Audible hiss from speakers - Final Update

Hobonono posted:

 

Original Post

 

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This is what I can hear Hissssss.........

sound appears at 36 second when the pre powers on fully

The 202 hisses .. that is just the nature of the beast. It cannot be "fixed". I can hear mine from the listening spot. 

How does the 282 compare?

It's just too distracting where I sit as it's all you can hear in the quite room.

I had a ATC SCA2 on loan while this was being investigated and you'd not have known the speakers were on when this was connected.

Not sure now the 282 compares, but i would certainly hope it is quiet. I had a 152XS before the 202 and it was dead silent as well. Not really sure why the 202 is so noisy, but I have tried more than one of them with the same results. 

Got Hi-Fi? posted:

Not sure now the 282 compares, but i would certainly hope it is quiet. I had a 152XS before the 202 and it was dead silent as well. Not really sure why the 202 is so noisy, but I have tried more than one of them with the same results. 

Thanks for the reply.  Looks like the 282 may be my next step but will have to home demo first it seems.

Yeah that will be my plan as well. The noise from this thing has lead me to look at other brands as it did annoy me for quite some time (as does some of the other system quirks) but, I cannot find anything that sounds this good nearby so I have decided to suck it up lol. Guess I am hooked on the naim sound! I don't notice the hiss as much anymore as I guess I have gotten used to it, but I do know it is there. If you do try a 282 in the near future, let me know how it fairs! 

While I would recommend the change from 202 to 282, I'm not sure it will make a difference. Fortunately (or unfortunately),my 202 never hissed , but the change to 282 was a large improvement. I would try not just a 282 but a different 202 (from dealer?) and see if the problem persists. It may have more to do with your power supply or grounding. Maybe , to experiment relocate the system, or even try a heavy gauge extension cord and different outlet (temporarily).  Good luck

benjy posted:

While I would recommend the change from 202 to 282, I'm not sure it will make a difference. Fortunately (or unfortunately),my 202 never hissed , but the change to 282 was a large improvement. I would try not just a 282 but a different 202 (from dealer?) and see if the problem persists. It may have more to do with your power supply or grounding. Maybe , to experiment relocate the system, or even try a heavy gauge extension cord and different outlet (temporarily).  Good luck

I tried this, both were brand new units from the dealer. Both hiss rather loudly. I also tried other outlets and such. It is def. a characteristic of the pre, many others have also agreed. I guess you got lucky, or have really insensitive speakers. 

I have a 200/282 combo and I can confirm these hiss, even with the volume right down AND there's a hum from the 200 which is audible from my rack and the speakers. I hadn't noticed it until I sent them off for a service and upgrade and switched them on the first time. 

I left everything on 24x7 and this hiss reduced substantially and the hum has all but disappeared after around 3 weeks I'd say. I spoke with my dealer and the authorised service centre and was told "it's normal, leave your kit powered on, never turn it off and it'll quieten down but never go away".

The only other thing I did was to invest in a good Hydra cable which was properly shielded. I can't tell if it's doing anything but I certainly like what I'm hearing!

Jonners posted:

I have a 200/282 combo and I can confirm these hiss, even with the volume right down AND there's a hum from the 200 which is audible from my rack and the speakers. I hadn't noticed it until I sent them off for a service and upgrade and switched them on the first time. 

I left everything on 24x7 and this hiss reduced substantially and the hum has all but disappeared after around 3 weeks I'd say. I spoke with my dealer and the authorised service centre and was told "it's normal, leave your kit powered on, never turn it off and it'll quieten down but never go away".

The only other thing I did was to invest in a good Hydra cable which was properly shielded. I can't tell if it's doing anything but I certainly like what I'm hearing!

 

Yep! that is pretty much the jist of it. And I guess this answers the OPs question if the 282 hisses as well! 

I have a 202 and it's normally dead quiet.  A few times I had some hiss and just moved the plugs around and cycled off/on and it never came back.  

Strange, I have never thought to associate hiss from a speaker with preamps before. My speakers don’t hiss driven by 282/200DR, or if they do, it’s only audible with your ears very close to the speaker cones. 

I believe the hiss from the speakers is caused by the high gain of the Naim pre-amps (I think I read that somewhere). When I had one, I always found it intolerable when I wasn't playing music, i.e. in a quiet room. The solution that worked for me was to set the pre-amp to use the 'AV bypass mode', i.e. make the AV input have unity gain such that the volume control is disabled (check the manual for how to do that, it is some combination of buttons to press). Then when not using the system to listen to music I selected the AV input on the pre-amp and the hiss from the speakers would stop (because, as I understand it, the AV unity gain mode effectively cuts out the pre-amp circuit by connecting the AV input directly to the pre-amp output). I had nothing connected to the AV input on the pre-amp. When you want to listen to music again just select whichever input your source is connected to, the hiss will return... just press play quickly!

Do you or a direct neighbour runs his internet via PLC (Power-line Communication) near to your system?

This is definitely the route cause for the hiss in my system. If PLC is turned off, the hiss disappears.

The solution is to place your system and the necessary power lines far away from PLC.

ChrisSU posted:

Strange, I have never thought to associate hiss from a speaker with preamps before. My speakers don’t hiss driven by 282/200DR, or if they do, it’s only audible with your ears very close to the speaker cones. 

