I did not open yet the Metrum, so I don't know its clock. I CAN predict if it is a clock under or equaling 45MHz (unless much more complicated order processes for custom cristals) it WILL be bettered by a super clock unless the strange über freq Metrum DAC has a very (much higher) clock than the normal range between 6 and 45 MHz.
As for the Yamamoto, I am 99.99% sure it will be considerably bettered by the DEXA Neutron clock with its own dedicated accurate stable pws. The most worst thing that can happen with a better clock is that the improvement in SQ is less than anticipated mostly happening as the sound reaching our ears will always be limited by the weakest link in the stereo chain
As for the Yamamoto, I am 99.99% sure it will be considerably bettered by the DEXA Neutron clock with its own dedicated accurate stable pws. The most worst thing that can happen with a better clock is that the improvement in SQ is less than anticipated mostly happening as the sound reaching our ears will always be limited by the weakest link in the stereo chain