Nagra IV-SJ Manuel utilisateur
- Catégorie
- Amplificateurs audio de voiture
- Taper
- Manuel utilisateur
INSTRUCTION MANUAL
o
KUDELSKI
SA
NAGRA
Tape Recorders Manufacture
CH-1033
Cheseaux/Lausanne
Switzerland
Tel (021)
91
21
21
Telex
459
302
nagr
ch
code
no. 20.01.004.151
MEASUREMENTS
chapter 1
SPECIFICATIONS
chapter 2
DIRECTIONS
FOR USE
chapter
3
BATTERIES
AND
ACCUMULATORS
chapter
4
ACC
ESSO
RI
ES
chapter
5
Printed
in
Switzerland by
KUD
ELSKI S.A.
Edition
August 1985
NAGRA,
KUDELSKI,
NEOPI
LOT,
NEOPI
LOTTON,
NAGRASTATIC,
NAGRAFAX,
sont
des marques enregistrees, proprit'!te de
KUDE
LSKI
S.
A.
fabrique
d'enregistreurs
NAGRA.
25
23
24
26
21
35
20
27 28
29
30
31
22
34
32
33
18
1719
107
70 8 6
60
9
16 15 14 13
11
12
5
4
1
TAPE/DI
RECT,
LINE
&PHONES:
switching
ofthe
play-
back signal
or
of
the
direct
signal
on
the
line
outputs,
headphones and loudspeaker;
switch
inactive
on
TEST
2
TAPE/DIRECT,
METER:
switching
of
the
playback
signal
or
of
the
direct
signal
on
the
circuit
of
meter
14;
this
switch
cannot
be locked
on
TAPE
3 POWER:
power
selector
switch
i.e.
built-in
batteries
or
accumulators
or
external
power
supply
connected
to
plug
48
21 BIAS:
5-position
bias
selector
switch
22
Pinch-wheel
23
Fast
wind
switch:
3
3/4
ips =
9.525
cm/s
1
1/2
ips =
3.81
cm/s
rewind
with
main
switch
4
any
po-
sition
except
STOP,
lever
32
in
disengage
position
fast
wind
when
main
switch
4
on
PLAYBACK
with
Loudspeaker
REW·444
~~~~~~
17
PHONES:
connector
for
mono
headphones,
impedance
25
to
600[2
18
CHANNE
L,
PHONE
& L.S.:
channel
selector
for
listening
with
headphones
and
loudspeaker
19
LEVE
L,
PHON
ES:
adjustment
of
the
headphones
volume
20
Tape
speed
selector
s.witch
15
ips =
38.1
cm/s
7 1
/2
ips =
19.05
cm/s
13
FI
L
TERS:
filter
selector
switch
for
channel
2, identical
to
11
14
Meter:
indicates
sound
level
and checking
functions
ac-
cording
to
the
position
of
selector
switch
12
15
PI
LOT:
indicator
which
shows
a
white
zone
when
frequency
and
amplitude
of
the
pilot
signal
are
correct
16
SPEED
&
POWER:
indicator
which
shows
a
white
zone
when
the
following
three
conditions
are
fulfilled:
power
supply
voltage
higher
than
the
maximum
admis-
sible value
motor
regulation
within
the
correct
operating
range
tachometric
speed
fluctuations
not
exceeding
the
maximum
value
24
Supply
reel
25
Tension
roller
of
the
supply
reel
26
Erase
head
27
Stabilizer
roller
with
50
or
60
Hz
stroboscope
28
Recording
head
track
1
and
2
29
Recording
and
playback
head
track
3
30
Playback
head
tracks
1
and
2
31
Capstan
32
3-position
lever
controlling
the
pinch-wheel
and
tape
guides:
lever
pulled
to
the
left:
for
threading
the
tape
(rewind
possible
in
this
position)
lever
at
45°
tb
the
edge
of
the
tape-deck:
motor
running,
but
tape
not
moving
lever
pushed
backwards:
tape
running
33
Tension
roller
of
the
take-up
reel
34
Take-up
reel
35
RECORDING
EQUALIZATION
ADJUSTEMENT
4 Main
function
switch
STOP:
recorder
at
a
standstill
TEST:
power
supplied
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
01
RECT if
the
output
signal
is
reintroduced
into
the
direct
chain,
see
42)
PLAYBACK
with
Loudspeaker:
playback
of
tape
using
loudspeaker
5
LIGHT:
meter
14
lights
up
momentarily;
remains
illu-
minated
when
the
button
is
turned
to
the
right
6 Main
attenuator
CHANNEL
2:
in
steps
of
10
dB
for
channel
2,
lower
track
6a
Vernier
attenuator
CHANNEL
2:
in
steps
of
1
dB
for
channel
2
7 Main
attenuator
CHANNEL
1:
in
steps
of
10
dB
for
channel
1,
upper
track
7a
Vernier
attenuator
CHANNEL
1:
in
steps
of
1
dB
for
channel
1
NOTE: dB scale:
for
the
microphone
inputs,
in rela-
tion
to
the
sound
pressure
level
0.0002
J.Lbar
=0
dB
Voltage scale:
effective
voltage
applied
to
the
line
output,
which
gives a reading
of
0
dB
on
the
RMS scale
of
meter
14
8
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
9 L1NE/MI KE: line
or
microphone
input
selector,
channel
2
10
L1NE/MI KE: line
or
microphone
