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MAY 1 1963




NAGRA
INSTRUCTIONS MANUAL




KUDELSKI
KUDELSKI S.A.

NAGRA Tape Recorders Manufacture CH-1033 Cheseaux / Lausanne SWITZERLAND
phone: (021) 91.21.21 telex: 24 392 nagra ch
NAGRA III TAPE RECORDER
INSTRUCTIONS FOR USE

I. PRECAUTIONS TO BE TAKEN

When out of use, turn the tape transport control to its mid position. In the "ON" position, when not running,
there is danger of producing a flat on the capstan roller. The working surfaces of the fast rewind clutch may
also suffer.




When batteries are exhausted, a corrosive liquid may escape and the containers may corrode. Never leave
discharged batteries in the Nagra If the machine will not be used for sometime (a few months), remove the
batteries, even if they are not discharged, as a precaution.

Take care that the batteries are inserted into the machine with correct polarity. Place them in the battery
compartment as indicated by the small diagram on the bottom of the compartment. When an external power
supply is used. Always check the polarity very carefully. If it is incorrect. the motor will run backwards. A
special protective circuit is used to prevent damage to important parts of the Nagra. But even so it is possible
that some electrolytic condensers could be damaged.
The Nagra III is very robust. But it is better to take no chance. Protect it from sand, sea being dropped or
from mechanical shock. Do not subject it to rapid changes of temperature. or to the curiosity of unqualified
personnel, and above all from vibration. For instance do not carry it unprotected in the baggage compartment
of a car.


II. DESCRIPTION OF CONTROLS AND EXTERNAL MECHANISM

1. Speed and Equalization Selector,

This switch may be operated by a coin in the slot. It simultaneously changes speed and equalization, both for
recording and playback. The following combinations are available:

38.1 cm/sec. = 15 1'/sec. (CCIR or Ampex)
This speed is normally used in broadcasting studios. The use of it insured the best quality; the azimuth
adjustment is not very critical while the response
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Curve is always excellent and varies little from tape to tape. At this speed the tape is little affected by
repeated play- backs." Another advantage is that editing is easy, and that a suitable machine operating at this
speed can usually be found in studios for playback of recordings.
19, 05 cm sec. = 7.511 sec. CCIR Equalization Standard
This is the normal speed for the general uses of the Nagra in studios working with the CCIR standards.
Where this is not necessary. the following position will be preferred:

19, 05 cm sec. = 7.511 sec. Ampex Equalization Standard
This is a better standard, as the modulation noise. medium range distortions and tape background noise are
reduced considerably.
9.525 cm/sec. = 3.751' /sec.
This speed is for use where high quality is not required and tape economy is important. One hour recording
time can be obtained with the use of 5" reels and using extra thin tape or two hours with 711 reels.

2) Tension Pulley

This pulley is movable and operates a brake on the spool, ensuring constant tape tension.


3) Microphone Input
The microphone should have an impedance of 50 or 200 ohms. This input socket on the Nagra is Cannon
type XLR 3-42. The plug on the microphone cable is Cannon type XLR 3 -11 C. Contact N o .1 is earth and
2 and 3 are the microphone connections. The input is symmetrical and floating, there being no connection
between primary and earth.

4) Shoulder Strap Button
For the attachment of a shoulder strap or ever ready case a small set screw is fitted for safety in the nut (3
mm. Set screw, for Allen key to DIN 913: a key 0.050" (1.27 mm} is provided}.

5) Modulation Level Meter

The upper scale on the meter is for measuring the input level (on Test or on Record), and the output level to
the line on Hi-Fi playback. Normally the pointer will not reach the black segment between 0 and +2db,
which is the region of over modulation. The recorder has a safety factor of about 6 db, so that an occasional
accidental incursion into this region is of no consequence. The level control should be adjusted so that the
pointer only reaches the black zone on the loudest parts of the recording.

6) Battery Indicator
The lower scale of the meter is for checking the state of the batteries. The meter is connected to the batteries
when the selector switch indicates "Play- back and Batteries Meter" that is when playing back on the internal
loudspeaker. The pointer should lie in the marked segment when the batteries are in working condition. This
indication leaves a good factor of safety when
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employing this speed, headphones should be used for monitoring. Then when the battery voltage falls to a
level unsatisfactory for recording an alarm signal will be heard in the phones. It is well to remember that
batteries used uninterruptedly for, say, an hour, will recuperate when rested for, say, 10 hours. Therefore
exhausted batteries may appear acceptable during a quick test before recording, but then collapse after a few
minutes use.

To recapitulate

- If one is recording at 15"/sec. always use monitoring headphones and read the battery meter
pessimistically.

- If one is recording at 7