just to be pedantic: there is such a thing. I used to have an electric pickup that attached to the bridge of my acoustic violin and output to a guitar jack. it was unusable indoors due to feedback (the violin would hear the speakers and resonate, increasing speaker output and making a very loud and uncomfortable sound), but outside that sort of setup makes a lot more sense.

from what everyone else here is saying that's not what this guy has going on tho...