@secretguy - I had a Cronus Mganum and will agree with others , to my ears it didn't have the warm, rich , smooth sound the Op is looking for
@twoleftears Googling the ATC - spec state 84db , minimum 50 wpc nominal 8 ohm NS5000 is 88db and HIfi Choice stated minimum 80 watt RMS and nominal 6ohm but drops to 3.5 OHM. They will need some juice