Hello, this is my first post, so here goes. Having owned Naim kit for 20+ years I’ve now (as of today) reached my “final” setup😀. Upgraded today my 282/Hicap to a new 252/Supercap combo. Sounds terrific, except for a very audible rumble / bubbling noise from the speakers, there all the time when music playing or not. Apologies if this has already been covered in other threads and I am aware of transformer buzz’s and humming noises from other Naim kit in the past. My question is surely this cannot be right, or is it? The noise is there with and without my turntable and streamer attached or powered on, it does stop only if pre amp is muted, having had initial contact with Naim support this afternoon I’ve tried a different power block, reverting my interconnects back to Naim standard cables, the usual disconnecting and reconnecting. Anyway i’m not asking for contributors to solve this issue for me but just a view on what unwanted noises, from the speakers or elsewhere, is normal and par for the course. As agreed with my very helpful dealer the next step tomorrow would be to take them back,
Are you using power line networking (Ethernet over the mains) or a Sky Q box ?
No Sky, but I’ve had Devolo power line for 10 years no issues, but I did install a Matrix power block which really improved sound quality from my systems. Unless the 252/Supercap is more pron to these issues I cannot see that’s the problem, but might be although my 282 and Hi Cap worked wonderfully last night… Tim
I’d try powering off the Devolo kit for a start and see if that stops the noise. At least it may give a pointer to the source of the noise that’s giving you issues when the 252/SC2 is in the system.
Why not try the SC on the 282 using the HiCap SNAIC to narrow down the issue.
I don’t think its any kind of normal. I have zero noise through the speakers except the pop on and off. I’d guess at earthing arrangements somewhere in the system.
Something similar happened to a friend who receive his 252 new and connected to a SCDR. He sent the 252 back to Naim for a replacement. It was not normal.
Doesn’t sound normal. My 252/SCDR is very quiet. Did you audition one from the dealer and, if so, was that ok?
Another vote for trying SC on your 282 to try and isolate the problem.
What’s the issue with that one and how? Thanks
As for the OP, “very audible rumble / bubbling noise” can’t be right. Though I do have a slight hiss that is also there on every input but goes away on mute. I can’t hear it from 3 meters away and Richard said that’s normal.
Sky Q boxes support power line networking and can sometimes cause noise issues, particularly with phono stages, if the owner doesn’t realise it’s been enabled.
Thanks. The UK must have a different Sky Q than in Germany (though the German Sky users were up in arms when Sky UK forced their inferior Q box on German Sky users LOL)
The one I have has a regular ethernet plug, so would only have powerline networking if you plugged it into such an adapter - and has no setting to enable ethernet over power in any other way
They may have now disabled it. It’s come up on here a few times with the Q boxes (Virgin media user here…)
Edit - just looked on the Sky forum and firmware updates removed this option.
Surely the fact that the old equipment didn’t have this problem makes a pre-existing issue with the mains etc unlikely…
Who knows, but it’s an easy thing to try as part of troubleshooting the OPs issue.
The powerline adapters were built into the Sky Q boxes, and there have been cases where they were enabled without the subscribers knowledge. I believe Sky no longer use them, but I dare say there are still some out there.
Thank you for your comments and suggestions, I have briefly switched off the Devolo powerlines this evening and yes the noise stops, 
the question of why my 252/SC2 seems to be so much more sensitive to this than my 282/HiCap lord only knows. Does anyone else use a Matrix power block or similar to reduce the impact of these issues, short of getting an dedicated 20AMP spur from my fuse box, assuming that would work, are there any other suggestions that work. Unfortunately we have to use these Devolo devices as are internal walls are feet thick cotswold stone, it’s a hybrid mesh and power line system from Develo which does works very well, but obviously need my brilliant Naim kit to work as well. Thanks again for any suggestions… Tim
I’m not convinced that a Matrix power block will be helping much, but you can easily test this by using a different regular block.
I would consider a decent Mesh WiFi network if you can’t run Ethernet cables.
I would really try and find a way of getting rid of the power line networking items. They are nasty things from a noise perspective and as you’ve found, can affect the Hi-Fi too. It may have been affecting your previous 282/HC but at a lower level.
Getting rid of the noise source is the best approach and as Chris mentions, a full Mesh system would be better than your hybrid approach if you really can’t use wired Ethernet.
A dedicated circuit with it’s own consumer unit won’t solve the issue I’m afraid. I had the same problem and have a dedicated circuit. I ditched the power line adapters and used a BT wi-fi booster which has an ethernet port on the back which I use for my Core. I’m on BT Halo 1 Broadband which works well for me, we don’t have a full fibre option.