Wire the House A/C or get Power Conditioner?

You should do both, but follow the path that Rushton suggests. Been there, done that and wish I'd done the double run of 10AWG & high grade outlets first. And an emphatic YES; high quality power cords are part of the equation also. I'm using an Audio Magic Stealth XXX, and have found it an excellent conditioner, coupled with Synergistic Research's power cords

Keep the runs separated by about six inches, over their total length, to avoid any induction.

I bought a brand new, American made, 250' spool of 10/2 Romex off eBay, for $75.00(shipped). That was about one third the price locally. It's YOUR aural satisfaction that's important, not your electrician's happiness! Use 10 AWG for your dedicated runs.