@willgolf - before the Internet, this was done through individual contacts and clubs, among other things (events too, something we haven't had much of recently). Audiogon does not have a lock on your ability to communicate with folks in the community. Most of the people who are really plugged in tend to be in the industry (or so close to it that they are readily known). Nothing prevents you from contacting such people. All you need to do is ask.
I've called musicologists, scientists, inventors of notable hi-fi, performers, producers and the like simply to talk shop with no monetary agenda in mind. If someone can make time (and you may have to schedule that, and possibly, put your thoughts into some notes to make sure you cover what you want), I think you'll find that there are people to "give." And if they are manufacturers, unless you are calling to bitch, they'll probably be more than happy to take the call. I called somebody at a manufacturer from whom I bought not a thing, simply because he knew how to use Jensen Imperials as bass cabinets. Have fun, Will. Life is too short. Don't worry about A-gon. From the sounds of it, you aren't trying to **** them. There was a whole industry out there long before this site appeared. Due respect, humble apologies to our host, etc.
Bill Hart