Connect a sub to stereo system


Hi! Everyone! I am seeking advice/solution to connect a subwoofer to my stereo system. I have a preamp Adcome GTP-500II connect to CDA-250C power amp then to a pair of Klipsch R28F. I also have a Klipsch R-12SW sub, how can I connect this sub to my stereo system? 
Thank you everyone in advance.
justinpham2012
The difference between the two outputs is that the "lab" is direct coupled and the "norm" is capacitive coupled. I agree, use "lab" to the power amp.
The best way to connect a sub, ime, is coming off the speaker outputs of the amp into the speaker inputs of the sub. It will be more coherent. Enjoy ! MrD.
I don't believe your Klipsch offers the speaker cable connection option...