Hi Phil, I'm not experiencing what you describe. I read through the whole thread on avnirvana and I have one suggestion that may help with your troubleshooting. You mentioned that you had experienced ground loop issues previously - since this problem is audible on the headphone output have you tried moving your Outlaw 976 and source to another outlet in your home, or to another home? I know you aren't hearing classic ground loop noise, but perhaps a rare power gremlin?