quiet hiss in backround?

It's normal.

wish i was.

I have no white noise at all, are you running the loudspeaker cables over the power cables by accident? Otherwise start by disconnecting all devices and reconnecting them one by one

here is the response from krell (2 days later)...

Through Watts it doesn’t surprise me to hear some background hiss through the tweeter. It is normal unless it is excessive..

so i guess it is normal! thanks for all your thoughts.

i did switch my amps today not just for trouble shooting, i really wanted to hear how the 3250 sounded alone anyway. it really reinforced how much control the fpb600c has, most notably in the mid and low bass as well as presenting a ton of air between instruments. actually very disappointed in the sound of the smaller (which really is not small) amp. a $6000 amp should sound much better in my opinion. the flip side, the big amp is a stellar old amp (not that old)...

update,,,

after doing some reading in old threads re hiss, i went through and shut down one at a time and it seems the theta is the root. when powered off, the hiss is reduced and the only remaining noise is a very, very faint noise, more buzz than what i had, at the tweeter audible from about 4", significantly less. now i am thinking about shorting plugs on the theta unused inputs as a possible solution.