So which one of these DAC chips are better ? WM8740 is E17's DAC chip and AKM4396 is D1's chip ...
Which one is better in terms of sound quality ?
I would guess the AKM4396 is the better DAC chip.
What "D1" are you referring to?
The wolfson (wm) and the akm are different tastes I would put them in the same level depends what the company does to fully use the chip that matters because they are so close together. Saber (es) is my personally favorite I would easily rank it above wolfson and akm. I would rank audioengine above the e17 slightly.