input
selector,
channel
1
11 FI L
TERS:
6-position
filter
selector
switch
for
channel
1
HP
=
high-pass
LIN. = linear
WEIGHTING
A,B,C,D =
weighting
curves
A,B,C,D
12
METER
FUNCTION:
six-position
selector
switch
for
meter
14
LEVEL,
RMS
FAST:
on
the
decibel
scale, RMS value
of
the
sound
level,
fast
characteristic,
red
needle
for
channel
1, green
needle
for
channel
2
LEVEL,
RMS SLOW:
the
same
as RMS
FAST,
but
slow
characteristic
LEVEL,
PEAK:
on
the
PEAK
decibel
scale,
peak
value
of
the
sound
level,
channels
as
above
BATT:
onthe
BATTERIESscale,
battery
or
accumulator
check,
reed
needle:
battery
voltage per cell
(VOL
TS/
CELL),
green
needle:
voltage
required
by
the
motor,
with
the
same
reduction
factor
as
battery
voltage
PI
LOT & 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
PI
LOT
+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
36
MICROPHONE
CHANNEL
2: channel 2
microphone
input
44
PILOT:
pilot
signal
input
for
the
3rd
track
EXTERNAL
VIEW
OF C
HAS
SIS
CONNECTOR
OR
PLUG FROM THE
SOLOERING SIDE
ground
Clapper: reference
oscillator
or
crystal
pilot
generator
control
terminal
3
Xtal:
50
or
60
Hz internal crystal
pilot
generator
output
4
PI
LOT
IN:
pilot
signal
input
LINE
OUTPUT
2:
channel 2 line
output
on
banana jacks
45
200V
voltage available
with
built-
120V
in
microphone
power
supply
supply
voltage, varies according
to
the
type
of
amplifier
-lOG:
-10V
stabilized voltage,
maximum
current
350
mA
chassis
preamplifier
supply
voltage
signal
input
signal
input
ground
4
1
2
3
5
6
7
8
EXTERNAL
VIEW
OF
C
HAS
SIS
CONNECTOR
OR
PLUG FROM THE
SOLDERING SIDE
46
LINE
OUTPUT
1:
channell
line
output
on
banana jacks
37
MICROPHONE
CHANNEL
1:
channel 1
microphone
input
connector,
identical
to
36
47
CUE:
connector
fo
recording and playback
on
the
third
track
38
Gain selector
for
channel 2
microphone
amplifier,
3 posi-
tions,
+40,
+60
and
+80
dB
39
Gain selector
for
channel 1
microphone
amplifier,
identical
to
38
40
MICROPHONE
TYPES:
B & K cartridge
type
selector
EXTERNAL
VIEW
OF
C
HAS
SIS
CONNECTOR
OR
PLUG FROM THE
SOLDERING SlOE
1 CUE
IN:
modulation
signal
input
2
-lOG:
-10V
stabilized voltage
3
PI
LOT
OUT:
pilot
signal
output
4
-10V:
stabilized voltage available
only
during
recording
5
-10V
FM: voltage
terminal
to
activate
the
FM
modulator
6 CUE
OUT:
signal
output
(direct
or
recorded)
7
ground
EXTERNAL
VIEW
OF C
HAS
SIS
CONNECTOR OR
PLUG FROM THE
SOLDERING
SIDE
41
CHANNEL
2:
channel 2
multiple
connector
VAR.
LEVEL
IN: line
input
impedance
100kr2,
input
voltage
> 1
mV
2
-10
G: stabilized voltage
-10V
4 Playback
output:
output
voltage
10
mV
at
0
dB,
load>
47 kr2
7 ground
EXTERNAL
VIEW
OF
C
HAS
SIS
CONNECTOR
OR
PLUG FROM THE
SOLDERING SlOE
48
POWER
PACK:
connector
for
external
power
supply
1
-BATT.:
negative pole
of
the
bat-
tery
box
2
+BATT.:
positive pole
of
the
bat-
tery
box
and
ground
3 STOP:
motor
stop
control
terminal
(connect
to
-10V
to
stop)
4 SPEED
CORRECTION:
tape speed
correction
signal
input
5
EXTERNAL
-12V
to
-30V:
12
to
30V
external
power
input,
negative
pole
6
-lOG:
-10V
stabilized voltage
42
CHANNEL
1:
channell
connector,
identical
to
41,
shown
with
strap plug
to
reintroduce
the
playback signal
into
the
direct
chain (switch 10 must be on
LINE)
EoIITERNAL VIEW
OF
C
HAS
SIS
CONNECTOR
OR
PLUG FROM THE
SOLDERING SIDE
43
OUTPUTS:
line
output
connector
1
LINE
OUT
2:
line
output,
channel
2,
output
voltage
100
mV
at
0
dB
in a load greater
than
10
kr2
2
-lOG:
stabilized
output
voltage
-10V
3
LI
NE
OUT
1: line
output
channell,
output
voltage
100
mV
at
10
dB
in
a load greater than 10 kr2
4 unstabilized negative supply voltage
5
-lOR:
stabilized voltage
-10V
available
only
during
recording
6 STOP:
motor
stop
control
terminal
(connect
to
-1
OV
to
stop)
7 ground
INSTRUCTION MANUAL
I
Direct
analysis
of
sound signals
Used solely
as
an
amplifier
the
NAG
RA
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
Ilbar, i.e.
