Nagra 3 p owners manual

Page 1

KUDELSKI PAUDEX- LAUSANNE SWITZERLAND
AUGUST 1962

Post - address: KUDELSKI, Faudex-Lausanne, Switzerland

Factory and office: 6. chenlin de I'Etang, Paudex-Lausanne
OfficeaHours: 7.30 - 12.00 a.m. and 1.30 ~ 6.00 p.m. (Saturday closed)
Phone: Lausanne (021) 28.62.62

Telex: Lausanne 24.392

mSTRUCTloNs FOR THE USE OF NAGRA m P, THE SLP SYNCHRONISER ETC.

CONVENTIONAL FILOTTON TECHNIQUES

So far as the recording and reproduction sections of the models are concerned, the Nagra III P is
exactly identical to the Negro lll B. Nagra lll P, however, differs from the Nagra lll B by virtue of the
Neopilot head and by additional electronic circuits. The Nagra m B enables recordings to be made

for broadcasting purposes. the productions of records. and the recording at mud effects, bird noises,
etc. The Nagra m P has the additional capacity of synchronizing sound wish in photographed image
("lip-synchronization", used in films and TV).

For reasons of its ease of use, sprocket tape or sprocket film is universally used for the editing
of the sound on Cinema films. But it is much more Eunvenient, at the time of shouting, (0 record
the sound track on regular 1/4 - inch magnetic tape and to utilize a system of pilotage to ensure the
proper synchronisrn.

Therefore, the sound is recorded on magnetic tape (a. g. on the ngra in F) together with a signal,
called the pilot signal, which originates at the camera, and which constitutes a form of invisible
perforation. It is necessary, therefore, to have two distinctly separate recording channels which do
not interfere with each other.

For the purposes of editing, the recording thus obtained is later transferred into sprocket film. Other
procedures which will be examined below, render it possible to obtain the sound track on sprocket
film exactly as if the normal procedure had been used, i. e.. by having the sprocket tape recorder

at the site of shooting. Because Of the portability of the Nagra, and due to the fact that it does not
require a three phase power supply, the procedure described above offers a great many advantages.

PILOTAGE PROCEDURES

There are an infinite number of possible pilotage pro edures. in practice, however, all the existing
systems record a pilot signal of so or so cycles, ori 'nating at the power supply of a synchronous
motor driven camera. When the camera operates on no batteries, these systems incorporate a
"Pilotton generator" in the camera which produces a similar signal (50 cycles per 24 frames in
European cinema, 50 cycles per 25 frames in European TV and 60 cycles per 24 frames in the United
States).

Of its own nature, the choice of the number of cycles, or the number of frames, is arbitrary; it is
simply necessary that the sprocket tape recorder on which the transfer is made, is of the same
standard. For example in the United States, a speed of 24 frames per second is used, while the
mains power supply is of so cycles per second; the sprocket tape recorders have been designed for
these values accordingly. Therefore, the pilot equipment must be ior so cycle s per 24 frames.

if the copy (or transfer) is to be made in the United states. The Nagra In P functions well with any
standard, as it is possible to record either a 50 or a so cycles pilot signal. The SLP synchroniser
is equally multi- standard.

The essential difference between the various Systems in use is the method used for Obtaining the
second channel (the pilot signal channel).

Some systems use stereophonic machines for this purpose, but half of the tape is wasted on the pilot
signal only, which brings about an exaggerated reduction of the signal-[0»noise ratio. Other systems
use two or three tracks, with very narrow tracks for the pilot signal, which is already in the nature
of an Improvement. A form of carrier frequency is also used which enables conventional machines
to be used, but it demands meticulous care and attention, as the recording of high frequencies must
be perfect. We have adopted the system that has become standard practice in Germany and in many
othercountries, nan-rely, the Pilotton system.

Mr W.

Page 2

Page 2
AUGUST 1962

in the original Pilotton system - to which the Ranger system is also very similar . the pilot signal
was recorded across the tape.

