the specs that i found online for the qs1500d say that it is 1x750 @ 4 ohms and 1x1500 @ 2 ohms and that it is class ab not class d - http://www.quantumaudio.net/quantamp2.html . is that correct?
in the the little instruction book that came with it thats the specs that it gives maybe its wrong idk...but i know it will hold 1ohm because my friend has his 12'' Cerwin Vega Vmax wired up to it at 1 ohm for about a month now, it does get hot after playin it constant for about 2 hours.