Nagra IV-SJ User manual

• TAPE/DIRECT, LINE & PHONES: switching of the playback signal o~ of
the direct signal on the line outputs, headphones and loudspeaker; switch
inactive on TEST
• TAPE/DIRECT, METER: switching of the playback signal or of the direct
signal on the circuit of rIleter 14; this switch cannot be locked on TAPE
• POWER: power selector switch i.e. built-in batteries or accumulators or
external power supply connected to plug 48
• Main function switch
STOP: recorder at • standstill
TEST: power sopplied to all circuits, except record and erase
RECORD: power supplied to all circuits and the motor; record and erase on
the 3 tracks
PLAYBACK: the recorded signal can be heard on the headphones and is fed
to the line outputs of connectors 41, 42,43,45 and 46 when switch 1 is on
TAPE (or on DIRECT if the output signal is reintroduced into the direct
chain. see 42)
PLA YBACK with Loudspeaker: playback of tape using loudspeaker
•LIGHT; meter 14 lights up momentarily: remains illuminated when the
button is turned to the right
o Main attenuator CHANNEL 2: in steps of 10 dB for channel 2,Iower track
• Vernier attenuator CHANNE L 2; in steps of 1 dB for channel 1
• Main attenuator CHANN.E L 1: in steps of 10 dB for channel I, upper track
• Vernier attenuator CHANNE L 1: in steps of 1 dB for channel 1
dB scale: for the microphone inputs, in relation to the sound pressure
level 0.OOO2pbar = 0 dB
voltage scale; effective voltage applied to the line input, which gives a reading
of OdB on the AVERAGE scale of meter 14
•REF. OSCILLATOR: switched on when the button is depressed, the
reference oscillator supplies a +10 dB signal to the direct amplifier on each
channel, after the attenuator
•
•
•LINE/MIKE: line or microphone input selector, channel 2
LINE/MIKE: line or microphone input selector, channell
FI LTERS: 6-position filter selector switch for channell:
HP high·pass
L1N. linear
WE IGHTING A, B, C, D weighting curves A, B, C and D
METER FUNCTION: six-position selector switch for meter 14
lEVEL. AVERAGE FAST: on the AVERAGE decibel scale, average value
of the sound level, fast characteristic, red needle for channel I, green needle
for channel 2
lEVEL. AVERAGE SLOW; the same as AVERAGE FAST, but slow
characteristic
LEVEL, PEAK: on the PEAK decibel scale, peak value of the sound level,
channels as above
BATT.: on the BATTERIES scale, battery or accumulator check
Red needle: battery voltage per cell (VOLTS/CELL)
Green needle: voltage required by the motor, with the same reduction factor
as battery voltage
PILOT8o CUE:
Green needle: on the PILOT 0 to 100% scale, overall frequency deviation
caused by the pilot and CUE signals, 100% on the scale corresponding to a
deviation of ±40%
Red needle: on the PILOT +4 to -4% scale, frequency shift, as determined by
the built-in OFMS frequency meter, between a signal recorded or played back
on the third track and an internal reference
Position M:
Green needle: same as PILOT & CUE
Red needle: on the 0 to 100% scale, current through the motor, 100% on the
scale corresponding to 250 mA
CD
•Fll TERS: filter selector switch for channel 2. identical to II
Meter: indicates sound level and checking functions according to the position
of selector switch 12
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• PILOT: indicator which shows a white lone when frequency and amplitude
of the pilot signal are correct
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SPEED & POWER: indicator which shows a white lone when the following
three conditions are fulfilled:
- power supply voltage higher than the maximum admissible value
- motor regulation within the correct operating range
tachometric speed fluctuations not exceedinq the maximum value
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«I» PHONES: connector for mono headphones, impedance 25 to 600n
• CHANNEL, PHONES & L.S.: channel selector for listening with headphones
and loudspeaker
• LEVEL, PHONES: adjustment of the headphones volume
• Tape speed selector switch
IS" = 38.1 cmls
7'/," = 19.05cm/s
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3% .• = 9.525 cm/s
1 'h" = 3.81 ·cm/s
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• BIAS: 5'position bias selector switch
• Pinch-wheel
6)Fast wind switch:
REW.
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rewind with main switch 4 in any position
except STOP, lever 32 in disengage position
fast wind when main switch 4 on
PLAYBACK with Loudspeaker
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• Supply reel
• Tension roller of the supplV reel
• Erase head
•• Stabilizer roller with 50 or 60 Hz stroboscope
• Recording head tracks 1 and 2
e. Recording and playback head track 3
•• Playback head tracks 1 and 2
CD Capstan
• 3'position lever controlling the pinch-wheel and tape guicles:
. - lever pulled to the left: for threading the tape (rewind possible in this
position)
- lever at 45° to the edge of the tape-deck: motor running, but tape not
moving
- lever pushed backwards: tape running
•• Tension roller of the take-up reel
• Take·up reel
6)RECORDING EOUALIZA TION ADJUSTMENT
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Direct analysis of sound signals
Used solely as an amplifier the NAGRA IV-SJ is a
precision sound level meter, which operates with
any calibrated microphone cartridge. The sound
pressure measurements must be taken in relation to
the
0 dB reference level, which corresponds to a
pressure of 0.0002 ubar, i.e. 20 J.lN/m
2
or 20 J.lPa.
This level coincides in practice with the audibility
threshold of the human ear at 1kHz; at this fre-
quency, the sound level can be expressed in phones,
the phones value being equal to the dB value read
in relation to the 0.0002 /-Ibarreference.
'.The frequency response of the human ear is not
linear and depends very much on the sound level; a
sound level meter must therefore include weighting
filters which modify the values measured in accor-
dance with certain criteria, so that they can be
interpreted in relation to the subjective impression
felt by the human ear. There are three standard
weighting curves, A, Band C. Curve A is used for
low and medium sound levels, which are the sub-
ject of most analyses; curves Band C relate to
higher levels. Curve D relates to contour-lines of·
perceived noisiness, in particular with noise pro-
duced by aviation: this weighting is used for the
measurement of sounds which cause annoyance
in general. Curves A, B, G and D are shown after
the specifications.
The sound level measured is shown on a dual
galvanometer. with one needle per channel. Its
measuring circuit determines the average value of
the signal on RMS and its peak value on
PEAK, with different dynamic characteristics in
relation to the integration time. On RMS
FAST integration time is 200 ms: a signal at 1kHz
lasting 200 ms gives a reading 1dB lower than that
which would correspond to the steady signal. On
RMS SLOW, integration time is 500 ms and
a signal lasting 500 ms gives a reading 4 dB below
that which would correspond to the steady signal.
These two integration times are in accordance with
INSTRUCTION MANUAL
I
Measurements
the GEl standard 179 for precrsion sound level
meters. Naturally, any signal which is shorter than
the integration time will be shown below its real
value. For analysis of pulse signals or strong
transients a more useful reading is obtained on
PEAK, i.e. peak value with an integration time of
only
5 ms. This very fast reading cannot be used
because it causes visual fatigue: in order to over-
come this disadvantage the measuring circuit holds
the signal for about one second, thereby increasing
the fall time of the needle.
