Amp/Preamps vs. High end AV Receivers

When you have separates, the equipment does not have to share power supplies. This reduces intermodulations and for that reason alone allows for better sound.

But there are additional benefits- frequently separates have better power supplies, better heatsinks (in the case of transistor amps), usually better quality parts and overall better circuits.

What is the model of your current receiver?
What speakers are you using? How many? 2, 2.1, 5.1, etc.?
What percentage of your listening time is movies/TV vs Music?  50/50, 75/25, etc.?
Room size?
Do you need video switching form the receiver/separates?

This information will give folks a reasonable chance of addressing your questions. Without it, it's just shots in the dark.....

Thanks for all your responses and let me add more details to get more intelligent inputs.

AV Receiver - Onkyo TX NR809 (Model from 2012) (HDMI, but no 4K)
5.1 Setup
Bowers & Wilkins Speakers and Sub.
Front: B&W CM8
Center: B&W HTM62
Rears: B&W CM5
Sub: ASW610

I watch movies and listen to music + music videos (frequently).

Hope this helps to give more solid inputs. 

Thanks for all your responses and let me add more details to get more intelligent inputs.

AV Receiver - Onkyo TX NR809 (Model from 2012) (HDMI, but no 4K)
5.1 Setup
Bowers & Wilkins Speakers and Sub.
Front: B&W CM8
Center: B&W HTM62
Rears: B&W CM5
Sub: ASW610

I watch movies and listen to music + music videos (frequently).
Looking to upgrade to Dolby Atmos Setup 5.1.2. Have not decided on the speakers for .2. My current receiver does not support it.

Hope this helps to give more solid inputs.

Well, I’m still using my TX-NR809 in my bedroom system. The thing is a 40 pound beast, and I’m not sure you can get much better audio quality with any of these newer AVRs.

And 4K capability is not really required in an AVR if you get a UHD Blu-ray player that has dual HDMI outputs, one for video and one for audio. You connect the audio one to your AVR and the video one to your 4K TV. This is what I’m currently doing with my Denon AVR-X5200 and Oppo UDP-203 in the family room system.

I’m also using a separate power amp for the front L/R channels in both the bedroom and family room systems.

Edit:  I see you added that you want to go to Dolby Atmos.  That WOULD require a new AVR or Pre-pro.