The hiss is inaudible when playing music. Surely this is what matters…
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Bit confused here. Isn’t the whole idea with Naim and expensive separate boxes to create a more black background? And then you end up with background hiss noticeable from your listening position?
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I see it as the canvas on which the music gets painted.
It’s a special feature as you up the range.
I got so used to the hiss that when the big Naim system wento into storage and I turned on my newly set up non Naim rig, I had a slight “on no!” moment when the speakers were just as silent with the amp on as off. I thought perhaps the amp was broken. Nope. It just isn’t Naim 
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The sensitivity rating probably isn’t telling you much unless you have a single driver speaker. 88db is generally 1Khz at 2.83v. So in a multi driver loudspeaker, that is really just a measurement of the bass/midrange driver and not the main hiss culprit tweeter which might have a different sensitivity.
While a bit of hiss certainly doesn’t affect the noise floor much above a certain listening level, it certainly intrudes if you do late night lower level listening. I suspect it comes from the overly sensitive inputs on classic range units. The Unitis and the 272 have much more realistic input sensitivity.
I have never understood that “black background” term and its relationship to the hiss. My cheap Rotel amps, for example, were nearly dead silent, with just the faintest hiss with the ear nearly pressed to the tweeter. Many other amps are built like that. Naim amps aren’t, but they still sound better to me. And they play the music with such agility and power in the notes that the space between the notes does in fact feel “black” to me. Maybe that’s what’s meant all along and was never meant related to the hiss (which I don’t notice when playing music)
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Yes, but if you read the pitch about 252 it to me sounds like it should be best in class no noise. Is this hiss not part of a bad circuit design then? A totally silent background would be better? To me separate boxes and great design should lead to lower noise floor but seems like that’s not the case. Could it be a noisy source or does it hiss even without a source connected?
Like many of our products, the NAC 252 stems from good stock: it descends directly from the NAC 52, still one of the finest preamplifiers ever made. Capable of exceptional clarity, its power supply components reside in a separate enclosure: the SuperCap power supply unit. This ensures optimum isolation from electromagnetic interference and provides each of the ten audio circuits with an independent, fully regulated supply voltage. Additionally, separate power supplies for the digital control and switching circuitry further isolate the audio circuitry from noise. It’s this attention to detail that makes the NAC 252 so special – that, and our determination to let nothing stand in the way of your musical enjoyment.
I believe (with no basis whatsoever, just a guess) that it is a consequence of Naim’s circuitry design. I suppose this design is what sounds best to them and if it comes with hiss, so be it. What we know for sure is that Naim would not go with a less “musical” (you know what I mean) design just because it has less hiss.
In the 252 description it says it sounds great, not that it does not hiss 
I can totally see other brands, e.g. German or Japanese, to find hiss unacceptable and taking measures to prevent it by design decisions
Sure but it’s easy to understand that people buying into the pitch above react if their expensive box create hiss from the listening position because what I read from it is that they spend a lot of effort in creating silent boxes.
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IIRC it’s just down to the very high gain in part of the pre-amp circuit. According to the golden ears at Naim, it sounds better that way.
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Thanks, yes, that’s what I meant, approximately - “sounds better”. (Though I could do without the very high gain as discussed in the past, there is enough unusable range on the volume pot above 9:30 )
I don’t know. I listened to them at the dealer’s and the hiss was there. My dealer even pointed out that it exists and and cautioned that I’d need to accept it, i.e., this may not be for everyone. But Naim always made the best music for my tastes, so that’s why I chose it.
Is the hiss just with the 252? I don’t have it with a SN2.
My progression was first a Rotel pre and later a NAD pre with a Rotel power amp. Nearly no hiss. Replaced the power amp with a 300 DR, hiss slightly increased. Replaced the NAD pre with a 252, marked increase of hiss. Which probably fits what Richard said - high gain
When I did my big amp shoot out years ago (1988?) between Exposure, Linn, Naim and I think Mission the Naim just did it for me. I don’t remember thinking yay, if only it didn’t hiss between tracks! My SBLs hiss if I put my ear up to them but it has no bearing on my love for my system. Either people are hypersensitive to this or they are overstating the issue. Ultimately there are other brands to choose from.
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Agreed, but it will depend on speaker sensitivity whether one finds it annoying. In my case, with 89dB sensitivity, I can barely hear it from listening position 2.7 meters from speakers - only when I actively listen for it. If the speakers were more sensitive and I could, say, always hear it from the kitchen table that is 5 meters away, when the system is idle, I can see it being annoying
I can understand that but I have never heard any system with that level of hiss, Naim or other. It seems a strange phenomenon to me Suedkiez.
If my speakers were, say, 92 db sensitivity instead of 89, I would probably hear it from 5 meters away in a silent room. And once you can hear it, it becomes a question of how sensitive you are to finding it annoying
I would have thought that people with 92db speakers would be using valve amps rather than Naim? Anyway I doubt this is an issue for most Naimees.
I don’t know the reasons for why some people complain or why they would buy a Naim if the hiss is clearly audible in a demo and they don’t find it acceptable. I just offered a guess based on speaker sensitivity. Like I said, it is no problem to me and I chose the Naim for the sound it makes although I was very aware of the hiss.