30 ampere outlets require very special 30A plugs. They're not common to see on typical audio equipment. I would use 20A circuits with 20A outlets; they are backward-compatible with 15A gear.
As to whether you should wire multiple ones, just keep in mind that different circuits might have a slightly different ground potential, and hence cause a ground loop (hum).
Michael
As to whether you should wire multiple ones, just keep in mind that different circuits might have a slightly different ground potential, and hence cause a ground loop (hum).
Michael