Platinum Blonde

Posts: 1,253 Member Since: 16/07/2012


Apr 18 15 12:04 AM

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From Jay McKnight:

  The book "3M -- Magnetic Media Maker" is an authentic history of 3M
  magnetic tape. Here is the book review that will be printed in the
  AES Journal:

“3M – Magnetic Media Maker, a history of the first four decades (1944...1985)”,
by Charles L Alden

Book Review by Jay McKnight and Bill Lund

The idea of magnetic recording dates from Oberlin Smith, in 1878, and was realized with wire
recorders from Valdemar Poulson in 1898, but wire was too expensive, too heavy, and too hard to
splice to be a real commercial success. Then in 1928 the Austrian inventor Fritz Pfleumer patented
a paper tape coated with a magnetic material. German companies soon started developing and
manufacturing magnetic tape and tape recorders, but it was not until the end of the war in the 1940s
that the Allies learned of the progress that had been made in tape recording in Germany during that

In 1944, Otto Kornei of the Brush Development Company wrote to the Minnesota Mining and
Manufacturing Co (“3M”) asking if they would be interested in developing a thin non-metallic tape
coated with an emulsion containing a ferromagnetic powder. 3M said that they would like to try, and
thus was born a major US industry.

In 1984, the 3M management asked 3M employee Charles L Alden to compile a history of 3M’s
activities in magnetic recording tape invention and manufacturing. This was the first time that most
of these ideas were revealed publicly. The result was a 134 page manuscript called “3M – Magnetic
Media Maker”, that was completed in 1987. But management decided that they did not want to
publish it, so it was shelved for about 17 years. Charles Alden died in 1989.
In 2004 a copy of an extract of this history found its way to my hands, and I passed it on to 3M
retiree Del Eilers. He and his wife Karen were able to find the complete original manuscript and
assemble it for publication. The book was finally published only months before Del's untimely death
in 2014 December.

Del's contribution to the Magnetic Tape Industry was huge. He was the best remaining 3M
person to put the materials together.

The book’s 25 chapters give the the history of 3M’s research, manufacturing, and selling of
magnetic tape, starting with the original proposal based on 3M’s experience in producing precision
coated tapes, and their known coating research capabilities. Of course 3M did not have, nor had it
even seen, a “tape recorder”. They weren’t even sure if anybody would want “sound recording tape”.

By 1946 there were several companies making tape recorders, and anxious to have a supplier of
recording tape. 3M developed or found vendors of magnetic materials, binders, base materials,
coaters, and slitters. By 1947 June they shipped the first Nr. 100 paper-based “Scotch” Sound
Recording Tape. Soon many companies were found that were anxious to record other signals –
“data” – on magnetic tape.

The following chapters detail the struggles of developing improved coating materials, methods,
and bases, and of selling tape into the expanding fields of sound recording, data recording, and
instrumentation recording.

By 1956 Ampex had developed the first really practical Video Recorder, without revealing it to
anyone outside of Ampex. And several tape manufacturers tried to make tape for it, but only 3M
made a working tape for it.

The story of 3M Magnetic Tape from 1985 to the end of its production on 1995 November 14, is
one of continuous improvement in quality and durability. The saga ends four years after the
introduction of Nr. 996, arguably the finest analog audio tape ever manufactured. Del Eilers was the
engineer behind its development and manufacture.

This book is now available for 20 $ per copy, directly from the publisher, Karen Eilers, at 11280
Kingsborough Trail, Cottage Grove, MN 55016, telephone 651-438-2344, email
karenmeilers@embarqmail.com .

-- Best regards, Jay McKnight Cupertino, CA 

Copyright 2015 by Jay McKnight


Alan Garren
Waltzing Bear Audio

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Platinum Blonde

Posts: 2,236 Member Since:07/07/2011

#1 [url]

Jul 1 15 9:43 AM

I can't imagine how they could get 25 chapters out of this topic. Must be action packed.

Dusk Bennett
Los Angeles Ca
Award Winning Engineering

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Aqua Marine

Posts: 4,162 Member Since:20/01/2011

#3 [url]

Jul 2 15 10:49 PM

It sounds fascinating.. the process involved cutting edge materials technology for the time, and the engineers at Ampex were learning so much from these experiments...

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