Help with Sub Woofer connection


How can I connect a sub woofer in my current system System consists of a custom made 25 watt per ch. integrated amp and JM Labs Electra 906 Monitors. Amp Does not have any pre outs.Is there any way to add a sub woofer to this set up?
oddmorning
All I'm saying is I've never found a subwoofer crossover to come anywhere close to transparent (when passing the audio signal forward to the main speakers).
Happy Holidays!
Dweller, I agree with you. I do not believe in extra crossover in.....if you study the set up I advocated, the integrated signal would run directly into the main speakers, without passing through a subcrossover. Furthermore, the sub would get a full range signal and its crossover or drive would reproduce the only thing it could. My wiring system does not send all signals to the sub crossover and then, some back to the main speakers, after it has been crossed over, by what is most likely an inferior design. The main disadvantage of this set up would be that the signals to the main speakers would the fullrange, thus not really cutting any output in the lower frequencies. Still, for what I can hear, it works fine. Cheers all!
Bmopti123: Yes, this sounds good. I didn't read your orig post closely enough. As long as this setup doesn't present some wierd impedance profile to the integrated.