Personal opinion: it is definitely underpowered compared to nearly everything out there, works superb for IEMs or bluetooth cans.updated it before i started using it. i think that the unit is defective.
I have the Asian NW-A105 (Made in Malaysia), updated to 3.00.07 as per below:
https://www.sony-mea.com/en/electronics/support/downloads/00016951
I find myself usually playing at around 75-90 for most tracks on what I would like to call a medium-high volume, my sweet spot.
60-80 it's actually quite listenable levels in quieter environments and most tracks.
For about 20% of them I need to pump up the volume to 90-110 specially on more quiet tracks and acoustic tracks.
I used to hate my NW-A105 when I got it, but it eventually grows on you even with all the flaws and lack of features. But not sure if I would drop again that kind of money on this thing, I'd rather get the A50 series or go chinese.