Recording and playback of the sound signals
In all cases where direct. measurement is not
sufficient for studying the signals picked up by the
microphone, these signals can be recorded on mag-
netic tape and analyzed later in the laboratory.
While the two tracks used for direct recording are
in use, the third track
C'IO record F M signals for
synchronization, a commentary, or a measuring-
signal from D.C. up to 4 kHz. The three tracks
thus store signals in fully-synchronized form, which
is an important factor for analysis.
However, this storage is restricted to some extent
due to the limitations of present magnetic tapes.
These limitations concern the following charac-
teristics in particular:
the response curve
Attenuation at the upper and lower extremes of
the spectrum depends on the speed used. Very low
frequency signals, which are difficult to play back
with a small reproduce head, should be analyzed
by frequency transposition.
distortion
This increases very rapidly as soon as the maximum
recording level is exceeded, and tape saturation
occurs, generating harmonic frequencies (in
par
ticular 2nd and 3rd harmonics), which falsify the
analysis of the signals.

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crosstalk
The juxtaposition of the two channels inside the
recording head and the playback head produces
crosstalk. This is the ratio, at a playback amplifier
output. between the wanted signal and the unwan-
ted signal from the other channel. Crosstalk
increases at high frequencies.
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The maximum peak level, which corresponds to a
tape flux of 32 mM/mm, is reached when the
measuring instrument shows +10 dB on the
RMS scale and +20 dB on the PEAK scale.
These two values are given in relation to the sound
·pressure reference level 0 dB
= 20 pPa or
0.0002J.1bar.
On RMS the integration time of the
measuring circuit is long enough not to indicate
short pulses at their exact value and risk exceeding
the maximum recording level, thereby saturating
the tape. That is why, on RMS , the maxi-
mum level is given at +
10 dB: the 10 dB lead avoids
the signals with strong pulse content saturating the
tape too Quickly.
In all cases where the nature of a signal is not
obvious it should be recorded with the measuring
circuit on PEAK, which is the only way to make
the peak value of very short pulses visible and to
avoid their exceeding the maximum recording level.
Frequency transposition
Playback speed may be different from recording
speed: this produces a frequency transposition of
the signals recorded within the ratio of these two
speeds. Since the response curve in the low fre-
quencies is limited to 25 Hz on playback only, it is
possible, if the tape transport speed is ten times
faster on playback than on recording, to play back
frequencies which are ten times. lower. Thus, a
2.5 Hz signal recorded at 1.5 ips will have a fre·
quency of 25 Hz if it is played back at 15 ips
(transposition
1: 1 0), and can be analyzed easily by
conventional equipment. In the same way, the
time needed to analyze signals which vary very
slowly is reduced in the same ratio by this process.
Conversely. it is possible to analyze in more detail
a signal which varies rapidly by playing it back
more slowly than it was recorded. However, in
both cases, care must be taken that the transposi-
tion does not alter the signals in any way, taking
into account the limitations of the frequency res-
ponse at the speeds used.
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Maximum frequency deviation t>fo
Frequency response at -3 dB
Signal-to-noise ratio for deviation
of ±20%
±45%
o to 4 kHz
44dB
Peak-to-peak input voltage for deviation of ±20 %
PILOT 2_8 V
CUE 2.0 V
I OPERATING CONDITIONS
Temperature
with manganese batteries
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with external power
- 4to+160°F
-20to+ 71°C
-67 to +160
0
F
-55 to
+ 71 °C
I The recorder functions correctly in any position.
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1

ht'
Wei21 In2 curve
A
dB Ffequency lEe Recommendation 179
N"GRAIV.sJ
Rt'I.tI~
Tolrnn~
Toler.nee
Respome
limitl
lImln
+10
H, dB dB dB
20 ·50.5
,.
3
25
-" •. 7
••
: :2.S
0
31,5 -39.4 oJ
.,
/
.•...•.
40
-34.6 oJ
. .,
./
'-..
SO
-30.2
oJ
.,
./
<,
63
-26.2
±3
t2
80 -22.5
12 11,5
-10
/
'00
-'9.1
11
t,
'25
-16.1
t'
11
V
'60
-13.4
.,
11
200 -10.9
.,
l'
-20
250
- •. 6
11 11
3'5
- 6.6
11
.,
.I
"""
- ".8
11
t,
/
500 - 3.2
±,
11
630
- 1.9
.,
11
-30
I
800
- O.S
.,
11
1000 0 ±1
11
/
1250
.•. 0.6
"
11
1600 + I
"
et
-40
2000 + 1.2
"
11
/
2500
.• 1.3
., .,
3150
+ 1.2
et
.,
/
4000 + 1 et 11
5000
-+ 0.5
.1.S
11
-50
6300
- 0.1 +1.5
-2
.,
J
8000 -1.1
+1.5
-3
%1.5
I
10000 - 2.5 +2
..
11.5
'2500 - 4.3 +3 -6
11.5
'6000 - 6.6 +3
_M
1:1.5
20000 - 9.3 +3
_M
t2
Hz
80 200 500 1000 3150 8000 12500
20 31,5 50 100 315 800 1200 5000 10000 20000
hti
Wet21 n2 curve
B
dB
frequency
tEe Aecommmdation 1N NAGAAIV·SJ
A.I.live Toleranoe
To~nlnce
Response
limits
limite
+10
H,
d8 dB dB
20
·242
••
12
0
25 -20.4
15 12
»>
~
-r---.
31.5
-17.1 13 12
.•...•.
40 -14.2
03 12
./
<,
SO
-u.s
03
t2
./
63 - 9.3
03 12
-10
eo
- 7.4
12
:1:1.6
/
100
- 5.e
., .,
120 - 42
.,
11
/
ISO
- 3
"
"
-20
200 - 2
.,
et
V
260
- 1.3 11
"
316 - D.e
.,
11
-30/
"""
- 0.5
11 11
600 - 0.3
., .,
830
- 0.1
.,
11
800 0
tI
11
, GOD
0
at
11
1260 0
., .,
-40
1e00 0
.,
.,
2000
- O.t
"
11
2500 - D.2
.,
11
3160
- 0."
"
11
4000
- 0.7
11 11
-50
6000 - 12
.11.5
11
8_
o 1.8
.1.5
-2
.,
8000
-a
1-t.fI
-3
.11.5
10000
- 4."
