pre-amp unacceptable noise level?


How much is an unacceptable level of noise/humming etc. from a pre-amp? I just bought a new tube pre-amp and when I replaced my old solid state one with it the noise level from the speakers practically tripled. There is an audible humming from the listening chair 10ft. away. I can't say I'm particularly happy with this considering the one I replaced did not do this.
fruff1976
There is an audible humming from the listening chair 10ft. away.
Just to be clear... is it hum or hiss? If it's hum, the advice above is all very good. If it's hiss, I suggest replacing the tubes with low noise variants. Tube hiss is common, but it can be fixed.
You should read this 10Audio review:

http://www.10audio.com/rogue_metis.htm

Particularly noteworthy:

"Downsides? A few. The Rogue is loud. There's much more spurious noise through my 89 db sensitive Soliloquy 6.2s than I'd like, and not just tube rush. I did have some issues with hum as well. Listen carefully and you can hear this from your chair at around ten feet."
I'd say hum and hiss + buzzing. It's just noise which can be heard in the room when the unit is turned on. About 20 seconds after you turn it on the buzzing/hissing/humming starts.
UPDATE: when I switch out to my old preamp the same type of noise is still there, just much quieter. You can hear it maybe up to 1ft. away from the speaker. It seems as if this amp is just accentuating the noise to an obnoxious degree.