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article number 466
article date 07-16-2015
copyright 2015 by Author else SaltOfAmerica
Magnetic Sound Recording Part 1; Wire and Tape Machine Development 1900-1945
by John Regnell
   

From the author’s 1957 Master’s thesis.

EDITOR’S NOTE: Nearly all of the many references are left out of this casual reading article but we do occasionally include special unpublished ones which indicated the dedicated research of the author. Of course, the author had the advantage of living at the time of historical magnetic recording developments so he was able to obtain personal interviews, letters and mimeographed documents.

Introduction

From the earliest reference to a magnetic recording device in 1888 to the present, this study (1) chronicles the major steps in the development of the medium and (2) summarizes the major broadcast applications of the medium in the United States.

The early development of the medium and its application to broadcasting occurred outside the United States. Some research was conducted in the United States prior to World War II, but professional broadcast quality in both machines and tape was not attained until after the war.

Largely instrumental in this development were John T. Mullin, the Ampex Corporation, Minnesota Mining and Manufacturing Company, Armour Research Foundation, and Bing Crosby Enterprises.

First adopted by the American Broadcasting Company for delayed broadcasting, magnetic tape recording quickly spread to the other networks and independent stations. Superior to the acetate disc recording technique which it rapidly replaced, magnetic tape recording also provided some new program production techniques which heretofore were impossible.

Today, magnetic tape recording is an indispensable tool of the broadcasting industry.

I. EARLY DEVELOPMENT OF THE MEDIUM

In 1888, Oberlin Smith envisioned a permanent-magnet recording technique. Although he never actually constructed a magnetic recording machine, he proposed that a cord of silk thread be impregnated with steel dust or short clippings of fine steel wire. He also suggested, but thought impractical, a length of steel wire for magnetic recordings.

A. Valdemar Poulsen

Ten years later, in Denmark, Valdemar Poulsen built and patented the “Telegraphone,” the forerunner of present day tape recorders. Briefly, Poulsen utilized a steel wire one one-hundredth of an inch in diameter which was drawn rapidly past magnetic cores through which “sound currents” passed.

When the wire was again passed through similar magnetic cores, voltages were generated in their windings corresponding to the original currents.

Judged by standards of the time, frequency response was excellent. The Telegraphone was operated with earphones, but everyone assumed that this difficulty would be overcome shortly. Actually, however, it was not overcome until the development of electronic amplifiers about 25 years later.

At the Paris Exposition in 1900, the “Telegraphone was awarded the “Grand Prix.” On November 13 of the same year, Poulsen was awarded United States patent number 661,619.

   
The Telegraphone.

Poulsen came to America looking for investment capital to finance the sale of his invention as a dictating machine. Although he got a start, his venture failed because of certain weaknesses in his machine.

The speed at which the wire traveled in recording was just about as fast as was practical at that time, making it impossible to speed up the rewind time. This meant a period of waiting before playing back the dictation.

Furthermore, threading a “Telegraphone” was much more involved than placing a cylinder on a mechanical dictating machine. Eventually the company failed, and its stock became worthless. For some years after the Telegraphone failure, magnetic recording disappeared from the public scene.

B. Advances In Germany

In the middle twenties Kurt Stille obtained backing from German financiers for his wire recorder, and a company known as the Telegraphic-Patent-Syndicat was formed. The company’s purpose was to sell licenses to manufacture magnetic recording equipment.

It was rumored at the time that Stille’s machine was a modified American Telegraphone. By dramatic salesmanship, however, he sold licenses to several companies who actually manufactured the machine.

About 1930, Blattner, a motion picture promoter, bought the right to manufacture Stille’s machine for entertainment purposes. He named his machine the “Blattnerphone.”

It was used quite extensively by the British Broadcasting Corporation and is believed to have been the first magnetic tape machine to be used in the Western hemisphere. The Canadian Broadcasting Corporation installed it in their Montreal studios for delayed broadcasts.

The Blattnerphone used a steel tape about three-thousandths of an inch thick and approximately a quarter of an inch wide, and operated at speeds of three to six feet per second.

It was discarded eventually for technical and economic reasons. It had only slightly better frequency response than the original Poulsen machine, noise was high, and the reels were unwieldy and quite expensive.

Kurt Stille also sold a license for the manufacture of dictating and telephone recording equipment to Karl Bauer who formed the Echophone Company. Its product was called the “Dailygraph.” It was the first magnetic wire recorder to use a magazine instead of separate reels, which considerably simplified operation.

