New electrical wiring specifications

Y’all need to run dedicated silver wire service from the substation to your distribution panel. Special silver circuit breakers. Enough circuit breakers for each component. And hard wire, with the silver audio wire, from each circuit breaker to each component. 
And buy a 6’ solid silver grounding round. Locate it outside near the service panel. Then run a nice silver grounding strap from the service panel to the grounding rod. 

Me I ran a couple 12 gauge lines from my distribution panel to some hospital grade connectors. Done.
Last week a fellow destroyed the electric pole which had an old transformer. So now there is a new transformer hanging on the pole next to my house. Made no difference. 

Tell him to put all 3 circuits on the same phase.  This avoids subwoofer ground loop hum.

Pretty much like the others mentioned, I did three 10awg Romex, 20 amp breakers, same phase, combo of PorterPorts and Oyaide R1 receptacles,  new grounding rod.. I use one line exclusively for amps and subs, never use power conditioner with these, another for rest of system, this has power conditioner, third line is mostly excess for me, although running one of my streamers off it at present.

All else aside, make sure it's all done to code.

Don't forget to use two 9' copper earth ground rods wired in series with #6 solid core ground wire to the panel ground landing. 

Interestingly, the rods need to be 9' earth covered but not necessarily driven vertically. what you want is grounding to damp soil. If you are lucky and have an iron well casing that is the ideal earth ground.