The NTK benefits hugely from warmup time, unlike most tube mics nowadays-
comparisons here:
Rode NTK tube & warming-up tests
Also, tube swapping is important:
Rode NTK Test 2 - Tube swaps
Under a foot distance for vocals is a good rule of thumb (with a pop filter, of course). All depends on the vocalist and the kind of sound you're wanting.
I rarely have to do much eq on my modded NTK, wouldn't use anything else for vocals.
M@
p.s the audio links are down on those reviews, just read my observations. On dialup, don't have the time to re-upload now.