Yes to all the above, but it was the microdynamics and to a lesser extent instrumental textures that did it for me, taking the ND555 level with and past my old CD555
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Hi DB - hope you don’t mind what is possibly a naive question. Why does a second 555PS make a difference - given that a single one provides the required dedicated supplies and has a transformer that looks like it could easily power a fleet of ND555’s. Just curious as to your opinion. Thanks
@darkebear - when you say lowest shelf, do you mean lowest, or below the 555-digital.
This is what I currently have:
555 digital on standard
555 analog on standard
552 PSU on medium (extra room below)
500 PSU (on fraim base)
Now - If I were to move the 552 psu all the way up, the cables would be too short hence this stacking order.
Yes - it is a lot more than the initial impressive changes is what I was getting at. 
I compared by analogy to the sort of differences upgrading a Turntable was compared to a Cartridge - the foundations that allow everything to work and express with ease is greatly improved.
DB.
Naim themselves say it is quieter - the ‘not-used’ regulators in the sense they do not require current from the transformer and main smoothing Caps, lowers the noise that the other ‘used’ regulators see feeding them - Naim say it is measurable.
It all seems to accumulate to make a difference.
DB.
Yes - lowest means both lowest (in my set-up) and below the other 555 supply.
I would keep the two 555 as a pair and not nest other supplies in-between them.
I would try - after powering down ND555 
and muting the Pre - swapping the feeds at the 555 PS boxes - move one ‘up’ and the other ‘down’ to the corresponding output it fits - it will only fit the one it is meant to so it is safe - if you turn off ND555 first!
Then try it for a while that way - play some music - then a bit later reverse and form an impression which you preferred.
This is assuming both 555PS ate the same age (and both DR…)!
It is different when one is more run-in and then you may be physically moving them to decide which is best - I did both to arrive at what I liked - and then left it all alone for years! 
I do not want to be authority here - I just try stuff and report what I like - others may prefer different.
The 500PS on base works good and puts nothing the other ‘side’ of it, so it gets it out of the way most.
DB.
Great! So I’ll leave things the way they are. 
I observed quite the same adding the Sarum t to the 555 dr: more clarity, more open sound , bass is tighter and instruments have greater extension.
I one day I go to Nd555 with twin ps, it will be chord music at both ends.
However we never know how digital will evolve. Someone just posted that his new Yamaha wx a10 ( 150 euros) is better sounding than the Cdx2. I doubt a bit but…
That’s quite enough from you, thanks Gazza.
Not listening!
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Hoooooo ND555 with twin ps and 2 Chord music to feed both 555ps…this is understatement and expensive… no doubt real special
Generally if someone has the funds for Nd555 / 2X 555 dr and all the system which goes with it, I doubt that 10 k spent more will change a lot.
Sometimes we encounter strange phenomenons, when members having 100k system are not ready to invest in an audiophile switch or better ethernet cables, preferring convince themselves that it’s not worth.
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i agree…thats what i m trying to do lately,although dont forget you need this extra funds to add and not always it`s easy to get
Meni, I was not referring to you specially, but globally speaking.
As I see the great benefit of the Sarum t on my nds / 555 dr, I know if I have one day the funds for Nd555/ 2X 555ps, I will not hesitate to invest at minimum in another Sarum t.
I have to point that all my money is going in system upgrades, so I am not reasonable.
But no children, house credit, or car to pay. And no holidays in Seychelles or Maldives too.
Just my 10 Ferraris to maintain in good condition.
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That’s great news Gazza! 
Can’t wait to receive mine 
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I am sure you will be pleased, although ex demo its still improving after the system was shut down to install. It’s much better than the dealer demo i had, very happy.
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My answer was also pointed globally,its great to achieve all those upgrade you mention, im going also into this direction…nothing is matter for me,only this hobby…i only intented to say its comes not easy for no one to get everything
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When I purchased Melco n10 I was confident not needing a switch anymore…now I realized I even need to get a better one over my Sisco 2960… meaning even Melco isn’t completely isolated
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I’m going to pick the second 555PS DR up this morning 
As I don’t like the “burning in” period (at all!), I’m planning to do the following:
-
replace the current 555PS DR with the new one
-
run the ND555 with the new 555PS DR for about ~240 hours (10 days)
-
after that period of time, plug both power supplies to the ND555
Goal : hearing the differences from one to two power supplies without all the biases related to the burning in, or being slowly accustomed to both power supplies and not being able to clearly distinguish the differences.
During that burn in period I’ll turn the NAP500 DR off .
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The new 555PS DR has arrived 
I’ll now replace the current one, and power the ND555 with the new one only (for about ~240 hours). As soon as the new 555PS DR sounds good, I’ll plug both power supplies to the ND555.
During that period of time, I have to finish designing the new rack 
Gathering the parts should take more time …
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