Interesting review, especially because i'm torn between getting an iDSD2 (blacklabel) or IDAC2. What is however interesting is that some of the comparisons you made seem to be exactly opposite to the findings of other people (including iFi/AMR engineers) so that makes it pretty complicated and slightly confusing.I suspect it has to do with your testing being done on headphones using the builtin headphone amps of the devices. Have you compared these also without using the builtin headphone circuitry, to purely test the DAC itself?
I'm curious because iFI reps insist that purely as a DAC, the iDAC2 is actually better than the iDSD, including the new blacklabel iDSD. And these statements were done in a threat promoting the iDSD blacklabel! At first this baffled me until I looked closer at the specs and realized the higher price of the iDSD has more to do with its headphone features than it's DAC (which is the same, except iDAC2 has a discrete class A output circuit where iDSD has to do with opamps running in class AB). iDAC has shorter signal path and better components due to more space in the housing after cramming in the needed features.
It seems a very easy estimate to make that the siginificantly more expensive iDSD is the premium and technically better device, so I wonder if placebo plays a roll in judging the sound, especially since i've not only heard opposite final opinion, but even opposite findings of the very same things (which sounds 'warmer', which is more detailed, which is faster, which has more neutral/reference sound) - I have literally heard the exact same lingo used to describe iDAC vs iDSD as was used by others to describe the opposite. Confusing!
I would be very curious about a comparative review of just the DACs in these two devices since that's what i'll be using it for. A