201lN/m
2
or
20
IlPa.
This level coincides in practice
with
the
audibility'
threshold
of
the human ear
at
1
kHz;
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
Ilbar
reference.
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,
C 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 1
kHz
lasting
200
ms
gives a reading 1 dB
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
Measurements
the
CE
I standard
179
for
precIsion 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
can record FM 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
cu
rve
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.
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.
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
,uPa
or
0.0002,ubar.
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
+10dB:
the
10dB
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
ti
mes
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.
INSTRUCTION MANUAL
R20
D and
L
90
120mA
205mA
260mA
465mA
305mA
DIMENSIONS
AND
WEIGHT
Dimensions
of
the
box
as
such
with
the
lid
closed,
without
knobs, feet, handle
or
handle
mounts
12.6 x 8.8 x
4.4"
-
318
x
222
x
110
mm
Overall dimensions
without
the
removable handle
13.2 x
9.6
x
4.5"
-
333
x
242
x
113
mm
Thickness
of
the
Anticorodal
sheet
used
for
the
box
.
080"
- 2
mm
Thickness
of
the tape deck
.120"
- 3
mm
Empty
weight,
without
batteries
or
tape
14 Ibs -
6.150
kg
Weight
with
ordinary
batteries,
5"
reels and tape
161bs -
7.300
kg
POWER SUPPLY
Supply
voltage,
direct
current,
positive
to
the
ground 12
to
30
V
Current
consumption
on Test
on Line Playback
on Record
direct
mic.
(1
BK
2619)
on Rapid Rewind
Type
of
batteries used (12 cells)
CE
I standard
ASA
standard
2
Specifications
MAGNETIC
TAPE
Nominal
width
1/
4
" -
6.25
mm
Admissible thickness
0.5
to
2
mils
- 12
to
50jlm
Maximum
reel
diameter
with
lid
open
7"
-178mm
Recording
time
at 7
1
/
2
ipswith35jlm
(1.5
mils)tape
45
min
.
Maximum
reel diameter
with
lid
closed
5"
- 127
mm
Recording
time
under
the same
conditions
22 min.
Rewind
time
with
5"
reel and
35
/-lm
(1.5 mils)
tape 2
min.
TAPE
TRANSPORT
Switchable
nominal
speeds:
15 ips 38.1
cm/s
7
1
/2
ips 19.05 cm/s
3%
ips
9.525
cm/s
1
1
12
ips 3.81 cm/s
Stability
of
the nominal
speed
in relation
to
the
temperature
(from
0°
to
50°C), the position
of
the recorder, the distribution
of
the tape between
the reels, and the supply voltage (except
for
1
1/2
ips). ±0.1%
Wow
and
flutter
weighted peak-to-peak value, in accordance
with
DIN
45 507 standard: (lEE
193-1972
1 ANSIS
4.03.1972)
26 hours
11~
hours
Approximate autonomy
with
Eveready E95 man-
ganese
dioxide alcaline batteries
Continuous
use,
recording
direct
with
mic.
and
2619 preamp.
15 ips
7 1/2 ips
3314 ips
1
1/2
ips
Starting time
±0.05% (0.07%)
±0.07% (0.11%)
±0.12% (0.15%)
±0.25% (0.3%)
3
seconds
DIRECT
RECORDING
TRACKS
Amplifier
chain
(without
microphone
amplifiers)
Input
impedance
100
kS1
Overall accuracy
of
the
attenuator
±0.1 dB (±0.2 dB)
Frequency response
from
2.5 Hz
to
35
kHz
±0.3 dB (±0.5 dB)
Record and Playback
Nominal
recording level, identical
to
Maximum
Peak Level (M.P. L.) =
320
nWb/m
for
NAB
405
nWb/m
for
CCIR
Bias
frequency
150
kHz
Bias
switchable per
10%
increments
Weighting curve accurac'{
better
than
CE
I
179
and
CEI
537
(for
exact curve
see
diagrams)
High
pass
filter
attenuation
- 3 dB
at
20
Hz, 12 dB per octave
± 1 dB
(2
dB)
3M
177
LPR
35 LH
82 dB (80 dB)
± 1.5 dB
(3
dB)
7
1/2
ips 25 Hz
to
20 kHz
33/4
ips 25 Hz
to
10 kHz
*1
1/2
ips 25 Hz
to
3.5 kHz
*recording possible
from
2.5 Hz
with
translation
to
15 ips in playback
for
NAB
Tape
used
for
testing
for
CCI
R
Erase
efficiency referred
to
M.P.L.
