Choosing proper gain for preamp. Am I screwed?

I am in the process of selecting a new preamp. Some candidates offer customized gain (output), all offer only three inputs (good forme: CD, DVD, cassette deck). I find it amazing how diverse my CDs are in their playback levels. For example, for normal listening levels some require my preamp volume be 15, and some 38!? I can understand some discrepency, but not that much. If I could turn my pramp up to 250 this would not be bothersome. But much past 42 seems to kind of approach maximum voltage territory to my power amp. My CDP puts out 2.3v RMS. My DVD player puts out 2.0v, yet I always have to crank the volume way up on my preamp to hear dialogue adequately (again, upwards of 38). (And my tape deck 490mv.)

What I do not want to do is have a preamp built for me which limits the gain so that I'll not be able to reach adequate levels for DVDs and my wimpy CDs. But I think I'd rather not have the standard 20dB of gain either. My power amp's sensitivity is just over 2v. Way more (10 times?) than my power amp can ever use.

I guess my first question is, what is likely the major cause of the playback level discrepencies?

And,not knowing what the gain is on my preamp (because it is an integrated and they don't specify), am I destined to specify 20dB gain on my new preamp outputs just to be safe? (Seems to me, 10 times the amount of gain necessary to drive my amp to full power would make for crummy low-level listening and also add a bunch of unecessary noise.)

Any ideas would be appreciated. Thanks.