DAC for AMP

Hi everyone. I have a fire tv cube connected via hdmi to a Sony bravia, and the TV optical audio going to a cheap dac which is feeding an amp+passive sterio speakers. I'd like to be able to play Spotify with the TV off. I was also getting some problems with audio lagging the picture. I decided...

Hello I'm kind of a noob with amps and dacs and I have this question that i need answer for before I buy anything. I'm going to build Objective2 headphone amp (building isn't a problem for me) but now I'd like to know if I even need a external DAC or am I good to go with my motherboards...