Sorry if this isn't the right place to ask ... I run a Mac Pro for lots of non-music-related work and for the last few years I've been getting sound via an Alesis Firewire8 mixer and Alesis M1 520 active speakers. The sound was so good that I stopped using my high-ish end computer speakers and stuck with the Alesis setup. Recently, the Alesis stopped working. So I got a newer generation of it that connects via USB, except my Mac didn't recognize it and Alesis still hasn't made Mavericks compatible drivers (thanks, Alesis!). So I figured no biggie and went a different route: I picked up a Focusrite Scarlett 2i2 USB audio interface. It's bus-powered and works like a charm, except ... the sound doesn't have any kick to it at all. If I crank it up, it's certainly not clean. This is a huge step down from the Alesis Firewire8. Figuring the Alesis Firewire8 have some sort of amplification, I decided to try using the Scarlett 2i2 with an amp. I first tried a Behringer iNuke NU1000. The sound seemed as good as it had been with Alesis, but the fan on the unit was so loud that it made the amp worthless. So I arranged for a refund, and then did a little more digging and purchased a Crown XLS1000 amp, for a little more $$$. The sound is equally good, the unit is silent, but now there's a loud hiss coming through the speakers. And if I crank up the amp past 60% or so, there's what I'm guessing is line noise. Sigh. The hiss is livable -- much more so than the fan noise from the previous amp -- and line noise is manageable, but am I missing something? Is there a better way to get great sound out of a Mac driving studio monitors like the Alesis pair I have? Obviously I'm buying things at the low end of the spectrum, but I'm just trying to replicate the quality of sound I got from the Firewire mixer, which cost less than the interface/amp combined. Is the problem that the Scarlett 2i2 is bus-powered, so it can't send out enough power? Any other thoughts? It's such a hassle returning things because my primary transportation is either a motorcycle or bicycle, so any suggestions are much appreciated.