I had the same problem, I play in a lot of rooms that are from the colo mining era circa 1881 with very suspect wiring, so i bought the carvin power conditioner and its dead silent now. And i think the class d gear is more sensitive to power surges as well causing some of the cutting out issues. I highly recomend the carvin, great features and delivered for less than $200.
Yep. Used the power conditioner I have all my studio gear plugged into and problem solved . . .