Telefunken Tube Information Sources?

@bdp24  Joe's tube lore is a good reference, but I would not call it accurate regarding 12AX7s. He makes no pretense saying he doesn't like this tube type. 

Brent Jessee has a better description of sonics on different brands and tube types.

One characteristic of Telefunken is they are extremely linear. So, no sweet mids, but great dynamics and open sonics.
 And it's true that Siemens rival Tely's. 

Thanks one and all. @jab, I know what you mean, but I'll be okay ;-) . I have only a coupla AX and AT in my RIAA phono amp (a Herron), my line stage using a pair of 7JD8, which are cheap. I'm not necessarily going to buy Telefunkens, but I want to know about them in case I find some for cheap. I recently worked with a bassist who is also a ham operator, and he tells me he has a large stash of vintage tubes. I'm gonna go have a look!