Dean Pace EUB w/ Fishman BII ?

Apologies if this has been discussed before, I searched but got too many results with these keywords.

I've had a 2015 Dean Pace EUB for a few years, I believe it is the passive pickup model. I've been playing it through a GK MB112 and it sounds okay. The other day I found my old Fishman BII and connected it to see if it would help the tone. Bass into the Input channel on the BII, Output channel to the amp.

The bass doesn't make a sound, LED doesn't light up. I put a new 9V in the BII, tried other cables, nothing. Remove the BII and everything works again.

Is the BII not compatible with the passive pickup?
TIA
 
FWIW as often happens, it was Operator Error. I realized that one of the guitar cables I was using is a stereo cable, and that's why the preamp wasn't working. Use two standard cables, and all good now.