According to the specs on the Pioneer website, the only preout on your receiver is for the subwoofer, so you can't add an amplifier to it. Your receiver will drive any main speakers with a sensitivity of 88db per watt or higher. You don't need to replace it unless you choose speakers with poor sensitivity.
The B & W 683 speakers are seriously over priced and not very good-sounding. They are a poor choice in any case. I have heard them described as "one of B & W 's mistakes"...lol. They really dropped the ball on its design.
The PSB Image T6 is a MUCH better speaker, for $1300 per pair. Read the review on it at the Stereophile website.
Put it together with the PSB C4 center speaker and a pair of B5 speakers for surrounds, and you will have a very nice system.
Another excellent system would be a pair of KEF iQ90 speakers; put them with the Q200C and a pair of C3 speakers, and you will be pleased. See the KEF Direct website for details.
Either of those will give much better performance than a system based on the 683.
The Onkyo 709 receiver has full preouts for all channels and will allow you to add external power amplifiers for the front channels if desired in the future.
Quote:
Originally Posted by
roblutts 
Hi, I bought a Pioneer VSX-50 last year and just figured out it will not be sufficient to power the B & W 683 speakers I want to
purchase. I need to replace the Pioneer and would like to know what anyone might recommend along with power amps. This would be for a 5.1 and eventually 5.2 set up. I have a Velodyne 10" powered sub and will replace the center and surround speakers with B & W's as well.
Thanks for the help!
Edited by commsysman - 7/21/12 at 5:58am