As HH says except that the last year or so’s production have a different display component as the previous one was no longer available. The new display needed a firmware patch (otherwise the display would have been upside down), but this was rolled into the last one or two firmware releases.
But I am not aware that there is any reason to look for one or the other version.
Best
David
Thanks again guys for the swift replies!
My first step back into Naimland was with my second system: NAC 272 NAP 200 and an HDX. Great system- I got the upgrade bug and got the 250 DR which made a huge improvement.
I have no plans to change anything- very happy with it.
In that case, it’s probably best not to try a 555PSDR in your system…
The thing is I just bought an NDX 2 for my my main LP system which is a 552 DR and 300 DR… if I am going to get a power supply I think I know which system will get it 
Yes, clearly the 272.
Because the 555Dr demands to be made best use of, i.e. powering the preamp of the 272 as well as its streamer/dac.
Whereas on your other system you’d need two different power supplies - one on the steamer/dac and another on the preamp. That would be an inefficient use of resources!
The 552 has it’s own power supply… If I did get an power supply it would be for the NDX 2.
I could upgrade my second system, but I think most music lovers want to get the best from the system they listen to the most. I am waiting for a Japanese cartridge for my vinyl system.
Not looking forward to the setup, but the sound… 2 days to go!
Thanks for explaining that to me.
In 40 years of hifi I had never thought of that!
For the sake of clarity, my suggestion above that you’d want to buy a PSU for your particular 272 first was meant to be read in a jocular idiom.
But the substantial point that I then made - that the PSU on a 272 does much more than merely improve the performance of the streamer and DAC - was not really aimed at you - it was intended to help the OP and any other interested readers to see why putting a PSU on a 272 is much more effective and efficient than putting one on a Naim box that is only a streamer/DAC (such as your NDX2).
geddit? (as they say in Private Eye)
I have a Uniti2 and a NAP200 with Neat Motive SE’s and am thinking about upgrading to a NAC-N 272 and adding a CD5si to play my cd’s. Is this a useful improvement?
Martin
Yes, the 272 would sound a lot better than the Uniti. But ask yourself if you really need a CD player. Why not rip them to a nas? That would sound better than using a CD5si.
I went from Uniti2 to 272/250 and it was a very nice upgrade.
What HH says. I would use the funds saved from the CD5si to put towards an XPSDR or Music.
I took the plunge and wait for delivery of the NAC-N 272 and NAP 200 (non DR) next week … 
Great stuff.
Enjoy, you won’t regret it. 
That’s the spirit!
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