If you're like us, you can't get enough of mics, whether new or old. Unfortunately, finding spec sheets on models that have been out of production for decades isn't easy. To help you out, here's some literature on 20 classic mics, presented here in convenient, downloadable .pdf format. Enjoy!
DPA Microphones 4003 and 4006
Shure Unidyne Model 55
Neumann U47/U48 (German brochure)
Telefunken Ela-M 25x