I have bought a Stageline N to unify my two systems into one, using my TT with the Supernait. I am going, for now, to use the SN's AUX2 in/out socket to power the Stageline, and observing the schematics I have realized that the SuperNait powers its phone stage with dual rail 24V, but its internal preamp with a single rail. The internal power supplying for the preamp could be dual railed too, like a lesser HiCap, but the choice was made to power the preamp section with a single rail. This explains why an external *cap is so recommended (and audibly beneficial) for the SN: its pre amp is not even powered as well as its phono stage output.
Ah, you Naim R&D smart guys: your flagship integrated's preamp needs an external PSU more than the optional phono stage.