LM13700 story by Don Sauer - Two CA3080 in a single package.
Mu:zines is a project to scan and re-publish old music production magazines
Overview of Audio System Grounding & Interfacing by Bill Whitlock
Analog Devices - Analog Filter Wizard
Filter used in analogue Roland synths
The Pultec EQP-1A Facts & Fiction by Cris Preston, VintageWindings.com
'This paper includes all of the Original EQP-1A filter data'
The Scientist and Engineer's Guide to Digital Signal Processing By Steven W. Smith, Ph.D.
Audio Handbook - SSM Audio Products
American Radio History - Scans of magazines and books
'Six million pages of AM FM & TV Broadcasting history online'
Audacity is a free, easy-to-use, multi-track audio editor and recorder for Windows, Mac OS X, GNU/Linux and other operating systems.