A number of different models were manufactured, the least expensive of which cost approximately $600. The Dailygraph had good acceptance.

In 1932, Bauer sold the Echophone Company to the International Telephone and Telegraph Company. It was then resold to the C. Lorenz Company in Germany, who completely redesigned the machine and marketed it under the name of “Textophone.”

The new machine was placed on the market in 1933, about the time Hitler came to power. The Gestapo bought the Textophone in large quantities and gave magnetic recording a considerable commercial value. The Lorenz Company also marketed the “Stahltonmachine,” a magnetic steel tape recorder which was adopted by the German Broadcasting Company in 1935.

   
Railroad wire recorder. Courtesy of the Brush Development Company.

While all of these business exchanges and maneuvers were going on, another German, by the name of Pfleumer, developed the forerunner of the modern magnetic tape recorder. He conducted experiments with magnetic recording media consisting of paper or plastic tapes coated with powdered magnetic materials. His first efforts were crude, and the results were a sandpaper-like roll of tape.

Hoverer, in 1931, several large research organizations undertook the development of his idea, I. G. Farben designed and constructed a magnetic tape of paper with a very fine powdered coating, and a recorder which could produce the best results yet obtained. Farben called it the “Magnetophon.”

At its first demonstration in 1935 at the German Annual Radio Exposition in Berlin, the “Magnetophon” was an immediate success. This success was primarily due to the astonishingly low cost of the ‘Magnetophon magnetic recording tape which was only $.15 per minute as compared to $1 per minute of steel tapes. The new magnetic recording material was also less unwieldy.

Very little information concerning the Magnetophon was available from that time until the end of World War II. When the Allies entered Germany they discovered that the Nazis had continued to work on magnetic recording despite severe shortages of manpower and material.

The equipment showed a remarkably high degree of development for both broadcast and military applications. Magnetic powder-coated tapes had been greatly improved, and the Magnetophon had been redesigned to take greater advantage of the capabilities of these tapes.

C. Early Uses by the British Broadcasting Corporation and the Canadian Broadcasting Corporation.

Although the major discussion of broadcast applications of magnetic recording is to follow, the writer has included this section here since the BBC and CBC were pioneers in the relatively limited use which was originally made of the medium.

1. England

The British Broadcasting Corporation was the first to use magnetic recording in a major broadcast effort. In 1932 the BBC presented the Christmas Day speech of King George V on magnetized steel tape. By 1937, although the system was unknown to most radio engineers, the BBC transmitted an average of five-and-one-half hours a day by magnetic recording. The principal use made of the medium even at this early date was for delayed broadcast of regular features.

In 1953 about 60% of the BBC’s requirements for recording programs for broadcasting were met by the use of a magnetic tape system. Plans were under way to increase that percentage with the installation of some 180 new tape recording and reproducing machines.

The new machines were to be of four basic patterns: static, for permanent installation in studio centers; mobile, for use in recording cars; midget portable equipment which could be carried and operated by a reporter; and rehearsal and training equipment.

The midget machines were suitable for recording speech, and were to be sent to broadcasting centers throughout the United Kingdom and to the Corporation’s foreign news correspondents overseas.

2. Canada

The Canadian Broadcasting Corporation also played an important role in the professional acceptance of magnetic recording, CBC began to use magnetic recording as early as 1934, probably making it the first studio tape recording of its kind in North America.

There we very little precedent for such a move in either commercial or government radio services, when, in the fall of 1934, the CBC ordered the Marconi-Stille-Blattnerphone “Steel Tape Recording and Reproducing system.”

During the latter part of World II, wire recorders were furnished to CBC’s overseas reporters and early in 1946, General Electric Models 50 and 51, and Brush Model BE0401 semi-professional magnetic tape recorders were introduced.

   
BK-401 Soundmirror magnetic tape recorder. Courtesy of the Brush Development Company.

The first modern studio tape recording installation went into service on October 12, 1949 at the Winnipeg studios. This instillation consisted of three channels of rack-mounted recorder-reproducers.

These units were installed to help carry the delayed broadcast load. This load was particularly heavy at Winnipeg as time-zone delayed scheduling is handled at that point for broadcast material which feeds from both west to east and east to west.

In 1950, three additional channels were added to this installation and about 350 hours of recording and reproducing were handled by this equipment during each four-week period on the air.

Although with the conversion to magnetic tape there was an increase in the total recording load, by using magnetic tape CBC saved approximately $100,000 in the fiscal year 1951-52 in recording materials.

