Noise

Eloise posted:

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!

:-)

Or, if there is no bass port, a snake on the sofa next to you (one each side if the sound is balanced)...

Innocent Bystander posted:

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)

You'll only get thermionic noise with a thermionic (i.e. valve) amplifier.

With solid state amps the noise sources are shot noise (statistical noise) and Johnson noise (thermal noise).

Muting the pre-amp and turning the volume control to zero remove the effect of any noise sources from the volume control and all previous elements in the chain (i.e most of the pre-amp and source components).  What remains are:
The buffer amp of the pre-amp (the line driver which follows the volume control and is usually unity gain)
The input long tailed pair of the power-amp (balanced current amplifier)
The gain stage of the power-amp
The output structures of the power-amp

The first two of these are by far the most likely sources of any hiss.

But yes exactly right that the hiss should only be audible very near to the speakers and about grounding (and other mains related) issues causing mains hum not hiss.

Eloise posted:

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!

:-)

I would also expect that the sound would be much more etiolated if that happened.

Beachcomber posted:

Eloise posted:

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!

:-)

I would also expect that the sound would be much more etiolated if that happened.

That's stretching it a bit!  

Guys - how is the above helping the OP???

His rig hisses - wheather on mute or not. To me that is a sign of a mains earthing (lack of a 3rd yellow-green wire).

It will hiss - muting will reduce the hiss as the amplifier is not amplifying any noise from the source but won't eliminate it completely - how much you notice it depends on the sensitivity of the speakers and how good your hearing is / distance from the speaker.

If it was clicks and pops, buzzes or hum then I'd suspect issues elsewhere but from the OP's comments, this isn't the case and is nothing to get concerned about.

james n posted:

It will hiss - muting will reduce the hiss as the amplifier is not amplifying any noise from the source but won't eliminate it completely - how much you notice it depends on the sensitivity of the speakers and how good your hearing is / distance from the speakers.

I disagree with you James. Now that I have dedicated mains circuits, no noise comes from speakers on mute (on either of my 4 Naim systems at home). When I unmute, a gentle 'hissssss' comes from the tweeters - tells me that the system is alive and ready for some action

Feel free Adam - it's still not a mains issue

Adam Zielinski posted:

Guys - how is the above helping the OP???

His rig hisses - wheather on mute or not. To me that is a sign of a mains earthing (lack of a 3rd yellow-green wire).

Hiss has nothing at all to do with mains grounding.

Huge posted:

Adam Zielinski posted:

Guys - how is the above helping the OP???

His rig hisses - wheather on mute or not. To me that is a sign of a mains earthing (lack of a 3rd yellow-green wire).

Hiss has nothing at all to do with mains grounding.

My experience is completely different. Hence my response - not a guess, but based on hand-on-experience.

Adam Zielinski posted:

Huge posted:

Adam Zielinski posted:

Guys - how is the above helping the OP???

His rig hisses - wheather on mute or not. To me that is a sign of a mains earthing (lack of a 3rd yellow-green wire).

Hiss has nothing at all to do with mains grounding.

My experience is completely different. Hence my response - not a guess, but based on hand-on-experience.

If that's the case then there's another major problem with that amplifier!  (This is based on experience of understanding, designing and building amplifiers!)

Huge I think we know. The reason why I mentioned a mains issue (after Adam though) is that it is at least not clear to me if the OP understands all the different variations on hiss, buzz, hum etc. I agree to all the things you and IB mentioned.

In my case, I always have the hiss (normal on all Naim systems) but also a very soft buzz which is either caused by my inbuild microwave in the kitchen or the inbuild transformator for some light bulbs. Sadly, I cant get rid of them without breaking things. I should start a poll on this forum whether it is expected to be the microwave or the bulbs ...

Hi Ardbeg,

I don't think the OP is confused about hiss vs hum, but maybe a little confused as to the distinction between noise and distortion.

Is your hum through the speakers or from the transformers of the PSUs in the components themselves?

In terms of the 'transformers' (actually they're probably SMPSs) for low voltage lighting, then these won't have any effect when the lights are off (no current = no power = no EMI), also the main house lighting will be on a completely different circuit to the mains power distribution making that a less likely source of interference.

For the microwave, there should be an isolation switch somewhere in the kitchen, try turning it off using that and see if the hum goes (if not it's something else - of course it could always be coming in on the mains supply from outside your house).

Huge posted:

Hi Ardbeg,

I don't think the OP is confused about hiss vs hum, but maybe a little confused as to the distinction between noise and distortion.

Is your hum through the speakers or from the transformers of the PSUs in the components themselves?

In terms of the 'transformers' (actually they're probably SMPSs) for low voltage lighting, then these won't have any effect when the lights are off (no current = no power = no EMI), also the main house lighting will be on a completely different circuit to the mains power distribution making that a less likely source of interference.

