Review on 🔌 TII 220 Ground Loop Isolator: Optimal Solution for Cable TV Applications by Jake Powell

Eliminated hum immediately after installation. Equipment: Furman IT Reference 20i Line Conditioner, Marantz AV7701 Preamp, McIntosh MC275 Tube Amp, McIntosh MC205 Amp, Oppo 105 BD Player, Martin Logan Montis Speakers, Samsung PN64F8500 TV, etc. Solved: 60-bar hum is gone Problem: when I installed a comcast cable tv box, when i connected the hdmi cable to the marantz i heard a loud 60bar hum. The volume control didn't make it louder or softer, and it did so whether the cable box was plugged in or not. With only the coax cable connected to the cable line and the HDMI cable connected to the preamp, I got a hum. If I touch the outer shield of the coaxial cable with the cable entry, I would get noise. Called Comcast Cable to send a truck - they spent 6+ hours installing a new cable line off the shelf to the house to try and reduce the line noise. They also grounded the house cable line to house ground and replaced my passive coax splitter with an active one (at their expense). I knew at the time that none of these efforts would solve the problem, but I did get a better signal from Comcast :-) The problem, of course, was the ground loop - my ground and theirs were at different voltages - possibly due to my audio equipment being powered by Furman, that completely redistributed the ground in addition to Comcast's poorly grounded equipment. Bottom line - this $20 isolation transformer is the *perfect* solution to this problem - nicely packaged in a very compact design, it electrically isolates the outer conductor of the coax line with a pair of transformers so no DC current flows through the line. only modulated voltage up to 1 GHz . I have no problems with my other two cable boxes. My guess is that high-end audio equipment is the only place it's needed, as all such equipment is grounded (three AC cord plugs), but TVs and soundbars are not.