I'm currently using a SB Live! with Coaxial out to my Yamaha DSP-A1 Amp. I mainly use the soundcard for DVD Movies with TheatreTek & WinDVD. Will I hear any difference if I upgrade my soundcard to a Revo 7.1 or SB Audigy 2 ZS? Since the Coaxial output to my Amp is digital, there should be no difference on whichever soundcard I use. Am I correct? Thanks!