… but do also consider NDX2 with external DAC. If you use it with a DAC you won’t need a PSU. NDX2 with DAC makes a great source for the 552 (as SiS and others will testify) 
1 Like
If you don’t intend to move on from your 250DR to say the 500DR I’d forget the 552 and go for the 555PS on your NDX2, and a Fraim if you haven’t already got one?
Some people will tell you that the 552 becomes the bottleneck with 500DR!
Phew.
G
as others have said I would also explore what can give you more music - either 555 PSU for the NDX2? 300DR to replace the 250DR or as you thought 552 onto your system and then explore active - one of the finest systems I heard recently was 552 with 3 x 250DR
me I am more than happy to stick with 252/300DR using NDX and my main source LP12, to me there is real sweet spot with the 252/300
1 Like
Whilst the NDX2 is excellent on it’s own I have heard the benefit of adding a 555ps the uplift is superb.
I use a 252/300 with a ND555 but over the last year i have had a couple of problems with it and the dealer has loaned me a NDS and then a NDX2 both excellent, very very impressed with the NDX2/555ps combination.
However the system is at its best with the ND555 so to me it is always source first.
If I upgrade my system the 552 will be the obvious choice.
If you can I would listen to the options as suggested.
The XPS DR would be the natural PS for the NDX2. The 555 is somewhat over specified and you wouldn’t be using its full potential whilst paying a lot more.
1 Like
@Mike_S whilst I don’t subscribe to the source first and only source first philosophy have you compared each?
1 Like
Says the man with two magnificent sources!
1 Like
No, I haven’t. The 555 is well beyond my “willingness to pay” threshold 
But, I think it’s consistent with the Naim range, classic components together, 500 series together.
@JohnF went from XPS dr to 555 dr on Ndx2. Seems to find still a clear improvement. He will clarify it to us. Maybe a bit of brain fooled by the expensive upgrade? 
Or really it’s that much better?
You really need to audition the 555PS Mike 
2 Likes
I’ve just had to eat my hat and order a Fraim LIte 
I know the 555 has the 2nd burndy connection but the size of the smoothing capacitors and the amount of kit within compared with the XPS is hilarious.
May as well get a ND555 to match.
2 Likes
Not straight away Mike but once the 555PS has been assimilated into your system and the finances recovered…
I agree, start with an ND555. Otherwise, you will never know how good your system can sound.
I don’t have a power supply for my NDX but have recently added a Chord Bridge to it. It’s certainly delivered a wow! factor.
brilliant, thanks for the input. God, can of worms!
1 Like
thanks a lot. 300dr. but there is a nag there. oh well. back here next year…
demo room hopefully soon.