Any way to reduce pre-amp noise floor?

Its normal to have a noise floor on any preamp. In this case from the last post by Shoff the noise is apparently not affected by the volume control.

So it can be the noise of the line stage and that of the amplifier. A lot depends on how quiet the environment is; if very quiet then the noise floor could be heard.

I would not worry about it unless it gets louder over time. Then I would look at replacing the 6922 in question. Until then, I suspect a new 6922 will be as quiet as the one in there now.

Do you have lights on with dimmers on the circuit? Dimming the lights can make your system buzz..it did with mine. All the way on or all the way off with dimmer-equipped lights!

Thanks for clarifying the volume-control/noise behavior. Clearly the unit is muting the output at volume=0.

I just looked up its specs: 25 dB of gain - holy COW that's a lot of gain (average these days seems to run ~ 11dB-14dB)! You're going to hear some noise floor with a linestage of such high gain, unless your amp/speakers are very insensitive (and thus would need all of that gain). Since it seems like the volume control comes before the tube gain stage, you're effectively "throwing away" gobs of gain without reducing the noise floor generated by it (I'm assuming you're keeping the volume control relatively low for listening). That's why your noise floor is discernible. I've got the same situation in my own setup (tube linestage, > 20 dB gain, 93dB/Watt speakers and 250-Watts@2V amps) - it's not detrimental to the sound quality in any meaningful way.

If this continues to bother you, you may consider sourcing some fixed attenuators to insert between your preamp & amp (i.e. attenuate AFTER the excessive gain stage). You'll effectively increase your signal/noise ratio by the amount of attenuation (maybe try 10dB). Just don't go too far to where you're gain starved on certain recordings.

Perhaps the gain is high so the 54dB phono stage can be used with a low-MC cartridge, with the extra linestage gain to cover the deficit. And I guess some manufacturers also try to accommodate for users with super-inefficient speakers.

Thanks again to all who have responded. (Sonic Beauty, reostat is not the culprit!) Although I plan to give CJ a call to get their take on the noise, for now, I'm going on the assumption that the noise is of the "normal, naturally occurring" variety and not associtaed with any malfunctioning equipment (although I might do some tube rolling!). I will post again if I'm successful in reducing or eliminating it. It is comforting that so many of you took the time weigh in. Thanks again!

I called CJ today. They said the issue was most likely caused by the noisy Electroharmonics 6922 (stock) tube. They recommended a Telefunken as a replacement. As long as I'm tube rolling, what else would make sense? I think I'll start another thread and ask the community.