I am thinking about upgrading the audio on my PC but have some really basic questions. 1. Does a firewire digital to analog converter bypass the need for an internal audio card? 2. Once I connect a firewire DAC, is there anything else I need to do "upstream" to hear music? 3. Why do all of the inexpensive DAC's (under $300) I've viewed online lack RCA outs that I would use to connect to my preamp/powered speakers? Is there a difference kind of cable that needs to be used? 4. Is there anything else I need to consider before selecting a budget DAC? Thanks.