This article originally appeared in the June 1966 issue of American Cinematographer, and is posted here with the magazine's permission.
The below photo, courtesy of the Swedish Film Institute’s Image
Archive, did not appear in the original article, but has been added
here for illustrative purposes.
The Academy Award-winning
”This equipment provides the motion picture industry
with a well-engineered, high quality, compact,
versatile recording system for location recording.”
Nagra III & SELA mixer
the fashionable crowd that packed the Santa Monica Civic Auditorium on
the evening of April 18 to witness the 38th Annual Academy Awards
Presentation, and to the millions of viewers watching the colorcast of
the affair throughout the nation, the big news centered on the ”Oscars”
awarded for Best Actor, Best Actress, Best Picture, etc.
to filmmakers everywhere, especially those who are frequently required
to record sync-sound under difficult location conditions, the
significant award was the Class II plaque presented to Swiss
electronics engineer Stefan Kudelski for the design and development of
the Nagra portable 1/4-inch tape recording system for motion picture
Concerning the Nagra, the Academy's official statement read:
equipment provides the motion picture industry with a well engineered,
high quality, compact, versatile recording system for location
recording. An outstanding feature of the recorder is the constant speed
characteristic resulting from its unique control circuitry.”
None of this is news to the thousands of users of the Nagra in the
Hollywood studios. United States radio and television networks and in
filming situations throughout the world.
However, few of these technicians, as well as those among the
glittering assemblage that witnessed the presentation of the plaque
could have had any inkling of the remarkable saga of a man and his work
that led up to that moment.
Stefan Kudelski was born in Warsaw, Poland, on the 27th of February,
1929. His family had an engineering background, and included, in
particular, several technical college professors.
His father studied as an architect, but his principle field of work was
in the chemical industry. His mother is an anthropologist.
In 1939, the Kudelski family fled in front of the Germans, and
regrouped itself in Hungary. From there, they passed on to France,
where Stefan Kudelski continued his education. After the German
invasion of France, the Kudelski family lived in the Vichy Zone. Stefan
Kudelski's father, being an officer on active service, organized a
resistance network, which fell in 1943, but the Kudelski family managed
to escape to Switzerland. Both his father and his mother were honored
for their activities during this period with the French Croix de Guerre.
Established in Geneva, Young Kudelski continued his studies at the
Ecole Florimont. He became interested in electronics before he had
finished his secondary schooling there. He built up a small laboratory
at home and worked on the problems of generating extra high tensions by
means of high frequency oscillators, with a view to electrostatic dust
extraction from the air. After that, he made an instrument for
measuring the accuracy of watches, based on a counter with a crystal
controlled gate. These experiments were in the nature of an
apprenticeship and, although he took out several patents, no commercial
exploitation was made.
In 1948 he started studying at the Ecole Polytechnique in Lausanne, in
the Physical Engineering faculty. As the electronics section of the
faculty was not sufficiently developed at this time, he continued to
work in his own laboratory, as well as doing his general studies at
About this time, the first magnetic recorders were put on the market.
During the war, the Germans made a few tape recorders, but they were
generally unknown to all but a few, but the principle was established
in the 19th century. Stefan Kudelski immediately realized the potential
of using the memory incorporated in a magnetic tape for the automatic
control of machine tools, but the science of magnetic recording was
still in its infancy and he decided that it would be better to
familiarize himself with all the aspects of tape recording before
specializing in sophisticated systems.
