Internal DAC vs stand alone DAC.....

Hello all. A year ago I purchased a Yamaha A-S801 as an "all in one" solution for my analog and digital connection needs. I run my mid-level Oppo universal player through it via coaxial connection, my tv via optical connect and run my imac through it via USB. Phono of course through built in phono. The Yammie reportedly has a very good built in DAC but I have been wondering recently how much "hearable" performance I may be losing by using it's internal DAC. I love the simplicity of this set up but like many of us, like to eek out as much performance as we can afford. How much would I need to spend on a DAC that takes the sound to the next level? I still spin silver discs regularly and have about 900+. A Bluesound Node2i is in my future I think so that adds another element. Thoughts and/or recommendations? Speakers are Klipsch RP 600M's with a subwoofer....
Thanks!