Greetings programs!

Yesterday I received my new EP175 to complement my old M3's and VP100. Unfortunately after I connected the sub to my AVR, I heard the dreaded hum. The hum appears to be intermittent. If I touch the ground loop screw, it goes away, but eventually returns. This morning I removed the screw after the hum started. It stayed away until I touched the TV with a dust cloth. After reading how the hum can sometimes be caused by the cable TV, I disconnected it from my cable box. The hum stopped. I then reattached the cable, and the hum returned. The hum also stopped if I left the cable attached, but unplugged the HDMI cable between the box and the AVR. Looks like I need a round-isolating transformer. Unfortunately it appears like the one offered by Axiom is no longer for sale. Does anyone have any alternative suggestions?

I found an Isolation Transformer from Bluejeans Cables, but this one attaches to the analog cables between your sub and AVR. Any idea if this would work?

By the way, Shaw Cable was of no help, and the hum is not present on any of the speakers connected to the TV, or the 7.1 Axiom system in my home theatre. My EP500 there is dead quiet until it goes boom.
"Not throwing my hands up or my dress above my ears don't mean I ain't awestruck." Al Swearengen