To this end, he made several tape recorders, and he saw that there
would be a ready market amongst radio stations for a small portable
tape recorder working off self-contained batteries, and such a recorder
was a practical proposition. In this idea, he foresaw that it could not
only be an exercise, but a means to earn a little cash to pay for his
studies, and to form a foundation for his future work. The Kudelski
family, of course, lost their entire fortune during the War.
so the first commercial tape recorder was made in 1950. Its dimensions
were 5"x7"x12" and weighed 11 lbs. It was called the Nagra. The motive
power for the tape transport was a spring motor of the type used for
portable phonographs of the era. The amplifiers used battery powered
tubes fed from A and B dry batteries. By modern standards, the quality
of sound obtained from the recorder was poor, but the radio stations of
the day found it acceptable. The worst fault was the flutter in tape
speed caused by the centrifugal motor governor. In 1953, the model was
improved by incorporating mechanical filters to smooth out these
variations in tape speed. This was the birth of the Nagra II, which
aroused the interest of the movie industry. One of the first full
length feature films to use the Nagra during shooting was ”Black Orpheus”.
Stefan Kudelski examined several systems for synchronizing the camera
with the tape recorder. One such system worked from a signal generated
by the tape recorder which then slaved a rotary converter feeding a
synchronous motor on the camera. This method had disadvantages, being
wasteful of power. At that time, power transistors were not
sufficiently developed to allow the elimination of the rotary
converter. The method finally adopted, as have others, is the reverse
of this method. The camera generates a signal which is recorded on the
same tape as the sound, thereby reducing the power consumption
From 1956, he researched into the possibility of a self-contained tape
recorder without a centrifugal speed governor, this latter causing
endless trouble with the clockwork drive. This resulted in the Nagra
III, which was launched in 1958. The success of this model was
enormous, and enabled the Kudelski organization to develop from a
specialized laboratory to a true industrial establishment.
At the present moment, he is developing smaller and lighter versions of
the Nagra, and he is trying to achieve the highest possible operational
reliability, using techniques previously employed only for military
equipment. This accent on reliability is aimed to eliminate as much as
possible of the servicing of professional tape recorders.
Stefan Kudelski is married to a Doctor of Medicine, and they have three
children, a boy of 6 and two girls of 4 and 1.
He takes a keen interest in jazz and classical music, photography, and
does some 16 mm cinematography. He likes to spend odd moments skiing
but, above all, he likes water sports, including skin diving.
For transport he uses a twin engine Cessna, being an Instrument Rated
Pilot. He bought this aircraft in the U.S. and flew it across the
Atlantic with the help of another pilot, via Newfoundland, Azores and
is the stranger-than-fiction story behind the remarkable Nagra recorder
and the remarkable man who conceived it — the same man who walked
modestly to the platform on the evening of April 18, 1966 to receive
his tangible symbol of the highest recognition the motion picture
industry can bestow.
In addition to receiving an
Oscar Plaque from the Academy of Motion Picture Arts and Sciences,
Stefan Kudelski, while in Hollywood, was entertained at a luncheon of
sound directors and sound engineers of the motion picture and
During this luncheon, Kudelski explained, in some detail, the evolution
that is now taking place in his manufacture of recording equipment, His
long-range objective is to provide a recorder which will run for five
years without service or trouble.
This program is underway in the recorders that are now being delivered.
It includes an increasing use of silicon transistors, tantalum
condensers, and the elimination of all belts. The recorders now being
delivered to include a larger percentage of silicon transistors. The
current model NTBH and NTPH have the same tape deck and controls as in
the past. These instruments will be followed by the Nagra 3D Non-Sync
and 3L Sync Recorders. These titles will be used for the recorders
which include all of the advanced features.
During his discussion, Mr. Kudelski pointed out that the steps that he
is taking do not obsolete the current equipment's and, that from
general performance standpoint, the customer will never know the
On a still longer range basis. Mr. Kudelski described the new IS
Recorder, which is even now in the start of manufacture. The IS
Recorder will incorporate all of the long life and reliability factors
which are being incorporated in the Nagra 3D and Nagra 3L, plus a new
motor and a simplified control system. The new motor is driven by a
closed loop servo system, somewhat similar to the earlier recorders.
