I am using PA on an LG G8thinQ as well. The Quad DAC only works with the headphone output, not with USB output (device dependent) or the built-in speaker (only native 16bit/48kHz). If using headphones, the device will play up to 24bit/192kHz with the HiFi DAC enabled (choose this option in settings>Audio>Output>Hi-Res Output>Wired Headset/Aux. The other benefit the to the Quad DAC is the impedance matching. It will drive High impedance headphones (50-600Ω) with more current