Frequency
response, recording at
20dB
below
M.P.L.
15 ips 25 Hz
to
35 kHz
66 dB (62 dB)
74
dB (70
dB)
80dB
(74dB)
at
Maximum
Peak
10
mV
RMS
1%
distortion
refer-
+8.5 dB (+8 dB)
Input
voltage
for
recording
Level,
maximum
sensitivity
Maximum admissible level
for
red
to
MPL
Signal-to-noise
ratio
linear
ASA
A weighted
Crosstalk
attenuation
at
1
kHz
METER
PEAK
indication
semi-logarithmic scale, usable
from
-10
to
+23dB
Third
harmonic
distortion
at
M.P. L.
1%
(2%)
Signal-to-noise
ratio
Linear
ASA
A
dB
dB
15 ips - 38 cm/s
NAB
58 (53)
63
(60)
CCIR
58 (55)
66 (63)
7 1/2 ips - 19 cm/s
NAB
60
(56)
64 (62)
CCIR
57
(55)
63
(60)
Crosstalk
attenuation
at 1
kHz
(60 dB)
at
10kHz
(50 dB)
Phase
shift
between tracks
at
71/2
ips
(19cm/s)
and 10
kHz
±15°
(±20
o
)
+10 dB ±0.2 dB
frequency response
from
30
Hz
to
35 kHz ±0.5 dB
(1
dB)
integration
time
for
2
dB
below
reference
deviation
5 ms
±20
%
RMS
(sonometer) indication
normalised scale, usable
from
-10
to
+12dB
frequency response
from
10Hz
to
35 kHz ±0.5 dB
(1
dB)
from
20 Hz
to
20 kHz ±0.2 dB (0.5 dB)
Outputs
Output
voltage
at
M.P.L. on
10
kS1
Output
voltage
for
1% distorsion
at
1
kHz
Output
voltage
for
200
S1
headphones,
adjustable
Built-in
loudspeaker,
power
output
of
amplifier
Reference signal level
RMS
1 V
(2.5
V)
o
to
1 V
1W
FAST
integration
time,
200
ms
for
1 dB
below
reference
deviation
SLOW
integration
time,
500
ms
for
4 dB
below
reference
deviation
±0.5 dB
(1
dB)
±0.5 dB ( 1 dB)
FM
TRACK
Operating
speeds,
15 and 7
1/2
ips - 38 and 19 cm/s
Input
and
Ouptput
centered at OVDC
Reading accuracy below 0 dB
above 0 dB
Peak
factor
(±0.5 dB)
(±0.2 dB)
>5
Carrier freqency
Static linearity
17 kHz
±0.4% (±1%)
o
to
4
kHz
(0
to
3.5
kHz)
Maximum
frequency
deviation
.6.fo
Frequency response
at
-3
dB
Signal-to-noise ratio
for
a ±20% deviation
±45% (40)
44
dB (40 dB)
Peak-to-peak
input
voltage
for
a ±40% deviation
PILOT
CUE
OPERATING
CONDITIONS
± 2.8V ± 0.5 dB
±
2 V ± 0.5 dB
with
external
power
Temperature
with
manganese batteries
- 4
to
+160
0
F
-20
to
+
71
0
C
-67
to
+160
0
F
-55
to
+
71
0
C
The recorder
functions
correctly
in
any
position.
All
values given
are
typical;
exact values
for
each
machine
are
given on its final measurement
protocol
sheet.
A
ht"
W
eifl
In~
curve
Frequency
lEe
Recommendation
179
NAGRA
IV·SJ
Relative Tolerance
Tolerance
Response Limits Limits
Hz
dB
dB
dB
20
-50.5
±5
±3
25 -44.7
±5
±2.5
31.5
-39.4
±3
±2
~
-
-
.........
40 -34.6
±3
±2
./
I"-....