For an average month, in 1952 approximately 900 hours of tap-recorded materials were used on the air by CBC. Tape is used at CBC for news event recording, delayed broadcast recording, auditions, air checks, and reference recording.

In certain areas where the station is mainly a network outlet, tape has been installed at both studio and transmitter. Evening operations originate from tape or at the network transmitter. Station calls, announcements, and programs are taped ahead of time. Short-wave receiving stations use tape for off-the-air recording and monitoring. Considerable CBC material, such as news and commentaries, is obtained in this manner.

D. Research in the United States Prior to World War II

On September 1, 1938, WQXR in New York City took a new step forward in broadcasting when they broadcast portions of “Carmen” by a method new to this country, “tape transmission.”

This quote from Newsweek magazine proved to be prophetic: “The significant event was that tape transmission, which gives some promise of revolutionizing broadcasting, had become a matter of formal record in this country.

Although substantially different from the line of development which tape recording eventually followed, here is the method then used for this innovation:

The recording medium was a 7mm continuous film. Upon the coated surface of this film a sapphire stylus, operated by a vibrating armature, traced minute lateral bands. These were converted into sound by a photoelectric cell.

Abroad, the system had been in use two years or more, the BBC and the Norwegian Broadcasting Company having used such broadcasts. In 1938, the superpower Luxembourg station ran off 35 tape-transmitted programs weekly.

The method was developed by the James A. Miller and the N. V. Phillips Company. The process was controlled abroad by the Phillips-Miller Corporation of Eindhoven, Holland, and in this country by the Miller Broadcasting System.

The American company hoped to install the system in 100 radio stations throughout the United States.

While reproducing machines distributed to these stations would remain the property of the Miller System, the tape would be supplied for a charge levied either on the station or in the case of sponsored programs, on the advertiser.

The chief obstacle at the time was the limited library of films because of the many difficulties facing foreign importations.

Research in the United States prior to the introduction of the improved German machine after World War II had been conducted by the Brush Development Company, the Armour Research Foundation of the Illinois Institute of Technology, and the Bell Telephone Laboratories, Incorporated. Their work produced a magnetic recorder which was used by the armed services.

   
Armour Research Foundation wire recorder Model 50. Courtesy of the Armour Research Foundation.

In 1933, C. N. Hickman of Bell Laboratories published an article in the Bell Labs Record on the use of magnetic recording in delayed speech experiments. In 1934 the Review of Scientific Instruments carried an article by H. A. Frederic on recording and reproducing sound in which magnetic recording was discussed.

In 1935 R. F. Malina of Bell Laboratories described Bell’s steel tape machine in an article in the Bell Labs Record entitled “A Mirror for the Voice.”

In 1937 C. N. Hickman of Bell Laboratories demonstrated a steel tape recorder producing excellent quality at a tape speed of sixteen inches per second. The machine was displayed at the New York World’s Fair and visitors were allowed to record and hear their telephone voices.

Another pre-war magnetic recorder was the “Sound Mirror” originally built by Acoustic Consultants and later taken over by Brush Develpment Company, which has retained the “Sound Mirror” name for its more recent recorders using coated tapes.

This early unit had an essentially flat response from 1,000 to 5,000 cycles per second with a dynamic range of about 40 dbs.

Western Electric Company manufactured the “Mirrophone” recorder in 1940 for use as a telephone company weather announcing device. It used steel tape in an endless loop and had response characteristics similar to those of the “Sound Mirror.”

in spite of these develoments, the only organizations that took any really vigorous interest in magnetic recording in this contry before the war were Brush Development Company and the Armour Research Foundation of the Illinois Institute of Technology.

The Brush Company inaugurated a research program for magnetic recording in 1939 and Amour Research soon followed. Armour was introduced to magnetic recording by Marvin Camras who has since accumulated many patents in the magnetic recording field.

He built his first wire recorder while still a college student and in 1940 Amour hired him to continue research on the subject. In 1941, Armour Research applied for a patent on A. C. bias in magnetic recording. The patent was granted in 1944.

In 1945, the Office of the Publications Board of the Department of Commerce displayed the new German magnetic recorder obtained by the Army in Germany. Details concerning its assembly and use were translated from the German and offered by the Office of the Publications Board at reasonable cost to American manufacturers.

The equipment was designed primarily for connection to a radio receiver for recording, and to headphones for playback. One of the interesting features of this machine, known in Germany as the “Tonschreiber,” was a pitch restoring head. This device, used when the tape was played back at speeds other than the recording speed, permitted restoration of the original pitch.

