"I will say this. When my hiss was audible to seating (to me) on certain passages played on certain sources" - (or another suggested fininsh to your sentence if you dont mind), its because its in the source.

Case in point - I just received MD - Kind of Blue yesterday on SACD. In the intro to "So What" what is there a lot of, HISSSS. Music kicks in, masks the hiss. Press pause, hiss is eliminated, between tracks, no hiss, and so on. This is also the case on Charles Mingus "Ah Um". If its gone between tracks and in pause, how can it not be in the master? Soundhound??