Ayre k5 Pre + subwoofer ??

Anyone running a sub in their system with an Ayre k5 Pre? How do you have it hooked up ? Can you run the balanced out to your amp while running the RCAs into a powered sub ?
I think you need to run your out to a crossover and then to your speakers and sub from there. Your sub may have a built in crossover. If so then I think you need to go to your sub and then to your speakers.