'2 -4
i1.6
12500 - 6.1 +3
-6
11.6
18000 - 8.4
+3
--
il,6
Hz
20000 -11.1
+3
--
"
80 200 500 1000 3150 8000 12500
20 31,5 50 100 315 800 1200 5000 10000 20000
_.-._--------_. ---
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2.4. Connection of Brliel & Kjaer Amplifiers fitted
with Brliel & Kjaer Microphone Cartridges
B&K
CARTRIDGE
~
B&K
PREAMPLIFIER
---1
QJ I
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~T-'
=-=1 I I
QSJA-BK
='iJJ
==[J
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The following types of cartridges
- 'h";4133,4134,4149and4163
- 1 ";4144,4145,4146and4161
- 1,4"; 4135 and 4136
- 1/8"; 4 138
can be fitted to the following types of preamplifiers:
- 1", 1/2", 1,4" : 261 5
- '12 ",1,4 ", 1/8" : 2614
- 1", '12", 1,4", 1/8" : 2619
- 1" : 2627, 2612 and 2613
- 1,4", %" : 2618
The cartridges can be fitted directly onto the pre-
amplifiers when the diameters match; if they do not
match, a mechanical adapter can be used. The
output plug of the preamplifier screws into the
OSJP adapter and the plug of the preamplifier
adapter fits into microphone connector 37: selector
10 should be on MI KE.
The recorder should be fitted with the QSJA-BK
microphone amplifier and the QSJC universal power
supply. These circuits can be installed as described
in the preceding paragraph,
Signals and Voltages
Chassis connector external side or plug soldering
side
+200Y
+120V
.J
r -
L_
,
-10G
,-----r-GND
+12,6V
2.5. Connection of Sennheiser MKH 110 Measuring
Microphone
The MKH 110 microphone consists of a capacitor
cartridge and an electronic circuit with a low impe-
dance output; microphone sensitivity is 2 mV IMbar.
It should be connected to microphone connector
37 by the QCJ-MKH cable; selector 10 should be on
MIKE_
The recorder should be fitted with the QSJA-MKH
microphone amplifier, which also supplies the vol-·
tage for the microphone.
Installation of aSJA-MKH Amplifier
Lock the lid of the recorder, turn screws 50 several
times and open the case to its full extent. Unscrew
the connector between the microphone input wiring
and the case interconnection board. Plug in and fix
this connector to the microphone amplifier and
secure the latter to the case interconnection board.
Unscrew the level adapter board. Place the shield
in position and fix it under tile ground comb and
under a nut screwed onto one of the two hinge
fixing screws (this screw should be longer - M3x8).
Reinstall the level adapter board.
Signals and Voltages
Chassis connector external side or plug soldering
side
~--..,.-- GNO
-8Y------
SIGNAL
-10G----~

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3. DIRECT MEASUREMENT OF SIGNALS
3.1. Position of the Controls
Set switch 1 on DIRECT: switch 2, which cannot
be locked in position, remains on DIRECT. Turn
main selector switch 4to TEST: the circuits are
then switched on and will stabilize after about 10
seconds.
3.2. Selection of Measuring Circuit
Set the METER FUNCTION switch on one of the
LEVEL positions:
- RMS FAST : average valu~ of the sig·
nal on the RMS' scale of meter 14,
integration time 200 ms.
- RMS SLOW : average value of the
signal on the same scale, but integration
time 500 ms.
- PEAK: peak value of the signal, on the
PEAK scale of meter 14, integration time
5 ms, with a memory circuit holding the
signal for about 1second.
The measuring circuit of the recorder should be
selected in accordance with the criteria given in
Section 3.
3.3. Adjustment of the Monitoring Circuit
The signals can be monitored on the headphones
with switch
4 in any position and with the built-in
loudspeaker on PLAYBACK with Loudspeaker
(see 6.).
The mono headphones, impedance 50 to 600 n.
plug into jack 17. The required channel can be
selected with switch
18 and the loudness regulated
by potentiometer
19, which can be adjusted with a
screwdriver.
3.4. Choice of Sensitivity
3.4.1. High·level Signals on the Line Input
Set selector 10 on LINE, turn main attenuator 7
fully to the left, or on GND, set vernier attenuator
7A on 0dB (CAL.),
Switch on the signal source connected to the line
input. While watching meter 14, turn main attenua-
tor 7 to the right until the red needle makes a
visible movement. Calculate the value measured as
described in paragraph 3.6.1.
3.4.2. High-level Signals on the Microphone Input
Same procedure as in the preceding paragraph, but
with selector
10 on MIKE.
3.4.3. Low·level Signals on the Microphone Input
QSJA-BK AMPLIFIER
With selector
10 on MIKE, set vernier attenuator
7A on 0 dB
Turn the cartridge type selector 40 to the position
which corresponds to the diameter of the cartridge
used. On
1f.t •• the positions of gain selector 39
become +40. +60 and +90dB, values inscribed in a
circle.
Turn attenuator 7to +20 dB and watch meter 14.
If the needle moves noticeably beyond +20 dB
PEAK or +10 dB RMS , turn switch 39 to
+80 dB. If the needle is clearly below 0 dB, turn
switch 39 to +40 dB. Calculate the value measured
and take into account the restrictions described in
paragraph
3.6.3.
QSJA-MKH AMPLIFIER
This amplifier has no gain selector or cartridge type
selector. The sensitivity can be determined by main
attenuator
7 only.
AMPLIFIER FOR GENERAL
RADIO MICROPHONE
The amplifier for use with the GENERAL RADIO
microphone is the QSJA-BK; please refer to the
above instructions for using this amplifier.
3.5. Choice of Filter
When filter selector switch 11 is on LlN, the fre-
quency response of the direct chain is linear at
:to.3 dB from 2.5 Hz to 35 kHz. Selector switch
11
should be set on one of the following positions
according to the kind of measurements being taken:
HP: high-pass filter, attenuation 3 dB at
20 Hz, 12 dB per octave
WEIGHTING A, B, C, D: weighting of the
frequency response as determined by
international standards, the exact value
of which is given at the end of the section
entitled Specifications.
The HP position should be used systematically when
the measurement of signals is not extended to very
low frequencies: in fact, since these are inaudible,
they are likely to falsify results and, in some cases,
saturate the amplifiers. Furthermore, this position
eliminates very low frequency noise from the car-
tridge itself.
The weighting positions A, B, C and D are used, in
the case of noise measurement, to obtain a value
corresponding to the subjective impression felt by
the human ear (see Section 1).

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The arrowhead opposite the +40 dB position on
attenuator 7 is to remind the user that certain
restrictions must be observed in order to avoid
saturation of the input circuits, when measurements
are taken by microphone, preamplifier and ampli-
fier.
The performance of the microphone cartridges and
input amplifier circuits is restricted by the occur-
rence of saturation phenomena which are produced
when the sound level measured becomes very high.
These phenomena may be detected by a trained ear
if measurements are being taken and monitored
simultaneously (see
3.3.). and if the operator is not
exposed acoustically to the sound source. If the
phenomena pass unnoticed the measurement will
be incorrect. The only sure way to avoid saturation
and its consequences is to impose a limit on the
attenuator which directly follows the input cir-
cuits; when the attenuator is at this limit, any sound
signal which makes the needle of meter
14 deviate
to the right to its fullest extent, saturates the input
circuits and cannot be measured. In this case, the
amplifier gain must be reduced by turning its selec-
tor from +40 dB to +60 dB or from +60 dB to
+80 dB; if saturation still occurs on this position it
means that the output level of the transducer used
is too high. A less sensitive transducer should then
be used or an attenuator inserted between the trans-
ducer and the preamplifier.
