I must say that the dual DACs really sound fine, even right out of the box with only an hour or so of use. While the amp can be powered by USB or battery power when using a USB signal input, the amp can only be used with battery power when using the Aux input.
I really like the 9v internal contacts...real contacts, not the cheap snap-in connector used by most 9v components.
After just a brief audition of the stock opamps, of course I just had to roll to the D4 Topkit!
I am using 9.6v 230mah PowerEx rechargeable cells, now I need to see what the run time is when using only the aux input/amp. BTW, the battery can be changed is less than a minute by just removing 2 thumb nuts.
It looks to me at this point as if iBasso has another real winner!