quiet hiss in backround?

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...

No I can't say it's a gain issue definitively but it might be. Gain may be adjustable internally which is the case with mine. Call Krell and ask them if they have any insight and if the gain is adjustable and try it.

I would be asking myself a few additional questions: Has it always done this? Did my old equipment hiss? When did I first notice it? Did anything change that might have caused it? Is it definitely the amp (i.e. turn everything else off, try different cables, single ended, balanced, speakers, etc.- borrow them from a store or a friend)? If it is definitely the amp and it's not affected by cables or speakers then I'd be talking to Krell.

thanks mike. it has always done this and i remember a few years ago i discussed it with some guys who are much more knowledgeable than i (they worked in a high end shop here) they said it was normal. i sort of let it go but as i started thinking about it again, i figured this would be a good topic. almost certain it is the amp as i have had different cables on both and it has always been there. i do think it is worth an email to krell.

If that is the case another amp may be in the cards for you.