3.6.3.1. Limits and Corrections with theOJPA
Preamplifier and OSJA-BK Amplifier
/
Same as below
G (preamplifier gain) same as for Brtiel
& Kjaer
2619 preamplifier.
3.6.3.2. limits and Corrections with Brfiel &
Kjaer Preamplifiers and the QSJA-BK
Amplifier
When main attenuator
7 is opposite the reference
at +40 dB, there is no risk of saturation as long as
the needle of meter
14 does not move beyond
+20 dB PEAK, with gain selector 39 on +40 or
+GOdB; when the latter is on +80dB (+90 dB fora
~" cartridge), the main attenuator may be set
beyond the +40 dB position as saturation then
depends only on the cartridge used and the corres-
ponding preamplifier.
With cartridge type selector
40 in the position
corresponding to the cartridge used, the sound level
is obtained by direct reading when the potentio-
meter of the QSJP adapter is adjusted to a correc-
tion value K, given in dB by the following relation:
I K = Ko - G - X I
Ko == open circuit correction factor given by
the manufacturer
G == preamplifier gain in relation to the
type of cartridge and its mechanical
adapter given by the manufacturer
X difference between the typical sen-
sitivity of the cartridge and the
50 mV/N/m
1
reference value, in accor-
dance with the following table:
Type of
cartridge
X in dB
1"
'12 "
1,4 ••
'14 I/~"
4135 4136* 4138"
0+12 +22 +30 +34
*With the 1/4" cartridge 4 136, 8 dB must be added
to the calculated value to obtain the sound level
(X
takes into account the adjustment range limits of
the QSJP adapter).
** Cartridge type selector 40 on 1/4": add 12 dB to
the calculated value to obtain the sound level.
Example
Ih" cartridge 4133 with preamplifier 2619:
Ko=+12.2dB G=-O,4dB X=+12dB
Value to which the potentiometer of the QSJP
adapter shou Id be adjusted:
K = 12.2 + 0.4 - 12 = +O.6d8

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4. RECORDING OF SIGNALS
4.1. Choice of Tape
It is essential to use the type of magnetic tape for
which the recorder was adjusted at the factory; it is
only in this way that the values indicated in the
technical specifications {Section 2) can be obtained.
It is possible to use another type of tape by reo
adjusting the bias, equalization and recording level
. The performance obtained may
differ from the values shown in the test report
issued with each recorder; it is necessary to check
the results obtained with a new tape before using
the recorder for taking accurate measurements.
The positions of bias selector switch 21 correspond
to steps of 10%.
4.2. Speed Selection
The tape speed should be selected in relation to the
upper and lower limits of the frequency response:
at 15"/s (38 cm/s) : 25 Hz to 35 kHz ±1 dB
at 7.5"/s (19 cm/s) : 25 Hz to 20 kHz ±1 dB
at 3.75"/s (9.5 cm/s): 25 Hz to 10kHz ±1 dB
at 1.5"/5 (3.8 crn/sl: 25 Hz to 3.5 kHz
± 1dB
At 1.5"/s recording is possible from 2.5 Hz, with
playback by transposition (see 4.8).
When the tape speed is being selected recording
equalization should also be taken into account; this
is higher for low speeds and may cause tape satura-
tion when the signal frequency is high, even if the
modulometer shows the recording level to be
correct (see 4.7.2. Restrictions).
The length of the recording to be made is also a
determining factor in choosing the tape speed.
Place speed selector 20 on the position correspond-
ing to the wanted speed; the speed can be switched
while the tape is running without damaging the
recorder.
4.3. Threading the Tape
Pull lever 32 forward to its fullest extent. Place a
full reel on the left-hand spindle (24) and fix it in
position with the knurled nut; place an empty reel
on the right-hand spindle (34) and fix it in position.
Lower the head shield. Unwind the tape slowly
from the supply reel arid thread it across the two
tension rollers 25 and 33 to wind it onto the take-up
reel; turn this reel a few times to that the tape is
pulled taut
:w:
••••
o •
Push lever 32 backwards to its fullest extent. Raise
the head shield.

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which is similar to the distribution spectrum of the
spoken word and of music - was used as the basis
for an inverted curve which determi nes the possible
pre-emphasis. For the three higher speeds, emphasis
and de-emphasis conform to the recorder standard
(mentioned in the test report and marked on plate
51). For the 1.5" speed, which is used in par-
ticular for recording very low frequency signals to
be played back by transposition at 15" Is, the
emphasis has been calculated in relation to compati-
bility for playback at 15"/5.
The emphasizing of signals during recording in
accordance with the standards has the advantage of
making it possible to play back the tapes on any
conventional recorder. On the other hand, this
process has one disadvantage: the frequencies
affected by emphasis are likely to cause tape
saturation, even if the recording level indicated on
meter 14 is correct. In fact, emphasis occurs in the
recording amplifier, i.e. after the measuring circuit,
which cannot under any circumstances indicate it.
Pre-emphasis depends on the tape speed: the lower
the speed the higher the treble emphasis will be.
Furthermore, the NAB standard also requires bass
pre-emphasis which, however, should not exceed
6 dB at the lower limit of the recording frequency
response. Treble pre-emphasis therefore pre-
dominates and, to avoid saturating the tape, high
frequency signals must be recorded below the
maximum recording level (+20 dB PEAK). Taking
into account the difference between the NAB and
cel R standards, if a recording is made at 6dB
below the maximum level, i.e. at +14 dB PEAK,
there is no risk of saturation, as long as the signal
frequency is not higher than:
20 kHz for the 15" speed
14 kHz for the 7.5" speed
5kHz for the 3.75" speed
2.5 kHz for the 1.5" speed.
Since the pre-emphasis curve shows a rise of about
6 dB per octave. it is possible to calculate the pre-
emphasis value at a different frequency and deduct
the recording level reduction in relation to the
+20 dB maximum peak level.
4.7.3. Signal·to·noise Ratio
When gain selector 39 is on +40 dB and attenuator
7on 0, maximum amplification can be obtained.
It is possible to measure signals at about +30 dB;
meter 14 then shows -10 dB, which is the limit of
readability. These signals are very weak, but can
nevertheless be recorded as such without decreasing
the signal·to-noise ratio of the cartridge and input
circuits. Thus, by using a BrLiel & Kjaer 4133
cartridge with its preamplifier and QSJP adapter,
the weighted noise level is 30 dB; with a 40 dB
signal the signal-to-noise ratio is 1OdB.
In the record/playback mode, the weighted
signal-to-noise ratio is always higher than 60 dB,
which means that noise inherent to the recording is
60 dB below the maximum recording level: this
level is reached when meter 14 indicates +20 dB
PEAK and, as gain selector 39 is on +40 dB, the
60 dB difference brings the noise level produced
during recording to 0dB, i.e. to the 2.10- 5Nlm2
reference level. For the 40 dB signal the signal-to-
noise ratio would also be 40 dB, therefore clearly
higher than the 10 dB signal-to-noise ratio obtained
with the cartridge and the input circuits used.
