Amp/Preamps vs. High end AV Receivers

@caphill
+1

I like the suggestion of  soundermn. I will probably start by using my AVR pre-out and buy an Amp and then build it from there. 

I will check out some 5 channel or 7 channel amps. 

https://www.audiogon.com/listings/lis969ff-b-k-components-reference-200-7-200-watt-x-7-powerhouse-mu...=

Any thoughts on the B&K Amp?

I don’t know about the B&K, but I’m sure others will. If you want new, the Monoprice Monolith 5 channel amp is $1300. It’s well reviewed... and I remember a very positive review by Sound and Vision a few months back where they really liked it. This weekend, they have a 20% sale for Veteran’s day. 200 watts by 5 channels... after the sale, $1039. Not bad.

https://www.monoprice.com/product?p_id=15593

Also, the B&K does look like a nice option as well.

@terrancej

If you only add a power amp and use your Onkyo receiver as a preamp processor/DAC you won’t be able to achieve optimal improvement in performance cause you’ll still be using your Onkyo receiver as preamp processor & DAC. Preamp processor & DAC plays very important role in determining the overall sound quality of your setup system. One must upgrade the front end components (DAC & preamp) first before upgrading the power amp, not the other way around. What’s lost earlier in the signal path cannot be restored downstream.

I know you’re on a budget and I can recommend a slightly used Marantz AV8802 av preamp processor (discontinued) which can be had today at slightly less than $2k used. its original retail price was $4k. This pre pro supports 4k video, hdcp 2.2, Dolby Atmos DTS-X & Auro 3D. This will be a step up sonically than using your Onkyo receiver’s preamp/processor section.
The AV8802 sounded very good for the money and I would say it is the best sounding Japanese mass produced pre pro. Noticeably better than Onkyo/Integra, Yamaha or Denon processors.

And pair this Marantz AV8802 processor with the Rotel RMB-1585 five-channel power amp and you will be set and will drastically elevate the overall performance of your system to a whole new level of sonic performance.
The Rotel RMB-1585 five-channel amp is a class AB design amplifier and it retails for $3k new but often times you can find a used one in used markets for around $2k ish. This is a spectacular sounding multi-channel amp especially for the money and will sound way better than the Emotiva, Outlaw, or B&K amps or any other amps mentioned earlier in the above posts.
However, do not get the Rotel class D amplifier such as the RMB-1575. it isn’t the same as its class AB design such as the RMB-1585.

Or alternatively for your B&W CM8 speaker system you can get the Rotel RMB-1555 five-channel amp, which is a step down from the RMB-1585. The RMB-1555 is also a class AB design. The RMB-1555 retails for around $2k ish brand new or it can be had for around $1300 used.

Rotel amps will sound really good on your B&W speakers. Rotel always pair really well with B&W. They are meant to be paired together. B&W speakers (especially the CM series & 600 series) were voiced using Rotel amplifications. They have great sonic synergy together.