I think this is the first time I’ve responded to someone on audiogon. But after reading what you want to do I thought I should pass on my experience.
I have had two dedicated supplies for my hi-fi and TV for about 10 years. it will make very noticeable difference, but only if you are aware of aspects that can degrade sound quality for various reasons.
over the years I’ve made many slight adjustments to make improvements, but mainly to isolate the two circuits better. Because the biggest problem you will have is if you have two separate circuits supplying your hi-fi, but your equipment is linked together, thus creating a bridge between the circuits through your equipment earthing and neutral cables.
I’m not sure what country you live, but here in the UK ring main circuits (sockets) are only switched by the live cable, the neutral (black wire) remains unswitched all the way back to the fuse board.
So straightaway you have to be careful because in certain circumstances you can create a voltage potential between the two circuits, if one fuse is off but the other is still on. This is because if the neutral cable of one circuit is somehow connected through your equipment to the other circuit the neutral cable isn’t isolated. Sometimes this can also happen through the Earth cable if there is a connection between neutral and earth through electronics. That situation is rare but it is possible, just wanted you to be aware as it is dangerous, or could damage your equipment over time if happens.
Anyway, the main problem I experienced is a link between the two circuits through earthing. This can occur in many different places unfortunately, and it takes a lot of consideration to be aware of them all.
So being aware that I have already written far too much and convoluted the point I’m trying to make, sorry, I will get to the point.
I have made great strides in improving sound quality, mainly by isolating the circuit for my hi-fi from everything else earth wise. Although the sound quality was good, it always had the typical higher tone associated with digital audio.
So I would highly recommend not to have your hi-fi spread over two different circuits. If you do try to consider in as much detail as possible all the possible ways that interference can be transferred through earthing of power cables, Ethernet cables, equipment casing, power supplies... between the equipment plugged into the two different circuits. as you probably know some equipment can be a bigger source of unnecessary interference than others, computers...
sometimes also it is good to unplug everything to completely isolate it from the power, because like I said neutral and earth cables in the UK at least are not isolated when you switch off the socket. With this in mind it is possible for electrical interference to build up in areas of electrical equipment, so properly isolating them occasionally allows it to dissipate.
So, sorry for the long and convoluted reply, I just thought I should pass on my experience. Like I said you will notice a difference, but how much depends on how well isolated your circuit is from spreading interference across from other circuits through earth connection of various cables...
Best of luck