50 -30.2
±3
±2
/'
'"
63 -26.2
±3
±2
80
-22.5
±2
±1.5
/
100 -19.1
±1
±1
125
-16.1
±1
±1
160 -13.4
±1
±1
V
200
-10.9
±1
±1
250
-
B.6
±1
±1
/
315 - 6.6
±1
±1
/
400
- 4.8
±1
±1
V
500 - 3.2
±1
±1
630 -
1.9
±1
±1
/
800
- 0.8
±1
±1
1000
0
±1
±1
1250
+ 0.6
±1
±1
/
±1
±1
1600
+ 1
2000
+
1.2
±1
±1
/
2500
+
1.3
±1
±1
3150
+
1.2
±1
±1
/
4000
+ 1
±1
±1
5000
+ 0.5
±1.5
±1
6300
-
0.1
+1.5
-2
±1
/
8000
-
1.1
+1.5
-3
±1.5
I
10
000
- 2.5
+2
-4
±1.5
12500
- 4.3
+3
-6
±1.5
16000
- 6.6
+3
-~
!1.5
20000
- 9.3
+3
-~
±2
Hz
80
200
500
1000
3150
8000
12500
-10
o
+10
-50
-20
-30
-40
dB
20
31,5
50
100
315
800
1200
5000
10000
20000
dB
Frequency
I
EC
Recommendation
179
NAGRA
IV·SJ
Relative Tolerance
Tolerance
Response
Limits
Limits
Hz
dB dB
dB
20 -24.2
±5
±2
25
-20.4
±5
±2
31.5
-17.1
±3
±2
40
-14.2
±3
±2
50
-11.6
±3
±2
63
- 9.3
±3
±2
80
7.4
±2
±1.S
100
-
5.6
±1
±1
125
4.2
±1
±1
160
-
3
±1
±1
200
2
±1
±1
250
-
1.3
±1
±1
315
0.8
±1
±1
400
- 0.5
±,
±1
500
0.3
±1
±1
630
-
0.1
±1
±1
800
±1
±1
1000
±1
±1
1 250
±1
±1
1600
0
±1
±1
2000
0.1
±1
±1
2500
0.2
±1
±1
3 150 -
0.4
±1
±1
4000
0.7
±1
±1
5000
-
1.2
±1.5
±1
6300
1.9
+1.5
-2
±1
8000
2.9
+1.5
-3
±1.5
10
000
4.4
+2
-4
±1.5
12500
6.1
+3
-6
±1.5
16000
8.4
+3
±1.5
20000
-11.1
+3
±2
B
ht"
elfl
In2
curve
~
~
r--
.........
/"
,/'
"'"
/
/
/
/
,
Hz
80
200
500
1000
3150
8000
12500
-10
o
+10
-20
-50
-30
-40
r-;::====W
20
31,5
50
100
315
800
1200
5000
10000
20000
c
ht
Wei21
in2
curve
dB
Frequency
lEe
Recommendation 179
NAGRA
IV·SJ
Relative
Tolerance
Tolerance
Response
Limits Limits
+10
Hz
dB
dB
dB
20
- 6.2 ±5
±1.5
0
25
- 4.4
±5
!1
.---
I-"
-
--.....
31.5
- 3
!3
!1
./
I"--..
40 - 2
!3
±1
/'
"~
50
- 1.3
±3
±1
63
-
O.B
±3
±1
-10
80
- 0.5
±2
±1
100
- 0.3
!1
!1
125
- 0.2
±1
±1
160 -
0.1
±1
±1
-20
200 0
±1
±1
250 0
±1
±1
315
0
!1
±1
400
0
!1
±1
500 0
±1
±1
-30
630
0
±1
±1
800 0
±1
±1
1000
0
±1
!1
1 250
0
!1
!1
-40
1600
-
0.1
±1 ±1
2000
- 0.2
±1
±1
2500
- 0.3
±1
!1
3 150 - 0.5
±1
±1
4000
- 0.8
±1
±1
-50
5000
- 1.3
±1.5
±1
6300
- 2 +1.5
-2
±1
8000
- 3
+1.5
-3
±1.5
10
000
- 4.3
+2
-4
±1.5
12500
- 6.2
+3
-6
±1.5
16000
- 8.5 +3
-~
!1.5
Hz
20000
-11.2
+3
-~
±2
80
200
500
1000
3150
8000
12500
20
31,5
50
100
315
800
1200
5000
10000
20000
SJ)
ht+
Wei21
In2
curve
D
Frequency
IEC
Recommandalion 537
--
Relative
Tolerance
""
"
Response
Limits (same
as
for
IV-
/'
Hz
dB
dB
/
",
20
-20.6
±
3.0
25
-18.7
± 2.0
31.5
-16.7
± 1.5
..--""""
'"
40
-14.7
± 1.5
/"
50
-12.8
± 1.5
/"
\
63
-10.9
± 1.5
V
80 - 9.0
± 1.5
/'
100
- 7.2
± 1
./
125
- 5.5
± 1
V
160 - 4.0
± 1
/'
200 -
26
± 1
250 - 1.6
± 1
315
- 0.8
± 1
400
- 0.4
± 1
500
- 0.3
± 1
630
- 0.5
± 1
800 - 0.6
± 1
1000
0.0 ± 1
1250
2.0 ± 1
1600
4.9
± 1
2
000
7.9 ± I
2500
10.4 ± 1
3150
11.6 ± 1
4
000
11.1
± 1
5000
9.6 ± 1.5
6300
7.6 +1.5
-2.0
8000
5.5 + 1.5
-3.0
10
000
3.4
+2.0
-4.0
12500
1.4
+3.0
-6.0
16
000
- 0.7
+3.0
~
Hz
20000
- 2.7
+3.0
~
80
200
500
1000
3150
8000
12500
o
+10
-10
-20
-30
-50
-40
dB
20
31,5
50
100
315
800
1200
5000
10000
20000.
1.
BASIC
EQUIPMENT
1.1.
Installation
of
Batteries
or
Accumulators
Select
the
type
of
battery
or
accumulator
accor-
ding
to
the
expected
working
conditions
for
the
recorder
(see
Section
4j.
