'outboard' high end dac's

+1 for Schiit DAC's.
You should call them/email them regarding the DCD/PSM issue-which I have no knowledge of.
Though I can say, they are very reasonably priced and perform as well as higher priced products.

I really like my PS Audio DirectStream. It is fairly high priced at $6k new, but there are used ones available for almost half that. The bonus is the firmware has been updated several times and each time it improves the DAC for free!

Do you have a budget in mind?

Send it to Modwright Instruments and let Dan work his magic on it! I love the rich tonality, sublime clarity, and sheer musicality of my modified 105D.

Cheers,
Oran

Thanks to those responding to my query.
Regarding budget, I suspect it will take $2-4000 to improve on the Oppo 105d, if that is possible, and I wonder if a unit such as the Luxman DA-06, which can be purchased from Japan for under $3000,00, would with its BB 1792 chips allow the best of both worlds, assuming the Oppo
allows switching at will from internal to external DAC...I need more
information regarding this.  I believe that high resolution DSD files currently offer the best digital sound available, and I wonder if decoding DSD as opposed to PCM is potentially optimized by one-bit or multi-bit DAD chips.  So thanks again for the info and any further
suggestions.