What makes the Codex outstanding is the diamond output stage with headophones. Really amazing. No DAC chip can replace that.
i don’t listen to headphones, and i feel the codex is one of the most 'analog', coherent, natural sounding dacs irrespective of price run as a straight dac ... tho i would add that it does seem to resolve a bit better via xlr out vs rca though
a real giant killer of a dac... sold several of the more expensive dacs i had on hand once i got the codex