I n practice, whi Ie the signal . of the
transducer and input circuits is below 60 dB, the
noise level does not increase when the signal is
recorded. On the other hand, as soon as the sound
level reaches 100 dB, the signal must be kept as near
as possible to the maximum recording level in order
to obtain the highest possible signal·to-noise ratio.
To record, set main selector switch 4 on TEST;
allow the circuits to stabilize for about t~n seconds,
then switch to RECORD: the tape begins to run.
4.7.4. Tape Monitoring during Recording
When main selector 4 is on TEST, the di rect signal
is present at the line outputs 43 and headphones
output 17 according to the position of track
selector 18.
When selector 4 is on RECORD and switch 1 on
DIRECT, it is again the direct signal which is
present at the outputs; but, if switch 1is on TAPE,
the recorded signal is immediately played back and
will be present at the line and phones outputs.
Switch 2fulfils the same function for meter 14,
which indicates the direct signal on DIRECT and
the playback signal on TAPE; this switch springs
back automatically to DIRECT.
TAPE/D IRECT switches 1and 2make it possible
to check the quality of the signal during recording;
any audible or visible deterioration of the signal
indicates a false manoeuvre or defect.
4.8. Frequency Transposition
Playback of signals recorded at a very low frequency
is difficult because of the smallness of the
NAG RA IV -SJ playback head and the lower limit
of the frequency response of the amplifiers. To
analyse signals with a frequency between 2.5 Hz
and 35 Hz, set the speed selector 20 on
1.5" = 3.81 crn/s, the filter selector 11 on LI N. and
meter function selector 12 on RMS SLOW
this position gives a more accurate reading than
RMS FAST and PEAK, which have too
rapid a characteristic.
Playback is at 15" = 38.1 em/s in the usual way
(see 6.).

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6.3. Interpretation of the Recorded Signals
It is necessary to fix a reference during recording
so that, when the recorded signals are analysed,
the exact value of the sound level can be
determined.
6.3.1. Written or Recorded Reference
Before recording is begun, the position of the micro-
phone amplifier gain selector (38 or 39), the main
attenuator (6 or 7) and the vernier attenuator (6A
or 7 A) should be noted on the recording data sheet,
or dictated on the third track using the QSCM
microphone. On playback, with METER switch 2
and LINE
& PHONES switch 1 on TAPE, meter 14
will indicate the same value as during recording
and the output voltage will be in proportion to the
meter reading. If the tape is analysed on the recor-
der itself, it is sufficient to add, in the usual way,
the value shown by the meter to the attenuator
and gain selector readings, which were taken during
recording. If analysis is done with the recorder
connected to exter.nal analysing equipment, the out·
put voltage can be compared with the 0 dB
references given in paragraph 6.1., thus making it
possible to determine the fraction of the sound
level given by the meter reading and to calibrate
the equipment. Finally, if analysis is done on a
recorder other than the NAGRA IV-SJ, the same
fraction of the sound level will be deducted from
the tape flux, the 0 dB meter reading corresponding
to 32 nWb/m on the tape.
In all cases, the position of the attenuators and that
of the microphone amplifier gain selector must be
known in order to determine the sound level at the
time of recording.
The accuracy of the meter reading on playback
depends on the quality of the tape used; even if it
is the kind of tape for which the recorder was
adjusted, the difference between the reading on
TAPE and on DIRECT may reach 2dB.
6.3.2. Recorded Internal Reference Signal
This method is more rapid and more accurate, but
still requires written notes or commentary on the
third track; it can be used to eliminate the playback
level inaccuracy due to the dispersion of the charac-
teristics of a tape of the same type. The reference
·generator built into the recorder applies a calibra-
tion signal to the output of the direct amplifier,
without passing through the attenuators. When the
microphone amplifier gain selector and the
attenuators are adjusted to obtain a correct record-
ing, the reference signal must be recorded at the
beginning of the tape and note taken of the sound
level to which it corresponds. This signal will be
used on playback for finding the sound level again
by conversion.
Example: the gain selector of the microphone
amplifier is on +60 dB, the main attenuator on
+30 dB and the vernier attenuator on 0 dB; record
the reference signal: the meter shows +10 dB; the
reference signal therefore corresponds to a sound
level of 60 + 30 + 10
= +100 dB. During analysis
the equipment will be calibrated at +100 dB when
the reference signal is played back.
6.3.3. Recorded External Signal Reference
An acoustic signal with a known sound level can be
used as a reference during recording. The B
& K
pistonphone supplies a 250 Hz signal at 124 dB
±O.2 dB, and the B & K calibrator a 1 kHz signal at
94 dB ±0.3 dB.
Insert the microphone into the sound source and
check the calibration of the recorder by trying to
obtain a deviation on the meter between 0 and
+10 dB, then record this signal noting the position
of the microphone amplifier gain selector and that
of the attenuators. On playback this signal will
rep resent a reference at +124 or +94 dB.
If the signal to be analysed is at a very different
sound level, after calibration has been checked, the
gain selector and the attenuators must be reset in a
position which allows correct recording, and the
positions noted again. On playback the level of the
recorded reference signal no longer corresponds to
+124 or +94 dB; it should be calculated by adding
the difference in decibels between the first and
second reading to these values.
Example: the gain selector is on +80 dB, the main
attenuator on +40 dB and the vernier attenuator
on 0 dB; using the pistonphone, the reference signal
will be indicated at +4 dB (80 + 40 + 0 + 4
=
+124 dB) and recorded. The signal to be ana lysed
must be recorded with the gain selector on +60 dB,
the main attenuator on +30 dB, the vernier
attenuator on 0 dB, and it gives a reading of +10 dB;
its level is therefore 60 + 30 + 0 + 10 = +100dB.
Attenuation indication for the reference signal:
80 + 40 + 0 = 120 dB
Attenuation indication for the signal to be analysed:
60 + 30 + 0
= 90 dB
Difference: 90 - 120 = -30 dB
Apparent level of the reference signal on playback:
124 - 30 = +94 dB

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•
INSTRUCTION MANUAL
Batteries and Accumulators
4
The NAGRA IV-SJ or IV-SJS has space for .12
1.5 V cells (nominal voltage). Batteries conforming
to CE I (e.g. R20 type) or ASA (e.q. D or L90 type)
standards are suitable; their diameter should not
exceed 15/16" (33.5 mm) and they should be bet-
ween 21 \132" (59.5 mm) and 2 j 5/32"(62.5 mm) long.
The central electrode is positive and the can
negative, with a few exceptions; polarity is generally
shown by EB and e signs. If the batteries do not fit
securely in the box, the cells can be packed with
cotton wool, which will prevent them from pro-
ducing unwanted noise while the recorder is in use.
