Well I think I just found a way to use the ZX300 DAC mode for watching video, Youtube,... (not recommended for gaming thou)
I use my Laptop as my main sever and my ZX300A as my DAC, everyone know there a 0.5 - 0.7 second delay when using the DAC mode, and it's irritating especially for watching video. Till recent, I bought a HDMI - HDMI cable to output from my Laptop to my LG TV, and well well, it has a nearly 0,5 sec screen delay also!
=> So, I tried to output the audio through the zx300 while the screen on the LG TV, and WOALA, they match quite perfectly nice!!!
Now I can enjoy watching Youtube and Movies from my TV while using the ZX300A as the audio output, sounded great!
p/s: I'm not sure this will work for everyone else, but it does for me, so... Lucky me I guess =]]]]]
p/s2: If anyone ask for my setup, I'm using a Asus ROG G501JW, and my TV is a LG Smart TV. Connect those with a Toshiba HDMI - HDMI cable. And of course the zx300 in DAC mode with the stock Walkmanport - USB Type B Cable.