Hi there, I appreciate this has been posted many times but I can’t really see anything definitive. I currently own a CD555(just serviced) and have a DR PS555 powering this, couple of years old. I cannot stretch to another DR version at this time but upgraditis kicking in! I have seen used non DR’s going for less than 2K. I appreciate these can no longer be DR’d but looking for some insight on how a Non DR and DR unit mix and match up. The plan would be to eventually get the older unit serviced only, provided these are compatible sonically and are good to use together. Also, am I right in thinking that the Non DR would be best to power the digital aspect of the CD555? In my mind the CD555 was originally designed pre DR, I have seen posts stating CD555 never designed to use two power supplies yet the manual states can be upgraded with an additional power supply!
Intuitively (I’m no techie!), I think your plan is right vis the powering.
Re the additional PS, some didn’t like this, as it enhances bass a tad and clarity (to my ears). Some thought this was a tad too much and it unbalanced things – plus using only half a 555PS is illogical. There again, some think a CDS3 + 555PS(pre DR) is very close to a 555 (I don’t).
If you give it a few months, I wonder if a few more 555PSDRs will emerge on the P/L market, as some change over to the NC gear, even though the 555PS(sans DR?) appears to be better than the NPX300.
I use a mix of DR and non-DR with my ND555. Not sure how the CD555 works, but I use the DR power supply for the “digital” section 1 and the non-DR on the “analog” section 2. This is a simplification but it’s my preferred method based on listening.
I’d suggest swapping sides and see what you prefer.
Thanks all for your advice, there are definitely more PL 555’s appearing, all comes done to price I guess.
Finally added an additional PS555 preloved DR in its 555 outfit. Still early days but given that is has only been powered up since Saturday afternoon, I am nothing short of shocked. Everything has more detail, presence and control, played a variety of new and old discs and it jut brings out the best in everything. Whether the CD555 was designed for two power supplies or not, the truth is, I don’t care, this is CD playback at its very best, and to my ears, there is nothing better. Whole system is now well and truly singing, Naim really did design something truly special here, I loved my CDS3 but just doesn’t compare. 
Yes a fantastic CD player,but outperformed by ripped CD’s into a streamer.
For those of us who have CD555s, some with 2 x 555PSs(DRs in many cases), to get the same performance from a streamer, it would mean an ND555 and all the gubbins = some way >£20k (even towards £30k?), assuming all new kit. And if you have a house which isn’t helpful with running cabling and router/NAS placement, it can be a challenge.
For me, the next iteration of (say) the ND555 could be the point to look to change.
- Socket 1 of the 555 provides ± 22V, ± 10V, 12V, 2 x 15V rails, hence the 7 regulator boards from 5 capacitors
Internals of a 555DR
Pin Out for the CD555
The streamers has a different Pin out as no Motor, but a Streamer board
Socket 2 only provides ± 22V
So the second 555 on a CD555, NDS or ND555 is only using 2 regulator boards and a bank of 2 capacitors, so much less than half of the circuitry is used. It remains powered up, but no current drawn.
There more efficient designs available that just provide the power requirements for Socket 2
- The splitting of the Power Supplies on a NDS has just the same wow effect. After 6 years of just a 555DR, I got a 2nd supply for Socket 2 and are blown away at the difference.
I preferred a 555 PS non DR on the analogue side and 555 PS DR on the digital on NDS.
I do not have any desire to go down the streaming route, I do understand how uploading your CD and then play back avoids the issues of mech playback etc. but for me, I enjoy the whole process of viewing my collection and then deciding what genre / artist to listen to. I appreciate CD is no longer a fashionable way to listen to music but not what it is about for me, these things just go in cycles. This simply cannot be replicated by flicking through my collection on a tablet, I would imagine this type of playback is susceptible to constant changing of tracks. CD playback in comparison to Vinyl is incredibly convenient in every sense whilst still providing a more tactile experience and feeds the collector in me! I do not feel in any way that my sound quality is compromised in any way using the CD555 with dual power supplies, superb quality.
I had a CD555 but I prefer ripped CD’s on USB sticks in a
Streamer or Dac,much more musical to me.
It would be nice if Naim could put a Spdif in the CD555,so it could be used as a Dac fed by a Streamer,that would also make it more future proof.
The CD555 is a phenomenal beast …… the best CD player l have ever listened too……it’s an absolute magnificent piece of engineering.
Originally mine was paired with a non dr 555ps and then l added a 2nd 555psdr….
Simply superb……
If anyone is thinking about purchasing one …. you will not be disappointed.
Totally second that. Incidentally I use the DR 555PS on the analogue side and the non-DR on the digital side, which is the advice I was always given.
Try them the other way round and let us know if it makes any difference.
Might try it next time I power down - but that is likely to be months away.
Its always been my understanding that’s the best option…
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