For the microwave, there should be an isolation switch somewhere in the kitchen, try turning it off using that and see if the hum goes (if not it's something else - of course it could always be coming in on the mains supply from outside your house).

Huge, I have a very distant soft hum in the loudspeakers of my home office. I think this is some mains wire being close to a cable, or a smps. It is unforuntatly a bit cluttered again in my hifi stack. Need to clean up things: all office hifi, printer, raspberry pi, my synthesizer, switch and pc are on the same power bar. I think the issue will go.

My SN1 transformer loves to hum pretty loud. I took it to my parents house and there the hum was pretty civilized. It was there, but much less than in my house. I've noticed that when I print a document the hum gets more intense - the Samsung printer seems to send a lot of noise on the mains. My microwave (from 1993) is giving the same hum as my SN1 and it is one of the few devices I can't disconnect. It is in-build in the kitchen. You are probably right about the lights. There is a dimming switch and there is indeed no audible hum or so.

By the way, I have an old house. My electricity is really a chaos. Livingroom, Kitchen, Home office and bathroom are all on the same ring. It is quite bizar but takes significant money to change. I'm actually impressed by how good the Hifi still performs. However I have earth wires, I don't think the earthing is operating properly. Several metal devices like my macbook or telly give 'resistance' when I stroke them.

I had a Naim 5i integrated and now a Supernait 2. With both amps, If the volume is all the way down, in a completely quiet room, with my ears 2-3 inches from my speakers, I hear a very low hiss. This hiss never interfered with the performance of the system. I asked my dealer if this was normal for Naim amps years ago. He said yes, but I don't remember the reason he explained to me. I never worried about it. 

There was no mute button on the 5i. Out of curiosity, when I get back home, I will use the mute button on my Supernait 2 to see if there is still a hiss. 

I hear a little voice from my system whispering "how much did you pay, how much? I hope it's worth it? Sssssssssss" or is it just in my head?  I just ignore it and enjoy the music. 

SimonPeterArnold posted:

I hear a little voice from my system whispering "how much did you pay, how much? I hope it's worth it? Sssssssssss" or is it just in my head?  I just ignore it and enjoy the music. 

Mine hisses

"Your mates system sounds better than yours and he didn't pay nearly as much"

I'm sure that's real ....not in my head

Since I replaced a NAP200Dr with a brand new NAP250Dr, I also have a hiss in the loudspeakers. It is not a constant, monotone hiss, but it changes constantly and comes close to "scratch" sound. It is at very low volume level and seems to come from the tweeters. Strange thing is: it is not there every day and only happens when I select streaming or Tidal as source (my TV Digital decoder is also connected through the NDX, but when I select this source there is never a hiss) 

This noise issue sorta reminds me of the man who visited a veterinarian with the problem of every time he pets his dog while the dog is eating, the dog snaps at him.  He has tried everything.   The vets replied, “when the dog is eating, don’t pet him”.   So, if I near hissing when I stand close to the speakers, don’t stand next to the speakers.  

Zackwater posted:

This noise issue sorta reminds me of the man who visited a veterinarian with the problem of every time he pets his dog while the dog is eating, the dog snaps at him.  He has tried everything.   The vets replied, “when the dog is eating, don’t pet him”.   So, if I near hissing when I stand close to the speakers, don’t stand next to the speakers.  

Indeed, and if the hiss - or indeed other noise - is quiet as it should be, and either inaudible at the listening position or so quiet that you don’t really notice it unless you focus on it, and completely inaudible below the lowest level of the music, then all is normal and nothing to worry about - different if it is loud enough to be intrusive in some way, which with decent equipment would suggest something wrong (other than, perhaps, if using highly efficient speakers like horns).

J.N. posted:

Quiescent amplification circuit noise. Normal.

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

John.

This has no effect on the hissing what so ever. At least on my system. 

Huge posted:

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).

And if you can? I can easily hear mine from the listening position. Still normal ... apparently. 

Got Hi-Fi? posted:

Huge posted:

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).

And if you can? I can easily hear mine from the listening position. Still normal ... apparently. 

 

Is that with the pre-amp muted (or the volume control set to zero)?
Is it the same on both channels?

If the answer to the first is 'Yes' or the answer to the second is 'No', then you need to measure the RMS voltage of the noise.

Huge posted:

Got Hi-Fi? posted:

Huge posted:

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).

And if you can? I can easily hear mine from the listening position. Still normal ... apparently. 

 

Then you need to measure the RMS voltage of the noise.

Is that with the pre-amp muted (or the volume control set to zero)?
Is it the same on both channels?

Yep, same on both channels, volume and mute have no effect at all, its the same when muted/vol at zero as it is when not muted/vol at half. With the 202 off and the 200DR still on, there is no hiss at all. I have been told that it is from the pre-amp. I also tried another pre-amp, and there was no difference. 

What are the speakers, something uncommonly sensitive?