Stereo pre-amp with AV processor?

Thanks @caphill , I will look into these brands you recommended...

@seif

The AV receiver’s stereo preamp sections aren’t good enough for stereo critical listening to stereo music especially if you plan on upgrading your speakers soon.
I suggest you get a very good stereo integrated amp that has HT bypass input. So you can use your AVR for surround sound movies (HT) use and use the stereo integrated amp for stereo music. There are countless options out there when it comes to choosing a good quality stereo integrated amp depending on your budgets. For your speakers I would look at the Hegel, McIntosh, Rega, or the Anthem STR integrated. For Rega I recommend at least the Rega Elicit-R ($3k) or the Rega Osiris ($10k). However all Rega integrated amps are pure analog and don't have built-in DAC. So you will have to get external DAC or streamer/DAC or CD/SACD player etc and connect using analog interconnects to the Rega integrated amp. 
Even if the stereo integrated doesn’t have a dedicated HT bypass input you can always use any analog inputs perhaps Aux and set the volume at usually around 80 on the integrated amp as 80 is usually (not always) a unity gain for HT bypass.

As far as the AVR goes between Denon X8500h and Anthem MRX1120 I would go with the Anthem as the ARC2 is much superior room correction calibration to the Audyssey in the Denon.

Or if you want to take it up to the next level of performance for your HT needs you should consider getting good quality AV separates : AV pre pro & multi-channel amp for your surround (HT) use. Still get a good quality stereo integrated amp for your stereo music use to drive your front LR speakers.

The Anthem AVM60 pre pro is awesome for surround sound movies or the Marantz AV8805 pre pro is another spectacular HT processor for your surround needs.

As for multi-channel power amp to power your center and surround speakers I recommend the following : Rotel RMB-1585 five-channel amp, the Parasound Halo A51 or A52 five-channel amp or the NAD M27 seven-channel amp, Classe Sigma Amp5 five-channel amp.

Thanks @theo , @audiotroy 

I will tell you more about my case, maybe whenever you get the chance you can share your insights about it.

I have a Denon X8500h, Paradigm Prestige 75F (fronts), 45C (center), 15B (surrounds), 7x Millenia Ones (2 surround back + 5 heights), and 1x SVS SB16.

This setup is awesome for movies, I am so satisfied, and to my knowledge it as a great sweet spot of value for money. I assume that further upgrades would costs much more money for marginal quality enhancement.

For music however, I am not at that sweet spot. I think there is a big room for enhancement, which comes at a cost for sure. I am considering the following:

Speakers:
I want to upgrade my fronts to Persona 3F. I am a big old Paradigm fan, and I assume it will bring a significant upgrade over the Prestige 75F.

Amp:I also assume the Persona will need an amp much better than the AVR's amp to show it's best capabilities. As a Paradigm/Anthem fan, I was thinking of MCA225, P2, or STR.

I am ignorant about all the other fancy brands like Macintosh, Krell, etc... I once heard the Macintosh on B&W and Paradigm, and it was incredibly good, but that's all I know.

Pre-amp:
I have plans to replace my Denon AVR with Anthem, because I am not happy with Audyssey. I hear lots recommendations about ARC, I like the idea of different room correction profiles.

I am hoping that a flagship AVR, MRX1120 or Denon X8500h, can suffice and double as a stereo pre-amp. And instead of paying for a dedicated unit that does a function that I already have, I would invest in a high quality dac for example.

If I am not mistaken, this is the only way to get multichannel music, which is something I like...

These are my upgrade ideas. If you can let me know your thoughts whenever you get the chance, it would be highly appreciated.

Thanks,
Seif

Self we are an Anthem dealer and we work equally with both Home Theater and music systems. 

The Anthem STR preamp is good there are better two channel preamps and even better dacs. 

It all comes down to what you are trying to achieve.

Please reach out to us  we can be of assistance with your quest.

Our shop has a lot of the top brand of gear and we actually do routinely merge these two types of systems.

Dave and Troy
Audio Doctor NJ

Thanks @theo ,

Since there is no key technical difference other than the improvement of a dedicated system for 2 ch, I will try to find a way to audition the 2 cases side by side and hear the difference...

The stereo pre-amp that I am considering is $4k, so if not necessary, I other things on my wish list that may make a bigger improvement to the overall experience.

I wish to buy a multichannel DSD DAC, Kaleidescape, etc...

On another note, what brands/models of 2 channel pre-amp would you recommend?

That's kind of what I'm thinking, only I'm using an integrated that I don't want to change or break.

The Anthem receiver (or Marantz) would give me HDMI switching + 3 more channels for movies.

By using a separate Stereo Pre-Amp vs 2 Channels of a AV PrePro you should notice an improvement and at the very least you will be able to run only the 2 Channel side of your system and not consume power for components not in use. That alone should aid in cleaning the signal path. I have been doing this for years and plan to continue till I die or go deaf which ever comes first. Make sure that the Stereo Pre has Unity Gain AKA HT pass thru , that allow the passing of the front channel signal and all volume is controlled via the AV ProPro.
As a suggestion I would consider not going with the same brand on both Pre amps, otherwise the benefits would be minimized by maintaining the “house sound”. Perhaps Tube on the 2 Channel?