AC Power - two circuits better than one?


Reorganizing my system starting from the wall receptacles (rewiring is not a possibility) but quickly ran into a conundrum. Is it better to source power for my audio system from several different circuits or one dedicated circuit?

More info: I have three possible options. Two 15 amp circuits (1 shared with a couple of lights the other with several wall receptacles including a pc) & one dedicated 20 amp circuit (but with only one single duplex outlet). I have mono blocks, power amp, preamps, digital & analog audio sources, & digital HT gear.

Should I distribute my system across these three circuits or try & source them all from the single dedicated 20 amp outlet? If distribute, what kind of break down makes sense?
salmonsc
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Jea48 Actually I have 4 separate circuits (not dedicated branch circuits as you described). I live in Mexico and had an electrician do the work. I would assume that circuits 1 & 3 would be on leg 1 because they are odd numbers while circuits 2 & 4 would be on leg 2. Here they use multi-strand wire, not romex so I had them pull three 12 gauge multi-strand wires from each respective breaker to the corresponding receptacle. The three lines were for hot/neutral/ground. The ground is grounded directly to the (USA) standard 200 amp panel which, in turn, is grounded to 8' of copper rod with #8 gauge wire.
I would assume that circuits 1 & 3 would be on leg 1 because they are odd numbers while circuits 2 & 4 would be on leg 2.
12-13-10: Puerto

Is the power that feeds your home 120/240Vac?
If yes do you have any equipment or appliances that use 240V? If yes check your panel you should see 2 pole breakers for the 240V equipment. (2 pole breaker takes two spaces.)

If that is the case then every other space down each side of the panel is the other Line, leg.

Line
L1 (1)......(2) L1
L2 (3)......(4) L2
L1 (5)......(6) L1
L2 (7)......(8) L2
ect.

Note: Twin breakers (slim) changes the ball game for the above example.
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What's the weather like?
COLD and snowy here in the Midwest!

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Jea48 Thanks, I don't want to get into the details but it's not possible - the outlet that's most convenient is part of a circuit that extends upstairs. In any event, it's not my house so reorganizing circuits on the breaker just isn't an option. I am going to load up the 20amp circuit as much as possible & divert the remainder to the cleanest 15amp circuit.
Jea48: We do have 120/240 servicing the house. Our A/C units use 240V with 2 pole breakers. Thank you for that input, now I can figure out how to get the pair of monos and the APC power conditioner/battery back-up on the same leg.

Weather here is chilly at night in the low 60's and gets into the mid 80's during the day! It is definitely "sweater weather" once the sun gets low in the sky.

Thanks again to Salmonsc for the informative thread. I hope others can benefit from the comments above.