Thanks mate, with my onkyo, the speaker provide really good bass, power but when listenning to symphony such as 1812 overture, I feel the sound become a little mess
I guess the reason is when it come to big scene，my onkyo start to losing control, also, its pre-part is not as good as a sperated preamp.
My attention is to push my speaker to its limit with my budget, only for stereo, So forget about the onkyo, I guess a pre/amp set ups would be a good solution.
I'm looking for a preamp good for symphony with KG5.5 around $500
For power amp , thanks for your advice....