Noise

Orca901 posted:

My Unitilite / Monitor Audio set up hisses, as did its predecessor NAC102 / NAP180 / Monitor Audio / Linn set up.  I always thought this was a Naim "feature" due to the high gain amplifier design.  Personally it doesn't bother me a jot and is only audible at very close range in a silent room.  

High Gain .. that was the exact reason I have been given, a few times for the hiss. Although, Naim isn't the only brand with hissing issues. 

IIRC, Naim power amps all have a gain of 29dB apart from the 500 which is 30d? These are fairly typical power amp gains in my experience, at least in modern amps - indeed my Brystons are also 29dB on their unbalanced inputs. If The hiss is still quite loud with the preamp disconnected, which is worth trying if still present with the volume control turned to zero or preamp output muted, than I don’t think the gain is the reason per se, rather In this scenario the gain of the power amp is only amplifying what its earlier stages are producing or what is reaching them from mains interferences, so they must be noisier or have poorer mains noise rejection than those of other amps of similar gain that don’t have as noticeable a hiss with similar sensitivity speakers.

if on the other hand the hiss is negligible with the preamp disconnected, then it is nothing to do with the power amp, but produced somewhere earlier, and any power amp of similar gain would reveal the same, which will include many common amps.

Innocent Bystander posted:

IIRC, Naim power amps all have a gain of 29dB apart from the 500 which is 30d? These are fairly typical power amp gains in my experience, at least in modern amps - indeed my Brystons are also 29dB on their unbalanced inputs. If The hiss is still quite loud with the preamp disconnected, which is worth trying if still present with the volume control turned to zero or preamp output muted, than I don’t think the gain is the reason per se, rather In this scenario the gain of the power amp is only amplifying what its earlier stages are producing or what is reaching them from mains interferences, so they must be noisier or have poorer mains noise rejection than those of other amps of similar gain that don’t have as noticeable a hiss with similar sensitivity speakers.

if on the other hand the hiss is negligible with the preamp disconnected, then it is nothing to do with the power amp, but produced somewhere earlier, and any power amp of similar gain would reveal the same, which will include many common amps.

I was told it was the pre-amp gain causing it. In my case, with the pre-amp off/disconnected and the power amp turned on, there is no hiss at all. Once the pre is turned back on, the hiss returns. Volume and mute have no effect, however, the during 30 second start up delay on the pre there is nothing but silence. 

Got Hi-Fi? posted:

I was told it was the pre-amp gain causing it. In my case, with the pre-amp off/disconnected and the power amp turned on, there is no hiss at all. Once the pre is turned back on, the hiss returns. Volume and mute have no effect, however, the during 30 second start up delay on the pre there is nothing but silence. 

Hmm. So if tbe hiss is not there with preamp disconnected, and there when it is but with volume reduced to zero, then it is not the overall gain of the preamp, but the output stage post-VC, or the cable picking up intererference. Have you tried a different cable? If not the cable then it must indeed br the preamp, either generating the hiss somewhere in that output section (which in some amps is a unity gain buffer, though I don’t know about Naim preamps), or, conceivably though it is not an area in respect I have much knowledge, that stage is susceptible to something getting through from the mains via the power supply (thinking here the effect someone else described upon ceasing using ethernet over mains). 

Innocent Bystander posted:
Got Hi-Fi? posted:

I was told it was the pre-amp gain causing it. In my case, with the pre-amp off/disconnected and the power amp turned on, there is no hiss at all. Once the pre is turned back on, the hiss returns. Volume and mute have no effect, however, the during 30 second start up delay on the pre there is nothing but silence. 

Hmm. So if tbe hiss is not there with preamp disconnected, and there when it is but with volume reduced to zero, then it is not the overall gain of the preamp, but the output stage post-VC, or the cable picking up intererference. Have you tried a different cable? If not the cable then it must indeed br the preamp, either generating the hiss somewhere in that output section (which in some amps is a unity gain buffer, though I don’t know about Naim preamps), or, conceivably though it is not an area in respect I have much knowledge, that stage is susceptible to something getting through from the mains via the power supply (thinking here the effect someone else described upon ceasing using ethernet over mains). 

