I got the bug.. but need some input

I bought a new pair of paradigm studio 40 v4, but they just don't sound the same as my mini-monitors did with my Marantz sr5600. The minis sounded great with that amp, but there is something missing with the 40's. I would also like to bi-amp the 40's, so I am leaning towards a Sunfire TGA-7200 for an amp. I would also like to have a tube preamp, and that's where my head is spinning. I understand that the function of the preamp is to bring the source up to line level and feed it to the amp. But do I need a special tube preamp to feed into a 7 channel amp? I would at some point be adding HSU subwoofer. I have been looking at the used Cary preamps here and they look delicious. I need to keep the price down around 1200.00 dollars. Also any suggestions or input is greatly appreciated.
Here is my thoughts to your questions.First a pre is what you said but also acts as a volume control and a selector as it switches your components.A lot of people don't use a line pre-amp at all,they just feed their cd player to their amp,those cd players were designed with some kind of volume control.Now a tube pre is preffered by some for the warmth it adds to the music .I also use a tube pre ,the Rogue Magnum 99 and I would suggest to look into it as it falls in your price bracket in used condition.You don't need a special pre ,what you need is a pre with a home theater pass through signal and a 7.1 home theater processor to take advantage of your 7-channel multi-amp.The Cary slp-98 is very nice but they are selling for more than your set price.
look at the Cayin line, either the 88's or the 100's.