Using a 7.1 (5.1) receiver... intriguing. Can you explain further the hook-ups? Not very tech savvy, just love to listen to great music.
pandacan
Okay, first of all don't bother with a 5.1 receiver, they're vastly outdated. Go 5.1 if you want, but use a modern 7.1 receiver to do it.
If you don't want to spend too much, you can get your feet wet with something cheap-but-excellent; Look into something like the
Marantz SR5003 B-Stock
Now let's assume you have two speakers right now, each powered by a single mono block, which in turn are driven by your pre-amp.
Am I correct in this assumption? Because if I'm not, we can't go any further!
Now the SR5003 for example has 7 channels of amplification itself, being a receiver and not just a separates processor.
However it does have a processor section with RCA pre-amp outs, just like the outputs on your current pre-amp.
You could use the pre-amp outs of your surround receiver to the inputs in the monoblock amplifiers. This will allow you to get up-to-date at least as far as things like Blu Rays. For Blu Ray players, I recommend the Oppo BDP-83 if you can get your hands on one (possibly on the used market). The marantz will also handle input of CD player and other inputs, and can bypass video towards the TV (this is prefered, as I don't like using any video processing on my receiver)
Now this still leaves a few things...
-subwoofer
-surrounds
-center
you still need these things for a proper home theater experience. Because the receiver has its own (90wpc in stereo, ~75 wpc into five channels) amplification channels, you can power the center and surrounds with those channels, and leave the monoblocks to handle the load of the main Left/Right speakers. You'll be able to watch movies in stereo mode until you add a center, surrounds, and subwoofer.
And finally, a subwoofer, preferably two, which can extend to 20hz or lower at 105-115db cleanly or so is recommended IMHO. This would also be connected to the receiver via its pre-amp outs; subwoofers need to be powered externally as receiver amplification is insufficient for this duty. Most subs are active anyways, so it's not an issue. We'll gladly recommend you some great subwoofers once the time for this arrives.
Your receiver (or pre/pro should you go that route and buy more separate amplifiers for the center and surrounds) will then handle the proper integration of all these parts. We can help you out with that as well when the time comes.
It would really help if you could elaborate on
1) What your current preamp is
2) What your current monoblock amplifiers are
3) What your current stereo speakers are
Now if you wish to listen to multichannel music, the concept of timbre matching becomes vital particularily for the center channel speaker.