Yeah, I tried a whole other 202 with its cable, exact same results. I have also tried a mains conditioner, as well as relocating the connection to 2 other circuits, again, with no change. 

I live in an apartment building with an electrical grid designed and implemented by artists instead of certified electricians. I have a transformer hum in both my 272 and 250DR and a hiss in the tweeters on top of that! I know for a fact the mains I connect my kit is not earthed as I can feel a small current in my fingertips if I touch the faceplates of my naim boxes. (same feels with my macbook if I connect it through the same main).

It's annoying and I hate this. Connecting a wire between my earth main pin to the closest heat radiator, clears 50% of the hiss and hum and the SQ is uplifted. So I know it's an earthing related issue. Tidying up the snake nest behind the hifi rack, should help as well but I can't really hear any difference. to be honest.

But there's still hum noise from the transformers and hiss from the tweeters. And before you might suggest something crazy, let me be crystal clear: I will not exchange my Naim kit for any other signature sound. 

Dan.S posted:

I live in an apartment building with an electrical grid designed and implemented by artists instead of certified electricians. I have a transformer hum in both my 272 and 250DR and a hiss in the tweeters on top of that! I know for a fact the mains I connect my kit is not earthed as I can feel a small current in my fingertips if I touch the faceplates of my naim boxes. (same feels with my macbook if I connect it through the same main).

It's annoying and I hate this. Connecting a wire between my earth main pin to the closest heat radiator, clears 50% of the hiss and hum and the SQ is uplifted. So I know it's an earthing related issue. Tidying up the snake nest behind the hifi rack, should help as well but I can't really hear any difference. to be honest.

But there's still hum noise from the transformers and hiss from the tweeters. And before you might suggest something crazy, let me be crystal clear: I will not exchange my Naim kit for any other signature sound. 

I have never noticed any difference with tidying up cabling behind my rack, I have tried all kinds of things just to experiment, no difference in any of it.

By your last sentence, I must ask, have you ever been tempted to exchange your naim kit for another brand because of these issues? Because I have, but I haven't done it for fear of losing the sound I love so much. I am very annoyed that I can hear hissing from my listening position though, yet I just cannot bring myself to take that risk. 

I have tried Cyrus and Electrocompaniet, both very very good. Better even, in some respects. But the boogie factor was lost on both accounts. I do not listen to music so I can analyze it. I listen for the joy. For the excitement. For the drama.

I really wanted to like the Cyrus kit (DacXP, X300, Streamline - all Signatures), it still has a strange appeal to me, especially mounted in a dedicated wall-mounted Cyrus Hark 1 rack. It is cut throat revealing and lightning fast with a black background to die for.  But the information conveyed to me lacks what I've come to love about Naim: the infamous PRAT that took me years to finally understand and appreciate.

 

Got Hi-Fi? posted:
Innocent Bystander posted:
Got Hi-Fi? posted:

I was told it was the pre-amp gain causing it. In my case, with the pre-amp off/disconnected and the power amp turned on, there is no hiss at all. Once the pre is turned back on, the hiss returns. Volume and mute have no effect, however, the during 30 second start up delay on the pre there is nothing but silence. 

Hmm. So if tbe hiss is not there with preamp disconnected, and there when it is but with volume reduced to zero, then it is not the overall gain of the preamp, but the output stage post-VC, or the cable picking up intererference. Have you tried a different cable? If not the cable then it must indeed br the preamp, either generating the hiss somewhere in that output section (which in some amps is a unity gain buffer, though I don’t know about Naim preamps), or, conceivably though it is not an area in respect I have much knowledge, that stage is susceptible to something getting through from the mains via the power supply (thinking here the effect someone else described upon ceasing using ethernet over mains). 

