It may very well be the yamaha not doing what you are looking for as a 2ch pre, a separate 2ch pre might work well for you possibly with home theater bypass so less swapping signal cables. When im listening to music i use a PS Audio stellar gain cell dac/pre instead of my marantz av8805 into a Parasound a31. Sound opens up a lot compared to the proc which is very good on its own, but not quite there vs the 2 ch dac/pre. From reading this thread it seems to be very similar to what you experience with the 2ch integrated, its probably working as a better pre for what you like.
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