New Dedicated Line - Almost No improvement

@laynes 

Have the grounding in your house checked.

I see people recommending adding 2 dedicated lines, one for amp and one for evrything else. If you do that, there is one more thing you can do that gives you opportunity. 

Your home has 2 legs of 120V power, generally one red and one black.  (Sometimes electricians aren't careful and they can get mixed up, since they are identical wrt 120V power).   But if you run one leg off of red and one off black, then you have 240V between them for running a european amp.  the great thing about that is that at 240V, the current is half that it would be at 120V for the same power.  Thus your wire is effectively larger.

What I did was just run 240V power to my audio wall.  I pulled 120V off the red leg for one set of 3 hospital grade outlets and 120V off the black leg for the other set of outlets.  I took the red and black to make a 240V outlet for my european amp (an Ayon).  

Those of you who understand electrical  (not many on this forum) may be asking yourself what about the neutral?  Indeed the neutral wire is shared between both legs but I don't find that to be a problem.  If the shared neutral concerns you then run 10-4 plus g instead of 10-3 and you can have seperate neutrals.

Jerry

@clearthinker You must be big on gedanken experiments--consistent with your name.   I'm pretty sure you haven't implemented what you suggest.  If you have, I'd love to hear how you solved the many problems you would have to overcome.  --Jerry

Isn't it against code to put 240V outlets in most rooms in the home? If so a good electrician won't do that for you.

I have my doubts a cheap sine wave inverter will be noise free. That's a giant switch mode power supply. Audiophiles are obsessed with perfect AC sine waves. It makes no sense.

My system sounds exactly the same at any time of the day when I am on holidays. When I am not it swings with my mood.

@carlsbad    Don't be so negative.  With most amps engineered to run on AC, one issue is the need to convert from DC. But apart from this, I doubt there would be difficult problems once suitable batteries are sourced.  Far less difficult than getting rid of noise on the mains.  And less costly probably.

But no I haven't implemented.  I've thought about it and am doing so more currently (sorry!).  Dedicated battery power supplies for pre-amps and phono amps have been around for years.  Running only them certainly improves SQ by eliminating noise on the mains at a stroke.  Certainly turntables can and some do run on battery supplies although, unlike some, I very much doubt mains noise finds its way to the stylus.

Having wrought some big improvement already at cheap cost, that leaves us with power amps.  I have read of powering single-ended flea-power valve amps on batteries, reporting positive results. But up to now running my big Class A Krells has put me off researching battery power because suitable batteries have not been in the mainstream.  But now I am guessing they are readily available given booming power tool and car applications  No-one could deny a car battery could easily run a big amplifier.  With my Krells it is noticeable the big draw is on switch on when the big capacitors are filled within a few seconds.  That dims the room lighting momentarily.  But once full, the topping up process draws a lot less amps.

@carlsbad  you have strengthened my resolve to start serious work.  Eliminating mains noise is certainly a very attractive proposition.