Yeah I have the 4490 and 4497, pretty big difference, if I use high impedance buds on both, then I would say the 4497 has a bit more detail, and bass seems more full, background a bit darker, nicely controlled all around.
If I use low impedance on both, 4490 has more control, tighter, deeper bass and less distortion
With larger over ears, the 4490 gets a bit louder, distorts far less then 4497 and has better bass (hifiman he4xx, Grado sr80, emu purple heart)
I would go for the 4490, but if you can get both, why not?
That's very helpful, thanks for your input. Personally, I've found the ak4497 doesn't perform very well with 200 ohms earbuds, a small amp does better. So I suspect the op-amp isn't legit.
This whole discussion gives me gas for an ak4490 :/