I upgraded my Sennheiser HD 660S2 wired headphones with a more powerful iFi DAC to unlock the highest quality audio — but I honestly wasn’t expecting these results

Sound quality is important to me. Whether I'm listening to hi-res mixes on Tidal or making music of my own, I want to hear it in the absolute best detail I can. That's why, during Prime Day this July, I finally pulled the trigger and bought the Sennheiser HD 660S2. But since then, I've started to wonder whether getting a DAC is essential to...