Nait 5si inconsistent sound and build

Hi - this is my first time on the Naim forum and would be great to get some input from some experienced heads.

I’ve recently bought my first Naim, a Nait 5si and experiencing some inconsistent performance with it. I’ve had it powered up for around 8 days and it’s had around 50 hours of music played through it so far. Within the first few hours the sound was very expansive and detailed with an airy performance but reasonably dynamic. With a farily large soundstage and high headspace it had excellent detail across the higher frequencies and although low frequencies are clear they’re not always present. Also, there is generally a large hole at the centre of the soundstage where things get a little muddled and sink into the background. All standard stuff I felt for a new bit of kit and running it in.

But then things started getting a little strange. I noticed that the sound was becoming very flat, with a lack detail across the board. The only stand out was around the edges of the performance, cymbals, high hats - but everything else just became very flat. Bass was lacking, detail on strings and voices sounded awful.

I thought it maybe the speakers, Dynaudio Emit M20’s - so I disconnected everything, repositioned the speakers and tried again. Still the same, flat, uninvolving sound.

I then swapped out the amp for my Rega Elex-R and the difference was huge. Detail, dynamics, a smaller soundstage breadth wise but foreground to background was marked - performances were now in the room. Id kind of expect this with certain types of music, dance, metal, rock etc but it was with everything. Even Classical and Jazz suddenly seemed much more expansive than the Naim. At this point I’ve felt confused, as tracks I played early on with the Naim sounded a bit strangulated and confined, and I’d already heard them be expansive and expressive, some vinyl performances were wonderful with the Naim and now they felt flat and dull.

So I’ve been going back and forth between amps and the Rega has been more involving pretty much all the time. And initially I felt the Naim was much more naturalistic - piano and strings sounded real whereas the Rega is so focussed on dynamics and timing that sometimes it feels a little clipped on the notes in comparison to the beautiful sustain the the Naim had (but now feels as flat as a pancake).

What is really freaking me out is that of all the people i’ve spoken with who know both Naim and Rega well they’ve all described the sounds pretty much the same for both amps… and yet i’m experiencing the opposite. The rega is much more powerful and dynamic, more expressive, and textured. The Naim had more detail initially and a smoother delivery, but it feels underpowered almost like it can’t drive the speakers effectively. I’ve been assured the 4ohm Dynaudios are a great match for the Naim but I’m not getting that at all. It’s literally all or nothing. on or around the 9pm mark on the volume dial it’s now become flat and weak. Little bass extension (but seems to come back occasionally). If the volume dial is above the 10pm mark it’s ,much louder but this is louder than i’d usually listen to - and the Rega easily matches it but still retains much more detail and expression. (I’ve also tried the Naim and Rega through 4ohm Dali Menuets and 8ohm Monitor Audio Bronze 2 where their different presentations were apparent but not what I’m experiencing now)

The Naim also has a light transformer buzz (something I expected) but it started phasing in and out every 20 seconds with a very loud buzz… it would do this every 20 seconds or so and disappear. No nasty electrical devices were running at the time. The next day this loud buzz (easily audible above my TV volume) returned for about 15-20 minutes solidly. And i’ve had the loud buzz return intermittently when everything in the house has been turned off. The standard transformer hum is ever present.

I also hear how the build quality is great with the Naim, but I can easily move the front panel with a finger and it seems to click in and out of place, easily shifting position, whereas the rega has the kind of weight and finish that you feel you could drive a tank over. All of this seems opposite to others experience and I’m a bit stumped. I keep hearing how big Naim watts are, but they seem fairly feeble against the Rega. When testing the 2 amps all cables etc have remained the same.

I’ve heard the Naim can be a little temperamental but it’s got to the point where I don’t experience the same track via the same source in a consistent way. A Stan Getz vinyl pressing sounded wonderful, rich and detailed when i first ran it through the amp. It now sounds flat, and dull. Once or twice it’s opened up some notes but seems to go back to be reluctant to balance the instruments out at all. The same goes for streaming, Sammy Davis Jr or Erik Satie sounded close to being in the hall… noiw they feel like they’re hiding behind the sofa… yet the Rega has Sammy sitting on my lap. I can’t even play New Order or AC/DC through the Naim - they sound truly dreadul. Confused, lacking in low end, way too overlapped and very withdrawn on the complexities of center stage. The Rega is still holding its own, with a big punch low end and tremendous timing.

Any advice would be greatly appreciated because I know a good Naim sound is closer to my natural preference than the Rega but I’m just not getting it. I know theres a good amp in there, but either it’s hiding through something temperamental that I’m unaware of, or it’s just plain faulty.

My room is around 12ft x 12ft square but has 2 alcoves either side of a fireplace that are around 1ft deep. The speakers are positioned at the edge of a bay window and the tweeter is 0.5m away from the wall with plenty more space into the bay behind it. The outside of the speakers are 0.75m away from the walls. Hifi runs off a different main to TV. I’ve tried to upload a bad diagram.

My sources are a Project 2 Xpereince with Ortofon Kontrapunkt ll a cartridge going through a Black Cube phone amp. I’ve recently acquired a Bluesound 2i and yet to put it through a DAC as I want to get the issues with sound sorted first. Im running Chord Clearway speaker cable to obtain a baseline performance and Chord / Van Den Hul interconnects (i can’t recall which models off the top of my head). There is nothing else plugged into either amp.

I’d appreciate any input at all because I’ve never experienced something so inconsistent before.

1 Like

Fifty hours is not a lot. Naim kit can go through a bumpy ride up and down before settling. Dont move it or switch it off.
The front panel is attached with torx screws, have a chat with your dealer about how to adjust/tighten it.

