Noise

Quiescent amplification circuit noise. Normal.

I always mute the pre-amp when the system isn't in use.

John.

Yes. See it as a canvas where the music gets painted on.

What hissing from the speakers?  Even on Phono mine is quiet up until about 2 o’clock. 

Unless of course it’s very loud. Do you hear it from the listening position or only close to the speakers? What Volume setting? Turntable or Digital source? 

Normal. You’re essentially hearing polluted mains and how it impacts your Naim boxes (ok - I simplified a bit, but it really boils down to that)

Only hear it when I’m close to the speakers.  From the responses I guess it’s normal.   

Zackwater posted:

Only hear it when I’m close to the speakers.  From the responses I guess it’s normal.   

Do you also hear it when the system is muted?

Zackwater posted:

Only hear it when I’m close to the speakers.  From the responses I guess it’s normal.   

Yes. Nothing to worry about. 

Adam Zielinski posted:

Zackwater posted:

Only hear it when I’m close to the speakers.  From the responses I guess it’s normal.   

Do you also hear it when the system is muted?

yes, same noise.

It's not from the quiescent current of the driver transistors or output stage, it's not from the mains...

It's from the long tailed pair at the input to the power-amp, or the buffer amp following the volume control of the pre-amp.

Huge posted:

It's not from the quiescent current of the driver transistors or output stage, it's not from the mains...

It's from the long tailed pair at the input to the power-amp, or the buffer amp following the volume control of the pre-amp.

so, in layman's terms--don't worry about it.   The system has it's own dedicated circuit, fancy $1000 power cords, and a $4000 surge protector and it still hisses.  My 1977 Marantz receiver, thoren turntable, and Klipsch speakers is absolutely quiet, my Naim is not---drives me crazy.  

Indeed, provided you can't hear it from the listening position, don't worry about it, it's normal for some designs (such as Naim).

If Naim were to design out the low level of noise, doing so would have a detrimental effect on sound quality (but quite how much detriment is difficult to say - the difference may actually be quite small but Naim's philosophy is to always maximise sound quality).

ALL amplifiers hiss. Of course some may hiss more than others, but ultimately a crucial factor in tha audibility of hiss from the listening position is the efficiency of the speakers, and the distance between listener and speakers.

It is from the first high-gain stage. In my system it was the 552 Pre - it is normal and nothing to be concerned about. I know it was the 552, as when I went to the S1 Pre that low-level noise reduced in level, as the S1 is a bit quieter, as perhaps you may expect for the price difference.

It never bothered me over many years use with the 552.

DB.

My (low) 5 figure Naim system is completely silent.  Either that or I've lost some hearing in the higher frequencies.

Just press mute.

docmark posted:

My (low) 5 figure Naim system is completely silent.  Either that or I've lost some hearing in the higher frequencies.

Try putting your ear right up to the tweeter.

I have to turn the volume up to maximum and put my ear close to the tweeter before I can hear any "hissing".

Should I be worried or is it just a sign of the aging process?

Dave

Now its my time for a show off: my 3 figure Naim system also gives a hiss.

Of course if you’re in some places (less an issue in U.K.) you should also check there’s not a snake crawled into the bass port of your speakers if the hiss changes or appears more from one speaker than the other!

:-)

Zackwater posted:

Adam Zielinski posted:

Zackwater posted:

Only hear it when I’m close to the speakers.  From the responses I guess it’s normal.   

Do you also hear it when the system is muted?

yes, same noise.

Actually - if your system is properly earthed, there should be no hiss whne the system is muted.

Hiss-on-mute may be indicative of inproperly earthed / grounded mains.

... or a loudspeakercable very close to a mains cable.

Level of his is dependent on the gain of the input. In my system much more his on a moving coil phono input than on a line level input.

Willy.

Adam Zielinski posted:

Zackwater posted:

Adam Zielinski posted:

Zackwater posted:

Only hear it when I’m close to the speakers.  From the responses I guess it’s normal.   

Do you also hear it when the system is muted?

yes, same noise.

Actually - if your system is properly earthed, there should be no hiss whne the system is muted.

Hiss-on-mute may be indicative of inproperly earthed / grounded mains.

Hmmm, actually hiss is generated in the power amp itself as thermionic noise, though should be at a very low level and in a good amp and normal efficiency speakers only just audible right by the tweeter or midrange drivers. That is different from hum, which is related to mains which indeed is lilkely to be indicative of earthing issues, a fault, or poor shielding.

Muting in the preamp, or reducing volume control to zero, will reveal the power amp hiss. Unmuted with volume control on max will reveal hiss from preamp (and anything connected)

Ardbeg10y posted:

... or a loudspeakercable very close to a mains cable.

Any induction from mains cables into the system would produce hum (or buzz), not hiss - and mains cables alongside interconnects are far more likely to be a problem than alongside speaker cables.