yamaha ns aw150bl 2 way indoor outdoor speakers pair black

 I am currently running a Denon avrx-1000 to power a 5.1 channel theatre system.  I recently added 4 outdoor Yamaha Ns-aw150 rated at 6ohms 35-120 watts. I want to use the pre out of the denon as a zone 2 for the outdoor speakers.  I know that I need a separate amp to power zone 2 but I have no...