Codex measurements are awful. Probabably is not necessary to spend that much to upgrade.
The Codex measure very very very closely to the Pono in Stereophile, and the Pono was one of, if not THE best sounding portable I’ve ever heard, especially with IEM’s. This makes me think that there's no relationship to the numbers AND that Ayre reused the design practically lock stock and barrel.
ASR’s entire process is deeply flawed. It isn’t science, it is quality assurance. The Oppo though, also measured poorly and man, I hated it from first listen. So, their measurements have no correlation to user experience. If you want to listen the way a scope does though, follow them.
To actually review these DACs scientifically they need to listen first, or independently before measuring, otherwise it is just confirmation bias.
Best,
E