Outlier,
My neighbor helped me put in a couple of dedicated 20 amps line in my house. It took us about 8 hours to do the job. We did cut one hole about 12 x 20 inches and a couple of much smaller holes to pull the wires. My neighbor is an electrician so I was pretty lucky.
After it was done, I didn't hear any improvement in sound quality. My house is fairly new and the ac wires are pretty short since the circuit breaker panel is right below the outlets so I may not have much voltage drop.
You live only a couple of miles away from me. If you are still interested in dedicated lines, I can check with my neighbor and see if he can recommend some good electricians.