Ground Loop?

@invalid I'm not an expert in all things that need to be tested and approved, but based on my amateur reading of the requirement for a class 2 insignia, the device needs to be double insulated, and, again, from my eyeballs, it's no better insulated than any other power amplifier.

Please see the middle picture where I show the bare fuse holders, with the AC cables to the right of them.  That is what you would see immediately upon removing the bottom panel.

To my poor unqualified eyes that is not a class 2 cabinet.  Maybe some one else can help me understand how it is.

Luxman 507uX.

I don’t see any indication the amp is Class II Listed. Can some one point it out...

Funny thing is, I didn’t remember seeing that either. I own exactly that model. :) I’m not breaking my back to find out. :-) AFAIK, double insulated gear has a dual square logo and I haven’t seen that. I’d have questioned if it was even legitimate based on how the unit is constructed.

Forgot to post the blog with the images I referenced, my bad:

https://inatinear.blogspot.com/2023/04/luxman-507ux-empower-project.html

There is a separate blog about how it seems the Luxman has the wrong leg fused here:

https://inatinear.blogspot.com/2023/04/luxman-507ux-ac-inlet-mistake.html

I kind of fixed it, no help from Parasound, but if I take a small piece of wire with a spade lug and slide it under the pot and connect it to the ground it goes away. I've never heard of such a thing it's not a hum but a chattering noise with static. Parasound has had it twice with no problems found. I've never spent so much money on something that's under warranty and the total lack of help is ridicules. Buyers beware.