Hi newbie here. I recently decided to join the audiophile community ( and possible slippery slope) and upgraded from a KZ AS10 to an UE-11 pro. Upon purchase + impressions, the store i got from and a few customers there kept on recommending to get a DAC/AMP although i usually listen through a 3.5mm jack in my Samsung Galaxy S9. So here is a few questions i am confused about. 1) Is a DAC/AMP really required to maximize the experience? 2) what specs or features should i look out for when choosing a DAC/AMP? 3) Why are some DAC/AMP way more expensive despite have lesser features (e.g. Fiio Q5s vs Phatlab Phantasy 2) 4) So far i did some research on Fiio Q5s and cord Mojo, (can't tell much difference in performance), any recommendations between these 2 and beyond? Thank you everyone for your replies and assistance.