As far as cleaning up A/C, I've had excellent results with a PS Audio regenerator. I've used a P-300 on my transport, dac and preamp. It does impart a certain smoothness, in the sense of a sheen or haze being lifted.
Upgrading to a Premier model allowed me to power my amp as well with good results.
Upgrading to a Premier model allowed me to power my amp as well with good results.