Given this, and the fact that it already sounded good before, my guess it that there is clearly something wrong with it.
(Temporary changes for the worse during burn-in notwithstanding - which can indeed occur, I experienced them too, in suddenly worse SQ that sounded even slightly broken. But a “very” loud buzz every 20 seconds? No)

1 Like

I have to agree with @Suedkiez the loud buzz doesn’t sound normal.

Has it got the right voltage rating ?

1 Like

I’d expect some inconsistency during the first few hours particularly if it’s new but not to that level. It could be a voltage issue, Naim amps can be more sensitive than some other brands. Do you have a friend who has a system, can you take it to their house and see if the issues continue? If they don’t then perhaps talk to an electrician about your mains. If the issues continue then there may be a fault. Did you buy the amp new or second hand? If new then definitely talk to your dealer. If second hand then talk to the seller first.
If you did buy it second hand and you don’t get any joy from the seller then it’s still worth talking to your local dealer although bare in mind they will probably charge you for any work as you didn’t buy it from them

Thanks for the replies… the Amp is new and I’ve sent video of the buzz to the dealer so waiting on advice.

It’s a standard 230v unit and I’ve run it through a standard mains cable. I’ve taken away purifiers etc to make sure there’s no compatibility issues. (I can tolerate the standard transformer hum while I get to the bottom of this issue).

The loud buzz is unsettling. I’m not aware that it’s made that same noise for the last 24hours but I’ve never heard that with any other amp.

One thing I did notice was that the standard transformer buzz gets louder when connecting speaker cables (but not every time). There is no Earth hum or audible hum from the speakers so it seems a component issue plus requiring some earthing / mains isolation in that instance.

In contrast the Rega is completely silent regardless of connection / mains.

I’ve not been able to take it to a friends due to lockdown.

I can try it on another circuit in the house But I’d only expect that to rectify or highlight the transformer hum

Mate I’d whip it back the the dealer. have them sort the facia panel issue and get the amp checked over. Too many issues at the same time for my liking. I’m sure the end result will be fantastic, best not to waste time. Just get it back for warranty checks, keep it simple.


A couple of points and checks to make (excuse if sucking eggs):

  • In normal circumstances a noticeably buzzing transformer in Naim gear means ‘polluted’ mains, perhaps caused by domestic kit (hence why dedicated hi-fi consumer unit feeds are best) but primarily from the general mains. The buzzing can go on for a few mins - but what you report isn’t ordinary and attributing the cause may be impossible. It could be a neighbour’s kit.

  • when switching between the amps, did you ensure the mains lead was pushed right in on the Naim and the speaker cables were wired correctly, noting Naim runs the Reds on the outside feeds.

Assuming you are using the lead supplied with the Nait I would also open the plug of the Naim Powerline-lite lead just to ensure all terminals are tight and wires suitably captured.

You are correct that these amps aren’t materially different, although on paper the Rega has more power.

It does seem a check-up by your vending dealer is the way to go.

Thanks for the tips guys - I really appreciate it.

I am using the standard Naim lead as supplied, and pared everything back so no exotic mains conditioners etc, so thats why i can accept the hum as I know this can be rectified once hooking it back up and eliminating sources of noise from other household appliances.

The loud buzzing has been the most distracting. Even though it’s intermittent it’s occurred when other household components are off and mainly (although not always) at night.

It has occurred to me that it could be the neighbours or irregular current. Going to the expenditure of getting a dedicated spur and consumer board fitted doesn’t warrant the expenditure for an 5si but totally worth it if I was in the league of a Supernait. It also seems a massive outlay to fix an issue with an ‘entry level’ amp when other amps have been functioning ok.

However, If it is an issue with equipment from the neighbours would a dedicated hifi spur even rectify this?

I’m still getting a relatively flat picture and poor imaging with most tracks although there was an improvement last night with a couple of tracks, but still not quite as it should be.

Does anyone know the current time of repair/diagnosis from Naim (I understand since Brexit that a lot of repairs are taking longer because of getting hold of components).

I’m going to hook it up to a pair of Revel Concerta2 M16s later and see if anything is revealed. Once I then get a baseline between speakers I’ll try a pair of 8ohm and then arrange the mains.

I’d recommend to talk to your dealer, let him find out repair times with Naim. I don’t know where you are located, but outside of UK it is often the distributor who performs standard work, so might be faster than Salisbury. (I had an XPS2 recapped at the end of November when apparently Naim had a months-long queue, and I had it back in not even two weeks).

And I still believe the buzz indicates an issue, plus the loose front plate is certainly not OK, so you should talk to the dealer in any case

I reckon you should try for a replacement if the dealer has it as a stock item on the grounds that the front panel moves - it really shouldn’t! Perhaps it’s been subjected to an impact in transit, it’s pretty heavy so would generate a fair bit of force. A Nait 5si is not a cheap component and it’s build puts most competitors to shame, I’m sure your dealer will sort it out to your satisfaction. I own one and it’s fantastic

1 Like

In reality it’s simple consumer law. It must be fit for purpose. Chat with your dealer. You should be in line with such a new product for a replacement or your money back.

If my experience is anything to go by you will always have doubts about this particular amplifier. This is meant to be an enjoyable process, don’t waste your time and energy.

New amp or money back and start again.

I don’t have great mains but didn’t run into any difficulty until I got to 250 levels. If you’re getting that level of hum with a Nait, well Naim isn’t for you in your current home.


I’ve run Naim for twenty five years plus, it is very well made , but occasionally like all products it may need going back or replacing .

It doesn’t sound normal.

Definitely get it replaced. I doubt the dealer would be happy knowing you’ve bought an item from them and are unhappy with it as you’re very unlikely to come back to them or the brand if you ever decided to upgrade later on.

1 Like

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.