Combining home theater with two channel

It isn't about watts, it is about your Marantz pre/processor being your two channel pre. As nice as the unit is (I'm sure) for HT, it is not a dedicated 2 channel pre for music. That is your problem. There is a still a lot of processing hardware it is 'shared with'.

I've been there/done that. And not until I separated my AVR (in my case) from my/a seperate two channel rig for music only, did I hear a significant increase in 2 channel sound quality. In my case, I did that with a dedicated 2 channel preamp that has HT bypass! via the AVR 'front' preouts, and then connected to a separate 2 channel amp. My music sound quality was greatly increased by getting the AVR/processor out of the signal path for 2 channel. And with the bypass, I simply switch that on when using my AVR for HT. The center and surrounds are then driven by the AVR. All of my 2 channel equipment is connected to the dedicated 2 channel preamp (turntable, tape deck, DAC, etc.), so the processor is not in the signal path at all.

Issue I see is you have a fairly expensive dedicated 3 channel amp and HT processor/pre. I'm not sure adding the Krell to this makes a lot of sense quite honestly as I don't see it has an HT bypass option.

What you might want to consider is selling both the Marantz and Emotiva, and getting a high end AVR with front preouts just for HT where the center/surround sound quality is not as critical as 2 channel music. Then, as was suggested, get an integrated 2 channel amp....*but with HT bypass*. in that way, your front channel will simply be powered by the integrated in 2 channel, but the front, center, and surrounds processed by the AVR/processor in HT bypass mode. 

+1 ^^^^^^^^^^^^^^^^^^^^^^^^^^

What he said is spot on

Do NOT combine unless marginal results please you.

@bkeske summed it up nicely.  I have the Marantz AV7705 that I use for HT.  I have a Herron VTSP-360 Reference preamp that has home theater bypass feature.  My amps for the front two speakers are Herron M1 monoblocks (150 WPC).  While these amps aren't pushing a lot of watts, they have huge transformers and can deliver a lot of current.

I am not one to say Emotiva is junk (I have an XPA-5 in my bedroom system), but the quality of the watts matters more than how many there are.  Your speakers appear to be fairly efficient.  You shouldn't need a huge amount of power for them.

A good integrated will have a much cleaner preamp and amp than the Emotiva/Marantz combo.

Think of music this way... it's ALL there, but when you have inferior components you're only letting part of it through.  The better your components, the closer you get to what's really there in the music. 

I am not "critically listening" when I'm watching a movie and I want the surround sound experience provided by the Marantz, but when I'm listening to two-channel music, I want as little as possible coming between me and the music. 

If I had the space, I'd have a dedicated system for music and another for home theater, but an integrated or pre-amp/amp setup with HTBP is a good compromise.

My dealer suggested that I add an integrated amp to the system to play music.

BINGO! Your dealer nailed it (along with everyone above). The cheapest option to dramatically improve your 2-channel performance is to incorporate a good stereo integrated (w/HT Bypass if possible but not absolutely necessary, which opens up more possibilities).

I'd try to work with your dealer to demo a good integrated — that being one that has the same characteristics you’re looking to improve upon — and see how that goes. Your speakers are revealing enough that I think you’ll hear quite a big improvement, and if they’re the model I think you have 150Wpc may well be plenty. Anyway, best of luck in your quest.