Active sub with a stereo amp

Does it make any sense to connect an active sub to a stereo amp?
I believe, in a multi channel receiver the sub output receives the lower frequencies for the sub.
What about the pre-out in a stereo amp? Is it meant to drive a sub woofer?

Another question:
If one connects an active sub to the amp, what happens to the bass drivers on the main speakers (if they have one like many floor standers have)? Do they still get the lower frequency signals?

The stereo amp I am going to use is the CA 640A V2

~dich

Yes, it does make sense to get an active sub for a stereo amp. In fact you would be best served by getting two subs! A passive sub is a needless drain of your amp's power and good tuning will let your active sub blend in quite well with the mains. To address the other part of your question please remember that in a multi-channel setup the sub also receives the LFE output which is responsible for rumbles and other... well... low-frequency effects :-) Thus it is not optional unlike a stereo setup.

Yes, the pre-out is meant for a connection to your subwoofer. There is nothing in the CA documentation to suggest that the pre-out connection will cut off any frequencies fed to the main speakers. In my CA manual it only states that the active sub is connected via the pre-outs. So I guess the safe answer is your mains will still receive the full range of sound.

Thanks you.
Now to start saving for an active sub.

~dich