Best kept secret in AC line filtering conditioning

That’s what the box is for and you can do a quick Google search to see the video and the explanation of the box. I pasted a link below. Without the box it would not be safe.  

http://www.puritanaudiolabs.com/products/ground-master/

There are now over 80 posts regarding the Puritan 156 on A'gon dating back to the end of 2019, the great majority of them positive.  It would be regrettable if this thread ended up doing a disservice to the unit.

@grannyring  "This noise can be defined as any unwanted signal which is corrupting/perverting the fidelity of the recording."
If there is no noise when the amp volume is up with no input signal, where and why does this unwanted signal become apparent when there is an input signal, and if it can affect the recording audibly, why can't you hear it when there is no input signal. A quiet amp is a quiet amp, it doesn't suddenly become noisy when it has an input signal.

Reread my post and you should understand. The audio signal is where the noise ends up.  Your amp with no audio signal entering it or being amplified through it is not playing music. 

@grannyring
Good explanation on the video. The box is creating a star-ground for all the components and sending an equal impedance to mother earth.

I bet it works great. But I still wonder about code. What will an inspector say when he sees a ground rod not tied to the service panel ground. The box probably prevents voltage returning and causing electrocution. But still, what will an inspector say?
(I am not an electrician)