Has anyone done any comparisons listening to their headphone output compared to an external DAC via USB. I have been reading of some folk who have done A-B comparisons and have found there to be be very little difference or only marginal. I must point out this is using the latest Macbook Pros from 2018 onwards.

The conclusions they have arrived at are that the Macbook Pro now has a much better internal DAC and headphone amplification section which has bought them up to the same quality of sound as many aftermarket DACs. It makes me ponder the idea that with the massive resources Apple has it can easily achieve this if it wanted too and may have indeed been quietly improving the SQ of its sound card /DAC/Headphone amp as a response to the massive uptake in Headphone listening.