AST will definitely be the one to shine, since this IEM was also likely designed with incorrect values of the source impedance dialed, similarly to AS16 pro.
Opposite to AS16 pro, AST will regain more of the treble for more balanced and potent sound to my ears, it will give you a good idea where AS24 are at.
On another note, I have received KZ USB DAC (AM01, top left in the image) and compared it to my other 20+ simple DACs (some fitting into the picture shown below; and talk about hoarding, pardon hobby) and Sonata HD pro as a neutral reference, as well as few IEMs with an integrated USB DAC.
To cut the story short, KZ DAC looks uneventful: no company logo, quite rigid cable, but feels ready to last and withstand some heavy use, perhaps.
The power provided by the KZ DAC is good: ca. 25% of volume on my old S10 needed for my normal listening with a good sensitive IEM, like ZAT, used in these tests. This power output is similar to the "louder" other DACs, such as Moondrop Click.
Power consumption of KZ DAC is reasonably low: 2 mA in idle, 16 mA when powered. The latter value is similar to the Apple dongle but KZ DAC provides significantly higher output power: 55% vs 25% volume, correspondingly.
KZ DAC is definitely tuned off neutral (unlike most of simple DACs) being a touch warmer and softer: to pair well with IEMs rich in treble, of older KZ, I guess.
P.S. To give a more general perspective on the current values: some USB DACs, like Muse M3 can consume upto 200 mA (1 Watt(!!) - data processing is energy costly! Good powerful USB DACs, like BHD pro draw 60-70 mA. Most simple USB DACs are under 23-26 mA, whiich is not much of a factor for modern phones.
If power consumption is your most important factor - use Samsung OEM buds (UrbanX) or Moondrop Droplet for more aesthetics - they both draw only 5 mA. UrbanX is noticeably louder, so one will get most "bang" per power consumed - Samsung/AKG know their engineering!
