Pretty much any amp from any reputable electronics manufacturer will do. If you want to save some money, try some Outlaw Audio Model 2220 Monoblocks (if you are in the USA). You could buy four of them, and bi-amp the Dali speakers, and have tons of headroom, plus it will only cost 1,600USD. There are other good amps, like Monoprice Monolith series, Anthem, Parasound, Starke Sound AD4, Marantz, Yamaha, and others. If you want to get spendy, look at Benchmark and Cherry Audio.