However, its new mechanical construction, greater power, and lower
starting inertia, should provide a better tape transport than any other
equipment that has ever been manufactured. The new IS will also have a
modernized version of automatic gain control. Instruments of this type
will also include all the features that are necessary for complete
automation. Models will include 1/4" stereo or multitrack 1/2" tape
During the discussion Mr. Kudelski indicated that there is going to be
a continuing evolution and continuing improvements in his recording
equipment. This will, in time, include a two pound recorder.
In closing, Mr. Kudelski pointed out that people who have need for new
automobiles do not wait for next year's model. As the improvements do
not justify the delay, he expects to see a similar trend in recording
equipment, which should not block the immediate sales of equipment's
now being offered.
UNIQUE MECHANICAL & ELECTRONIC FEATURES
OF THE NAGRA RECORDER
TWO MICROPHONE INPUT CIRCUIT
The Nagra is normally equipped for mixing with a single microphone plus either a line or bridging input.
By the addition of a BS preamplifier the line input can be converted to
a second microphone input for two microphone mixing.
4 microphones and a line input are available through the use of the BM auxiliary mixer and normal input.
Using 15" Speed, only available on Nagra, frequency response flat to within 1 dB from 30 cycles to 18,000 cycles.
HI QUALITY SELF-CONTAINED SPEAKER
High-powered Class B amplifier provides 2 watts of power for undistorted reproduction.
HI QUALITY AUXILIARY SPEAKER
The DH self-contained auxiliary speaker-amplifier provides remote
quality monitoring either during recording or reproduction.
COMBINED SYNCHRONIZING TRANSFORMER AND POWER SUPPLY
The auxiliary ATN power unit can be used as a synchronizing transformer
when the camera is being driven by a 60 or 50 cycle power supply.
The ATN power unit can also be used to provide external power to the
Nagra, operating independently of the internal batteries.
CLOSED LOOP SERVO-DRIVE
The Nagra is the only recorder using a closed-loop servo drive. This
provides the lowest flutter and wow of any known portable recorder.
ELECTRONIC SPEED CONTROL
3 Speeds are available with no mechanical linkage, as the speed is
controlled electronically by accurately tuned resonant circuits.
The recorder is equipped with stroboscopic discs for speed comparison with 60 or 50 cycle power source.
The SV auxiliary speed variator can be used to change the speed of the
recorder (at 7 1/2"/sec) for purposes of music-pitch change during
recording or to correct for improper camera speed during synchronous
transfer from 1/4" tape to sprocket-driven magnetic film.
TIME SYNC GENERATOR
Provides complete portability of recorder with no cable connections.
Camera can be driven separately from a time control or a power line.
NEOPILOT SYNCHRONIZING SYSTEM
With high-frequency bias, this system provided the first trouble-free method of synchronization.
SYNCHRONOUS PLAYBACK CAPABILITY
The auxiliary Synchronizer is used for synchronous transfer from tape
to sprocket-driven film. This is the least expensive reliable system of
The Synchronizer is also used for synchronous playback of pre-scored
music for lip synchronization during camera action.
The Synchronizer can also be used as a source of a synchronizing signal
when the camera is being driven by a 60 or 50 cycle power supply.
BLOOP TRANSFER CAPABILITY
When the SLP or SLO is used for synchronous transfer of 1/4" tape from
the Nagra to sprocket-driven magnetic film, a bloop can be introduced
on the transfer sound at the point of camera start.
CONTROL FOR EASY EDITING
The forward and reverse control and the tape tension rollers are
arranged for easy fast forward and fast backward monitoring, fast stop,
and normal reproduction for easy editing.
The exclusive straight-line threading feature not only provides a simple but also a foolproof method of threading.
The self-contained lineup oscillator is used to provide a level index
on the tape, thus all transfer prints and reprints from the Nagra will
be at the correct level.
Included in the Nagra is a bloop oscillator which can be made to
function automatically with the flashing of a hand-held bloop lamp in
front of the camera or the flashing of a bloop lamp installed in the
1200' 7 inch reels can be used on the Nagra when operated with the lid open.