8 Track Heaven Fascinating site devoted to history of much-maligned format and its 2- and 4-track antecedents, with interesting links.
Altec Lansing (unofficial) Homepage In-depth resource on Altec-Lansing products
Ampex Mailing List Invaluable resource bringing together users and designers of Ampex tape machines
Audio Annals Commercially-sponsored “portal for the history of Audio Technology”. Extensive information, including patents and very extensive group of biographies. Worthwhile.
Audiotools Site devoted to audio in general, with pages devoted to various parts of the recording and playback chain. Consumer-oriented, but with good history of reel-to-reel recorders, including Soundmirror.
Electrocompaniet (Otala amplifier) history Resource created by former designer for Electrocompaniet covering Norwegian Otala ampliers
Excerpts from "Magnetic Recording" Web versions of chapters 1 and 6 from comprehensive 1949 history by Semi Begun, founder of Brush Development Corporation (manufacturers of the Brush Soundmirror). Excellent period illustrations, well presented.
H.H. Scott Hi-Fi Stereo Archive Site devoted to H.H. Scott tube products. Schematics and marketing materials, mail-list.
H.H. Scott tube amplifiers, H.H. Scott tube tuners and Radio Transmission Technology Site with sections on Scott amps and tuners, and many links to mid-century U.S. radio transmission technology
Sony APR group's web page Low-volume Yahoo group focused on Sony APR series recorders.
Heathkit Museum--audio products Exhaustive range of information on Heathkit products
Heathkit page by Bill Wilkinson Another extensive resource on Heathkit
James B. Lansing Heritage and Legacy Superlative resource on Lansing and the products of his various companies.
Loudspeaker and public address systems history In "Western Electric History" (part of "A Memorial to the Bell System")
Paul's Virtual Museum of [chiefly British] Tape Recorders The name says it all! Focus on consumer reel-to-reel machines.
Quadruplex Park Museum of Broadcast Technology Private “museum” devoted to video broadcast technology
Roger Russell's McIntosh History Page Comprehensive McIntosh resource
Presto History Excellent ongoing project to document history of Presto, U.S. manufacturer of recorders and amplifiers from the 1930’s through the 1960’s.
Revox History in English and in German Unofficial site devoted to Revox history.
San Francisco Bay area broadcasting history Excellent resource, with particularly good archival photo section.
Studer List Similar to the Ampex list, a unique resource for Studer information.
Studio 3 History Site devoted to the career and studio of David Sarser, violinist, Ampex rep, engineer and electronics designer.