The Vintech Audio 273 is a dual channel microphone preamplifier with built in EQ. It is an analog piece of outboard gear that doesn't have any effects or anything beyond the preamp and the EQ. It has XLR connections in the back and has 1/4 inch inputs in the front for using this as a direct input box if you so choose to. It is indeed a rackable piece of gear and will take up a single rack space.
The configuration of the Vintech Audio 273 isn't too hard to follow, especially if you have experience with channel strips or mic pres and EQ in general as the parameters seen on here are all pretty standard. Each channel on the pre has parameters for gain, output, and two bands of EQ. It also has buttons for impedance and to choose between either a mic or line input. It then has switches for phantom power, phase, and EQ in/out. I haven't seen the manual for the Vintech Audio 273, so I can't say if it would be useful or not, but I can say that the unit is easy enough to use on its own that most people will probably not need a manual.
The sound quality of the mic pres on the Vintech Audio 273 is outstanding. This is just like having a great console pre and EQ combination in a racked pair and definitely lives up to this in terms of sound and clarity. They are great pres for just about any application and the EQ sounds pretty awesome as well, although I don't always use the EQ. The pres won't really color your sound exactly as I do believe that it presents a clear picture of the signal that you are sending it, but like all pres, each one is different and will bring its own sound to the table. Overall, this is a great sounding set of mic pres and it is always a pleasure to use them.
I've been using the Vintech Audio 273 stereo channel strip on and off for the last year or so and I'm always happy when I get a chance to track with these pres as I always seem to get extreme clarity and warmth in terms of tone. The price isn't cheap, but also isn't all that expensive for a two channels of mic pres and EQ that sound as great as this one does. While definitely suitable for both professionals and home studio owners alike, I would make a case that home studio owners without a board could get a lot out of having one of these as you then have a great pre to record two channels with at once, which is a huge upgrade from just using the pres on your audio interface. Anyone looking for a stereo mic pre/channel strip should definitely consider buying the Vintech Audio 273 channel strip.