I might consider selling the B&K in favor of a Placette or an FTAudio(no remote) passive preamp if your setup will work with a passive pre. I know you can try the Placette for 30 days risk-free(and maybe the FTAudio too), so it might be worth a try to see what kind of improvements you get. These units fall between active preamps and attenuators in terms of transparency, so I guess I'd think of them as a convenient compromise. My guess is the improvements will be substantial assuming your source puts out at least 2 volts and your amp isn't a bear to drive. Best of luck.
Tim
Tim