Speaker Hiss with Krell Amp

dsper, 

I also own Krell evolution series components.  The hiss you're hearing is common among Krell components. As long as 'hiss' sound is not audible 5-7 feet away, you're A-ok. Here is a in-depth article that explains audible hiss,

http://www.gcaudio.com/resources/howtos/systemnoise.html

Hope this helps! 

Personally, I would stay far away from any component that causes hissing.   Why would anyone buy a Krell Evolution knowing it produces hiss?

Well Stereo5 that is what I am thinking given all the info about noise floor and retrieval of low level detail not to mention something could be wrong with it.

I also know that there are not connectors between the XLR pins so Almarg could have this right.

The hiss is audible about three feet away.

I would find that unacceptable. This awkward, as I've been pushing a Krell audition for your CS 5's for some time. Perhaps, Al is right. He usually is. IME, most Krells seem to work best when used in balanced configuration, though I can't really comment on Krell's CAST usage. 

dsper,

If you are hearing 'hiss' 3 feet away then something else is also contributing to that noise.  Unless you favor Krell sound over the rest of the aforementioned components I would not recommend Krell amp in your setup.  

In my setup, I only hear 'hiss' sound when I draw my ear close to my 800D2 tweeter. I used to own Classe SSP-800/CA-2200/CA-5200 components that were dead quite.  Call me crazy, but I prefer Krell sound over Classe, even with that faint 'hiss'. 

Good luck with your search!