Next thing to do is to have those 3 circuits put on an isolated ground. That is a seperate ground from the rest of the house. The new grounding rod should be at least 10 ft. from the original rod. You have gone half way, so you might as well finish the isolation process. Good luck.
Best Upgrade I've ever made
Like many I've been upgrading components over time. In the last year I've upgraded from Thiel 3.6s to Revel Ultima Salons, from a Krell KSA200s to a FPB300cx, from a SF Line 3 to an Ayre K1xe, and recently from a Sony XA777es to an Ayre C5xe. The sound kept getting better and better. But yesterday I installed three dedicated circuits in my house, one for the amp, one for the preamp, and one for the CD player. All other components are on the shared normal circuits in the house. The stereo now sounds like I've upgraded everything once more. Dynamics are better and most noticably the bottom has fallen out of the system noise. Hum and grung on the very bottom few dbs are gone.