Bell System Technical Journal, 1922-1983

http://bstj.bell-labs.com/BSTJ/

"The scientific discoveries and technological innovations produced by Bell System research and engineering were critical not only to the evolution of global telecommunications but, more widely, they had a considerable impact on the technological base of the global economy and, indeed, on our daily lives.

Bell Labs is the source of many significant contributions, of course, in the area of telephony, but also in memory devices, imaging devices, system organization, computers and software technology, as well as acoustics, optics, switching, transmission, wireless and data communication....

With this posting of the Bell System Technical Journal from volume 1 issue 1 in July 1922 to the final issue published in December 1983, we are pleased to be able to open the vault of this knowledge to our global technical colleagues."

This one popped up on the AH list. You'll find a number of papers including "Synthesis of Voiced Sounds From a Two-Mass Model of the Vocal Chords" and "Thermionic Vacuum Tubes and Their Applications"

via cheater cheater:
"Page 57 and lead up on page 56: this is a tuned band pass filter with variable Q. You just need one tube, one variable capacitor, and one variable inductor. Works well up to "2,000,000 cycles".

Also see the next point on page 60: Feed-Back Amplifiers. Looks fairly interestingly like a ladder filter, don't you think? And uses resistances. This means: voltage control!!"

Update via Eric Barbour of metasonix in the comments: "No. It is not a 'ladder filter'. This was a very early article about tube amplifiers, and all the discussion focuses on their use in telephone installations, primarily as repeater amps."