Subwoofer for Marantz SR4500

Hi everyone im new here but need urgent help because i have no bass!!

lol

I just got my hands on a Marantz SR4500 i have speakers for surround and front but they are only small ones and i have no sub!

I originally had a "theater in a box" style system where the amp was attached to the sub box so the sub had no "input" except for 1 pair of speaker cable going straight to the speaker itself. What i need to know is, is there a way of using that sub (without the amp attached) through the sub preout on the marantz without the sub having its own amp?

just to clarify, the sub is just the sub in a box with speaker cables going to the sub, no preamp or anything.

HELP ME NEED BASS