I’ve been running an additional (S/H) 555PSDR now for a week and it’s a much bigger upgrade than I had anticipated. Such a scale jump.
If anyone is hesitating or wondering ‘how can it improve on one 555PSDR?’, just try it.
My Tab 10 Sigs have simply vanished and there’s no sense of any equipment between me and the music…there’s just music. That sense of hearing right into the recording studio or venue is wonderful.
G
My argument when upgrading from an NDX2 to an ND555 was: the PS555DR only uses half of its potential, so an ND555 will use it to it‘s full potential. Getting a second power supply for my ND555 would be diametral to this argument.
This forum is no good for me 
Head and heart reasoning works…until you’ve had two in your system for a week.
Blimey, it’s good.
(Sorry)
G
Oh dear. I may have to block your posts! I am not listening at the moment !
Enjoy 
I often joke the ND555 is unlistenable with one power supply. But the benefit of a second power supply cannot be denied. It opens everything up, much more “air” and improved dynamics. I run my streamer with a mix of DR (on the digital side) and no-DR on the analog side. A highly recommended upgrade for every 555 owner.
Interesting choice of DR on digital rather than analogue side Chris. I guess you tried both congfigurations.
G
My theory is the quieter DR power supply improves the “digital” end of the playback. In my listening tests I preferred it in this configuration.
There is no pure split inside the ND555 between Digital and Analogue when it comes to the DAC chips. These are the interface between the digital world side and the Analogue world side and the charge-pump converts the Digits into the Analoge signal that is then filtered and output from the box.
So in some respects the most sensitive part of the ND555 is exactly where that initial conversion happens - the timing-edge jitter and noise there will get put into the Analogue side with no way to remove it after, so getting the very best PS at this point makes sense.
My two 555DR PS are on their own Fraim and I tried the Analogue and Digital PS on the Base level or one level (Medium) up - the Digital PS on the level-up sounds better and I generally find the units on shelves are a bit better than the Base-level Fraim … so I’m saying the Digital PS likes the best shelf.
The two PS option of ND555 is a no-brainer obviously superior source and it is not subtle.
It is just nice Naim allow you to buy it in stages as funds permit.
DB.
In Meg Ryans words Yes YEs YES!!! totally agree amazing upgrade!!
Hi DB,
Forgive me, can you remind me for the millionth time what is the digital and analogue connection on the ND555? 
I just want to,check I’m connected correctly!
One of the “many” things I enjoy about the Naim is the opportunity to “grow’ the system as funds permit. Two power supplies ain’t cheap, but as Graeme has found out…to coin a “young un” phase…OMG!!
Wow, thank you Graeme. Phew, just checked I’m good!
Congratulations on the 2nd P/SU. Keep sharing your journey, I love reading your posts!
(Straight face)….The journey has ended.
G
Yeah, yeah…. 
Enjoy
Digital Burndy has one bar on it and Analogue Burndy has two bars marking.
And as shown above - Analogue is the power connector closer to the Analogue outputs - that is how I always remember it.
DB.
#sourcefirst 
I was always intrigued by these sorts of threads on the old forum when the CDS555 first came out. So using a separate 555ps to power analogue and digital circuits is better. The same appears to be the case with the top of the line streamer. As before I was amazed by the 3 box CD player and now the 3 box music streamer. Shame that the thing cannot to be designed as a minimum with a maximum of 2 boxes
It is designed to use two boxes - you can just add another if you want too. 
Previous discussion on it seems to be that the use of a totally seperate Transformer and associated Regulator Caps means that the measured noise is acually lower on either Burndy feed - and that translates into a better performance.
But you do not need to use two PS boxes - just a nice upgrade option.
DB.
@GraemeH Did you ever consider buying new speakers? Looking at your system you seem to follow the source first approach to the max. As you can see from my Ovators thread I was convinced to buy a better amp and source instead of replacing speakers. Now with an ND555 and just one PS in place I consider new speakers. I wonder if another PS could be more important before moving on with speakers…
