Preamp hissing detectable at low volume?

Tubes can make a hissing sound sometimes called tube rush. I have a tube preamp and when I put my ear up to my speakers with no music playing I can hear a steady hiss in one channel.

Tubes do have many fine characteristics but they can be noisy. Some can be dead quiet too. I'd swap some tubes if you have extras and see if it affects the noise.

You should be able to buy some very quiet tubes if that is your problem. Some sellers grade their tubes on how quiet they are. Phono stage grade being the most quiet.

Thank you all so much for your responses! This rushing sound is audible from my listening position during idle, and it is evident to me during quiet passages. And thanks for your thoughtful instructions Viridian. I am a little nervous about messing with the tubes in my discontinued SFL3, Special Edition. Can anyone suggest a good outfit for replacement tubes and/or upgrade of other elements within the piece?

Jim McShane is a good guy for tubes and info. He is a hobbyist, like us and appreciates nice gear:

http://www.mcshanedesign.net/

Good luck in solving the problem.

Oh, Jim's site is pretty rudimentary. Best to always call him, he will be receptive.

Great! Thanks Viridian. I'll give Jim a call on Monday. I appreciate everyone who took the time to help point me in the right direction on my tubular journey. Best wishes.