I agree that offset is way too high. I'm at a loss to really pick out anything in your pics, though - except the resistors. Cobaltmute spec'd the resistors around the opamp at 1% tolerance. Those aren't V-D RN50's that you've used, so I'm not sure if they're in the recommended tolerance. Just an FYI, but even Tangent used to (still does?) have articles online about matching resistors around an opamp for ensuring the minimum in offset with his amps designs. Matching resistors used to be de riguer when the CMoy, PIMETA, and PPA were first in vogue (not that they still aren't). Cobaltmute even designed the very critical resistors to be installed on the PCB bottom - right next to the opamp - in an effort to reduce lead lengths and potential oscillation issues. The pupDAC will definitely result in opamp oscillation (especially with the OPA2836) if everything is not just so-so with the resistors and lead lengths.
I'm not saying for sure that's what's going on - it's still only a guess. Perhaps the resistors could be causing the issue and maybe the opamp is oscillating. Strange things can go on when that happens, including ticking sounds when the oscillating opamp causes regular/intermittent capacitor discharges.
Edited by tomb - Yesterday at 6:39 pm