Turn
the
recorder over
so
that
it
is
resting
on
its
lid;
turn
the
screws marked
A and remove
the
cover
of
the
battery
compart-
ment. Insert the
12
cells in
the
position
shown,
u
+
+
/,
1r 1r
o fjJA
~
~A
0
\
0
H H
~
then replace the cover and secure
it
by
turning
the
screws marked A. Set POWE R
switch
3 on
Batt.
1.2.
Connection
of
an
External
D.C. Source
Connect
the
12-30 V voltage source
to
the
POWE R
PACK
connector
48,
with
the
negative pole
to
pin
5.
Set POWE R
switch
3 on
External.
1.3.
Connection
of
Mains Power
Supply
Connect an
ATN
or
ATN
2 mains
power
supply
to
the
POWER
PACK
connector
48.
If
necessary, check
the
position
of
the
voltage selec-
tor.
Set POWE R
switch
3 on
External.
INSTRUCTION MANUAL
Directions for use
1.4.
To
Check
the
Power
Supply:
Turn
METER
FUNCTION
switch
12
to
BATT.
and main selector
switch
4
to
TEST:
the
red needle
of
meter
14
indicates on
the
lowest scale
the
un-
stabilized
battery
voltage expressed
for
one cell:
the
total
voltage
is
therefore
obtained
by
multiply-
ing
the
meter
reading
by
12. The
pointer
at
1.25 V
indicates
the
minimum
voltage
at
which
the
man-
ganese
dioxide
batteries should
be
recharged so
that
they
are able
to
go
through
the
discharge/charge
cycle several dozen
times
(see
Section
4).
Turn
main selector
switch
4 back
to
STOP.
2.
CONNECTION
OF
SIGNAL
SOURCES
Since
the
two
direct
recording channels are iden-
tical,
instructions
are given
for
channel 1
only,
but
they
are
also valid
for
channel 2.
2.1.
Connection
of
a High Level
Line
The recorder can
be
connected
to
an appliance
or
a
measuring
instrument,
the
output
voltage
of
which
is
equal
to
or
higher
than
1
mV
RMS:
input
is
direct
on
the
main
attenuator
and
input
impedance
is
100 kQ.
The
lower
the
output
impedance
of
the
signal
source,
the
better
the
signal
to
noise
ratio
is.
The external signal source
is
connected
to
connec-
tor
42:
the
wiring
of
the
corresponding plug
is
shown in General
View
lion
the inside cover.
Selector
10
will
then
be
on
LINE.
2.2.
Connection
of
a High Level
Microphone
or
Transducer
Input
identical
to
2.1.,
but
using
connector
37,
with
selector
10
on
MIKE.
The
wiring
of
the
plug
is
shown in General
View
II:
only
contacts
4, 5, 7
and 8 can be used;
contact
3 supplies a -10- V
stabilized voltage
which
can feed
an
external pre-
amplifier,
if
desired.
2.3. Connection
of
the OJPA Preamplifier
fitted
with
a Bruel & Kjaer Microphone Cartridge
~[]I
-------L..I~I
~
~
---.JI
\\
MECH.ANICAL
ADAPTORS
-;:=======-
======:::/
C
I .
QSJA-SK
=-=~-i
~d
~
--T---'
-1
I
QSJC0
~
I
I I I
L
-L
.l
-={T~
~
I
QSPB
B&
K
CARTRIDGES
~
M3x8
Signals and Voltages
Chassis
connector
external side
or
plug soldering
side.
"'---
+12,6
V
----=--SIGNAL
,-----~GND
F
A
::
..
:
.':.-;~
c:1+-:
_~!;_;.
_~
~::::r::::G~_~~~~~~~~
B
M2x6
-10G-----1
+200V------.
+
120V--
........
Bruel & Kjaer
V2"
4133,
4134,
4149
and
4163
microphone
cartridges screw
directly
onto
the
QJPA
preamplifier,
and
the
preamplifier
output
plug
fits
into
microphone
connector
37.
Other
cartridges
can be screwed
on
using a mechanical adapter, i.e.
-1
":
4144,4145,4146
and 4161
type
-
V4":
4135
and
4136
type
-
Ih":
4138
type.
The
25
m or 50
m.
QCPA extension cable
can
be
inserted between the
output
plug
of
the QJPA pre-
amplifier
and
the
microphone
connector.
Set selector
switch
10
on
MI
KE.
The recorder
must
be
fitted
with
the
QSJA-BK
microphone amplifier
and the QSJC universal
power
supply.
Installation
of
aSJA-BK
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 A.
Carefully
position
the
metal
ground
strap B and slip
it
under
the ground
comb
C.
The
two
switch
spindles 0
should be
passed
through
the
corresponding holes
in the
box,
then the
blocking
rings E threaded on.
Introduc~
the
spindle
into
the
switches, press the
rings against the ground strap and
tighten
them.
Place the shield in
position
and
fix
it
under
the
ground
comb
and
under
a
nut
screwed
onto
one
of
the
two
hinge
fixing
screws (this screw should
be
longer -
M3x8l.
Reinstall the level adapter
board
A.
