On-board streamer NDS vs 272?

The functionality is the same, but the NDS is better. 

thanks, do you know of the major technical build differences that explain why the NDS is much better?

If you look on Naim's website at the two units and look at "Technology & Craft" then you will see that there isn't much information published, but it seems as if for the NDS Naim have deployed all the tricks they have to improve SQ for a given circuit build whereas for the 272 they have had to balance that with the need to get more into the box and to keep the cost down.  I don't think you will find anyone here who will be able to tell exactly what circuit and build differences produce the better sound but at such a high premium.

best

David

I've been reading the NDS whitepaper a while ago. Remember 2 things: a lot of reclocking and optical isolation done in the NDS. Maybe half of the circuitry is related to that. And the NDS is floating ... you'll double the amount of copper in your house when you buy one.

The architecture between the two is quite similar. The NDS just has more real estate to play with and no power supply in the box to worry about either. The engineers can optimise the board layouts more effectively and have been able to isolate the network, digital and analogue sections, both physically and also electrically via the greater number of power rails available (especially with full 2x burndy 555PS). As mentioned by others, mechanical decoupling with the sprung, brass mounted boards and more screening around the streaming board.

In the end, it's all about compromise to get the best solution given budget and space constraints - the NDS has less to worry about in this respect. 

that is excellent info, learned a lot, thank you guys!

Yep, James has nailed it.