I have a doubt. I really like to play my guitar through Amplitube in my Windows 7 64 system. Currently I have my Guitar->practice amp->on board souncard through line in. Sounds great. But I like to have an option amplify the sound and I'm guetting a PA System so going to connect the soundcard to the PA system. I'm not intereseted in recording. But I'm worried that if I amplify the sound my current setup is not going to be good. I need an audio interface? for the use i will going to take is any advantage? Also other problem I have with my current setup is that Media player doesn't sound when amplitube is working. When I turn off Media Player strats to work. This is resolved with an external audio interface?