Yeah, I tried a whole other 202 with its cable, exact same results. I have also tried a mains conditioner, as well as relocating the connection to 2 other circuits, again, with no change. 

so let me get this right 

250 on its own, no input connected, doesnt hiss.

250 with an input cable attached but not connected to preamp, doesn't hiss.

250 connected to 202 turned off, doesn't hiss.

turn on 202, and tge hiss appears, irrespective of mute mpbutton or volume control setting. And does exactly the same with a different 202.

Ok, some more questions:

1) have you heard either 202 in a different location (e.g. shop, someone else’s house), and was the hiss present if not your own speakers? (you’ll need to allow for relative sensitivity if there was some hiss but a different level, and liisten right by the speaker to eliminate any effect of the room.) if not, that could be a test worth trying, preferably exactly tbe same equipment just in a different place (and not the same building). 

2) does it make any difference whether or not there are sources connected to the 202 (if so, what?)

3) does it make any difference if you turn off everything else electrical in your house apart from the 202 and 250?

Innocent Bystander posted:
Got Hi-Fi? posted:
Innocent Bystander posted:
Got Hi-Fi? posted:

I was told it was the pre-amp gain causing it. In my case, with the pre-amp off/disconnected and the power amp turned on, there is no hiss at all. Once the pre is turned back on, the hiss returns. Volume and mute have no effect, however, the during 30 second start up delay on the pre there is nothing but silence. 

Hmm. So if tbe hiss is not there with preamp disconnected, and there when it is but with volume reduced to zero, then it is not the overall gain of the preamp, but the output stage post-VC, or the cable picking up intererference. Have you tried a different cable? If not the cable then it must indeed br the preamp, either generating the hiss somewhere in that output section (which in some amps is a unity gain buffer, though I don’t know about Naim preamps), or, conceivably though it is not an area in respect I have much knowledge, that stage is susceptible to something getting through from the mains via the power supply (thinking here the effect someone else described upon ceasing using ethernet over mains). 

Yeah, I tried a whole other 202 with its cable, exact same results. I have also tried a mains conditioner, as well as relocating the connection to 2 other circuits, again, with no change. 

so let me get this right 

250 on its own, no input connected, doesnt hiss.

250 with an input cable attached but not connected to preamp, doesn't hiss.

250 connected to 202 turned off, doesn't hiss.

turn on 202, and tge hiss appears, irrespective of mute mpbutton or volume control setting. And does exactly the same with a different 202.

Ok, some more questions:

1) have you heard either 202 in a different location (e.g. shop, someone else’s house), and was the hiss present if not your own speakers? (you’ll need to allow for relative sensitivity if there was some hiss but a different level, and liisten right by the speaker to eliminate any effect of the room.) if not, that could be a test worth trying, preferably exactly tbe same equipment just in a different place (and not the same building). 

2) does it make any difference whether or not there are sources connected to the 202 (if so, what?)

3) does it make any difference if you turn off everything else electrical in your house apart from the 202 and 250?

250 on its own, no input connected, doesnt hiss. Correct

250 with an input cable attached but not connected to preamp, doesn't hiss. Correct. 

250 connected to 202 turned off, doesn't hiss.Correct. 

turn on 202, and tge hiss appears, irrespective of mute mpbutton or volume control setting. And does exactly the same with a different 202. Correct. 

Ok, some more questions:

1) have you heard either 202 in a different location (e.g. shop, someone else’s house), and was the hiss present if not your own speakers? (you’ll need to allow for relative sensitivity if there was some hiss but a different level, and liisten right by the speaker to eliminate any effect of the room.) if not, that could be a test worth trying, preferably exactly tbe same equipment just in a different place (and not the same building). 

