have this dap for about 6 mos. bought am3 which made difference with my
audio technical ath mx 30 40 and 50x series. the problem imo about
audio equipment is everyone has different hearing. some here hear at
different ranges and tones what may sound superb to one may just be ok
to another. the big improvement with this dap was android 5.1 update.
The x7 is now more smooth operating. also a footnote if you are having a
problem updating from 4.4 firmware using download tool for windows 10
it worked for me temporarily disabling anti virus to download
happy listening