552 service?

At the risk of being hung, drawn and quartered, has anyone come to the conclusion to remain with a 252 after comparing 552?

Currently experimenting with a 2011 model 552 (DR’d in 2013 but not serviced) against my 2018 model NAC 252 / Supercap. The 552 is from a good home and is in unmarked and apparently pristine condition. I know it has been in constant use since 2011 though.

At present my thoughts are that there is something amiss with the sound.

My initial thoughts are (surprisingly) that the 252 is more detailed and that the 552 is at present powerful but lacking in pitch / timbre. The 552 appears to be slightly better with vocals but not by a huge margin. (Appears to add a little weight.)

My impression so far is that the 252 is giving more detail especially in the bass, and particularly in what I would call the “percussive” elements of instruments. For example the 252 is revealing subtle clues like that feeling when you can hear the touch of a finger on the guitar string ( Not the squeak as it is moved but the actual touch as the string meets the fret) It also appears to have more texture and tunefulness in the bass, with a real ability to follow every change / nuance. The 552 which has been powered up for 4 days doesn’t play bass tunes so convincingly. It all seems to be a tad dull albeit fuller in that regard. I guess less alive and less real is an apt description.

Piano notes appear more realistic on the 252 with better representation of complex decays. This is also mirrored by resonation and decay with acoustic guitar. All of this is the opposite of my experience in previous demos.

I have experimented with cable dressing and made sure I followed the Burndy de-stressing dance! Hopefully the neighbours didn’t see.

Overall there is more body to the sound with the 552 but it is clearly excluding the subtle details which are present with the 252.

All of this is counter intuitive to me !

If I keep the (bargain) 552 I would want to get it serviced and I am wondering if the slight lack of detail etc is indicative of a need for a service.

I’m confident that if serviced I can recoup the cost and I’d really like it to be spectacular. At present it is very good but underwhelming compared to the 252. That is totally at odds with my expectations as I am more than confident in the fact that it should be as detailed as the 252.

Specifically asking those who have experience of the 552 as to whether I persevere to see if it comes into it’s own or whether what I am describing might be indicative of service need?

At the end of the day I can stick with the 252 but would really like the 552 to sing!

I’ll put my tin hat on now and run for cover!

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It should show the 252 a clean pair of heels, so if the cabling is correct………i would have a nagging doubt about lack of servicing. If you could post a picture of your set up that might help, the 552 likes a lot of air beneath it and nothing above it preferably.

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How many hours is the 552 playing in your system ?
@NigelB went from 252 to 552 last year , he can say if he heard the differences straight after a few hours or not.

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Hi Gazza, did experiment yesterday with positioning but had no real effect. I have had it on top of the rack and I took out the streamer to an adjacent table but no change. So nothing above and a spare self below. The 252 was more than happy in the position the 552 is in but as you say, they may have different needs.

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It’s been powered up since Thursday and has had e few hours actual playing time but of course may need a few more!

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I’ve been using an ex demo 2019 build in my system (see profile for details) for nine months this replaced a six year old 252 and as Gazza has said it should show the 252 a clean pair of heels and in my system it does.

Wonderful detail and control it just takes you into the music more trust you get things sorted in order to reap the benefits of the 552.


I heard a difference straight away but my 552 was well run in (2008 model). The 552 did however improve over a few weeks mainly in the areas of poise and separation but with added cohesion, if that makes sense.

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Thanks Nigel. I have followed your posts and hope you are now happy with the 552 / 500 combination.
At the moment with the 552 I am struggling to perceive much improvement and it’s the lack of detail in comparison to the 252 which really strikes me. I had already accepted a service might be needed but I am surprised that it hasn’t trounced the 252 in any respect really.

Was it moved with all 4 transit screws fitted and are they all out now ?

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Hi , Yes all four in place during movement and all four removed carefully on installation, keeping the amp level during removal.

(Probably would have been my first question )

But did you heard the same characteristics as the OP describes in the beginning of the thread? He has now a 2011 552, and finds the 252 more detailed and the 552 a tad dull, after 4 days running in.
I feel it needs service.


No I did not have the same issues the OP had when moving from 252 to 552. As for needing a service, my 552 is even older than the OP’s (2008 model) and I don’t feel the need to service it. A 2011 552 shouldn’t be in desperate need of a service.

