Has anyone ever done a comparison between API's two preamp modules, the 212 and 512? And we might as well throw in Brent's version of the 312. I like the idea of a simple, straightforward preamp like the 212, without extras like multiple I/O, etc., and its also a couple of hundred cheaper than the 512. The big downside is that it doesn't fit in my 500 series rack empty slots. Brent's 312 seems like a good compromise in that it costs around the same as the 212 but fits in the 500 series racks. I don't know of anyplace that will set up all three for me to listen to (including a comfy chair and a few beers), but I'm gonna guess that they are all capable of sounding great with the right mic and certain sound sources. So how does somebody make the right choice among these three?