Your Adikt cartridge has a 6.5mv output which is 30 to 60% higher than typical MM cartridges. You need a phono preamp that has low enough gain to avoid conditions which sound as you are describing with your NAD.
The typical gain for your cartridge by the book is 34 db. Very few preamps have gain this low- most begin around 40db of gain which could be too much.
The Luxman E250 has 38db gain for MM which should be fine.
The Chord Huei has user adjustable gain from 25 db to 35 db which should also be fine.
Both are of very high sound and manufacturing quality.