So I just received my AP98 and unfortunately I'll be requesting a replacement or refund, whichever works best with the Ali store I bought from. The AP98 4.4mm jack has a defect where I can't fully insert the connector. As a result it doesn't playback from the right side audio. I can force it in but it'll slowly eject.
I also have a Fiio KA3 to compare. I'm an amateur but my impressions are as follows. Via Sundara 2020 AutoEQ.
-AP90 (AK) sounds a tad grainy but overall smooth listening.
-AP98 (CS) just clear and smooth. Interesting to note that dimensions have the AP98 slightly shorter in length than the AP90. Also it starts in low gain whereas AP90 starts high gain.
-KA3 (ESS) sharper than either. More treble?
I also bought a CX31988 4.4mm DAC I'm waiting delivery on but I'm guessing I won't hear anything better albeit it will have less power output.
Lastly I have Apple and Google USB DACs but I didn't do a side by side comparison as that would mean I'd have to use the 3.5mm jack which isn't loud enough for me with the Sundara.
Honestly I just wanted to get an impression of these 3 DACs and to me any of the 3 I'm happy with. I bought the Sundara recently too as an upgrade over the HD6xx and K7XX I've had for years and I get better listening upgrade value from the Sundara. I'm satisfied...