This is like a shot in the dark. Alright first of all I have a Music Hall MMF 5.1 Turntable with a Clearaudio Maestro cartridge. Next is a Rotel RC-1580 control amp. Then the Jolida JD9 tube phono stage. All going into the Creek Audio Evolution 50 power amp. Oh I forgot the APC G5 filter/surge protector which was recently added a week ago. All the components are plugged into it as they should be. Mind you when I turn the gain up half way or less with no music playing I get the hum. I'm ashamed of myself for not being able to trouble shoot this down. I know all about stereo gear, what's good and what's not, but that is the extent of it. I know this will be a process of elimination but don't know where to start. And what needs to be grounded to what? The turntable to the control amp? One of the pairs of input cables has a ground wire? Never have seen that. Where is that supposed to be grounded to? Any help would be great.