If the batteries are too short and do not produce
the required contact, nickel or bronze (not alu-
minium) coins can be inserted between the cells. A
mechanical adapter is available for use with NAGRA
recorders; this can be fixed to the contacts when
cells shorter than the minimum length are used
consistently.
1. Power Supply Voltage
New carbon-zinc batteries supply a total voltage of
18 V. The recorder will still function correctly
with 12 V at 15 ips (38 cm/s) and 11 V at the three
low speeds, when it is in perfect condition and wor-
king at a normal temperature. The built-in voltage
stabil izer means that the functioning of the recorder
does not depend on the unstabilized supply voltage,
except during fast wind which is at a speed in
direct proportion to the supply voltage.
2. Danger of Polarity Inversion
A diode connected in parallel on the power supply
will short circuit it if polarity inversion occurs.
The discharge current may overheat the wiring
insulation, which disintegrates and produces cor-
rosive agents. 2,5A fuses inserted in the battery box
breaks the circuit; this fuse should be replaced
if the recorder still does not work after the cells
have been replaced in the correct order.
3. Check on Supply Voltage and Condition of
the Batteries or Accumulators
Set meter function switch 12 on BATT. and main
switch 4 on RECORD. The red needle of meter 14
shows the unstabilized voltage expressed for one
cell (VOLTS/CELL); the total voltage is obtained
by multiplying this reading by 12. Simultaneously
the green needle indicates the voltage required by
the motor, with the same reduction factor; the
wider the angle between the two needles, the greater
the voltage reserve.
The index at 1.25 V on the scale marks the mini-
mum voltage at which manganese dioxide batteries
should be recharged so that the discharge/recharge
cycle can be repeated several dozen times.
SPEED & POWER indicator 16 gives a warning
signal when the recorder is in operation: it shows a
white segment when voltage and speed are correct,
but turns black as soon as the supply voltage falls
below the minimum admissible value.
4. Operating Conditions
The following data have been extracted from docu-
mentation obtained from various suppliers. The list
of makes quoted here is not exclusive; the manu-
facturers mentioned are those which provide the
most accurate and readily-available information.
KUDELSKI S.A. does not accept any responsibility
for the degree of accuracy of the values indicated.
In general, thr, performance of a battery cell or
accumulator depends largely on the conditions and
length of storage before use. Care should therefore
be taken when suppliers are selected

5. Leclanche Standard Batteries (carbon-zinc)
These batteries are light, inexpensive and sold every-
where. Their capacity varies considerably, depend-
ing on how they are used: it is high with low current,
but low with high current and acceptable with an
average current of about 350 mA, if periods of use
are interspersed with rest periods during which the
cells can depolarize (e.g. 4 hours use every 24 hours).
Normally the batteries can be used at temperatures
from 32° F (0° C) to 122
0
F (+50° CI, and certain
special types can be used at a lower temperature.
If batteries are stored at or below 68
0
F (+20° C)
their shelf life should be more than 12 months,
with remaining energy content 75 to 90%. This is
reduced to three months when the storage tem-
perature is "04° F (+40° C). Above 122
0
F (+50° C)
batteries deteriorate rapidly. Cold storage produces
excellent results and certain cells retain their full
capacity if deep-frozen.
A carbon-zinc battery is considered to be com-
pletely discharged when the voltage at its terminals
falls to 0.9 V with normal current flow.
6. Manganese Dioxide Alkaline Batteries
Of more recent design, these batteries have a higher
capacity, with the same current, than carbon-zinc
batteries. They can be used between 4
0
f (_20° C)
and 158
0
F (+71
0
C) and stored for more than
24 months at 68° F (+20° C) and even for more
than 12 months at 113° F (+45° C) according to
MALLORY. The discharge current is constant and
does not require rest periods as there is no need to
depolarize. However, these batteries are about 50%
heavier and cost more than the standard type. They
are suitable for use when:
- the temperature is unfavourable for carbon-
zinc batteries
- a long storage period is required
- the ratio of weight or volume to recording
hour must be as low as possible (ease of trans-
port and forwarding)
- the recorder is used for long uninterrupted
periods
there is high power consumption using
measurement microphones and preamplifiers
with a heating circuit.
Some manufacturers indicate that it is possible to
recharge their manganese batteries under certain
conditions; WONDE R sanctions recharging their
manganese batteries when their charge falls to 80%
of their total capacity. Voltage per cell is then
1.25 V and this value is indicated by an arrow on
the VOLTS/CELL scale of meter 14.
Recharging can be done with a maximum current
equivalent to one fifteenth of the nominal capacity,
i.e. 0.5 A fora 7.5 A cell; charging should be stopped
when the voltage at the cell terminals reaches
1 fiR to 1.7 V. It is important not to continue
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charging the cells beyond this limit, thus shortening
their life. A completely discharged cell can also be
recharged, but only once or twice.
Warning
WONDE R recommend recharging their battery
cells: MALLORY forbid it and warn the user of the
danger of explosion. EVEREADY produce a
special cell which can be recharged.
Before recharging manganese batteries it is absolu-
tely essential to consult the manufacturer or supplier
to make sure that the type used lends itself to this
procedure.
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7. Mercury Cells
The capacity and shelf life of these cells are greater
than for manganese batteries. However, they are
heavier and more expensive and they do not per-
form so well at low temperatures, their lower limit
being 50
0
F (+10
0
C]. except for certain special
types.
In the majority of cases polarity is inverted - the
can is the positive pole - and a mechanical adapter
is required for using the batteries with a NAGRA
recorder; the only known exception is WONDE R
Pilat which has conventional polarity. As there is a
high risk of inversion, the polarity of mercury
batteries should be determined very carefully.
The voltage at the terminals of mercury cells
remains almost constant at 1.2 V during discharge;
it istherefore impossible to estimate their remaining
capacity by measuring their voltage.
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8. Danger of Leakage
Electrical energy is liberated through a chemical re-
action which fundamentally alters the constituants
of the battery cell and, in particular, attacks the
can. When the cell is completely discharged, it may
leak a corrosive liquid which can cause serious
damage to the inside of the recorder. The batteries
should therefore be checked frequently; if the
recorder is not going to be used for several weeks,
the batteries should be removed.
Leak-proof batteries are available which almost
completely eliminate the risk of leakage.
9. Nickel-cadmium Accumulators
The information below is again based on docurnen-
tation obtained from manufacturers and is an
indication only, as the evaluation criteria used are
different in each case.
Length of Life
The essential advantage of accumulators is that they
have a long life. Even if only 100 charge/discharge
cycles can be obtained, the cost per hour of opera-
tion is approximately one-tenth that of battery

12. Conclusion
Generally, since battery or accumulator cells are
chosen according to the power consumption of a
given recorder, the following uses are possible:
- NAG RA IV S-J plus accessories, with .accumu-
lators or with mercury or dioxyde manganese batteries
- NAGRA IV S-J without accessories or
NAGRA IV S-JS, possibility of using carbon-
zinc battery cells.
