There is my combo:
IBASSO DX80 + IFI MICRO IDSD + Beyerdynamic DT770 PRO 80Ohms /Beyerdynamic DT801 since 1996/
I have absolutely no problem with playing any music as mp3/flac/aiff/dxd/dsd on Ibasso DX80, firmware 1.1.4.
I don´t use EQ.
I´d like to have better choice for album order , work with long names of songs and and playlist, but for sound quality i have no complains...
I use 32GB Sandisk Extreme Plus SDHC card, I tried 1st and 2nd slot without problems.
I tried DX80 as DAC as well, without problems.
Sound output from DX80 is really nice, but with IFI is better
With IFI MICRO IDSD, it is "killing system", DX80 as player and IFI as output system...
I tried DT770 PRO with 80Ohms and 250Ohms as well, my choice is 80Ohms, very similar sound to my old DT801,
250Ohms version has less deep bass then 80 Ohm version, sound is nice as well, but I prefer 80 Ohms version.
I tried X3II as well, I wanted something just as portable player for IFI. X3II as player for IFI is ok, but when I compare sound output X3II and IFI, there is big difference.
And because I didn´t want to bring my Ifi every day to work, I tried to find some portable player /DAC AS well/ with sound output near IFI quality and I chose DX80 and no regret.