When I am out walking I listen with the teeny tiny Shanling M0 DAP and a pair of Tin T4 earphones. Sounds great. Trouble is I get lost in the music and keep walking into puddles. The little Shanling sounds fantastic for its size.
For slightly bulkier portable listening I strap an iFi headphone amp to my LG V40 ( the one with the supposed audiophile DAC) and listen with my Oppo PM2 phones. Unless people are around and then it is Beyerdynamic T90s.