Aragon 2002 Pre amp to a Monitor Audio subwoofer


I have never used a sub with this setup but am doing so now. Can I use a 2 male to 1 female Y adaptor on my preamp out and run a single RCA to the subwoofer?
Or do I need to run 2 RCA's out? I know it is a monaural signal. My Monitor sub does have 2 inputs - but if can can use one RCA - that be be mu choice.

Thanks
timdavenport1967
Sorry - The power amp is the 2002. The pre-amp is an Aragon 24K. Hope this helps. Thanks for all the help!
I am assuming there are two pre outs,   run one pair to the amp and a pair to the sub.  You really dont want to tie the left and right preouts to each other .  Let the sub's crossover sum to mono.
If the pre has a single pair two "Y" adapters are required for each channel.   Connect left and right to the sub just as you would any other component. 
The problem with most such outputs is they are driven by a single output stage. If you short them, they will become mono.

Subwoofer inputs however are buffered, and keep the L and R separated as far as the preamp is concerned.

Best,

E
Thanks all. I will run 2 dedicated RCA cables and set this up like any other component. No short cuts. Now to run a second line under the house and back up through the walls.