Installation
of
OSJC Power
Supply
Plug in
the
power
supply
circuit
and
fix
it
with
screw G
to
the connector.
Pass
a
M2x6
flat
head
screw
through
from
the
inside
of
the
battery
box
and
through
the
bracket
of
the
metal
box,
and
fix
with
a
nut.
2.4. Connection
of
Bruel & Kjaer
Amplifiers
fitted
with
Bruel & Kjaer
Microphone
Cartridges
-,------l
OSJt
~
@ I
I I
L~
--....1....
~
B&
K
PREAMPLI
FI
ER
MECHANICAL
ADAPTOR
B&
K
CARTRIDGE
~======-..===::::::!J
The
following
types
of
cartridges
-
Ih":
4133,4134,4149
and
4163
- 1
":4144,4145,4146and4161
- Y4":
4135
and
4136
- 1/8": 4138
can
be
fitted
to
the
following
types
of
preamplifiers:
-
1",
Y2", Y4" :
2615
-
Y2",
Y4", Y8" :
2614
-
1",1/2",1/4",Y8"
:2619
-
1"
:
2627,2612
and
2613
-
1,4",
1/8" :
2618
The cartridges can
be
fitted
directly
onto
the pre"
amplifierswhen the diameters match;
if
they
do
not
match, a mechanical adapter can
be
used. The
output
plug
of
the
preamplifier
screws
into
the
QSJP
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 precedi
ng
paragraph.
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
/i.Lbar.
It
should
be
connected
to
microphone
connector
37
by
the QCJ-MKH cable; selector
10
should
be
on
MIKE.
The
r~corder
should be
fitted
with
the QSJA-MKH
microphone
amplifier,
which
also supplies the vol-
tage
for
the
microphone.
Installation
of
QSJA-M
KH
Amplifier
Lock
the
lid
of
the
recorder,
turn
screws 50 several
ti
mes
and open
the
case
to
its
fu
II
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
the
ground
comb
and
under a
nut
screwed
onto
one
of
the
two
hinge
fixing
screws (this screw should be longer -
M3x8l.
Reinstall the level adapter board.
Signals and Voltages
Chassis
connector external side
or
plug soldering
side
Signals and Voltages
Chassis
connector
external side
or
plug soldering
side
+200V
GND
GND
+120V
SIGNAL
SIGNAL
r-
L_
+12,6
V
-8V
-10G
-10G
2.6. Connection
of
General Radio 1560-P42
Preamplifier
fitted
with
a
Microphone
Cartridge
This preamplifier can
be
fitted
with
the
same
car-
tridges and mechanical adapters
as
the Bruel & Kiaer
2619 preamplifier. Its
output
plug
fits
into
the
input
connector
of
the QSJP-G R adapter;
the
out-
put
connector
of
this adapter must
be
plugged
into
microphone connector 37; selector
10
should
be
on
MIKE.
Preamplifier 1560-P42
can
also
be
fitted
with
GR
1"
and GR
V2"
ceramic microphone cartridges.
When Bruel
& Kjaer cartridges are being used the
recorder should
be
fitted
with
the QSJA-BK
amplifier
and QSJC-power supply, version 2
only,
which should
be
modified
to
supply the
+16
V
voltage required
for
the
GENERAL
RADIO
pre-
amplifier.
Version 2
of
the QSJC
power
supply
differs
from
version 1 (which
can
supply
only
+12 V) in the
value
of
certain components, e.g. resistances R24
and R25:
@
@
@
o
@
@
R26
R24
G
o
R27
R25
o
Version 1: R24 =
33
kn,
R25 = 27
kn
no
modification
possible
Version 2: R24
= 47
kn,
R25 =
33
kn
modification
possible
It
is
not
possible
to
transform
a version 1
circuit
into
version 2,
as
the osci IIator coiI
of
the converter
is
different
in
each
case.
Before
modifying
a version 2
circuit,
it
is
essential
to
measure the negative voltage available
at
terminal
6
of
connector CUE 47, in relation
to
the
ground
(terminal
7)
with
no
modulation.
Bridge terminals
5 and 2 and set main switch 4 on
TEST;
note
the
value
of
the negative voltage at
terminal
6
(see
para-
graph 7.6
for
the meaning
of
this value).
To
obtain a.+16 V voltage, remove resistance R26
(180
kn),
which
is
soldered
to
two
pins;
it
is
not
necessary
to
dismantle the
circuit.
After
this
modification
has
been made, the voltage
available
at
terminal 6
of
connector
CUE 47 shoulQ
be
adjusted
to
the value noted before the
modifica-
tion
was
made; this
can
be
done
by
adjusting
potentiometer
R83
of
circuit
A24
(THIRD
TRACK
CI
RCU ITS).
If
it
is
impossible
to
obtain
the
value
noted, replace resistance R82
of
this
circuit
by
a
10
kn
resistance and adjustable
potentiometer
R83
by
a 2.2
kn
model.
Signals and Voltages
Chassis
connector
external side
or
plug soldering
side
~-~-GND
-----=-SIGNAL
-------
+
16
V
-10G--------J
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 4
to
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 value
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
1 second.
