quiet hiss in backround?

I do get a slight white noise from my speakers,but you have to put your ear to the tweeter to hear it..I would assume that is normal..But if yours is audible from more than a couple inches away from the tweeter something isn't right..Did you try removing the Audio Prism???

yes. i think it is a bit louder without it which seems to suggest power issue.

My system is dead quiet even when I press my ear to the speaker. I personally couldn't live with any noise at all. I did recently have an issue on an amp I bought and the manufacturer explained the difference between a hiss and a hum. He said a hum usually comes from a ground loop issue which is easy to diagnose by lifting the ground using a 3 to 2 adapter plug from the hardware store. He said a hiss is usually a gain issue from the amplifier and can often be user adjusted. If the amplifier gain is set very high it may hiss audibly. In the end my problem was an errant single ended/balanced switch at the amp input.

it does bother me. i would describe it as a hiss, not a hum so by your post it is a gain issue? i don't see how i could adjust gain on this amplifier...