What is the benefit of a second amplifier .

I’m still trying to decide what direction to take. Play all my speakers through my B & K 200.7 amplifier or have the main speakers run by a Second dedicated 2 channel amplifier. I’m trying to get the best sound possible from my main speakers, B & W 803s. When listing to 2 channel music I want to hear all the detail, and everything the speaker has to offer. When watching theater I want the full effect of the movie. I spoke with a gentleman from Morantz, who said I would gain nothing with the second amplifier and all speakers should go through a 7 channel amplifier and processor. I could then just hit the 2 channel button for analog. He also said in 2 channel analog the 200 watts are dedicated to my main speakers. I should hear everything I want to hear, there must be some other problem. The 200 watts would only allow me to listen to the music louder. There is no need for a second amplifier. If you say the second amplifier is better how do I hook this up? Please explain why it’s better. When watching theater all speakers should work together. When listing to 2 channels all speakers are off except the mains. I don’t want to move speaker wire between two ampfliers.
My advice is that if you are serious about a second amp for analog then you might want to consider a separate system altogether. It is a major step and not the most economical but if you want truly great 2 channel you need to think in those terms. Movies as you have pointed out require other attributes. Think about it, to me a separate system no matter how humble would be the begining of building a better system until you reach your destination. Buy cheaper mains for movies and use the B&Ws in your analog rig as a starting point. From there you have a world of choices.
This is a very complex discussion and how you go depends on how serious you are both from a sonics, and from a budget point of view.

The guy you spoke to is partially correct I expect. If your processor does indeed bypass all of the digital when in 2 channel mode - this may (or may not) help. Your power amp will indeed optimize on 2 channels when you're only driving 2, because the power supply is only supplying those 2. Your amp is a pretty good amp too; however, I doubt your amp compares favorably to a quality 2 channel only amp, and likewise the 2 channel performance of your processor probably compares poorly to a quality 2 channel pure analog preamp. What you need to consider is whether you want to invest in a separate 2 channel system, and connect it in "bypass mode" with your front speakers.

Bypass mode worksa as follows: You buy and install a high quality pure 2 channel preamp and a hi quality 2 channel power amp (or better still IMHO: 2 mono block amps) and connect then to drive your main speakers.When you are listening to 2 channel music exclusively, you are using this system, and you processor and 200.7 amp is turned off.

To listen to theater, the "main speaker" outputs from your processor are connect to your stereo preamp "passthru" inputs, which pass the front channel signal through to your main speakers. This can be an expensive way to go, but it is hands down, and far away better for 2 channel music performance, and no worse for theater performance than whayt you have.

Some stereo preamps have built-in passthrough channels, but even if the one you want doesn't it's possible to set it up to work this way. The nice thing about preamps with passthrough built in is many of then need not be powered on for HT mode.

Finally - could you improve your performance by simply adding a dedicated 2 channel amp and not adding an analog stereo preamp? yes you can - with the right stereo amp (or pair of monoblocks). This won't get you all the way there though . . .
The system you have currently is plenty good enough unless those B&Ws are in a very large room. I would simply connect the B&K amp to a nice 7.1 processor and be done. Emotiva makes a well-regarded units, the UMC-200, and is due to release their up-scale XMC-1 soon...

