What makes a DAC so expensive?

Those discrete R2R DACs are expensive even back in the day when they ruled. Yes and there’s circuit board layout, earthing , filtering, output stages it all adds up. IMO though it’s not relevant to how it sounds unless it’s been purposely designed to not be accurate. The only connection DACs have with the "outside world" is the output terminal. If we measure the magnitude frequency and phase well beyond anything a human can hear does it really matter how it was achieved? DS, R2R , which brand of chip, exotic components? If the output is accurate what difference does it make ? I don’t even know what DAC I have, what chip it uses no idea. I know I have class D amps but no idea what brand. They’re inside my active speakers and all I know they are the most accurate most detailed, smoothest speakers I ever heard. That’s where the rubber hits the road , the speaker, it’s the least accurate component with the most distortion in the chain, along with the room.

That's where REW comes in to help with the room.

The GAIA can even accept multiple inputs, so a many-2-many distribution point.

My interest in it is to try different DACs into the system while comparing against my reference Benchmark DAC3B. These DACs would not measure the same so their will be sonic differences.

@Listening99

This forum is a microcosm of our larger culture. I appreciate your pursuit of truth- in this case in DACs, but I am guessing based on your writing skills this is standard for you. I would probably thoroughly enjoy a shared skull session on a variety of topics. I do get discouraged when I see the attacks, especially when I believe we all have similar goals and a shared appreciation for music. I am not certain how old you are, and please don’t feel disrespected if I offer some unsolicited advice. Days may seem long, but years will fly by. Chasing the truth too vigorously can rob you of simply enjoying. Peace be with you. 

listening99, forgive me for offending you. 

I felt offended several times back when I was a budget audiophile. Nearly any honest criticism of my equipment or methods was cause for disgust. But, looking back, those critics were right. 

FYI, The terms "objectivist" and "subjectivist" are not particularly name calling in the sense of calling someone a fool, but are used widely in the industry and among hobbyists as descriptors of methodology. 

I have spent enough time on this. Blessings to all.