I currently use 10W Tripath amps in my main system. The amps are powered by 150W Tamura SMPSs, which are in turn fed by what has now grown to a small maze of power conditioning components. The maze grew from my little restrained drive to experiment (how did John Mellencamp put it, "I'll try anything once but then do it to death ..."). I heard improvements adding each component: isolation transformer --> active conditioners --> balanced AC transformer --> SMPS. The look of my electricity on a good day sans conditioning has a nice square top.