Any way to reduce pre-amp noise floor?

If you believe your system otherwise checks out and there are no identifiable connection problems, grounding issues or faulty components and all that, then you are very likely indeed looking at electronic noise. This can be thought of as noise from the power lines coming into your house, but is actually EMI/RFI in general which also comes into your system through in-wall wiring, from within your components themselves and even through the air. There's also the issue of power supply crosstalk that's too lengthy for me to go into here, but it looks like some form of power conditioning solution should be on your system to-do list. Your assumption that that the noise may be preventing you from hearing all the music is correct, but likely much more than you may feel you have reason to suppose. There is the noise you can hear itself, which as you rightly point out can have a masking effect. But, there's also the purely electronic component to the noise which is far more destructive to the sound than most 'philes realize because it obscures the sound signal before it ever reaches the speakers...and that sound you never hear no matter how loud you turn it up or how good the system is. This second, purely electronic, effect of noise typically has a far greater adverse impact on the sound than the above acoustic one, but when the acoustic problem is present enough to be problematic you can bet the acompanying electronic component of the noise is disproportionately large and would well benefit from some power conditioning. PC has been around for a good couple decades or more so there is a ton of it out there these days, but traditionally there have been problems with getting it to properly filter out the noise without also restricting the audio bandwidth as well. Any more, all-in-one-box-solution power conditioners in the big leagues START at around 5 grand, but none of that is what you'd need to be looking at...IMO no one does, really. The one-box designs necessarily can't take into account the EM/RF problems with in-wall wiring and through the air, anyway...let alone they're unnecessarily expensive. For my money, I'd try going to Alan Maher Designs' facebook page and at least see how inexpensively things can be tried and/or get done. His new Quantum solution is what I'm talking about. Yes, I've tried it and no, I don't work for him nor am I acting on his behalf as anything other than a satisfied customer. Consider other options as you will, it's just that I don't see how you'd be able to impact the problem more effectively for less money (we're talking 40 bucks here, for something called the Q-mini, to dip your toe in the water, and even that may do it for you). You need to become a facebook friend of Alan's before you order, but he'll help you with that and all the rest. But, the main thing is that you'll not just be pleasantly surprised by the effects of good power conditioning, but absolutely blown the f away by the difference it makes...I mean, if not, then I think you may be doin' something wrong if you know what I mean, but I think you easily stand to come away from the original problem with the sound of a whole new system. Hope this helps.

All that said, a noisy tube could very well be the culprit though if there's no noise at zero volume.

Thanks to all of you who have responded. Here is some more information to address your questions and comments. (1) I am running a Balanced Power Technology (BPT) CPC power conditioner with H-20 filtering. (2) All of my power cords have been upgraded from stock (Transparent and Cullen Cable). (3) CD is the only source component. (4) My listening position is 12 ft. from each speaker at which point the noise is only somewhat audible. (5) The noise floor DOES NOT increase as the volume is raised. (6) The 6922 stock tube used by CJ has less than 500 hours on it and I can honestly say that I CAN NOT hear the noise with music playing although I intuitively suspect that it is contributing to overall sound degredation.

Keep the comments coming but I think my first plan of attack is seek a low noise 6922 tube. Any suggestions?

Use low noise resistors in that circuit. But you are always going to get some kind of thermal noise from a tube depending on the gain of the circuit.

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.