Why don’t you go and listen to both options at a Naim retailer?
I’m no fan of the 252, so if I were in your position I’d go for a NAC552 first. If you’re looking secondhand, I cannot say for sure whether you need to look for DR, but I have heard the non-DR setup which @Filipe uses and it sounded jolly fine to me.
My dealer’s audio suite is upstairs with no lift unfortunately. He’ll drop off demo units for a trial if I want though, he’s great that way. But I’d only do this if I intended buying from him.
Just sounding out the experience of those who have been here before me meantime.
Truth is Graeme, you have a beautifully balanced system now. Indeed, I have used the same amplification as you with a NDS/PS555DR. I would only go for a 552 (DR or non DR) or ND555 from where you are if you will eventually get both, in time.
IMV, you will only get the best out of the 552 with a ND555, and vice versa. Even with both, I do not see the Tabs or the 250DR as significant bottlenecks, although spending more on either, especially going to a 300DR or 500DR, will of course move you even further forward. But not as much as paring the ND555 with the 552.
Absolutely, as long as there is a plan to take that second step, to get the best from both the 552 and ND555.
When I added the 552 to my NDS/555DR (not dissimilar to your NDX2/555DR) it was a whole new system. As pre-loved 552s are rare, I’d grab it if you see one.
If you only have one source then instead of the nd555/555ps or 552dr delamere, you might want to try a different streamer/dac that has a built in pre? As you may find you dont need the 552 pre amp at all.
Plus not having to find the money for the above items, means you could either up the budget on the streamer/dac or save the rest for music or holidays