I don't know why so many seem surprised by the test results. I have actually predicted in one of my posts that the degradation could be in the high 80's. That was solely based on the PCM5102A DAC IC's lower SINAD than the AK4458. Logic and math don't lie!
The difference is a whopping 14 to 15 dB difference as shown by the datasheets. The measured 10 dB difference is actually good news relatively speaking and should be expected as well because the prior models were limited by the volume control IC and could not take full advantage of the 107 dB SINAD that the AK4458 offers anyway.
I am more disappointed with the higher IMD, but overall if we compare the two in a tightly controlled DBT, I would bet 10:1 less than 10% of the audience would be able to tell a difference. 0.05% THD+N, 20-20 kHz is still excellent for most people included those with trained ears and has minimal hearing loss lol.. I thought
@Brian6751 would agree might agree with me.
For use as an AVR, this is the graph that really counts, and if you compare it with the X3700H's you can see why I do not believe one can tell a difference between it and the X3800H, regardless of the DAC chip difference.