CD 555PS DR product history?


When looking at the Naim website for product history I can’t seem to find the power supply 555PS DR (CD 555PS DR) at all?

Anyone know when this power supply was upgraded to DR specification?

I’m looking at a second hand unit manufactured 2011 according to the serial. It has a DR marking close to the power connector, but not as current units where the DR marking is below the unit name next to the serial. It could of course be an older unit DR:ed, maybe they where marked this way.

Would the year of a DR upgrade also equal/involve a service of the power supply, and in all make it fully comparable with the current 555PS DR ?

Kind regards

Interesting but you’re right. No mention on the product history page. The CD555 was introduced 2006 so it’s fair to assume the PS was introduced at the same time. Other PSUs were DRd in 2012 so again that’s a fair assumption for the 555.

I think the DR upgrade involved swapping out the whole internal sled retaining the case only. A peep inside will show that it has discrete regulators.

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DR version was definitely introduced in 2012 as that’s mentioned in the product description. Very odd that it’s not listed in product history.

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It is probably not the only ‘hole’ or error in the Product History, sadly… :neutral_face:

Maybe the 555PS is regarded as part of the CD555…?


Thanks, yes 2012 seems to be the year of DR.

If the whole internal sled is replaced when upgrading from non DR to DR it seems like the year of DR upgrade should be considered as starting point for when to consider a service. Not the year of production of the unit as per the serial number?

Thanks, good spotting. I didn’t catch that the product description had this information.


Are we sure the whole sled is exchanged? So just the sleeve is original.
I assumed the exiting regulators were simply exchanged for dr units?
Is the original s/n on the bit that is exchanged?
Also begs the question as what naim would do with the original trabsformer, rectifiers and baked bean size caps?


I found this from NeilS in a thread about DR upgrade of the XPS power supply.

the XPS DR upgrade involves replacing the main PCB which contains all of the reservoir capacitors, so everything bar the transformer & rectifier bridges is refreshed as per a service.”

Of course this can be different for how the 555PS DR upgrade was made. Maybe @NeilS can help us out again?

Some before/after photos. I’m sure there were upgrades to the circuit board as well but I might be wrong. Not sure about the caps.

To be honest, the non DR soldering looks a lot better :flushed:

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caps look untouched though. I thought DR upgrades were initially independent of a service, only toward then end of DR upgrade availability did Naim change to say it had to include a service as well.

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Thanks for finding the pictures. Yes the caps look untouched on this one. But it would be good to hear, if possible, from NeilS. How do one mark his name the way I see some people do in posts to make him aware?

Edit: found out how to.


Spot on @kwhitmarsh !

FYI - none of the DR upgrades involved entire chassis assembly replacement (like the CDS to CDS2 did).



…or like the 52PS to Supercap upgrade.


Thanks all, so the conclusion is that a DR upgraded 555PS doesn’t have serviced caps, unless it was asked for, or the upgrade was made in the last years when Naim did both at the same time.


My CD555PSU upgrade to DR did NOT include caps so I had those replaced separately with an added Invoice.

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I believe at one time, Naim would not do the upgrade without a service, I guess the view being, good money after bad if the power supply was not already performing in the way it was intended.

I think it was in the last few years of the DR upgrade being offered that a service was included as compulsory with it. Not sure what year but in the years before 2020 I think.

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