Thanks for the feedback. What I want to do is to listen the front, rear and back speakers using external amps; and use the receiver's internal amp just for the center channel. Is my first time using both: receiver and amp. My prevoius system was a prcessor to pre-amp, to 3 amps. I read an article saying that in one receiver (don't remember which one) the speakers terminals were disabled when the pre-outs were used to avoid having both simultaneously. My doubt is that if I use pre outs except for just that center speaker: the internal amp will work for that speaker???; or if it could affect the receiver for just using one channel from the 7 of the receiver.