I have no experience with the SansAmp BDDI, but I do have the RBI. That preamp is clear as a bell, and unless it is damaged, should not be adding any noise to your setup, even in active mode.
Boss pedals can get noisy, depending on the effect type and power source. One at a time, remove each pedal from your train and see if the noise goes away.
If you're using batteries, make sure they're fresh. If you're using an adaptor, then you may have a ground looping/phasing problem. That's a situation remedied by the Voodo Labs power supply - a great unit for players with lots of different types of effects.
Another good place to check is in your cables. Make sure they are all working properly, as short as possible inbetween pedals, and are not overlapping or near your power cables of any sort, as they can pick up interferance.
I hope that helps out some.
- dan