Coschi

I'm not familiar with the Profire, but the general idea is Mic -> Mic Preamp (analogue out) -> A/D Converter -> digital out (firewire, ADAT, SPDIF etc..) Ideally, if you get a great preamp that you want to use instead, you need to access the A/D converter direct, bypassing the ProFire's preamps. I know my mackies can do this by using the tascam 25 pin connector at the back. They bypass the preamps and go straight to the converters. If your ProFire doesn't have this ability then you may or may not benefit from a top notch external preamp. I guess it comes down to how the ProFire's preamps deal with the signal coming in. It may come down to a matter of level only, impedance is a big thing and typically the mic inputs on these interfaces (like your ProFire) are setup to accommodate the impedance seen at the output of a typical microphone, not necessarily a preamp. It just depends on how far you want to take this, and how serious you are. If you are serious, then I'd start saving a lot of money ideally, sell the ProFire (when you're ready to step up), and replace it with something like Apogee interfaces which accept line level inputs such as those from nice preamps, and outputs in ADAT (i think they have firewire option as well). The Apogee will then become your analogue front end and is greatly capable of producing some mighty fine results. You then need to think about preamps, there's a lot of different stuff out there. But perhaps a fully loaded API 500 series rack, along with some great river, neve, and $50K later you'll be able to do some stuff