Background Hiss on my system

I have a Sasui 9090DB that is in fantastic shape. and I am playing a Sansui SR-717 Turntable with a Grado P Gold cartridge. It is going through a Shittz MANI preamp before going into the 9090DB. The system is all on a battery backup and also a mid level ($200) serge protector. When I play CD’s or radio it all sounds very clean (especially the CD’s) no background noise. But when I play the Turntable I get this background hiss (not a hum, like with a ground issue) The hiss goes up as I turn the volume up. I get the hiss if I use the 9090DB preamp section and if I bypass it using the MANI preamp. I have upgrade ALL of the cables.
Here is where it get’s odd. When I play the turntable on ether of my other systems I do not get the hiss. Well, that would be the 9090DB then, problem solved… but wait. When I play the turntable into the MANI and then into a headphone amp I get the hiss. What breaks my brain even more is that when I hook up our other turntable to the 9090DB I get this hiss as well.
It has to be something with that room.
Any thoughts?