No, if you only use the Cenima 30 it is dead silent.
If you do that, you will be back where you started more likely than not. In these complicated systems like you have and are putting together, installation is complex, and there are plenty of snake pits for the unwary.
When putting together a complex system then designing and installing the ground plane is a complex and not a simple task. The inexperienced will drop into the snake pit.
I would bet that if I were in your home, I could solve your problem.
I note that your cinema 30 is double insulated and has now ground for the AC cord. This sometimes helps and sometimes it is a problem.
You have to understand that ground loops are errors in the installation of equipment and not usually the fault of the equipment per se.
A ground loop is always caused by a resistance between ground, so that a current can flow between grounds.
So the key to prevention is to have ONE good ground and everything flow to that ground.
You did not state what your power amp is, and whether it has two or a three pin power plug and cable.
So we need to start with that information.
One other point is that sometimes these problems reside within the house wiring.
One thing I can say, that this problem is very likely solvable without returning equipment.