I think it's the pre as it does this when there are no sources connected 

NAC202 -> HiCap -> ATC 

SPE posted:

I believe the hiss from the speakers is caused by the high gain of the Naim pre-amps (I think I read that somewhere). When I had one, I always found it intolerable when I wasn't playing music, i.e. in a quiet room. The solution that worked for me was to set the pre-amp to use the 'AV bypass mode', i.e. make the AV input have unity gain such that the volume control is disabled (check the manual for how to do that, it is some combination of buttons to press). Then when not using the system to listen to music I selected the AV input on the pre-amp and the hiss from the speakers would stop (because, as I understand it, the AV unity gain mode effectively cuts out the pre-amp circuit by connecting the AV input directly to the pre-amp output). I had nothing connected to the AV input on the pre-amp. When you want to listen to music again just select whichever input your source is connected to, the hiss will return... just press play quickly!

Now this makes a lot of sense.

I had spoken to Russ Andrews to see if I could get an attenuated cable for between the 202 and HiCAp as this seemed the best place to put this.

The hi gain is noticeable as I can get 130dB from the speakers with the volume at around 11 o'clock with he right tracks and when the volume is down and the source is still playing you can still hear it.

But I'll have a look at setting this as it may be the solution I have been looking for.

Now if anyone has the instructions please do post them 

Polyphenol posted:

Do you or a direct neighbour runs his internet via PLC (Power-line Communication) near to your system?

This is definitely the route cause for the hiss in my system. If PLC is turned off, the hiss disappears.

The solution is to place your system and the necessary power lines far away from PLC.

No.  Detached house and dedicated mains and fuse.  The only things connected is the Naim kit and ATC's.

Hobonono posted:

ChrisSU posted:

Strange, I have never thought to associate hiss from a speaker with preamps before. My speakers don’t hiss driven by 282/200DR, or if they do, it’s only audible with your ears very close to the speaker cones. 

I think it's the pre as it does this when there are no sources connected 

NAC202 -> HiCap -> ATC 

Perhaps you are right, maybe there needs to be an external source of noise for the pre to pick up. When I get home next week I have a plan to remove my 282, so I’ll see if that removes what little hiss there is coming from my speakers. 

I did remove my 202 from the chain when troubleshooting originally. There was no hiss at all when connected only to the 200DR. The hiss is for sure generated by the high gain 202.

Perhaps.....I was thinking of connecting an alternative rather than nothing!

I should try that with my DAC V1

Could be worth a try, V1/200 is a nice combo, although I’m guessing you prefer the 202.

Hobonono posted:

But I'll have a look at setting this as it may be the solution I have been looking for.

Now if anyone has the instructions please do post them

Google is your friend :-)
https://www.naimaudio.com/downloads/manuals

This is the relevant part:

"AV Bypass enables an audio-visual processor to be integrated
such that its volume control takes over command of signals
connected to selected preamplifier inputs. On the NAC 552 AV
Bypass may be selected on DIN input sockets 4 and 5. On all
other preamplifiers it may be selected on only the av input.
To select AV Bypass, first switch the preamplifier into program
mode by pressing and holding the handset prog key (with the
handset in preamplifier mode). The front panel source mute
button (NAC 202 mute button, NAC 152 XS av button) will
illuminate if AV Bypass is selected. If it is not enabled it can be
switched on by pressing the same button twice.

...

AV Bypass only becomes operational on exit from program
mode by pressing and holding the handset prog key.

Note: The preamplifier will leave program mode automatically if
no control commands are received for five minutes.

Note: The AV Bypass feature must be used with care. It
effectively by-passes the preamplifier volume and balance
controls leaving any signal connected to an AV Bypass input to
be passed to the power amplifier and speakers at full volume.
In order to reduce the potential for inadvertent mishap, any
subsequent modifications to input assignment will automatically
disable previously set up AV Bypass inputs. Additionally, if an
input is selected which has AV Bypass enabled, the preamplifier
volume and balance handset functions will be disabled and
their indicators will turn off. This will be flagged by the volume
or balance indicators flashing if either handset function is
operated."

Note that the above is a one off operation, once it is set in AV bypass mode you just have to press the AV input button to activate it. As it says, the way to tell if it is working in AV bypass mode is to look at the green LED on the volume knob - in AV bypass mode the green LED will go off when you select the AV input to indicate that the volume control is disabled; it will illuminate again when you press any other input to indicate the volume control is enabled.

Please do take note of Naim's warning text in italics. Do not connect a source signal to the AV input when it is in AV bypass mode (unless that source has its own volume control). Otherwise you are likely to damage your speakers, or your power amp, or your ears. The source can be connected to any of the other inputs which will work normally. When you are playing music it will drown out the hiss on those inputs. Just select the AV input to effectively disconnect the preamp circuit from the power amp when you are not using the system to play music.

ChrisSU posted:

Could be worth a try, V1/200 is a nice combo, although I’m guessing you prefer the 202.

Yeah, i have listened to the V1 as a pre before, and it sounded horrible in comparison to the 202. Very flat, and no life. As a dac however, it is completely opposite. 

SPE many thanks for the response and the advice 

I put the 202 into AV bypass mode mode last night and when the input is muted the speakers go quite.

If I don't mute I get a low level earth hum from the speakers but as soon as they are muted all is well in the room and the speakers are silent.

But as usual doing this has brought up another issue as now I can hear the HiCaps humming  

Tough decisions ahead I think as I don't think I can live with the issues Naim is causing me which is a shame as I really do like the sound it gives but yesterday while listening I noted I was spending more time listening to the noises the rig was making rather than the noise the music was making (it's noticeable on some tracks where I uses to get silence between notes now I can hear the hiss............ and when a note fades it no longer fades into silence)

One last thing to do and that is get a 282 on demo and see if this in any better otherwise I thinks it's a choice between Linn and Atc Pre amps going forward. 

but again thanks all for all your help