Y connector from pre-out to powered sub and...

I have a CJ Premier Ten tube preamp with two line level outputs. One set goes to my CJ MV-60 amp. The other goes to a Sunfire powered sub. I would like to play with surround and wondered if I split the second set of pre-outs to both the Sunfire and to a surround processor (and then to a surround amp), might this cause any problems? Would the two amps (sub and surround) "see" each other as loads and cause issues? Or, might it cause any sonic degradation to the main speakers in any way?
Thanks for thoughts.