question about pre amps and digital boxes..

i use the audio box. it's a digital interface in which you plug in your mics. i assume there is a pre amp built in. I am thinking of buying a preamp to get better or different sounds, but if i plug a mic into a pre amp and then into the audio box(because the audiobox goes into my computer via usb which runs my studio program) will the sounds or effects of the pre amps be watered down through the audiobox's pre amp? in other words, what do pre amps tend to be plugged into if not audio interfaces?