my two sets of active atc’s are somewhat older models but i doubt the company has significantly altered the tonality of their speakers
when i was using those speakers, my trying any top solid state pre made the atc’s too biting in the treble and thinned out the midrange a touch too much to my ears -- so i found happiness in time with the lovely audio research reference 3 balanced tube linestage... it was one of the very best at the time, now surpassed by successor models in the arc reference line
as such, i personally would advise against using benchmark or chord tt2 (which i have currently) to drive active atc’s, as i think this would most likely result in ’negative synergy’ in all but the most dead listening rooms