Mismatch Nait 5Xs and Nd5xs.

Posted by: fred40 on 05 March 2013

This worries me al lot. Someone is complaining about the harsh sound playing with a Nait X and ND5xs network player. and Harbeth speakers. According to Mr Shaw the owner and designer of these speakers this is due to the fact and I Quote"

 

The ND5XS network player: Minimum Load Impedance: 10kΩ Analogue Outputs: DIN and RCA, 2.1V rms at 1kHz at full level (Fixed) Output Impedance: 32Ω maximum
The NaitXS Amp: Input Sensitivity: 130mV Input Impedance: 47kΩ

 

This is not good. What we see is that your CD player is outputting 2100mV as its peak white loudness and ramming that into an amplifier which, according to your spec., would develop peak output from a signal of only 130mV. That means the output from the CD player when replaying musical peaks is sixteen times greater than the signal required to fully drive the amplifier flat-out across the speaker load. This is not uncommon.
The result will be chronic overload distortion through amplifier clipping which could destroy tweeters.  I was working around to covering this very point in the dynamic range thread, and to answer your anticipated questions a) why do manufacturers make such a crazy mismatch between CD player output and amplifier input sensitivity and b) what does chronic clipping actually sound like so that I can identify it.

 

Any comments welcomed. This troubles me actually.Since I, when my ND 5xs comes in ( still waiting) will have the same combination.

 

Moderated Post:  Fred, please ensure your posts comply with forum rules re. cross-forum discussion (which is not allowed). Thanks

Posted on: 05 March 2013 by Richard Dane

Fred, by that argument, all CD players and other digital sources are equally or even more unsuitable. 

 

Naim stick to Redbook standard on their output at 2V +/- 5%.  Not many other makers do this, as this output is often exceeded by a considerable margin - up to 3V or more - it can give the impression of a louder unit, and hence in the ears and mind of the uninitiated, a better sounding unit. 

 

As for overload of the Nait XS, it would take a heck of a lot to do this.  Naim's overload margin allows up to 7V output before overload is reached.  With a unit outputting 2.1V the Nait XS is well within it's comfort zone.  It would be pretty daft of Naim if this were not so...

 

For all that, yes Redbook standard of 2V was always argued by Naim to be too high in relation to line level of other sources at around 700mV.  However, Naim amps are more than capable of taking it and much, much more.

Posted on: 05 March 2013 by Adam Meredith
Originally Posted by fred40:

This worries me al lot. ......

 

This is not good. What we see is that your CD player is outputting 2100mV as its peak white loudness and ramming that into an amplifier which, according to your spec., would develop peak output from a signal of only 130mV. That means the output from the CD player when replaying musical peaks is sixteen times greater than the signal required to fully drive the amplifier flat-out across the speaker load. .......

 

Any comments welcomed. This troubles me actually.

If this is a problem - might a "Volume Control" be a (bleeding obvious) answer?

Posted on: 05 March 2013 by fred40
Originally Posted by Adam Meredith:
Originally Posted by fred40:

This worries me al lot. ......

 

This is not good. What we see is that your CD player is outputting 2100mV as its peak white loudness and ramming that into an amplifier which, according to your spec., would develop peak output from a signal of only 130mV. That means the output from the CD player when replaying musical peaks is sixteen times greater than the signal required to fully drive the amplifier flat-out across the speaker load. .......

 

Any comments welcomed. This troubles me actually.

If this is a problem - might a "Volume Control" be a (bleeding obvious) answer?


Not if you are playing with moderate volumes. And seemingly this is what happens.The original poster in that forum ( Not me Btw since I still waiting for the ND5xs to come in ( Sigh) But if this is a serious question with Harbeth speakers ( beats me why this could only concern Harbeth speakers) I'm beginning to sweat a lot. Although Mr Dane put me at ease a bit.

Posted on: 05 March 2013 by Felix H

Fred, the claim is that some preamps/integrateds have problems handling the over 2V output of digital sources. In such a situation it would be the preamp that is distorting, and that would have nothing to do with Harbeth speakers. The remedy would then be to lower that over 2V feed to something less (e.g. with a passive attenuator). But it's good to hear that the Nait XS doesn't have this problem.

Posted on: 05 March 2013 by Adam Meredith
Originally Posted by fred40:
Originally Posted by Adam Meredith:
If this is a problem - might a "Volume Control" be a (bleeding obvious) answer?


Not if you are playing with moderate volumes.

 

It may just be a failing on my part but: -

 

Consider the "amplifier" as two sections and DIFFERENTIATE between them - control/pre amplifier and power amplifier.

 

Richard has explained that Naim pre-amplifiers won't overload until fed a greater-than-7v signal.

 

The power amplifier section would overload if fed an unsuitably high signal - which is why the pre-amplifier section is designed to attenuate the signal to levels suitable for the power amplifier to work within its designed limits.

 

The attenuation of signal is controlled - by the Volume Control.

 

Where is the input overload?

Posted on: 05 March 2013 by fred40

Nothing  to worry about In my case. The combi Nait/Harbeth is wonderfull in my ears and opinion. Surely the harsh sound the poster in the Harbeth forum is talking about must have some other cause.

Posted on: 06 March 2013 by engjoo
I am trying to understand.
 
By definition based on an input sensitivity of 130mV on the Naim Nait XS, it means the pre amp stage of the amplifier will give a maximum output when the input is at 130mV.
 
What happens if the input is at 200mV ? Will it clip the output ?
Posted on: 06 March 2013 by Richard Dane

Engjoo,

 

the pre-amp stage will take an input of 7V before overload.

Posted on: 06 March 2013 by Adam Meredith
Originally Posted by engjoo:
I am trying to understand.

It might help explain your lack of understanding if you explain how you think a pre-amplifier volume control works.

Posted on: 06 March 2013 by engjoo
Yes. Perhaps I do not understand the definition of sensitivity.
 
When does 130mV means here for the Naim Nait XS ?
 
 
 
Originally Posted by Adam Meredith:
Originally Posted by engjoo:
I am trying to understand.

It might help explain your lack of understanding if you explain how you think a pre-amplifier volume control works.

Posted on: 06 March 2013 by Adam Meredith

Forget that.

 

A volume control works by reducing (throwing away) signal.

 

At Full Volume (zero attenuation) it passes ALL the signal and, yes, a 2V signal would probably cause the power amplifier section to overload/clip.

 

I perhaps haven't emphasised this enough - this is why we have a volume control before the (fixed gain) power amplifier section.

 

Posted on: 07 March 2013 by MangoMonkey

I run the ND5XS/NaitXS with the harbeth P3ESR and they sound great - or not - depending on the room.

 

The op on the harbeth thread (that was me) was complaining about room acoustics and placement issues of the harbeth speakers, and Alan started off on a rant about source/amp mismatch issues. I had started a thread on the very same topic on this forum for some clarification, but your post got the responses I was looking for.

 

With the harbeths placed in a much bigger room, with lots of room around it, I can get the volume as high as I want it without any clipping. The issue in the small room wasn't clipping: it was just that the room is way too small and there is a source/amp/speaker/room mistmatch: not a source/amp mismatch which is what Alan was trying to suggest...

Posted on: 07 March 2013 by MangoMonkey
Originally Posted by Richard Dane:

Fred, by that argument, all CD players and other digital sources are equally or even more unsuitable. 

 

Yes, and Alan was complaining about the industry in general and pretty much how everything except Habeth speakers are broken. ;-) Well, not really, but you get the gist...