Re: kurt cobain MTV acoustic pickups?
Walters, the pickup you actually hear on the record was a bartolini soundhole pickup. I believe it is active but I could be wrong. In any case, the DeArmonds above and below didn't create much output with the strings he was using. Anyway.
As for your other question, if I'm interpreting it correctly, it is pretty unusual to see ordinary magnetic type pickups on an acoustic (which is a shame, in my opinion). Some people use special soundhole humbuckers, which are really the best sounding acoustic pickups in my opinion, instead of a piezoelectric or soundboard transducer. These are specifically designed to have an acoustic sounding response.
You can indeed put an ordinary magnetic pickup on an acoustic - lots of jazz guitars have mini humbuckers that are sort of clipped onto the sides of the neck - and back in the old days, a few guitar companies sold acoustic guitars with single coils on them. John Lennon, for instance, played a gibson j-160 (I think) that had a pretty hot single coil in it. That's that great chunky rhythm sound you hear on all the early Beatles records. Gibson still makes this model, and Epiphone makes a version of it specifically called the John Lennon tribute something something.
If you want to install one on an acoustic, be aware you will probably need to cut away part of the soundboard. This isn't necessarily a problem unless you happen to cut into one of the soundboard braces. That would significantly weaken the soundboard, causing you slightly better tone for a short period, and then an explosion of strings and spruce.
Also, I believe Kurt's Martin had an output jack mounted into the soundboard. Don't do that. That's totally stupid - the soundboard is quite delicate, and all it would take is one good yank on the cord to crack it. Mount the jack through the thick block of wood at the bottom of the guitar (where the strap pin goes). In fact, you can get an output jack that also functions as a strap pin.