assuming that you already own a good amplification system and speakers ....note... better is system, and more you can hear difference.....no cable has so tangible improvement
there are two things only, that would bring about improvement of system
1) clean power source
2) good digital source
.... so I would not rule out having to talk about power source yet.
about the warranty ... it's the same manufacturer that recommends, as alternative choice, a powerbank for...., battery pack is not best choice, because the batteries inside have voltage of 3.7v, then by a switching DC / DC converting circuitry,
without any filter, it exit at 5V, but try it if you want. for this I would not worry about warranty...
I have not seen any online video review that used the Qutest with factory PSU.
therefore I am not the only one to think that it is not made for best performance, but it turn on the system anyway....
do not worry, you can always use it to turn on led lights of a small Christmas tree.
if you still do not believe it ...... take as reference the high end DAC of Chord or other firm, tell me you see something as Qutest PSU.
instead you can easily find DACs that use it under $ 400 / $ 500 range, over $ 700 nobody uses a few dollars PSU, but best power source for DAC price range.
