Ground Loop Hum caused by hardwired AC MAINS FILTER - help needed

Wait, so you are saying that the ground loop is happening on a circuit that is not protected by this device??

@erik_squires 
@lak 
I thought the hardwired filter may have been causing a problem.
Today I had an electrician (lived close by) who popped by. He disconnected the filter/surge protector in the electrical box.
I turned on all the audio but alas, it still had the buzz. I asked him just reconnect the filter again. 
So, at least I know its 'not the filter'. 

I have swapped all my components (except power amp) and still the buzz is there. That means it must be the power amp.
I will start another thread in the amp/preamp forum. I have photos of my amp and a short video of the system and buzz. I now suspect the problem stems from a Ceraphim capacitor (power) I had installed a while ago. The cap value may not be matching.
TBC...
Thx, 


 

Out of curosity have you tried a two prong adapter (temperaly) on each peice of equipment (one at a time) to see if you can find the culprit?

@lak 
Hi,
No, I haven't tried that. It makes me a little nervous to cut out the ground. 
But I guess I could try it. 
So, if the component with the two prong adaptor stops the hum, then I should try grounding it with another component instead? Is that correct.?

I believe so. At least you will have more information to work with and someone more knowledgable than me (like erik or others) could make some good suggestions.