Musical Subwoofer for 2 Channel System BUT....


I have an integrated amplifier (Karan Acoustics i180) with no sub out: only inputs and the speaker posts.

Does anyone have a suggestion for a great musical sub that would work with this setup? I am looking to spend under $1000, new or used, and the amp is paired with KEF Reference 1 speakers. Oh, and I listen to a wide range of music, but tend toward Blues, Jazz, and female vocalists (e.g., Nina Simone, Natalie Merchant, Margo Timmons).

Thanks, really, for any help.
mbwd
I use the Karan Kai-180 to drive my Quad 988's with a pair of Rega Vulcan subwoofers.The subs hook up similiar to the Rels(speakon connectors that take the signal from the Karan binding post).I feel that this is the best way to hook up subs.
I have to second the ACI suggestion.
Any used Titan or newer models is a great deal and incredible value.
I have upgraded my system countless times the past 6 years and the ACI Titan sub hasn't budged.