The Pilotton system originally presented many ditiiculttea, but on account at its many advantages,
it rapidly became normalized. The obvious iaults oi the system were acceptable at the time

(the quality oi l/4 inch tape recorders being something then which we cannot accept today). but they
became uniortunately highly exaggerated when compared with the pertormance oi the Nagrn iii.

For this reason we undertook the study oi the system, and as a result produced the head which was named
NEOPILUT. The Neopilot is compatible with the original pilctton, in that the Neopilot can he played back
with the normal pilotton equipment and vice versa. But the inadequ-te channel separation in the normal
Pilollon system. which permitted the passage oi the pilot s'ignal to the sound channel. and the irregularities
in the level oi the recorded pilot signal. have been completely eliminated.

THE PRACTICAL FUNCTIONING OF PILOTAGE EQJJIPMENT
This section is for the benefit of those who are not yet [amiliar with the system.

Let us suppose that we use a synchronous motor driven camera. it is powered by a rotary convertor
which gives, ior exemple. 50. l cycles per second. The speed or the film is then 0.1/50 or 0. 2'7.
faster. The 50.1 cycles per second will be then recorded on the pilot signal track.

Back in the studio, the sound is transferred irom the i/4 inch tape recorder to a sprocket tape

recorder. But instead or the sprocket tape recorder being driven off the mains. the pilot signal

(50.1 cycles in our case) is taken irom the 1/4 inch tape recorder. amplified and used to drive the

synchronous motor oi the sprocket tape recorder. which then turns at a. 1/50 or o. 27. taster. Thus,

the same resins are obtained as it the sound had been recorded directly on the sprocket tape recorder.
powered by the same rotary converter as the camera. it this procedure is examined more closely,

it will be observed that this system also corrects variations in the speed oi the 1/4 inch tape recorder.

changes in tape length. etc.

The system described above is frequently used. It ensured synchronisation even where the speed of
the camera and of the t/4 inch tape recorder are highly disparate. lt was highly necessary at the time
it was developed, as the recorders were driven by Spring-motors which had a speed preciswn far from
acceptable norms today.

it is equally possible to pertorm the exact opposite in order to ensure synchronized transier. The
sprocket tape recorder is driven oil the mains, and the speed of the play back equipment is so modiiied
that the played-backpilot signal synchronizes which themains. in principle the result is the same,
in practice, however. there is an important advantage with the second method. in the first method
there was always a slight discrepancy between the played-back pilot signal and the mains frequency:
as it was impossible to avoid completely parasitic induction, interierence was produced in the head
Ind the pilot amplifier which could result in considerable wow. Since this did not occur in the second
method, this method was obviously preiersble.

When the plauback equipment is of conventional construction (Ampex etc) this second method is very
complicated and consequently expensive. With the Nagra. which is driven by a servo-motor, it was iound
possible to make a transier synchroniaer which was particularly simple and economic. namely the SLP.

This instrument. properly called the SLP synchroniser. received iroro the N531: the playedrback
pilot sigial and is also connected to the mains. The SLP compares the phase between the pilot

signal and the mains, and if one Of these signals shows a tendency Io be faster then the other.

the SLP modifies automatically the lpead of the Nagra in order to eliminate my difference between
the two signals. Thus the Pilot signal and the mains signal are locked together and the desired result
is obtained.

However, the 51.? was conceived to work with high quality equipment. and its margin or speed correction
was limited to t/a l. 5%. It is possible though, to transier recordings even where the speed error is
higher than i. 5%, but this necessitates manual prcadjustnieni. This procedure will be explained later.

it must be remembered that the lock between the picture and the sound. made by the SLP. stays very rigid.
and ii the rotary converter used produces wow, the sound will wow by the same amount. Certain transier
installations existing today have a much less rigid look. which enables recordings made under these
conditions to be saved, but it is also possible to correct this manually with the aid oi the SLP.

SHOOTING
Now it the camera is driven by a synchronous motor supplied by the mains, or by a very stable
oonvertor. there is no problem. The pilot signal is taken directly irom the ATUF power supply. which
can supply the necessary signal, ( 1 volt at low impedance. less than in ohms) with the regular power
tor the Nagra.