How important do you think power conditioning is for class D (as opposed to other topologies)? I assume part of the answer is that it depends upon the power grid that feeds your home.Today there are a number of class D amps out there that are worthy of attention by any audiophile whether you prefer SETs, class A amplifiers, or whatever. They have gotten that good. Take it from someone that has been about as dedicated to class A and tubes as it gets
My amps sounded fine powered directly by the outlet, but power conditioning makes them really sing, however the kind of conditioning that worked for my previous A/B amps did not work well with the class D.
Regarding solar power: paying $24/month is fine with me (the monthly cost of a grid-tied meter).