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.
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.

If this only happens at full max volume rotation, could be the pots wipers are going open circuit, and the input of the next stage (output line amp section) is seeing this open circuit and will be noisy. If this is the case and it’s fine when you back it off from full a little, then don’t worry about it.

Cheers George

Thanks for the replies. The speakers are Legacy Audio Focus rated at 4 ohm and 96db. The "noise" does stop just below full volume and there is no way one could listen at this level. I usually don't use more than about 33% of the potential volume level.
The "noise" does stop just below full volume

Then it could be the pot wiper going open circuit. If it doesn't start playing up elsewhere on the rotation, don't worry about it, as it's looks from pics I saw on Google a motorized one, and isn't going to be cheap to replace. 

Cheers George

I agree with the others that it's nothing to be concerned about.  The cause could be what George suggested, or it could be the inherent self-generated noise of the input stage of the preamp amplified by everything that follows (any electronic circuit inherently generates a non-zero amount of noise), or it could be noise introduced into the preamp as a result of a ground loop between it and the source component (ground loops can cause high frequency noise as well as low frequency hum).  Or it could be a combination of some or all of these things. 

Contributing factors are undoubtedly that your speakers are more sensitive than average, and the gains of your preamp and power amp are a bit more than average. 

-- Al