Although the OP uses a 250 (as I do) their profile does not say if it is a DR model or not. The main difference between the OP’s and my system is that I use a ND555 whereas the OP has a NDX2. Their 552DR should still beat the 252(DR?) in that system. I suppose it is possible the the added detail the 552 delivers might be showing a weakness in the 250 driving such revealing speakers as the T606s, but this is pure guesswork on my part.

The OP says the 552 has been in constant use since 2011, so I guess some of its components might be a little ‘tired’.

I would be tempted to leave the 552 to settle in and see if things improve.


Hi Steve,

This all seems a little odd and you should be hearing the 552 deliver a significant improvement over the 252, even using a 250, as I did.

Could you advise how you are supporting the system and which rack you are using. Some idea of the cabling (beyond Morgana and Chord Epic) might also shed some light.

The added detail and extension at the frequency extremes the 552 delivers might mean you have to reposition your speakers and/or your listening position. That is well worth experimenting with.

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Possibly some room / speaker interaction at play as the 552 probably produces more bass and that may be adding to the perception of detail loss. The system is on a Fraim (Single stack - I’d never get away with two)and the 250 is a DR version. The Snaic and Burndy are standard but the source and pre - power interconnect are WH Morgana. The system is showing the difference in the two pre- amps but not entirely as expected at the moment. As you say it may take some time to come back on song. The 252 does I feel have a “cooler” character and lighter touch which may be suiting the room better. I’ll have a play with speaker position but possibilities are limited and to be honest I think that could influence the bass but not so sure about the detail aspect. I’d go as far as to say some “air” is lacking at present.

Yes, I would leave the 552 to settle in before drawing conclusions.

Don’t just experiment with speaker positioning, also play with listening position (towards and away from the speakers) if this is possible. Small movements can make a big difference.

Also don’t forget to make sure all connections are good and pay attention to cable dressing - it makes a difference. Try to get all cables off the floor and not touching walls or each other - particularly the Burndies. Keep signal and power cables apart. These things make a difference with the very sensitive 552.

One last question - which mains block do you use, or is everything plugged into the wall?

Finally, try to get your network devices (router, switches, Server, NAS) away from your Naim system and on a different ring main if possible.

The 552 is a very sensitive soul and needs lots of TLC.

Failing all this, it could be your 552 has had a hard life and needs a service.


A recent experience was quite illuminating (and frustrating!!) I basically took my entire system to a dealer to demo some new kit. My current system sounded amazing in the demo room. Significantly better than at home. I struggle to really pick apart subtle differences at home, but was loving the demo at the dealer where every change was discernable.

It was frustrating as I’m not sure I can justify many upgrades to my existing kit in its current location as a result. I don’t think I’ll hear the ultimate benefit. I wonder, as you allude, if your room is limiting the ability to tell things apart significantly here? Are room/speaker issues something you’ve suspected previously?

As a postscript, I temporarily moved my system to a larger room at home (actually I could just move the speakers through an alcove, so it was a “cheap” move), it immediately sounded closer to what I heard at the dealer, really excellent in fact… sadly I cannot make that change permanently!


Swapped a well run-in 2021 252 for a freshly serviced 2012 552 DR. It took about an hour to really hit me after a cold start, then it blew me away.


My experience is similar to Stu299. Swapped my 2021 252DR for a mint (looks new) 2005 552DR serviced / DR’d in 2019, within an hour or so I soon discovered that the 552 is in a different league to the 252. Three weeks in and its still improving.

Is anything else plugged into the power block (which) other than 250,552,XPS2 when trying the 552 and just for completeness what is their order?

Steve, you’ve received some excellent advice/suggestions, especially form Nigel. I would concur that either the 552 needs more time to warm up or it badly needs servicing. I can think of no reason that an optimally functioning 252 should be in the same conversation with an equally functioning 552.

I made the move from 252(non DR) to a newly DR’d and recapped 552, each powered by a 500 DR. There was no need to have a conversation about the comparison. Night and day does not begin to explain the difference. Since then, I’ve moved on to a full Statement rig with incredible improvement again.

Over the years I’ve had several Naim iterations starting with Olives. I have never been anything but thrilled with each upgrade!

My only suggestion is to keep playing the same source material each day to see if it improves with the extra burn-in of the 552.

Good luck!!