Hard to be certain w/o knowing what kind of speakers you have or what their efficiency is and how far away you are standing, but at full volume you hear a little white noise, that does not sound unusual to me.
What's that noise?
I am running a Plinius Tautoro into a Plinius SA103 amp. When I turn the volume to maximum with no input, I can hear low level white noise from the tweeter and a similar but more "jagged" sounding white noise from the mid range driver. I am running the system on a standard household circuit (including outlet) through a Furman Elite 15PFi. What might be the source of this noise? It does not sound like 60 cycle hum.