Thanks for the thread. many of those threads are helpful. The sum total of all the info is confusing...lots of opinions. I will review them again and then see what my ears hear.
To others: Quite right abou the grounds. I know some people actually remove the ground from the main box after their electrician leaves and rely on their separate audio grounds. I might try this for a minute but it seems like a risk for prolonged lengths of time.
Supplemental grounds are perfectly ok by code and safety and are helpful. It is the method used in high tech computer installations. Even more, the benefit can be measured by checking the resistance across the (-) and the ground.