You can run analog-in from either line-in or mic-in or both, but if you try to run a digital signal into 7&8 you will get an error message if there is no digital signal on 5&6. I did not know this when I had the dongle wired, I thought I was adding versitility by having one RCA-in and one AES, but since it was wired with the RCA on 5&6 I have to use RCA first, no big deal, I just had to get an AES-to-RCA cable made. I see no problem doing what you ask, you'll need Binder connectors wired to whatever cables your mic uses, and correctly pinned-out to provide phantom or not. For a line feed you need a male 1/8" stereo plug from your preamp. One really nice feature is that you can set the voltage for hitting 0dB, the factory default is 0 dBu, which is fine for my DPA/MMA6000, but for a hot mic into the DaviSound TB12 I was setting the knobs too far down, so I run it at +15 dBu (you can also choose +6 or -10 dBu). The meters are about the best I've used in the quiet area, it shows every bit of noise so I've had to clean up some of my other equipment (DC correction for my V3 and replacement of noisy DC power stick with a clean one). It is not so easy to use near clipping, as the scale is not as non-linear there as I'm used to. With the DPA/MMA I have no trouble as I've got a pretty good grip on levels at this point, and don't have a way to check while running anyway. WHile fooling around with other mics and preamps I tend to run too conservative. The meter is always lit, easily visible, it's just hard to tell when you are in the danger zone. The problem is that there are no markings telling you where you are except for one line, default set to -9 dB. I will probably move this to -6 dB as I think it will be more useful to me there.
Jeff