Point of diminishing return for a DAC


I am currently using a Mac mini as a Roon Server with an entry schiit DAC. I am considering buying another DAC. My question: what are the opinions on the point of diminishing returns for a DAC. My system is Golden Ear Triton 2+, Prima Luna preamp Carver tube amp. Quobuz for streaming...

Look forward to thoughts and advice...
128x128fastninja12
So, a few have commented about the noise from the Mac.  Unsure what you mean...mechanical noise?  It’s dead silent from a mechanical perspective.  The fan very seldom evens spins up.  My mini is the latest iteration with an ssd.  There is nothing on the SSD except OS, Roon Quobuz...I can pause the music at a very loud volume, and again no noise....I don’t hear noise while playing music.  Please elaborate...
I'm a firm believer in spending a good chunk of your budget on the digital front end.

Good clocks + reduced jitter + w/e other mumbo jumbo is happening = improvements in PRaT, low end tonality, reduced sibilance, better staging, holographic imaging, blacker backgrounds and just a sense of ease/liquidity. 

It's effectively replacing a CD player. 
I Love it when reviewers tell you ,the dac for 2500  you just bought is not as good as a 500 dac....