555DR, choice of putting on NDX2 or NAC272

I have NAC 272 555DR feeding NAP300DR into Ovator SA400 and just buying NDX2. Keeping 272 in the interim purely as preamp, where would the best improvement be for my 555DR?

Or should i dispense of the 272 for a 282?

272 to 282 needs 2 extra power supplies. A napsc (included with pre) and a hicap or a supercap or a flatcap (not very suitable for this pre)

I would use the 555 to power the 272 then feed the NDX2 via coax into the 272 then the 555 would power both pre and DAC.

But ultimately you are at the stage to look for a standalone Naim pre whether the 282 is good enough but probably 252 of higher.

Try the 555DR on both and let us know the result please.
Also compare digital out vs analogue out and let us know please.


I‘be been wondering the same thing, where best to use the 555 in this upgrade. How would feeding the signal via co-ax power the pre and dac? And would the same apply to an NDS?

If OP is sticking with the 272 disconnecting the 555 from the 272 will have a huge impact to the overall system performance especially using the 300s.

Big question is whether to use digital or analogue from the NDX2 into the 272 an interesting test.

My money is on a digital feed into the 272 as this has the 555 powering the DAC hopefully the OP can try both and report back.

My next upgrade is going to be the 272.2 but if this never materialises I will be looking at the ND5XS2 or NDX2 feeding the 272.


I should add I have SL XLR 's between 272 and 300DR and SL cables to Ovator, so possibly SL Din to Din may be the answer, with 555DR powering NDX2…Damn this lockdown !!!

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NDX2 arriving tomorrow as will another Powerline and SL din to din, so watch this space

Excellent John should be an interesting test :slightly_smiling_face:

Well NDX2 Super Lumina din to din and Powerline arrived yesterday and have been installed and now warming up, first comparison appears to be much more depth and definition with 555DR attached to NDX2 and not 272 but many more hours of A/B comparison required during lockdown before arriving at a definitive conclusion to my ears!

Is that with NDX2 into 272 as a preamp?


Yes I am only using NAC272 as a preamp

So your streamer/DAC should be working extra hard, but your preamp now has no external psu.

But logically you wouldn’t want to keep a 272 as a preamp without external psu to use with NDX2/555DR.

Surely just PX it for a 282/Hicap or better.

So why are you planning to do “many more hours of A/B comparison required […] before arriving at a definitive conclusion to [your] ears”?

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Cost justification !!!

Ah - yes - it’s very important to forensically analyse one’s way to the conclusion that it sounds £X better than the previous rig. :grinning:

Hi John, still the same conclusions ? Better sound with the 555 on the NDX2 ?

Depending on genre of music there is not significant difference either way but not utilising the 555PSDR at all does have an impact… :sunglasses:

Thanks for the feedback.
Based on your experience, what type of music works best with what type of setup ?
It would be nice to check the impact of having two 555s … one on each unit