Yes, run S5 headphone line out to C5 line in. Headphone out from C5 to your hd600. Set Galaxy volume at 3/4 to start and after turning on C5 raise its volume only slightly so as not to ruin your hearing. There could be a problem with using your S5 but you wont know until you try this. Further, set C5 gain to High, and leave the bass out to start.