One or two dedicated AC wire ?

Would it have a signeficant audible in performance between: FIRST- a dedicated AC wire for an audio stereo system connected to a power distribution bar with good AC cable and Furutech Duplex. SECOND- the same as first version, but adding another dedicated AC wire, and an other wall Furutech Duplex, to connect only the stereo power amp. Would I hear a significative improvement for the investement of time and electrical parts ?
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+1 Elizabeth, " some point on the upgrade path..."
IMO that point occurs after you have done a dedicated room, correct set-up for the best sound quality, and room treatment. Then, consider a dedicated line(s). The room and the setup are going to determine at least half of the sound you will hear.
 audiosens, you have a beautiful system and it deserves to have dedicated lines to the service panel. Your power setup has good cables and the distribution block will receive cleaner unrestricted power with dedicated lines.

Your attention to detail with vibration control and system layout is to be commended. 
Are you in a position to run lines to your service panel?
And what power cables and conditioner are you using?
You may find yourself wanting the second dedicated circuit depending on what gear you're using. I have 4 dedicated 20A circuits, and 1 dedicated 15A circuit, and I'm finding I could have benefited from having at least one more added. But I'm a bit of an extreme case.
It’s almost what you "don’t hear" that might sway you-- if you equipment is on a circuit shared with other outlets, fixtures or appliances, dedicated lines can help reduce overall system noise. I’m not talking about obvious electrical interference from other non-audio devices (more about that in a second), but what, for lack of a better term, may help with a lower noise floor: the ability to hear more against a quieter background. That’s the ideal, anyway. It comes from fresh wire, fresh receptacles, best practices in routing the cable in wall, among other things.
As to electrical interference, it doesn’t fully "isolate" from the rest of your household electrical system since it ties back to the same ground, per Code. I’m not an electrician or a Code specialist, but there are some here who really know this stuff and can probably explain some of the practices you ought have your electrician observe, starting with an examination of the present panel. (I assume you are in the States since I have no experience with audio and electrical wiring in other countries).
If you are already busting through walls, making a mess and hiring some electricians, why not install several lines- it will make life easier later, especially if you change or expand your system, run digital or video in the same room, etc.
I did my most recent install when we moved to Texas a couple years ago; hired a commercial electrician who pulled a permit, set up a new subpanel, used very heavy gauge feeder (4 gauge) to a subpanel adjacent to the room and 10 gauge to feed the outlets. I did opt to install a large (10kVa) isolation transformer system for the hi-fi.
I had four dedicated lines with multiple outlets installed in the listening room fed through the isolation transformer and a fifth fed from ’dirty power’ on the same floor for my air compressor and record cleaning stuff.
The results of this work may depend on the infrastructure where you are located: when i lived in NY metro, our electricity had issues. Here in Texas, with far newer infrastructure, even without the isolation transformer, the power was better.
My experience has been that electricians don’t necessarily talk ’audio’ and may even think some steps audiophiles take are unnecessary or just dumb. It pays to educate yourself a little here-- some of the folks I look to are @Almarg and @Jea48, among others.
You’ll also get some views from people who have gone to the trouble to get their power sorted and how that affected system performance.
I guess my short answer is: part of it is peace of mind to eliminate potential gremlins on the branch circuit you may be sharing, and old funky wiring and receptacles that should probably be replaced for better overall performance. That’s not voodoo. The other thing I’d recommend is interviewing a few electrical contractors to get a sense of their views, experience and knowledge. Having owned a number of homes over the years, and having gone through this exercise multiple times, the caliber of electricians I have used has varied widely.
You’ll want that permit pulled and approved by your local authority when the work is done. Not only for safety and Code compliance, but to avoid issues if you ever sell your residence.
I’m sure you’ll get more detail from others- this was intended to answer the more general question of benefit and multiple runs.
I'd suggest going with: "SECOND- the same as the first version, but adding another dedicated AC wire, and another wall Furutech Duplex, to connect only the stereo power amp". You might hear a significative improvement for the investment of time and electrical parts, but there are no guarantees when it comes to high-end audio, its all system, room set up and power dependent.
Whart makes several good suggestions in his post above.
lowrider57, I already run one by myself so, the "audio senibilty" power distribution bar is already having a dedicated AC wire, I wonder if to add another one for the Moon W5 LE would help to have a better insight full music details ? I use Vibrapods on all of the equipements and they do, specialy, a good job under the speakers. If I insatall another AC wire, I would also need to replace the breaker for a split breaker (2 in one, Tandem Breaker) because the electrical panel is already full. The AC cable are also "audio sensibilty" and one "Harmonic Tecnology" Fantasy AC10. As I have 4 Furutech Duplex on the power bar, I would also be able to utilize and remove one Furutech NCF on the power distribution bar to be install on the wall with the new AC wire. On the power bar, I could install a new Duplex of less quality, because it would be use only as a spare. Is there a better way than to install a Tandem Breaker for best results ? I wonder if it worth the expense and work ?
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I hope somebody experienced in this area chimes in, but I don’t think a tandem circuit breaker should be used in this situation.... the 2 dedicated lines would be on separate legs.

IME, audio AC lines should be on the same phase and the current draw of devices in the home  should be evenly distributed across both legs on the panel.
Unless I’m wrong, you would need to put each dedicated line on their own breaker with ground tied from the ground buss to each receptacle (not self grounded).

lowrider57  Thank you. I will search for installing another small electrical panel near the main boxe, for the two AC audio dedicated wire
mental.  I have already a dedicated AC wire for the stereo only... no Tv or Video in this system.  So I was thinking in a second dedicated  only for the power amp. But it's seems not to be so easy
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Luckily my electrician owned a nice audio system and made great suggestions. Instead of adding to my small circuit box with old wiring and questionable grounding, he installed a subpanel for two dedicated lines (upgradeable).
A 60A tandem breaker was used in the main panel to supply the subpanel.
Example of a 20 20 Tandem Breaker.

Two single pole breakers in a common 1" enclosure. Both breaker units share a common buss connector.

More examples of Tandem breakers:
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