Musical Sound Quality of AV Surround receiver vs. pure Stereo


Running Linn LP12 turntable, Bluepoint No2 stylus, with Jasmine phono pre-amp, Marantz sr5008 with B&W 685s2 on LR fronts with 686 S2 LR surround,  Paradigm CINEMASUB Cinema Sub 300W Speaker.

3 questions; 1) While I canceled out the center channel (using Marantz Audyssey setup), I am playing 99% from my turntable and CD player (Yamaha w/ DAC built in). The depth and spacial separation of the music is uncanny, but difficult to phase given it is being played in a digital (Music setting) format from one of the settings on the Marantz receiver. When I switch to pure stereo, the volume has to be turned up and the depth of the soundstage just isn't there. Would upgrading to a more powerful and musical integrated amplifier help (i.e. Anthem  Anthem MRX  720?) help with its killer room correction or 2) Do I look for a 2.1 integrated amp or tube amp to compliment my B&W 685S2's and sell the 686's or 3) do I just bite the bullet, look at a traditional good integrated amp or tube amp for around $3K with $3K Audio note AN-K speakers. Traditional sound....

Thanks, I am new to this group and have read a number of discussion threads. Obviously, a lot of you are infinitely more knowledgeable than I am, so any and all replies would be greatly appreciated. PS No man cave, this system is in my living room, so the wife is a little particular about too much gear ! Thanks everyone.
128x128phill55
Is the Hegal an iij integrated amp which CNN accepts a powered sub woofer? Thanks,
Sorry hate auto typing. Will the Hegal accept a powered sub woofer? I thought it was pure 2 channel and I know from the Marantz that the sub woofer digs a little deeper than the b&w 685's by themselves. Thanks
I use the same speakers (L+R) for HT and 2 channel, just switching out speaker cables. The 2 channel amp is better. But, that said, I could live with the HT receiver in pure direct mode if I had to. The difference in amps, contrary to what some say, is quite minimal.
@phill55 -- The Hegel has line-level outputs, which is all you'd need to connect your subwoofer.

The difference in amps, contrary to what some say, is quite minimal.

I'm just going to flat out disagree with @secretguy here.  If you at all care about 2-channel sound reproduction, you'll hear a big and meaningful difference between a $3500 highly-regarded, dedicated stereo integrated amp like the Hegel and a $900 mass market audio/video receiver with your speakers.  And if you do decide to upgrade speakers in the future, the H160 is good enough that it will let you get more out of them as well.  Oh, and no switching cables required to change between multichannel and stereo -- just push one button.  Nice.