After the introduction of the German machines into the United States, research and development companies continued to improve on both the machines and the tapes. The result has been the astonishingly fine fidelity and efficiency of the current machines. Notable in their contributions to this development were the Ampex Corporation and the Minnesota Mining and Manufacturing Company.

Also in the 1930’s, some work was done in Japan on magnetic recording. First articles in Japanese publications appeared in 1936, and in 1937 and 1940, patents were issued in Japan. This later resulted in the Japanese communications industry, Tokyo Tsushin Kogyo, halting the import, use or sale of American tape recorders in late 1952. The resulting patent litigation between the Japanese and Amour Research was settled out of court in 1954 by which the Japanese company became an Amour licensee.

   
A wire-recorder with cover removed. Courtesy of the Brush Development Company.

II. DEVELOPMENT OF EQUIPMENT IN THE UNITED STATES AFTER WORLD WAR II

Although research had progressed in the United States, it is questionable whether development would have moved quite as rapidity had it not been for the introduction of the German Magnetophon following World War II. Chiefly instrumental in this development were John T. Mullin, Marvin Camras, the Minnesota Mining and Manufacturing Company, and Bing Crosby Enterprises.

A. World War II

With the advent of World War II the United States Armed services found a demand for a recording device which could be used under field conditions. To meet military demands, Armour Research Foundation put Marvin Camras’ recorder into production and later General Electric and two other firms began manufacturing the units to keep up production. Some 10,000 of the Armour units were built.

Brush Development Company also built wire recorders of its own design for the military and turned out more than 2,000 of the units. In addition, however, the Brush Company received a Navy Research and Development Committee contract for special recording equipment which would use coated magnetic tape rather than steel tape or wire.

In September, 1944, Brush contacted Minnesota Mining and Manufacturing Company to inquire if the company would develop a thin tape coated with an emulsion containing a uniform dispersion of a ferromagnetic powder. It was pointed out that such a product should have considerable post-war applications.

The 3M Company assigned the project to its tape laboratory electrical section for the purpose of finding a suitable binder for the magnetic powder, uniformly dispersing the powder in it, and coating the dispersion uniformly on a backing.*

* from: “The Development of Magnetic Recording,” (Unpublished information of Minnesota Mining and Manufacturing Company), 6.

At this time, the 3M Company had no test equipment and no tape recorders were available, so each sample had to be sent to Brush for evaluation. Later tape samples were also submitted to Armour Research and others, but this procedure was time-consuming and progress was slow.

Although a recordable tape had been made by 3M, it was not considered satisfactory for general production. By mid-July of 1946 however, the 3M Conpany’s Special Products Division developed a suitable binder for magnetic tape use.

Later in 1946, Brush Development Company brought out a redesigned “Sound Mirror” recorder and a paper-backed magnetic tape. The Brush machine and paper tape were the first such American products on the market.

Armour Research, however, anticipated that a number of manufacturers would rush into production of wire recorders for amateur and professional use. While Webster-Chicago, Sears Roebuck, Radio Corporation of America and others manufactured many machines from 1946 to 1948, the expected wire recording boom failed to materialize.

B. The Magnetophon

As Fortune Magazine reported:

"There the matter might have stood except that word began to spread of a phenomenal German instrument called the “Magnetophon” which produced high fidelity recordings on a magnetic tape made of plastic.

"The Magnetophon had been known to a few United States sound engineers before the war, but it was not then a perfected instrument. In its improved form it was sensational.

"A large portion of all German wartime radio programs were recorded and played back by Magnetophons and combat models were widely used by the German armed forces during World War II. Comepared to the American wartime wire recorders, the Magnetophon was a jewel.

   
Magazine for Navy wire recorder.

“The wire recorder had a maximum frequency response of only 5,000 cycles per second; the human ear can hear 15,000 cycles. The best pre-war phonograph records cut off at about 8,000 cycles and a great many home radios and record players produce less than 5,000 cycles.

"But the Magnetophon recorded to a full 10,000 cycles (later extended to 15,000) with uniform signal strength, low distortion, and negligible wow and flutter.

“While Armour Research Foundation had built experimental wire recorders late in the war with a frequency response equal to the Magnetophon’s, wire had one fatal defect for professional use: it could not be edited easily, and if the wire accidentally spun off the reel, it became hopelessly tangled."

The Magnetophon tape recorder was found by the American aimed forces as they advanced into Germany after D-Day. Various army groups had technical teams examining captured German equipment for the express purpose of uncovering anything that might be useful to the Allies in prosecution of the war.