Leak-proof battery cells are preferable. A PAR
charger is recommended for recharging accumula-
tors as they do not have to be removed from the
recorder
if this accessory is used.
m
TOTAL LENGTH OF use
OPERATING CONDITIONS 4 Hours
every Continuous Use
24 Hours
Average Recorder
I
Nickel·cadmium
Current Setting in Eveready 1150
I Eveready E95 Accumulators
Relation to Inputs and Accessories Carbon· zinc : Manganese·
I
Length of Batteries dioxide Capacity Capacity
Use Batteries 2-2.5 Ah 4Ah
240mA 50% TEST; Line input (without microphone) 10 h 25 h 9h 17 h
50% RECORD
310mA 100% RECORD line input
lor Fast Wind
or 50% TEST Microphone inputs with 1 OSJA-B K amplifier 6h 22 h 6.5 h 13 h
50% RECORD 2 QJPA preamplifiers with heating
-
400mA 100% RECORD Microphone inputs with 1 QSJA-BK amplifier 14,5h
or Fast Wind 2 QJPA preamplifiers with heating 4.5h 5h 10h
460mA 100% RECORD Microphone input with 1 B & K 2619 or 2618
or Fast Wind preamplifier with heating, QSJP adapter and 3h 11 h 4.5 h 9h
QSJA·BK microphone amplifier
620mA 100% RECORD Microphone inputs with 2 B & K 26 19 or 261 B
or Fast Wind preamplifiers with heatinq, QSJP adapters and
-
5.5 h 3h 6.5 h
QSJA·BK amplifier
765mA 100% RECORD Microphone inputs with 2 B & K 2615 pre-
or Fast Wind amplifiers, QSJP adapters and OSJA·BK
-
3h 2h 5h
amplifier

NAGRAIY.SJ
configurator
Internal electro accessories
Synchronization
SlO 13400
SlO-3 13419
GClS 16300
OSV-2 14600
OSlS 16350
f
Automatic speed synchronizer
Synchroniseur automatique de vitesse
Crystal pilot generator for SlO
Generateur pilote a quartz pour SlO
Adapter for connecting SlO to NAGRA IV-SJ
Adaotateur pour la connection SlO NAGRA IV-SJ
Manual speedvariator
Variateur manuel de vitesse
Synchronizer for NAG RA IV-SJ
Synchroniseur pour NAGRA IV-SJ
Modulation
OSPB 11001
QSJP 11025
QSJP- 11050
GR
QJPA 11075
QCJ- 11902
MKH
QSSF 16450
OCJE 11900
QCJC 11901
QSCM 16001
OSSC 16475
Preamplifier for BK microphone cartridges
Preamplificateur pour microphone a capsule BK
Adapter for connecting BK preamplifiers to NAGRA IV-SJ
Adaptateur pour connecter lespreamptlficateurs Bk iau NAGRA IV-SJ
Adapter for connecting GR preamplifiers to NAGRA IV-SJ
Adaotateur pour connecter les prearnplificateurs GR au NAGRA IV-SJ
Preamplifier for BK measuring cartridges
Preamplificateur pour capsulesde mesure BK
Cable for connecting MKH 110 microphone to NAGRA IV-SJ
Cable pour connecter les microphones MKH 110 au NAGRA IV-SJ
Amplifier with balanced outputs
Amplificateur avecsorties tlottantes
Line input cable with banana plugs
Cable d'entres ligne avec fiches banane
CUE input/output cable
Cable d'entree/sortie CUE
Commentary microphone with AlC
Microphone de commentaire avec RAS
Synchronizer for slide projector
Synchroniseur pour projecteur de diapositives
OFMS 06780 Frequency meter for 50 Hz pilot signal
Frequence-rnetre pour signal pilote 50 Hz
06781 Frequency meter for 60 Hz pilot signal
Frequence-rnetre pour signal pitote 60 Hz
QSGX 06698 Crystal pilot generator for 50 Hz
Generateur pilote a quartz 50 Hz
06699 Crystal pilot generator for 60 Hz
Generateur oitote a quartz 60 Hz
QSJC 01128 Universal power supply for measuring microphones
Alimentation universelle pour microphones de mesure
QSJA- 01165 2-channel amplifier for QSPB preamplifier
SK Amplificateur a 2 canaux pour prearnpliticateur QSPB
OSJA 01170 2-channel amplifier for BK preamplifier
BK Amplificateur a 2 canaux pour preamplificateur BK
OSJA- 01175 2-channel amplifier for MKH 110 microphones
MKH Amplificateurs il2 canaux pour microphone MKH 110
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NAGRAI\l..SJ
configurator
Power supply E)(ternal electro accessories
ATN-2 14350 Mains power supply 110-250 V with pilot signal output OGB 14001 10 1/2" reel adapter
Alimentation secteur 110-250 V avec sortie signal pilote Adaotateur grande bobine 267 mm
OCAS 98001 Mains cable with Swiss plug OCA 14102 Start-stop cable for remote controt
Cable d'alimentation secteur avec fiche suisse Cable start-stop pour commande
a distance
OCAW 98003 Mains cable without mains plug OGBC 14005 Normal 8 mm cinespool holder
Cable d'alimentation secteur sansfiche secteur Parte-bobine cinema (standard I
PAR 13200 Charger for PA type rechargeable cells OGBN 14006 NAB-type hub holder
Chargeur pour accumulateurs du type PA Porte noyau type NAB
PPO 14150 Multiple connection box OGBA 14007 AEG-type hub holder
Bolte de derivation Porte noyau type AEG
PO 98202 Set of 12 standard cells OSM 14700 Field monitor and amplifier
Jeu de 12 piles standard Maniteur-amplificateur de reportage
PA-R 98251 Set of 15 rechargeablecells withextension 2,5 Ah IACC 17910 Removable cell compartment for OSM and IS
Jeu de 15 accumulateurs avec rallonge 2,5 Ah Magasin arnovible d'accumulateurs pour OSM et IS
Set of 12 4 Ah rechargeable cells OCAS 98001 Mains cable with Swiss-type plug
PA-4 98254 Cable d'alimentatian secteur avecfiche suisse
Jeu de 12 accumulateurs 4 Ah
Stabilized power supply for measurements OCAW 98003 Mains cable without mains plug
AST 90400 Cable d'alimentatian secteur sansfiche secteur
Alimentation stabilisee de laborataire
Mechanical accessories
Carrying eases
OHP 14120
OTIM 14650 Tape driven timer
Compteur temps eruralne par la bande
OLEN 14655 Tape driven metrical counter
Compteur rnetrique entralne par la bande
OAAC 06260 Tape cleaning blade
A.deur de bande
,
MAG
9OBOI Electranically-contralled degausser220 - 240 V
Demagnetiseur Acommande electronique 220 - 240 V
90802 Electronically-controlled degausser110 - 117 V
Demagnetiseur a commande electronique 110 - 117 V
OSH 14130 Lid when using 7" reels
Couvercle pour I'emploi de babines 178 mm
Carrying handle
Poignee
Spare carrying strap for NAGRA IV-SJ
Courraie de rechange pour porter Ie NAGRA IV-SJ
OHTP 99009 Standard carrying casewith pocket
Saooche standard avec poche
OHTRC 99220 Leather cover for OSET
Cauvercle de sacache pour OSET
OHC 14125
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Corresponding level with
Bruel & Kjaer cartridge
1/2" 1"
+4 dB +4dB OdB
44 dB 20 dB 22 dB
32 dB 10 dB 14 dB
BACKGROUND NOISE
Potentiometer position "K"-------------
Linear measurement
20 Hz - 200 kHz
Measurement weighted
according to ASA A
BRUIT DE FOND Niveau correspondant avec
I
capsules Brliel & Kjaer
1/2" 1"
Position du potentiornetre "K" +4 dB +4 dB
o dB
Mesure lineaire
20 Hz - 200 kHz 38~ V 44 dB 20 dB 22 dB
I
Mesure ponderee
selon ASA A 10J.. V 32 dB 10 dB 14 dB
11.
