preamp + amp (not PA)

i usually use this setup:
passive bass---preamp---amp---cabs

i mean that i use a preamp before the amp (not poweramp). this way i use two preamps. it's something, i think, like a bass with onboard preamp thru an amp. the preamp is a hughes and kettner tubeman plus and the amp is a swr sm 400s. i connect the pramp output to the amp instrument input. is there someone else who do this? i'd like to share comments on this solution.
thanks