To be honest, you can't. There has never been an official home video release of Star Wars with both the '77 theatrical video AND the '77 theatrical audio. If you must go with official releases, you have to pick one over the other. The 2006 DVD bonus discs have the 77 video, but with the revised 93 audio, which I find to be grating. Empire and Jedi fare better--it's actually possible to get theatrical audio & video on the same release (VHS or Laserdisc), but they still suffer from some more subtle flaws that affected many home video releases of these films.

The despecialized editions, in spite of their flaws, are closer to recreating the theatrical versions than any official home video release. If you buy the official releases, IMO, you'll be disappointed.