I know that you need to use preamps on microphones before running them into the inputs on the Delta 66. Should I also be runing my acoustic guitar pickup through one as well? I have an ART Tube MP right now. Do I need something like the DMP3?
The ART is a preamp, so you have all you really need. There are better preamps that work well as direct boxes, though; the DMP3 is one of them. You could run the guitar signal through one channel and mic the guitar with the other. I use the DMP for all kinds of stuff, so if you got one it's unlikely to sit on the shelf much. Nice unit.