Speaker noise - hissing

Came across thread while searching for solution to my problem of low level hiss emanating from my speakers. Have a SS amp and a tubed pre (Audible Illusions). I've cleaned all the connections in my system, made sure all connections are snug, made sure turntable ground wire was securely grounded, switched out the tubes in the preamp, rerouted cables and wiring to make sure they did not cross each other, and I still hear the hiss from my listening position 9 feet away. It's like the pea under the mattress; a minor annoyance, but an annoyance non the less. Previously, system was dead quiet between songs or during quiet interludes. Now, low level hiss is always on my mind. Only time it goes away is when I wear earplugs; but have a hard time hearing the music. So, thinking that may not be my best solution.

Rockyboy, When you changed out the tubes, did you replace the tubes with tubes tested for low noice? Lots of NOS, and new production tubes are not all that 'low noise' in demanding applications like your AA.

I went back to the tube set (E88CC/6922) that I had replaced in April. I never heard any degradation of sound while using these tubes; I replaced them only because of their age. I don't recall hearing any hiss during their use nor do I recall hearing any hiss after installing the new tube set. It's only been in the last couple months that I've noticed the hiss. I'm racking my brain trying to identify what event coincided with the onset of the hiss. For the life of me, I can't come up with one.