I had the V5xe Calypso combo. Not sure if you are talking about hum through the speakers or of the amp itself. I had no hum through the speakers, but no matter what I did the transformer itself in the amp was buzzing a bit. Ayre went out of their way to try to fix this...ultimately sending me a different amp which was quieter. Interesting fact was that the amp also hummed at the dealers in a different setup (though also tube preamp), and that his V5x was dead quiet, unlike my evolution. Note that I have the Vandersteen 5a's so a crossover was between the preamp and amp. Ultimately I sold the amp and went to tubes, which I have found to be more musical in my system. I suggest you take the top off the Ayre and see if pressing on the stamped metal transformer cover makes the amp more quiet.