feet ?   Is there any minute movement in the shelving?   etc,

Dedicated mains can help here. Even if it doesn't cure the hum, it will boost sound quality.

Mike...everything is rock steady! When I did my rack overhaul, I made sure it was 100% level, side to side, and front to back. I even put spikes on the feet of the rack, which embarrassingly, I had previously forgotten to do. 

I have just removed the ND5 from the rack, and powered it up without any other cables attached, and the hum is still there. I appreciate amps and power supplies do hum, but didn't think Streamers did. To be fair, because the ND5 is now on the top shelf, and more 'open', is probably the reason I can now hear it. Can I hear it from the listening position, answer no. Just the HiCap!

Dedicated Radial, and separate consumer unit Installed.

Then don't worry - it has a transformer, it's connected to the mains. You'll get a small amount of hum.

Fair point James. 

No harm in questioning. We all want to make sure our equipment is working as it should be. Naim power supplies tend to hum more than other components (my 300PS could make a right racket at times). From what you describe it sounds like your ND5 is working fine 

You can always put it back the way it was

If the Hicap hums louder than the ND5 then it'll hardly be noticeable  

Sounds like normal transformer hum then.

Perhaps Edison was right and we should use DC power instead of Westinghouse's AC transmission system (just kidding - I do know the reasons ).

At least it isn't the glass!

Meerkat,

Just a reassurance that this problem(?) is not exclusive to Naim. I have just purchased a Lindemann 858 Power Amp, which I would describe as perfect in almost every way, but there is a slight hum from the transformers. However, since this cannot be heard from my listening position, it doesn't concern me in the slightest.  

I wouldn't worry about it.

Now - the HiCap! If you can hear that from your listening position, and especially if you can hear it during 'quiet' passages of music ........! 

Just borrow Lloydys cat for extra case damping 

I don't need to.  I'm already employed* by a cat, for food, fuss, warmth and housekeeping.  At least for the moment - she has cancer and renal failure (she's 17).

*  Dogs have owners, cats have staff!

Thanks to all for your advice. I'll put it down to normal behaviour then.