An odd idea

NEVER feed one amp's output into another's! The output impedence of the "disconnected" amp is MUCH lower (0.1 ohms or less with ss) than any speaker, and you'll quickly blow up the unused amp, right?

Unless you feel your system is lacking in dynamics or sounds like it's straining at your listening levels, you might not want to replace the amp just yet. There are a bunch of tweeks you can to to the typical H/T setup to improve performance. The first would be to adjust speaker location and make sure there is plenty of room between the TV and L/R speakers. You may even have to move them forward so that they are not on the same plane as the TV. TV's are bad for sound and the bigger they are, the more problems they cause. Even better would be to get a plasma and get rid of the box altogether.
You could also try is getting new CD's. One reason people are happy with home theater performance is because movie soundtracks are recorded at a higher sampling rate and sound much better then your typical CD. But there is alot of variablity even amoung redbook cd's. Look for newly remastered copies, HDCD's or enchanced versions of your favorite songs, DTS cd's, or even DVD video. I wish there was more out there in terms of multi-channel audio because the sound really is fantastic.
As a last resort you might want to consider a tube CD player. Some people like the tweekability aspect they provide, but i personally never found them to improve the sound as much as finding a better recording.

Again, thanks to all for the suggestions!

Tok2000, you make a good point . . . . I guess the speakers are the key, moreso than the amplification.

Subaruguru, thanks for the warning!

Perkadin, interesting suggestions! My speakers are already set up as you suggest -- about 2 feet out from the TV (any farther and they are too close to the side walls) and about a foot in front of the TV. I hadn't considered the CD quality issue, though . . . . and my system is definitely not lacking in power or dynamics. I've thought some about the tube CD player idea, too.

I think what I'm going to do is finish all the tweaks I can with the existing hardware -- install the 2-channel passive preamp, upgrade the 2-channel path cables from Audio Ones to Audio Twos, upgrade the power cables on both the 9000ES and the Rotel 985, and apply some isolation/damping treatments to both -- and try to isolate what I feel are the system's shortcomings in a little more detail.

I also want to play around a little with some room treatments -- I don't know much about that, but I figure that there's no shortage of places on the web to learn.

THEN, if I decide the new amp is a necessity, I'll pick one based on what I want for 2-channel, without worrying too much about HT integration, since I know that a) it should work OK, and b) I can always go with seperate speaker cables if it doesn't.

Again, thanks much to all!

Pat

I had a similar experience. I have a home theater system consisting of PSB speakers and a Yamaha 5.1 amp. I wanted to use a Cambridge A300 integrated to just run the mains. I could not, and still can not figure out a way to use both of the amps at the same time without turning up volume on both of them as the movies played. I ended up going to Radio Shack and buying a switch box for just the mains. As some of you pointed out, a mistake will eventually be made. I'm just lucky that the protection circuits in BOTH amps were up to the task and kicked out when I had both amps connected together at the same time. I like the idea of using bannana plugs and NEVER having the amps connected together.

Here's one that'll make you smile :) (And yes, this is a serious suggestion...) replace your TV with a front projector - and then use a retractable screen. This will eliminate a large sonically reflective surface right between the main speakers, becaues the screen will be retracted when you're listening to 2-channel. It has a surprisingly audible impact on 2-channel imaging. I learned this by accident, because I upgraded to such a setup purely due to space concerns when I wanted a big screen, but until I find enough money to build a dedicated theatre room (as opposed to a combined theatre and concert room), I'm not going back!

Also, I've gone down the same path as you have - my speakers aren't identical but they're pretty close. However, I discovered that even adding some very different surround speakers made less difference than I would have expected. In my case, I upgraded my surrounds from Triad Silvers (dipole in-wall cone speakers) to MartinLogan Scenarios (bipole floorstanding electrostatics), and I found that both worked equally well with the main MartinLogan panels up front. Their signatures are different, but this is only perceptible when playing 5-channel audio. I don't perceive the difference AT ALL when watching movies, except that the Scenarios obviously have more bass punch. There is a difference in 5-ch music, of which I have little so far.

I can also report that my amplification is quite different front to back, and this too is not an issue. I have vertically biamped my ML Odysseys with a Classe CA200 for the cones and a Counterpoint SA220 for the panels. (This took a little tweaking!) That's the equivlaent of 800wpc@4 ohms with mixed tubes and transistors for the fronts. The surrounds make do with just a single 3-channel B&K ST3140, at 175 wpc@ 4 ohms, all transistor. This is a pretty big difference, and the only one that can be readily identified is that there is some timbre change from the mains to the center and back. I don't notice the difference to the surrounds very much. I will have to upgrade the center amplifier sometime, although I'm having a hard time imagining precisely what I would put there...