You're probably overloading the input of the pre with your digital source(s). However, I DO think that some pre-amps have more gain than is necessary. 12db is probably enough..maybe less if there is no phono pre in the system.
Depends on the amp gain, and/or speaker sensitivity, room size, volume levels required, etc. etc. .....
32db of gain TOTAL is sufficient for most installations.
YMMV..
WEEZ