The Pro Co Sound DB1 is both a standard direct input box and also offers up a variety of extra features that makes it seem more like a pedal than a DI box. The unit has 1/4 inch connections that includes a standard input and output and a direct output as well as a parallel output. This isn't a rack mountable piece of gear as it is a stomp box.
The unit has a clean volume knob as well as a section for distortion that includes parameters for volume, blend, trigger, and gain. The box also has EQ knobs for bass, mid, and treble as well as a variety of situations including phantom power, color, and gate. This is pretty much all that there is to the box and unless you are a beginner, I don't think that a manual is necessary.
While it will give you a pretty clean sound if you aren't using the distortion, the distortion doesn't have a realistic sound in my opinion. The EQ is helpful but isn't the cleanest sounding one in the world. While this is probably designed for use in the studio, I think that it works better for live shows as you can get away with a little bit more and the extra parameters are more useful in a live show setting. I don't think that this is best sounding DI box/effect pedal, but it is usable and does offer a good amount of versatility.
Having the built in effects and provides a variety of options and features that are handy for bass players on the stage. I wouldn't use this in a studio however as I don't think that the signal is clean enough to put on tape. The price of the Pro Co Sound DB1 is reasonable, but again I would only recommend looking into it if you are a bass player looking for a DI box to use on stage.
The ProCo Sound DB-1 is a passive direct input box that I have used in the recording studio. Like pretty much all DI boxes, you could use this for live sound as well but I haven't done so as I don't do very much with live sound. This is an analog piece of gear consisting of a 1/4" input and output, and an XLR output. It also has switches for ground lift, high cut, and for speaker/instrument line. It doesn't require any external power supply and isn't rack mountable as it is a box.
There isn't very much that you need to know in order to operate the ProCo Sound DB-1. For the most part it is self explanatory what everything does, and if it isn't I would recommend doing some research on direct input boxes. I don't think that a manual is necessary at all, as most users will be able to figure out everything on their own.
The sound of the ProCo Sound DB-1 has the perfect amount of clarity, punch, and fullness for a direct input box. It will give you back the same signal that you send to it, meaning it is has great fidelity and is reliable. I've used the box for a slew of different applications including for recording bass guitar, keyboards, and for routing purposes for electric guitar. In my time using it I've only found it to be a good sounding direct box without any noise or loss of quality.
Overall, I really don't see any problems with the ProCo Sound DB-1. It is reliable and will do the job very well. The price falls right in line with what else is out there, so I don't think the price should be a factor here, but I will say that it is on the cheaper end of high quality direct boxes. I'd also recommend checking out the Countryman DI Box Type 85, the Radial Pro DI, and the ProCo Sound CB-1, but definitely include the DB-1 on the list as well...