neither of these need an amp, the dusk sounds better, isolation wise I dont remember since I had the shure 535 with them that blew these 2 out of the water in that department, but the Dusk I kept has decent isolation. I remember the 7hz sounding musical with good details but had worse soundstage and detail retrieval than my AKg N5005 which I kept. The Dusk that replaced the AKG did almost everything right and is great with all genres (Still smaller soundstage than the N5005). Just my thoughts.