Naim newbie needs advice re the "Naim Hiss"

With my system, which I believe is normal behaviour, you can hear hiss from the speaker tweeters with volume at zero. However it is only audible when I place my ear within 6 inches of the speaker. Can't hear any hiss at normal listening distances, unless its a poor recording being played. Have a word with your dealer. Don't think it will change the hiss problem, but NACA5 speaker cable would be an improvement in general performance I'm sure

I'd change the speaker cable. Your cable is high capacitance, low inductance and Naim amps work far better with lower capacitance, higher inductance. I'd get some naca5 or TQ black cable in there. There is always a very low level of hiss on Naim gear. Mine goes when I hit mute, but is completely inaudible during listening, even at low volumes 

Two possible issues: speaker cable or mains 'polution'.

Is your mains properly earthed? Do you have other devices plugged into the same circuit?

Not disagreeing with a change in speaker cable Finkfan, but the OP's Atlas Hyper 1.5 is not high C & low L,  at 74.44 pF/m & 0.5062 µH/m its very middle of the road & in the same range as any twisted pair cable that are commonly used with Naim.  

I have a NAC-N272 with a NAP300(DR):  I've just checked...

No significant hiss when muted or at volume 50, Analogue input; the hiss is only just detectable with my ear very close to the tweeter.

The capacitance of Atlas Hyper 1.5 is 74pF/m, which classifies it as medium capacitance: Higher than ideal for a Naim amp, but not high enough to cause damage or other serious problems, it shouldn't result in noise from the system.

Do you still get the noise when the 272 is muted?
Does the noise appear on all tracks?
Have you tried unplugging the network cable playing a file from a USB stick, if so is the noise still there?
Is the noise present on the analogue inputs, if so is it only the analogue inputs?

Thanks for the replies. There is no hiss when muted or even when i turn the volume up to 70 with nothing playing. The hiss starts when i start to play music and actualy disappears between each track when nothing is playing, then starts again when the next track begins. I dont use any anologue inputs just sfreaming from a nas.

Might this be an issue with the 272?

Cheers.

I think it's your network - you seem to be picking up some interference - most likely from your NAS and its power supply. 

Mungo - any example tracks where the 'hiss' is more noticeable ?

To check if the problem is with 272, network or NAS,  copy a known track or a whole album to a USB flash drive,  disconnect the ethernet from 272 & play from USB.   

Thanks so much for this help! Just tried a known track on a usb and just as hissy. Bizzarely the hiss is much more present on some tracks - But this definately isnt some kind of residual noise from the recording. On one particulary hissy track if im near the speaker it sounds almost like someone is letting down a bike tyre! This track ndver hissed on Cyrus equipment.

Any other ideas as to how to tell if amp or 272? I dont have anything else i can connect to the amp.

Thanks.

Mungochatney posted:

Any other ideas as to how to tell if amp or 272? I dont have anything else i can connect to the amp.

Try headphones...

What about switching it to an analogue input, you haven't answered that yet.

Did you disconnect the network cable when you used the USB stick?

Still get hiss from usb  with network cable disconnected. Havent got anything analogue to plug in. Just tried radio 4 internet radio - no hiss.

Just tried headphones and still get the hiss - Do you think i have a faulty nac n272? It is a 2016 model that i bought used from a dealer on ebay at the beginning of feb - the warranty isnt transferrable so i guess if this is not normal im going to be stuck with a repair bill....

Ok - can you send me your hissing track via WeTransfer? Email address is in my profile. 

I will test it on my streamers. 

Adam

OK, it seems there may be a problem with the 272, somewhere in the streaming module.

Take the 272 back to your dealer.

(btw you didn't need anything plugged into the analogue input as that never mutes the pre-amp - where as the streaming board does between tracks).

Mungochatney posted:

Just tried headphones and still get the hiss - Do you think i have a faulty nac n272? It is a 2016 model that i bought used from a dealer on ebay at the beginning of feb - the warranty isnt transferrable so i guess if this is not normal im going to be stuck with a repair bill....

Warranty should be transferable - at least in the EU. 

When I first set up my system I was absolutely convinced there was a really annoying, very hi frequency noise (almost out of ear range) coming from the speakers. If I got really close to the speakers I could hear a slight hiss, but this was something else.  After fiddling with my stereo, and the HF noise not going away I was desperate.  It turned out the noise that was bugging me was actually coming from the back of the TV.  Moral of the story; before handing over cash for new wires or kit check EVERYTHING.

Thanks all. The unit was bought used on ebay from a dealer in scotland - im in derby so cant take it back. If the warranty is transferrable i presume i can take the unit into any local naim dealer and they will return to Naim. Perhaps Ill pjone Naim on monday as it appears there is a fault with the unit?

Cheers.

Did you try to put, ugly in to a different sockets?  It might be a very dirty electricity thing

What is the origin of your music files, and what format are they stored in? If the hiss is only audible when they are playing, and still audible through the USB input, I'm suspicious that the noise is there on the digital file? Maybe your old system was less revealing, so you didn't hear it before.

I have spent the evening looking jnto this and Chrissu I think you might be right. I have listened to the flac througn my pc and the hiss is still there. Ive just tried a particularly bad example - impossible germany by wilco and the hiss is there on flac and equally on the source cd - sounds terrible! Dont think my previous system was good enough to show me how bad some of this stuff sounds!

Thanks all for the advice - I think the unit is fine, i just never realised before the amount of hiss on some cds...

Mungochatney posted:

 Ive just tried a particularly bad example - impossible germany by wilco and the hiss is there on flac and equally on the source cd - sounds terrible! Dont think my previous system was good enough to show me how bad some of this stuff sounds!

Really ? - just having a listen to this track now. There is a small amount of background hiss on this track but only really noticeable if i go and put my ear near to one of the tweeters. It's certainly not a terrible sounding CD - this is via PMC GB1i's too (you mention you use those). 

James

That is strange - sounds full of hiss when i play it. If the hiss is equally as bad when playing the original cd on my pc i wonder if there is an issue with my pc cd drive? This is the same drive i use to rip to my nas. I use db poweramp so would have thought that it would tell me if the rip was imperfect?

It's more likely that in this case it's just a crappily mastered CD casually thrown together to get more sales.