It's a sad sad thing when I "get" what he means; but it takes days. I mean, I totally understand your panel grounding scheme explanation. I better. I wire that exact thing every dang day at work. Makes you wonder how I even have a job? Bare panels come to me with components all over it. And two chassis ground bars are there. First thing I do is wire from each device over to the bars. And on DC power supplies; the ground and neutral are run together. I should understand this. But I swear......... I just have days man. 
I will admit to this forum, I am NO engineer and barely a qualified technician. "yet". I do not have a Bachelors or masters degree in anything. Just a little Associates that's ten years old. And I have only been doing this for three months. I AM a newbie by all respects. I only WISHED I understood this stuff the way Joe does. Or you or Jerry. What I wouldn't give to know. 
The easiest of all would be to unplug the three prong amp on my high end and turn the system on with just the WOA two prong amp on. See if the hum is there? I'll try that in the morning. If it is still there, i will try the polarity checker. If ok and its still there, i will unhook all three pronged devices, leaving no ground prongs in the monster filter. If hum is still present then hell. I am out of ideas. Since Jerry said no hum was present when he sent it back, then it cant be in the amp? Has to be something i am missing......... Lets see what happens tomorrow.
The easiest of all would be to unplug the three prong amp on my high end and turn the system on with just the WOA two prong amp on. See if the hum is there? I'll try that in the morning. If it is still there, i will try the polarity checker. If ok and its still there, i will unhook all three pronged devices, leaving no ground prongs in the monster filter. If hum is still present then hell. I am out of ideas. Since Jerry said no hum was present when he sent it back, then it cant be in the amp? Has to be something i am missing......... Lets see what happens tomorrow.
