Slightly vague title, and a forum and google search haven’t presented the answer..
I have a 282 with napsc and 2 x Hi-Cap DRs
From my understanding the napsc powers the switching and digital logic of the pre-amp, keeping the internal power supply of the 282 for the audio side
Now, adding one Hi-Cap presumably negates the internal torroidal transformer of the 282 in favour of a larger external one in the HCDR, providing potentially more stable supply to the audio side of the 282.
Now, when adding a second HCDR, what happens ? Does one HCDR power one audio channel, and the second HCDR the other channel ?
Not really as the windings and regulation are shared. When you move up to the NAC252 and a Supercap then there are are dedicated windings and regulators just for AUX2.
I would guess they serve a function as Naim designs have always used the casework to dissipate heat. With so much regulation and the increase in ICs even pre-amps could get quite warm these days.
One case to get manufactured. For low heat items the fins are redundant. But fins in my experience tend to require care when moving; only downside i can see.