New Dedicated Line - Almost No improvement

@jea48 , while I agree in principle that an earth ground connection is generally not the cause of noise, it is not always not the cause, and when one considers emitted EMI, it can be critical. The earth ground connection (in theory) holds the metal in the equipment, cable shields, etc. to the same potential as earth, but we can call it a ground plane. Now as noted, that connection is more than just cable resistance, it is also impedance. If you remove the earth ground connection, then all the metal floats, and it floats in comparison to earth ground, which means you have a capacitor to earth ground and a "new" path for EMI that you would not have if connected to earth ground. This will never be an issue at analog audio frequencies, but it can be an issue at higher frequencies even with the higher impedance to earth ground.

You know what is really foolish? Those ground boxes filled with dirt that don't connect to anything.

@lowrider57   I think the grounding issue has assumed a life of its own, per the above comments.  I used 1/2 or 5/8 solid copper pipe (not an iron/copper grounding rod., 6 feet long. We drilled straight down, hammered the rod in and then filled the hole with a high-clay content soil. Was told this clay compound would help with grounding and conductivity. I was skeptical, but for the additional $15, I wasn't going to argue that point.  

My point really is there are many factors to consider with stable, clean power to the audio room. I didn't want to inadvertently omit one thing that might render all the other work wasted.  And as pointed out, we are still at the mercy of the grid.

You are at the mercy of the people who designed your equipment @papafrgog.

I used 1/2 or 5/8 solid copper pipe (not an iron/copper grounding rod., 6 feet long. We drilled straight down, hammered the rod in and then filled the hole with a high-clay content soil.

Is the grounding electrode only 6 ft deep in the earth? If so unless it rains a lot and soil moisture content is high you have a poor high resistance ground, imo...

I hope this is not the only earth connection for your electrical service. The System Ground, Grounding Electrode System, is mainly for lightning protection. It also somewhat protects the electrical service from a high voltage fault of the high voltage power line onto the low voltage secondary side of the power transformer from entering your house. The lower the resistance of the Grounding Electrode System the better. IEEE recommends 5 ohms or less.

Example of grounding electrode depths in the earth. (Climate Change and droughts would make things worse)

http://www.cpccorp.com/deep.htm

https://droughtmonitor.unl.edu/

A practical guide to earth resistance testing