Germany’s surrender in the spring of 1945 greatly speeded up these investigations and brought to light many developments. Magnetic recording was one of those which was not immediately fully appreciated.

Among the reports made by American and British groups was a United States quartermaster Corps report which covered German recorder and tape development. The information was gathered by a three-man team which ranged all over Germany between May 20 and September 1, 1945, and is one chapter of a book dealing with the German plastics industry.

The Magnetophon was described as an important recording and transcribing device using plastic tape carrying magnetic ferric oxide. Sound recording by this system was cooperatively developed by A. E. G. (Allgemeine Electrizitats Gesellschaft) of Berlin and I. G. Farben Industries, A. G. Ludwigshafen.

In operation, the tape passed from a roil across the gap of a small armature to a take-up reel. In recording, sounds were electrically amplified inducing strong magnetic fields across the gap of the armature, thus establishing many small permanent magnets in the iron oxide of the tape.

In playing back, the machine operated in reverse fashion. The magnetic variation in the tape induced small magnetic fluxes in the armature which were amplified and re-produced as sound.

The tape could be cleared of recording by passing it over another properly magnetized armature. New recordings could then be made on the tape and, if desired, the erasing and recording could be done at one pass.

This system was in general use on the German radio networks, and was used extensively by the German Army and Navy for fixed station recording, propaganda, orders, news, and for mobile communications from jolting vehicles and ships where disc recorders failed.

Haversack-size units were in use by front line listening posts. Voice demonstration of recording and transcribing was very successful at the regular tape speed of eighty centimeters per second. The instrument would record and reproduce frequencies as high as 10,000 cycles per second. One tape would record for twenty minutes.

Through 1943 and 1944 the Germans made 6,000 tapes each month and, even after bombing, their Wald Mittelbach plant made 3,000 tapes a month.

For the future the Germans were considering recordings transmitted by phone or radio at eight times recording speed to permit accurate, rapid communication. This was the same objective which the U. S. Naval Research Laboratory was considering in the 1920’s.

Data on the German tapes and machines was obtained from Dr. Karl Pflaumer. He told Mr. DeBell and two other members of the Quartermaster Corps team that Allgeneine Elektrizitats Gesellschaft had worked primarily on the Magnetophon apparatus while the Farben plant devoted its research to the magnetic tape and its large-scale production.

He pointed out that steel tape had been used first, but by 1939 a practical plastic magnetic tape had been achieved from the standpoint of sensitivity and low noise level. The changeover from steel tapes to plastic tapes in the German Broadcast System occurred at the beginning of the war.

   
Magnetophone. Courtesy U. S. Department of Commerce.

During the war special apparatus was developed for many purposes. These pieces of equipment involved field recording, portable equipment for war corespondents, and broadcast playback sets. The I. G. Farben Company did not then know of many of the military details since Allgeneine Elektrizitats Gesellschaft had been secretly commissioned to do the developmental work on machines. A Berlin company called Magnetophon, Inc. sold both the machines and the tape.

“The several recorders made included:
- Sound recorder B—a tape recorder with variable speed tape drive for the Wehrmacht.
(This unit may be the one called the ‘Tonschreiber’ which would record at its slowest speed for 70 minutes. The Tonachreiber featured a rotating playback head allowing recordings to be made at one speed, then played back at a different speed without changing the pitch of the recorded signal.)
- Sound recorder C—a portable knapsack recorder with a spring motor drive for Wehrmacht use and use by radio correspondents.
- Sound recorder D—a portable automatic transmitter and recorder for military and Broadcast use.
- Sound recorder RE-3—a special recorder for use by the German navy and also used in broadcast work.
- Sound recorder K-7 a Magnetophon for high fidelity music recording and use in radio stations. This unit used the latest type of magnetic tape and was the best unit from the point of view of fidelity.

“Still another experimental Allgeneine Elektrizitats Gesellschaft recorder used a scanning-type head on an 8 ½ by 11-inch sheet of oxide impregnated plastic which would record up to eight hours at a time.

“There were three stages of German magnetic tape development in the following order:
- Magnetophon tjpe C—two layers of cellulose acetate made by film casting.
- Magnetophon type L—a single layer of polyvinal chloride base material made by calendaring.
- Magnetophon type LG—a double layer tape made by calendaring one layer and casting a second layer over it. Research on this tape had been completed shortly before the end of the war and was not in general use.

