Judas Priest's major-label debut Sin After Sin marks their only recording with then-teenage session drummer Simon Phillips, whose technical prowess helps push the band's burgeoning aggression into overdrive. For their part, K.K. Downing and Glenn Tipton employ a great deal more of the driving, palm-muted power-chord picking that would provide the basic rhythmic foundation of all but the most extreme heavy metal from here on out. Sin After Sin finds Priest still experimenting with their range, and thus ends up as perhaps their most varied outing. Yet despite the undeniably tremendous peaks here, the overall package doesn't cohere quite as well as on Sad Wings of Destiny, simply because the heavy moments are so recognizable as the metal we know today that the detours stick out as greater interruptions of the album's flow.