Entsprechender Pegel mit
Kapseln Brliel & Kjaer
1/2" 1"
+4 dB +4 dB OdB
44 dB 20dB 22 dB
32 dB 10 dB 14 dB
STOE RSPAN NUNG
"K" Potentiometer position -------------
Linearmessung
20 Hz - 200 kHz
Gediimpfte Messung
nach ASA A
I
The QJPA preamplifier is calibrated
in order to obtain an average fre-
quency response for 1/2" and 1"
cartridges (R10LF = 2,7kU). It is
possible, for a given measuring car-
tridge to better the very low fre-
quency range by adjusting an internal
element of the QJPA. In this case,
the frequency response will not be
as good with other cartridges.
Le QJPA est regie de sorte a obtenir
une courbe de reponse moyenne pour
les capsu les 1/2" et 1" (R lOlF =
2,7kn). II est possible, pour une
capsule de mesure donnee, d'arnelio-
rer la partie TBF du spectre en ajus-
tant un et.~ment interne du QJPA.
Dans ce cas, la courbe de reponse
sera evidemment moins bonne pour
une capsule differente.
Der QJPA ist zur Verwendung von
112" und l"-Kapseln fur einen mittle-
ren Frequenzgang eingestellt. (R10lF
= 2,7kn). Fur Kapseln mit gegebe-
nen Messwerten ist es moglich. den
sehr tiefen Frequenzbereich durch
Anpassung eines internen Elementes
des QJPA zu verbessern. In diesem
Fall wird [edoch bei Verwendung
einer andern als der gemessenen Kap-

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QSJP
Adapter for Bru et & Kjeer Preamplifiers
ENGLISH
The OSJP is an external acces-
sory for the NAGRA IV-SJ which
connects the Bruel
& Kjaer 2619
type preamplifier, as well as the
2615 and, if desired, the 2618 and
2627, to the recorder; the latter
should be equipped with the
OSJA-BK microphone amplifier and
the OSJC power supply.
The adapter is fitted with a plug
which can be connected to a micro-
phone input of the NAG RA and a
Connector corresponding to the plug
of the Bruel
& Kjaer preamplifiers.
The K factor of the Bruel &Kjaer
cartridge used can be directly com-
pensated using the potentiometer
with a -2 dB to +4 dB scale.
FRAN~AfS
Le QSJP est un accessoire ex-
terne du NAGRA IV-SJ qui permet
d'utiliser Ie prearnplificateur type
2619, ainsi que Ie type 2615 et, Ie
cas echeant, les types 2618 et 2627
avec I'enregistreur. Celui-ci doit
etre equipe de I'amplificateur de
microphone OSJA-BK et de l'ali-
mentation QSJC.
Cet adaptateur est muni d'une fiche
qui se branche
a une entree micro-
phone du NAG RA et d'une prise
correspondant
Ii la fiche des pre-
amplificateurs Bruet
& Kjaer.
Un potentia metre gradue de
-2 a
+4 dB permet de campenser directe-
ment Ie facteur K de la capsule
Bruel & Kjaer utilisee.
DEUTSCH
Oer QSJP ist ein externes Zube-
her zum NAGRA IV-SJ, mit wel-
chem der Bruel & Kjaer Vorverstar-
ker Typ 2619, sowie der Typ 2615
und gegebenenfalls die Typen 2618
und 2627 an das Bandgedit anzu-
schliessen sind. Dieses muss mit dem
Mikrophon-Verstarker OSJA-BK und
der Speisung QSJC ausqerustet sein.
Der Adapter ist versehen mit einem
Stecker, passend zur Mikrophon-
eingangsbuchse des Bandqerates und
mit einer Buchse passend zum
Stecker des Bruel
& Kjaer Vorver-
starker.
Ein van
-2 bis +4 dB geeichtes Po-
tentiometer errnoqlicht die direkte
Anpassung an den K-Faktor der ver-
wendeten Briiel &Kjaer Kapsel.

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QSJA-BI<
Microphone Amplifier
Plug-in Module for NAG RA IV-SJ
ENGLISH FRANCAIS
Le QSJA-BK est un amplificateur a
gain commutable pour microphone
de mesure a condensateur, enfi-
chable a l'interieur du NAGRA. Get
accessoire permet d'utiliser Ie pre-
amplificateur Bruel & Kjaer type
2619, ainsi que Ie type 2615 et, Ie
cas echeant, les types 2618 et 2627
avec l'adaptateur QSJP, ou Ie
prearnplificateur General Radio
1560 P42 avec I'adaptateur
QSJP·GR.
DEUTSCH
The QSJA-BK is a switchable gain
amplifier, for capacitor measuring
microphones, which can be plugged
in inside the NAG RA. This acces-
sory makes it possible to use Bruel
& Kjaer 2619, as well as 2615 and,
if desired, 2618 and 2627 type pre-
amplifiers with the QSJP adapter, or
the General Radio 1560 P42 pre-
amplifier with the QSJP·GR adap-
ter.
The amplifier, preamplifiers, adap-
ters and cartridges can function only
when the QSJG microphone power
supply is installed in the recorder.
L'amplificateur, les prearnplifi-
cateurs, adaptateurs et capsules ne
peuvent fonctionner que si I'alimen-
tation de microphone QSJG est
mantee a l'interieur de l'enregi-
streur.
Der QSJA·BK ist ein Verstarker mit
schaltbarer Verstarkunq fUr Konden-
sator-Messrnlkrophone und ist im
Inneren des NAG RA eingesteckt.
Mit diesem Zubehor konnen fol-
gende Einheiten verwendet werden:
BrLiel &Kjaer Vorverstiirker Typ
2619. sowie auch 2615 und gegeben-
enfalls 2618 und 2627 mit dem
Adapter QSJP. oder General Radio
Vorverstarker Typ 1560 P42 mit
dem Adapter QSJp·G R.
Der Verstarker, die Vorverstiirker,
Adapter und Mikrophonkapseln
werden durch die Mikrophonspeise-
Einheit QSJC gespeist, die in das
Innere des Tonbandgeriites einge-
steckt wird.