One thing I haven't tried is in a different building. I did try with 2 pairs of speakers though, ELAC BS244 (88 dB/2.83V/m) & B&W CM8S2 (88dB spl (2.83V, 1m) with pretty much identical results on both (not surprising given their specs). I also tried a different circuit, which pretty much killed all transformer hum at start up, but had no effect on the hiss. I am considering an extension cable as I may be able to remove my DC offset blocker if I can plug into that outlet instead (another issue altogether). 

2) does it make any difference whether or not there are sources connected to the 202 (if so, what?)

I tried will all sources disconnected at the pre-amp end. With sources, no change in hiss volume either way. 

3) does it make any difference if you turn off everything else electrical in your house apart from the 202 and 250?

Haven't tried this one ... yet. I will try this this weekend by shutting down power to other parts of the house from the main breaker box and will update. 

To me it seems increasingly convincing that it is some building related interference, possibly mains-borne, and if the big switch off yields nothing a check in a different building, though a hassle significant hassle, would prove it is if the hiss drops to negligible.

if it is building related , it will first be necessary to try to identify whether it is mains-borne or possibly direct radio frequency noise being picked up in the 292’s circuits. Naim might be able to advise on whether the latter is possible based on the amp design. However I do note your observation about earthing. Conceivably that could be significant. Do you have any source of earth potential in the building - e.g metal water pipes? If so, you could try wrapping a bare wire end around a bare metal pipe, and attach the other end to some metal part of the preamp chassis (maybe tape it to it with adhesive tape), and see if that has any effect. But can I suggest doing that with the amp powered down, and powering up only once the earth is connected, as any fault while you’re fiddling with the preamp on and touching an earth wire at the same time could be unpleasant. This of course is just a test, not permanent connection!

Yeah definitely hiss, and white noise from my midrange. I have no buzz/hums from my speakers what soever. I do have a fair bit of hum in my hicap transformer though.

Do you really think this is building related? Because I would be happier than a pig in sh*t if I could fix this problem lol. My dealer has told me that this is just the way the 202 is, he said they are the same at his place, which is why I haven't really tried much to rectify it.  But, now you have me wanting to experiment! 

Got Hi-Fi? posted:

Yeah definitely hiss, and white noise from my midrange. I have no buzz/hums from my speakers what soever. I do have a fair bit of hum in my hicap transformer though.

Do you really think this is building related? Because I would be happier than a pig in sh*t if I could fix this problem lol. My dealer has told me that this is just the way the 202 is, he said they are the same at his place, which is why I haven't really tried much to rectify it.  But, now you have me wanting to experiment! 

The thing that is puzzling me and making me wonder, while also picking up on someone else’s cured hiss after stopping wifi over mains which I had not expected to have caused hiss, is the fact that the hiss is there when 202 powered up but muted or with VC on min, and unchanged by the VC setting. If it was arising through the gain of the preamp I would at least expect a difference - yes, maybe some hiss from the output stage, but all of it, with nothing arising from earlier stages? And with two amps identical, while apparently so much worse than most people report (admittedly that being subjective).

Maybe I am wrong, but it just may be worth checking everything you can in case not. Maybe @Huge might be able to offer thoughts as to whether this is a possibility, as I think he has more detailed electronics knowledge than I.

For heavens sake, it's normal, deal with it, I have owned Naim amps for over thirty years, and what you describe is absolutely normal.

If you want electronics that don't hiss when connected to speakers, I personally have never heard electronics that don't have some hiss that's audible from the speakers, you might be looking  for something that doesn't exist!!!

badlands posted:

For heavens sake, it's normal, deal with it, I have owned Naim amps for over thirty years, and what you describe is absolutely normal.

If you want electronics that don't hiss when connected to speakers, I personally have never heard electronics that don't have some hiss that's audible from the speakers, you might be looking  for something that doesn't exist!!!

This is what I have been told of Naim kit, however, I have had many amps that do not hiss at all (unless maybe you plant your ear right into your tweeter), so plenty of them do exist. Unfortunately, none of them have even close to the sound quality of Naim. 

