Grouding for dedicatied lines?

I'm using a single 20 amp circuit that uses an isolated ground outlet (ugly orange) and 12-3 BX back to main panel. Grounded to main buss bar. Got great (no noise) results and pretty cost effective. Red wire wrapped in green tape to designate ground. Maybe Gbeard can comment as to whether BX or conduit is over kill compared to romex (will certainly increase cost) and add a simple definition of "Star Ground".

Some schools of thought recommend monoblock amps be connected on opposite sides of main (common noise cancellation). General consensus in non-monoblock situations is to keep all lines on same side of main. May also be some benefit to locating potentially noisy house lines (those with motors, dimmers, computers, etc) on the opposite side of the main. My computer for example has it's own 15A (14-3)iso grd circuit on opposite mains side.

If you still have noise issues after a code compliant install look for the source by switching off suspect items. Deal with not generating the noise rather than floating the ground and risk floating to heaven.

I don't really think that BX, AC, MC cables, or conduit are probably any better than romex of reasonable gauge wire. #12 or #10 should be sufficient for most applications. Especially since the terminals for a 20 amp duplex receptacle are not designed to accept a conductor larger than #10. However, when entering the galaxy of the audiophile, anything is possible--as long as it is safe.

I don't really understand your comments about circuits being placed ahead of the "main". It must be a different definition of the word than what is common in the electrical industry. Nothing should be tapped ahead of the main circuit breaker (or fuse), unless it has its own main circ. breaker (or fuse) within the code approved distance per the tap rule. I am sure I am not discussing the same situation you are refering to.

I am not an expert on star grounding, but I believe it is a method of grounding electronic systems--audio, video, computers, etc.--that begins at one point in the system, and branches out to each piece of equipment in a star configuration. It can be very technical, and I am not well versed in its design criteria. However, I do know that the grounding point at where the "star" begins is itself grounded to the main grounding electrode (or mat in larger systems).

I hope this helps.

Alexander,
After re-reading your post, I think I totally misunderstood.

You must be refering to balancing the load by placing mono-blocks on opposite phases (A or B) of a 120/240volt system.

I don't really know about an improvement in sound--I've never owned mono-blocks! ;?)

The ground point for my house is a clamp around the copper water pipe that enters the house. I found that paint had covered the pipe. I removed the clamp and sanded the pipe down to the copper and sanded the paint off the ground cable. With regard to separate lines, I have two lines that share the same ground but if I use both outlets there still seems to exist a difference in ground potential. Hum is least when everything is connected to only one circuit.

I would recommend hiring an electrician to handle this type of work, lest you become a famous conducter.