Nagra 2 Owners manual

STEFAN KUDELSKI -Prilly, Switzerland
Telephone: [phone] (Lausanne)

NAGRA II

Operating Instructions

1. CONTROLS

Right knob: Starting and stopping

Stop Complete stop: the motor stops and the amplifier is off.
ON B Amplifier on -position for testing and making adjustments.

ON E Motor and amplifier on -working position for recording and playback

Attention!

In the ON B and ON E positions the batteries are being used. Do not leave the button in these
positions unnecessarily. The knob is turned clockwise to stop the recorder; on B the motor
stops, but the amplifier is on. If one rewinds the tape in this position with the selector left on
RECORD, the tape will be acted upon by the recording and erasing heads (unless the tape is
removed from its channel) and the recording will be irreparably damaged. As a precaution,
one should therefore always move the right-hand knob to STOP and the s.elector to PLAY
after each recording, before rewinding the tape,

Middle knob: This is the selector switch which determines the machine function.

RECORD S Recording with low frequencies attenuated. Gives a crisper and clearer sound than the

next position, RECORD M. In the RECORD S position, low-frequency ambient
noises, e.g., sound of automobile, airplane, and boat engines which are rich in low
frequencies, are strongly attenuated.

The low frequencies are not perceived as loud by our ear which is not sensitive in this range of
the spectrum, but the recorder hears them all, and they can saturate the tape and cover other
sounds that one wishes to record. The RECORD S position is also useful in enclosed spaces
which have a pronounced echo or low-frequency resonance.

RECORD M This is the usual work position. The recording is linear from 50 to 12,000 Hz,

according to C.C.I.R.

PLA Y M Playback through the built-in speaker, this position permits to listen to the recordings

to check their contents and quality.

PLAY S Playback through an external amplifier. The output jacks of NAGRA must be

connected to the amplifier. Depending on the amplifier used, one can connect it to the
high impedance output, obtaining approx. 0.7V eff for a normally recorded tape. The
input impedance. The amplifier should be greater than 50 k. This is the value typical
for the pick-up connections of regular radio receivers.
A low impedance output is provided near the handle. The load should have an

impedance of 3.or more. The maximum level is then approx. 20 m V. The black
terminal is the ground. The centre terminal is directly connected to the NAGRA
chassis, and should be used for connecting the shield when a 3-wire cable is used.

Left knob: Volume Control

This knob controls the amplifier sensitivity. During playback it determines the level of the output, i.e.,
the sound volume. During recording, it adjusts the sensitivity of the instrument to the intensity of the
sound source (see " Recording").

Erasing:

To obtain best recordings, it is necessary to use virgin tape or tape which has been erased on a
machine having a high frequency erasing head (which is the case for all quality machines powered
from the mains), or by a bulk erasing device. If one is short of virgin tape, one can erase the tape on
NAGRA. The selector switch must be turned to the red point. The background noise of the recording
will be significantly higher, but still acceptable for many applications. The background noise of a tape
erased on NAGRA is lower when the tape is of good quality and was not much used.

Vu-meter: (Modulation meter)

This instrument is attached to the left side of NAGRA and serves to measure the modulation
amplitude, i.e., the recording intensity, as well as the state of the batteries and the pre-magnetization
(bias) level. Its function is selected by a switch next to it, the positions of which are:

Double yellow dot: Measurement of the recording level.
The needle must not enter the red zone, in which the tape becomes saturated. For speech it is
permissible to occasionally penetrate into the red zone. For music, and especially for very high notes,
it is better to set the recording level somewhat lower to assure that the needle never reaches the red
zone.

Green dot: Measurement of high-frequency pre-magnetization (bias).
The needle should indicate 0 situated between the red and green zone. An error of one unit can be

tolerated. The pre-magnetization level is adjusted using a potentiometer located in" the right rear
corner of the panel, after unscrewing its protective cap. This check should be carried out every 3 to 5
hours during recording and playback, and