Janis Woofer substitute

I have a Janis A-1 Crossover amp with out the original 12"subwoofer & cabinet what can be used as a suitable replacement?
I had the same. The Janis is great for music and can't really be beat. However, for home theater, it is too weak. I ended up with a 15" 400 watt velodyne and don't miss the janis at all. Resale price on the Janis gear is the hardest pill to swallow.
Greetings, Do you remember how much power was in the Janis A-1 amp. I was told that subwoofers to day are to power hungry for to amp to drive.Emrys