And from descriptions of the hiss and others’ comments it seems that the OP’s may be worse than many Naim owners experience, while he does not have abnormally sensitive speakers to accentuate it. Of course he could simply have more sensitive ears than others, or lower hiss-irritation threshold...

badlands posted:

For heavens sake, it's normal, deal with it, I have owned Naim amps for over thirty years, and what you describe is absolutely normal.

If you want electronics that don't hiss when connected to speakers, I personally have never heard electronics that don't have some hiss that's audible from the speakers, you might be looking  for something that doesn't exist!!!

I investigated my system yesterday, I have no hiss, I checked with my ear right next to the speaker, and I don’t recall having one when my pre was a 282 either. The tuner signal can be heard very very faintly on other inputs only with the volume on maximum.  There is noise from the superline which has a gain of 65dB. I used to hear voices from this (mostly in Russian) but they went away when I put the system on Fraim. Turn the volume up enough on the superline with nothing playing and there’s a roar with a mix of several radio stations superimposed but even here the volume is well past usable level before it’s audible. I have a 40A type B MCB feeding a dedicated radial of 10 square mm cable but it’s in the main consumer unit and shares an RCD with half the house. House earth is a connection to the neutral cable were it enters the house.

 

Two types of extraneous noises are common: hiss and hum. Hiss is high frequency in nature, hum being lower frequency, most commonly 60Hz.

First we should understand that some amount of noise is normal. A system that is totally silent is probably off! To determine whether we are in the realm of normalcy, I’ll ask the question “with volume set to a normal listening level, how close to the speaker must you be to hear the noise.” If the answer is a few feet (or less), the noise level is likely normal. If you can hear it from the listening position (or, especially if it intrudes upon the listening experience), we have a problem that warrants further investigation. Be advised that raising the volume to maximum is not the way to check for noise levels. Set the volume control to a normal listening position to understand whether the amount of noise generated will be noticeable while listening.

Where do these noises come from?

Possible Remedies -

        Ok, so now we have an understanding of the problem, how can we reduce or eliminate the noise? The first step is to determine the origin of the noise. It is a simple matter of checking the components one by one to find the trouble maker. Here's what to do.
        Turn off all the components, and then disconnect the inputs to the amplifier (or all the inputs from an integrated amplifier or receiver). That will leave us with just the speakers connected to the amplifier. Turn the amp on and listen for noise. If all is quiet, we can assume that the problem lay upstream. Onward.
        Now turn the amplifier off and connect the preamp (be sure all other components are disconnected from the preamp). Turn on the preamp, then the amplifier. If the noise returns, we can assume the preamp is at least part of the problem, if things are silent, then the problem is further upstream.
        The next step is to begin connecting your other sources, one at a time, listening for when the noise returns. Since system noise is the sum total of the noise generated by all the components in the chain, it may be that you’ll find the noise level increases slightly with each component you add to the mix. If this is the case, there is no simple way of reducing noise levels, short of changing equipment.
        If you find hum to be a problem, check for ground loops and experiment with cable layout and locations. Be sure to route interconnects to keep them away from AC cables. If they must overlap, cross them at right angles to minimize hum pickup.
        Grounds loops (constant 60Hz hum that does not vary with volume setting) are the result of two or more components being at different AC ground potentials. They can occur in any system and often pop up when a new component is added to the system. Many people feel there is "problem" with the new component, or that it is a mismatch. Neither is true and it is simply happenstance that the grounding scheme of the new piece of gear is different from those currently in play. Follow the step by step process outlined above. At some point your 60Hz hum will appear. Floating the ground on that component (and maybe others in addition) should cure the problem. A common source of ground loops are cable and satellite TV connections. There are specially designed in-line isolation transformers designed specifically for this problem.

Much more on this topic at:

https://www.gcaudio.com/tips-tricks/system-noise/

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