I have a hybrid 2 channel stereo and 7.1 channel movie system. I have the 200.7 amp. My speakers are Sonus Faber Cremona. The 200.7 had plenty of power to drive them, but the sound was bright, something B&K is noted for. It works well for theater, but less so for 2 channel. I ended up with a separate 2 channel pre-amp with home theater bypass and a separate 2 channel amp. The 2 channel is definitely better through the separate pre-amp (Cary SLP-05) and a Levinson 432 than through the 200.7 A separate 2 channel amp is a step up from the 200.7 and the pre-amp further steps up the sound. My guess is that your 803's would also should the advantage of a separate pre and amp. Depends on whether you are willing to pay of it. Can you borrow a high quality 2 channel amp to give it a try?
Dtc is on the $$$...A separate 2 channel amp will benefit you if you wanted to venture more into the 2 channel mode. Try a Rotel RB-1572 amp for those B&W's you might like it as I was impressed with this combo from my local dealer. But this will force the movement of an interconnect and speaker cable
I have kept my B&K 200.7 amp and use it for my home theater that is processed by a Pioneer Elite (through the pre-outs). These do run a mix of speakers as they fit for my arrangement but do run a pair of B&W CDM7NT as the main front L & R and Martin Logan Motion 4's for the side surrounds. But I too have a hybid 2 channel system that runs either through my Coda CSi integrated amp to a pair of Tyler Acoustic Woodmere II's or my Modwright SWL 9.0 to the B&K for some tube to solid state action. I have this tri-fecta easily changable via an interconnect and speaker cables. I purely use my B&W's for home theater and the Tyler's for 2 channel. I am blessed with a very large room that gives me the capability to run such a large front of speakers without losing its stage presence. The new Oppo BDP 105 is my only source since I run a variety of music and movies via hdmi or dedicated 2 channel. I really wanted to have a universal unit that could perform well in both departments and I have been pleased so far.
I agree with Mechans. 2 channel and HT should be totally separate systems.
Rrog - if you have 2 independent systems, do you advocate having 2 sets of front speakers, next to each other? That is what Mechans is suggesting. That seems unnecessary in most cases, although Shakedown seems to like it. Most people do not have room for 2 sets of large speakers next to each other. I wonder Shakedown, do you have a wife :)

The advantage of a home theater bypass situation on the 2 channel pre-amp is that it allows one set of speakers for L&R in both 2 channel and 7.1. If you have a nice set of L&R mains, why not use them for both? Rather than use cheaper HT mains right next to the big boys, why not invest the money is a very good center to compliment the big mains?

My Cary/Levinson/Cremona setup gives me great 2 channel and I use a Yamaha receiver and ATI amp for the 7.1 setup (minus the mains), but with a good center hooked to the ATI. (The 200.7 has been moved to a second 7.1 setup.) The L&R from the Yamaha go through the Cary home theater bypass. I really do think this hybrid setup gives you the most flexibility while allowing you to tweak the 2 channel or 7.1 system as needed.

Unlike Shakedown, I am not interested in changing cables when changing between systems. My wife is very tolerate and loves the music, but I do not think I could sell her on having a second set of mains. We did build a dedicated theater with 7.1, but not everyone can do that. We still use the hybrid system for 7.1 a lot also, especially for TV. Its critical to have that NFL crowd noise blaring from the surrounds :)

Anyway, the bottom line is that I think the OP can do better than the 200.7 for high quality 2 channel.
LOL...yes I do have a wife and she totally approves of my set up...its not her gig but she does enjoy it when anything is playing...Our room is a converted sunroom that is 30 x 35 feet with the farther part of the room is her computer central while the other half is the entertainment area. While I am not a big fan of moving cables, I have simplified that process for my ease and it does work for me (not too lazy yet). Prior to my purchase of the Coda CSi integrated amp, I was using the Modwright pre-amp and its HT Bypass to the B&K amp and totally loved it with the B&W speakers...I just wanted to up the game a bit on the 2 channel and find something that would fill this tremendous room. Luckily the best of worlds...happy wife and hubby too...
I actually advocate a sparate listening space for 2 channel.
2 mains next to eachother are thought to produce artifact by sound pressure cause the "quiescent" pairs' drivers to vibrate.
Mechans - 2 separate rooms is great. Unfortunately, for most, that is not an option. If you have one room for both, what do you think of a hybrid system?
Mechans...Yep...we cannot all have a separate area for two systems and must work with what we have...plus my mains seem to be far enough from each other to not represent this vibration you speak of....I truly love my set-up as it brings volumes of music and entertains the video aspect too whether its movies or satellite tv and sports action.
2 mains next to eachother are thought to produce artifact by sound pressure cause the
Mechans, can you elaborate on this - not sure what you mean. I thought there was one set of main speakers - being driven by one 2 channel amplifier, but using a 2 channel preamp for music listening (while the HT equipment is all switched off), and a HT pre-pro for HT use (ie connected to the amp/mains through the 2 channel preamp passthru). Where does the artifact come from?