“All three tapes were 6½ mm. wide, one kilometer long and had a film thickness of 45 to 50 microns with good frequency response to 10,000 cycles at a tape speed of 80 centimeters per second. The tapes could easily be cut and glued together using cyclohexanone for type L and LG tapes and cohesan for type C.

“Considerable difficulty was encountered in manufacture of the tapes to obtain uniform quality, temperature range of operation was satisfactory between minus 20 degrees C. and plus 50 degrees C. There was no change in the magnetization of the tape while stored in roil form.

"Type LG had a white backing which could be marked with black pencils. The latter differed from type L tape in that it could be recorded on one side only.

"Type L tape was impregnated and hence either side — but not both — could be recorded. The tape could be played back on the wrong side with some loss of high frequencies. This feature resulted in some confusion as to which side of the tape had been recorded.

"Figures on the production of tape and machines are as follows:
1939-40 — 379 machines and 9,000 tapes
1940-41 — 302 machines and 6,340 tapes
1941-42 — 870 machines and 21,200 tapes
1942-43 — 844 machines and 52,000 tapes
1943-44 — 937 machines and 86,000 tapes"

C. John T. Mullin

In addition to the Quartermaster Corps, the United States Signal Corps also investigated the German communications field. John T. Mullin went to France with the Signal Corps Technical Liaison Division to examine captured enemy equipment.

Several tape recorders ware found, but it was not until the Americans entered Frankfurt that Mr. Mullin found the Magnetophon. He had been a telephone engineer before the war and had also done considerable work in the sound field, and thus he recognized the potential of the Magnetophon.

He uncovered the maintenance manuals for the machine and photographed the entire instruction book, page by page.

   
Drive system of the Magnetophone. Courtesy U. S. Department of Commerce.

One of the features was that the frequency range of the machine could be extended to the fantastic figure of 15,000 cycles simply by a few modifications. The Army already had numerous machines which had been sent back to the United States, but the one in Frankfurt was now in use by the American forces and could not be removed.

However, Mr. Mullin redesigned the older models to provide the same fidelity as the latest broadcast models. He rebuilt one of the machines and sent the information on to Signal Corps headquarters in Washington. Subsequently, he dismantled two of the machines and shipped them piece-by-piece to his home in San Francisco. Since the recording heads were small and really the key parts, he kept them with him.

When Mr. Mullin returned to San Francisco, instead of going back to his old job with the telephone company, he joined William Palmer of Palmer Films and put the Magnetophons to work recording sound tracks early in 1946. In May of 1946 he made the first of several demonstrations of the Magnetophon before the Institute of Radio Engineers. It was an immediate success.

As a result of the demonstration, Mr. Mullin was called upon the next day by Alex Poniatoff, Myron Stolaroff, Harold Lindsay, and Charles McSharry.

These men made up the Ampex Electric Company. Mr. Poniatoff had formed the company which had made electric motors during the war but now he was looking for a new product. After hearing the Magnetophon he and his associates were convinced that this was the product in which they were interested.

Mr. Mullin and Mr. Palmer were retained as consultants by Ampex Electric to assist in building an American tape recorder patterned after the Magnetophon. Eventually Mr. Mullin turned one of the recorders over to Ampex for study, and Ampex started designing a production model of its own.

Mr. Mullin’s a second big demonstration of the Magnetophon came at a meeting of the Society of Motion Picture and Television Engineers in Los Angeles in the fall of 1946. Many technical papers on wire recording were given at this meeting including one from Magnecord, a company which was manufacturing wire recorders at that time.

Also present was Dr. Begun of Brush Development, who had just introduced their revamped “Sound Mirror” and Brush paper magnetic tape.

Mr. Mullin was discouraged, since he hoped that he had the only tape recorders in the country. However, he found that the Brush equipment was not meant for high fidelity and was far from the Magnetophon in quality.

After a subsequent demonstration at Metro Golden Mayer, Colonel Richard Ranger decided to enter the field of tape recorder manufacture and went to Germany and brought back his on Magnetophon. He had been in the electric business prior to the war.

Mr. Mullin and Mr. Palmer tried to make an agreement to distribute Colonel Ranger’s proposed machines on the west coast, but no agreement had been reached during the winter of 1946 and 1947.

Meanwhile Ampex was making slow progress on its machine with Mr. Mullin supplying information and assistance.

All patents on the Magnetophon and German plastic tape were held by the United States Alien Property Custodian and relevant United States patents were available for licensing. Therefore, any company which wished to do so could copy the Magnetophon.

   
Silvertone wire recorder-radio-phonograph combination. Courtesy of Colonial Radio Corp.
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