I just purchased a used 770 and am experiencing a ground loop. I have identified the cable going to my set top box as the culprit. Called the cable co. and they re did the ground but the humm is still present. I see that Jensen sells a cable ground loop isolator for about 60 bucks and was wondering if anyone has any experience with it...or possibly another solution. Also having problems getting the 12v trigger to work with my pio 56txi. Do I need a special cable or will any cable with a mini jack do? Thanks for any input.