Passive pre with Bryston 7B ST??

I am wondering whether the Bryston monoblocks are suitable for passive attenuators/pre while the Bryston preamps (are said) to be the weak link of this pre/power combo. As the Brystons are pretty well known I'd gues that someone would have tried it with a passive pre (FT Audio LW1 for example)

The Brystons have a high sensitivity (0,8 volt) and a high input impendance. My cd-player (Musical Fidelity Nuvista 3D) has a low impendance 2 volt output according to the red book standard.

Any comments?