Service/DR upgrade question re: 552

I have a 325k s/n vintage ( so late non-DR) 552/552 PS. I’m toying with doing the DR upgrade and want to know what that would entail. Obviously, the PS would be DR’d, but what else would be needed? Would the head unit box need service as well? Recap? I believe Naim in the UK at least (I’m in the US) requires a full service at the time of the DR upgrade. Not sure if that’s the case for the US centers though it does make sense to have it done all at once.

I’m just struggling a bit with the decision whether to do the whole shebang (DR + service/recap) when the equipment is only about 8 years old and probably not due for a recap yet. I’m ok with spending the (pretty significant) $ if the value is there; i.e. if there’s a noticeable improvement, but if the improvement is only minor I might be better off waiting until the recap is due and doing it all then.

I’m sure I’m not the first person to feel challenged by this decision. Anyone have any thoughts?

For a 552 you really should be talking to At least for the power amps the DR bit is in the head unit as far as I know, the DR label is also on the head. For the XPS, where the DR is in the PS, most of the innards are changed during the upgrade, it is more or less a new PS in the old casing, hence a full service is now mandatory. No idea how much is changed in a 552.

I’ve recently had my 552 DR’d and serviced. As I understand it the power supply gets both a service and the DR elements installed, the 552 head unit gets just a service. This involves replacing the tants and caps and checking everything conforms to the latest tuning specs like cable runs and ties plus any mods they’ve discovered since your unit was manufactured.

To be honest I’d always been a little disappointed in my 552 despite others saying that it was the best product Naim make. Compared to my 52 it was better but not loads better, it was only after the servicing thet it finally went WOW and understood what all the fuss was about.


I bought a preloved serviced 20 year old 552/500. 500 series places demands on everything else being setup just right. DRing may be worthwhile for you, but probably it will go to 15 years before needing a service.

There is always a degree of overlap between individual setups of the same boxes that means it is worth working on the setup. The 500 Power Amp brings out the best in the 552 IMO. Fraim, cable dressing, box spacing, room acoustics and mains power all help.

I’m not at all disappointed with my unDRed 552/500.


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