When I bought my NDS I had an XPS DR on my NDX. I didn’t want to go to a 555ps straight away as the XPS DR was recently bought and I wanted to let the cash replenish first.
The (respected) dealer advised to hold on for a 555DR saying that the difference between an XPS DR and 555 non DR wasn’t a cut and dried improvement but swings and roundabouts and not a justifiable upgrade. The 555DR on the other hand was a significant upgrade.
I’ve since changed to a 555DR which is a tremendous improvement.
Note this is with an NDS which is designed to take advantage of the dual burndy arrangement of the 555ps.
I’m not convinced using older non DR power supplies with equipment designed in the post DR era is a good idea. I suspect Naim will have designed the NDX2 assuming a DR power supply will be used to upgrade it.
I’ve just removed it and gone back to original bare set up, actually sounds better to me, seems the 555 was pulling the NDX2 down somehow or just not a great match, says a lot for the NDX2 native ps.
…give the XPS DR a demo, myself and many others on the forum immediately noticed an demonstrable uplift in performance with the NDX 2. I am sure the 555 DR would be wonderful and it should be at 14K vs 6.5K USD for XPS DR.