Any way to reduce pre-amp noise floor?

I take it the noise is apparently equally loud in both channels? Did you yourself ever buy a new tube (stock or any other kind) for the CJ before the tube you have now, and do you recall running into this issue then (or any other time with your system, for that matter)?? How old is the preamp and how long have you had it? As it is, at this point I'm leaning toward either possibly some sort of bias problem (some preamps have or can develope them) or the tube itself may even be out of spec, but I'm not real certain how to diagnose it short of being able to compare it to another identical tube and I'm not that familiar with CJ's, but I don't recall running across this being cited as a natural trait of CJ's before. I'd try calling a known reputable repair shop, it can't hurt to just ask some questions. If it were me I'd call Wayne, my go-to man at In-House Stereo Repair in New Jersey. I tust him because time and again he's both discouraged me from unnecessary repairs and been upfront about not charging me anything for repairs he found he couldn't see through to the end. They're on the web. But, if you could try another indentical tube briefly and it gave you the same results you're getting now, then I'd say the problem may be in the preamp's bias setting, and if the new tube stayed quiet, then the problem would most likely be in the tube you have now.

My experience with a CJ ET3-SE was a soft white noise exactly as you described. Tubes do have a higher noise floor than SS, but the noise (I call it SHOT noise or thermal noise) seem perfectly normal with tubes. In my situation, the shot noise seemed to be "fixed" so as the volume went up, it falls farther and farther into the background. Turn your volume knob "up" and the noise should seem to stay about the same, in other words. This is why it isn't too bad with music playing. Eventually, the tube went bad, and made a scratching or sizziling sound in one channel...time for a new tube.

Go here for some tube basics on noise. I think your unit is just fine.

http://www.john-a-harper.com/tubes201/#Noise

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.