If sources with 2 V output go into some kind of distortion mode ( running out of steam, if you will ), how can a preamp help the distortion ? Enjoy ! MrD.Your right MrD, they can't.
By reducing that 2v source with the volume control of an active pre, just shunts part of the 2v to ground. The other part being used (just as "distorted") goes to the preamps volume control then the gain stage, "yes" to be boosted back up again along with it's own distortion and noise also.
Cheers George