Have to disagree about the R2R11 pairing well with planars, specifically the HE560. the HE560 is forward and treble focused, the LCD2 and 650 are a very forgiving, the 560 not so much.You can't rely compare them both since R2R11 is true NOS (no op amps,filters,etc.) very coherent,smooth/sexy , pairs very well with planar magnetics - bright cans should behave very nice with this set up (HiFiMan Sundara calling my name)
D50 sounds like OPA1612 (3x) it's not dry ,clear ,good separation and sound-stage,good low end -round + Sabre which gives you that sparkle ,accuracy
I liked it so much that I end up getting cheap amp to roll some op-amps and see what works best ,so far tested OPA2107,OPA2111,OPA2134,..and few more coming soon
All based on testing with only two can's HD650 and LCD-2
I'm pretty sure most will like/love this little D50
The R2R11 to me was a coarse sounding DAC (upper mids were the culprit I think) and I upgraded from the ODAC hoping for a much smoother sound but it wasnt much better. With well recorded music it wasnt an issue and could sound very nice but It isnt very clear sounding, the HE560 has amazing clarity and I felt bored listening with the R2R11 because of the lack of detail.
I cant recommend the Hifime UDA38Pro enough if you are using more analytical cans, everyday I like it more. It is liquid smooth but beats both these DACs in clarity and detail... its a perfect match for the he560. Im sure it would sound great with HD650 but It seems like waste to use warmer can when the treble is so smooth.
I suspect it would pair particularly well with the HD600.