Don't share transport or CD player to your amp's on the same outlet. This seems the most effective way to remove the grainy high if rest of components are already fine. I used to have Martin Logan, and it is the best sensor to power line noise. You can hear the background noise after turning on lights or refrigerator running. Add one conditioner do help to reduce that noise. So, I think a good conditioner make sense if you can't isolate noisy electronics like air conditiner, refrigerator, PC, transport... to differet outlets. If you already isolate your noisy component, then it is not so critical.
