I listened to a system with a Bartok on Saturday; sounded lovely. Into a Gryphon amp.
At the price, the Bartok is a bargin really.
The rossini and even more so with the clock, is just astonishingly good and well beyond anything else i have listened too in the dac/steaming world. Plus its future proof to a point with its its upgradeable chip set, which is nice to know going forward as we all hate lossing thousands when your gear becomes yesterday news
Nice choice of music 
I hear this as the purity of bass improved - the fundamental note is not spread-out into distortion harmonics surrounding and blurring the note and its timing. There is greater power - energy is retained where it should be in the produced notes as they are played and the rhythms are more time-accurate and musical - they convey the Artists intent with their flow and pace drawing you to them…
A ‘small’ point or aspect of your nice summery of differences perhaps - but how many ‘small’ differences mount together into a rather large difference, in not normal basic HiFi parameters, but eclipsing these into the background where they really belong - and offering-up real musical insights and connection to the performance.
It is nice to experience these things. 
DB.
I just got all of the above on my NDX2/XPSDR with the addition of an Isol-8 PowerLine Axis and 3 PL-Lites in place of an old Hydra.
G
Shouldn’t have come in here, should I? Anyway I am safe. Not enough shelves to add a second one 
How was it, FR?
Jim, I didn’t remember that post, and it was not mine. Is there a bug somewhere?
Thanks Richard. So my memory was good. It was Michael original post. But I don’t specified it enough clearly, like in black characters or big characters.
Hi DB,
Just did a quick and easy experiment : disconnecting the second 555PS DR.
The difference is baffling!
Going from one to two PSs is impressive.
But removing one PS even more, much more, impressive!
The airiness and overall control added by the second PS, in the low end in particular, is really something.
Interesting how we notice more clearly things when they disappear.
Adding that second PS really changes how the ND555 performs 
I noticed that other manufacturers (MSB, Soulution, and probably others) use similar approach for their DACs : one power supply for each section of the DAC, analogue and digital parts.
That’s exactly what I said a few months back
I really got this when I chose my SL2s- listened to them and then put the SBLs back in. I had decided not to have the SL2s but then listening to the SBLs again I realised that there was more difference than I had realised. Obviously the main learning outcome should be not to listen to any new bits 
Indeed - you get used to what it does and removing it always shows-up what you are now missing that you were accepting as the ‘normal’ baseline before.
With all demos there is this effect - you add an item that is better, but a brief listen will tell you ‘it is not that much better’ and for that time it is not - but over extended listening when your subconscious mind has woken-up and begun to use the extra information - and even to gently reveal to your conscious mind intellect what is added that was not there before…then removing it after that is more of an effect.
It is easy to settle for less and be happy with it - than have an extended home demo ‘just to be sure’ and then realize you really want to keep the item.
Why Dealers do this - and why they are so called!
DB.
Indeed - it is not exclusive to ND555, just that the Second PS on it makes these kind of effects.
I’ve not heard it achieved on other equipment in ways that retain the ND555 strengths of ‘just there’ balance of harmonic-structure and micro-dynamics and the large-scale dynamics in the music.
Different sources pick out a mix of these performance aspects (as I hear them) but it was the ND555 that first showed me I could ‘have it all’.
I’ve also found all the implementation around the ND555 very important and also plays strongly into the clarity and precision of timing information and sense of musical flow - these will also impact other sources I’d suspect.
Maxing-out the source you have will probably be more cost-effective before moving into very expensive items like ND555 let alone 2x PS for it - but overall system context is also very important here. For my own system - this really made sense.
DB.
A real “dealer” would split of the additional 555ps in thousands of pieces and sell you every day one thousands piece of the device…
But indeed I agree with the observation, you very often get quickly used to the new stuff after the first awe…, removing it will give you the feeling what you missed…
I had this experience once when my ex-wife didn’t agree to buy the 552, and you constantly are plagued with the improved sound signature in your head when listening to the 252…
Thus the reason of being “Ex”:))