Adding a subwoofer to a system question

Wasnt sure if I should post this here or in the Misc. Section, but figured I would get more answers here.

Here is my question : If a subwoofer such as the Sunfire True Subwoofer Super Jr. ( using this for example ), is added to the system, is a Preamp needed IF the CD Player that is used has volume control ?

Here is another question regarding that....I have a pair of Klipsch Forte 11's which dont require a lot of power to play loud, so could a inexpensive tube amp be bought such as a 2a3 tube amp ( or any low power tube amp for that matter ) that has nice mids / highs but doesnt have the low end be used and that is where the sub would come in the picture ?

Advantages / Disadvantages ?
Here's a low-cost but very good performing solution.
Get a Paradigm X-30 crossover (about $100-125 used here when they show up). Run your volume controlled CD player into the X-30 and the outputS (now 2 for sub and amp to speakers) from the appropriate outputs on the x-over. You will then be set!

An even cheaper way would be to split the signal from the CD player using a simple line-splitter (radio shack has them)
but with that, both the sub AND your amp would be seeing a full-range signal. The X-30 is a NO brainer!

Also, 2a3 amps usually cost MORE then a KT88 or EL34 amp and have low watts (usually 1.5) I don't know the sensitivity of the Forte 11's, but they'd need to be close to 99db for a 2a3 amp. If looking for the SET sound, consider an 8w 300b amp. But if looking for a lower cost route, try an EL34 or KT88 amp.
Good Luck and Good Listening!
Myraj hit it perfectly!
Since bass is so power hungry, a sub with a nice crossover will take all of the strain of reproducing low bass away from the tube amp and you will get much more bang for your buck. ie 6 watts to drive everything above 80hz and 250 watts for the bass?
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Thank you for your input on this.