Question about using external power amps in 5.1

[kexodusc]

I just brought my old Rotel upstairs and hooked up to my yammie. I made a few quick observations which led to questions I thought I'd ask here.
First, when playing back in stereo, the Rotel (hooked up to the Yamaha RX-V795a's pre-outs) and the Yamaha sound noticeably different. In my probably biased opinion the Rotel sounds better.
Second, when playing a 5.1 track, the difference between the two units isn't quite as noticeable sound wise. The Rotel clearly has more power and handles better at louder volumes, more bass, etc...but at my normal listening level, the differences were subtle.

I'm awaiting a second hand Adcom amp to arrive to take over the Rotel so I can put it back in my main system. This got me thinking though, with all the hype about timbre matching speakers, does the same rule of thumb apply to matching amplifiers? That is, should you stive to have all external amps of the same make/model, components, or is there more flexibility with amplification? After all, amps don't all sound the same. I assume that the audible differences between amps at moderate volumes is less than the audible differences between speakers, which can vary substantially.

Second, I've only tried hooking the amp to the front main channels, is this the best way to go about this, or would I be better off to connect the power amp to the center channel. I ask because I keep hearing that 50-80% of all sound comes through the center. Would I be relieving more of the burden on the receiver's power supply if I connected to the center, or should I just stick with the mains?
Thanks

[topspeed]

when playing a 5.1 track, the difference between the two units isn't quite as noticeable sound wise. The Rotel clearly has more power and handles better at louder volumes, more bass, etc...but at my normal listening level, the differences were subtle.

I'm awaiting a second hand Adcom amp to arrive to take over the Rotel so I can put it back in my main system. This got me thinking though, with all the hype about timbre matching speakers, does the same rule of thumb apply to matching amplifiers? That is, should you stive to have all external amps of the same make/model, components, or is there more flexibility with amplification? After all, amps don't all sound the same. I assume that the audible differences between amps at moderate volumes is less than the audible differences between speakers, which can vary substantially.

Yes and no. Are you listening to multi-channel hi-rez thru your 5.1 se-up? You might be able to tell the difference a little more simply because the discs are mixed to utilize all channels versus a two channel recording being played back in DPL2, NEO 6, etc. which simply reconfigures the 2 channel signal over 5 speakers, manytimes not very well. There's a big difference. Also, the vast majority of dialogue and sound during movie playback comes over the center channel so you might not notice the two mains as much. If you have multi-channel hi-rez and plan on using it a lot more, it is best to have the front three powered by the same amp to ensure coherence across the front stage. You can probably get away with a different amp for the rears. In an ideal world it's best to have all channels driven by the same amp of course.

Second, I've only tried hooking the amp to the front main channels, is this the best way to go about this, or would I be better off to connect the power amp to the center channel. I ask because I keep hearing that 50-80% of all sound comes through the center. Would I be relieving more of the burden on the receiver's power supply if I connected to the center, or should I just stick with the mains?
Thanks

Most audio enthusiast that I know listen in two channel, with the exception of the those that have jumped into multi-channel hi-rez (which I can count on one hand). Putting your Rotel/Adcom on your center is a waste of an amp. If you can't hear the difference anyway, leave it on your mains so when you listen to two channel (if you do), at least you'll be getting superior sound to your Yammie. If this is really bothering you, look for a used 3 channel amp (Adcom makes one btw) to apply to your front and move the two channel to the rears.

Good luck.