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 0 dB
(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
oli
the
Microphone
Input
Same
procedure
as
in the preceding paragraph,
but
with
selector 10 on
MI
KE.
3.4.3. Low-level Signals on
the
Microphone
Input
QSJA-BK
AMPLIFIER
With
selector
1"0
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
V4"
the
positions
of
gain selector 39
become +40,
+60
and
+90
dB, values inscribed in a
circle.
Turn
attenuator
7
to
+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
fi
Iter selector switch
11
is
on
LI
N,
the
fre-
quency response
of
the
direct
chain
is
linear at
±0.3 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).
3.6. Calculation
of
the
Value Measured
3.6.~.
Measurement
of
High-level Signals
by
the
Line
Input
A 1
mV
sine wave signal applied
to
the
line
input
gives
a reading
of
0
dB
on
the
PEAK
scale
or
on the
RMS
scale, when main
attenuator
7
is
on
0.001
V
or
0 dB.
Meter 14
is
graduated in decibels
only;
since the
value indicated
by
main
attenuator
7 corresponds
to
a reading
of
0 dB on the meter, the exact value
of
the signal - in decibels in relation
to
t!"Je
0 dB
reference level -
is
obtained
by
adding algebraically
the value shown on meter 14
to
the value shown on
main
at4!nuator
7 and, when necessary, on vernier
attenuator 7A. The
number
of
decibels obtained
should then
be
converted
into
a voltage ratio, and
the line
input
voltage deducted
from
the 1
mV
reference voltage.
It
is
a convention in electro-acoustics
to
express
measurements taken at peak value in terms
of
the
RMS value which
would
be
given
by
a sine wave
signal
with
the
same
peak value;
the
input
sensitivity
and the
output
voltage
of
the
recorder
are
therefore
expressed in terms
of
their
RMS value, assuming the
signals
are
sine wave.
On
RMS,
the measuring circuit
of
the recorder
responds
to
the
RMS
value
of
the signal
and
indicates,
after decibel/voltage conversion, the
RMS
value.
On
PEAK,
the measuring
circuit
of
the recorder
responds
to
the peak value
of
the signal and
indicates, after decibel/voltage conversion, a value
which
is
the RMS value
of
the
signal
only
if
it
is
a
pure sine wave; the actual peak value, whatever the
form
of
the signal,
is
obtained
by
multiplying
the
value indicated
by
1.414.
A 1
mV
RMS sine wave signal applied
to
the
line
input,
with
the attenuators on 0 dB, gives
an
iden-
tical reading on
PEAK
and on
RMS
,
which
is
equal
to
0 dB,
A signal
without
a well-defined
form,
applied
to
the line
input,
gives the
following
values
after
decibel/voltage conversion
of
the reading:
-
on
PEAK,
peak
value divided by 1.414
-
on
RMS,
RMS
value
The line
input
impedance
is
100
kn.
On
the
maxi-
mum sensitivity position
(9
dB) there
is
no
increase
in
input
noise
as
long
as
the
sound source impe-
dance remains
low
in relation
to
the
100
kn
input
impedance.
Select the attenuator
position
for
which the needle
of
the meter shows the closest possible value
to
+10 dB
RMS
or
+20 dB
PEAK,
without
exceeding this
limit.
The
attenuator
knob
then
indicates a decibel value
which,
when added
to
the
value shown
by
the needle, makes
it
possible
to
determine
the
voltage applied
to
the
input,
i.e.
for
xdB:
x
input
voltage in
millivolts
= 10
20
Basically, vernier
attenuator
7A remains on 0 dB
(CAL.).
With
this
attenuator
it
is
possible
to
make
afine adjustment,
if
necessary, in steps
of
1 dB: the
value shown
by
its switch should
be
added
to
that
of
main
attenuator
7.
The graduations
in
dB
of
attenuators7
and
7A
and
meter
14
are also usable
for
relative measurements
without
pinpointing
the
reference.
3.6.2. Measurement
of
High-level Signals
by
the
Microphone
Input
Proceed in
the
same
way
as
described in
the
pre-
ceding paragraph,
but
with
selector 10 on
MI
KE.
3.6.3. Measurement
of
Low-level Signals
by
the
Microphone
Input
The sound level, measured
in
decibels, in relation
to
the
2.10-
5
N/m
2
reference level,
is
equal
to
the
algebraic sum
of
the
values indicated
by
gain
selec-
tor
39, main
attenuator
7, vernier
attenuator
7
A,
the
reading on meter
14
and a specific correction
value given according
to
the
cartridge and
amplifier
circuits used.
The
correction
value includes, amongst
other
things,
a correction
factor
K
o
. This
is
the difference,
expressed in decibels, between the sensitivity
of
a
standard cartridge (50
mV
/N/m
2
)
and the actual
sensitivity measured in the
laboratory
by
the
manu-
facturer. The K
o
factor
is
given in
the
calibration
chart issued
with
each Bruel & Kjaer
microphone
cartridge.
To
facilitate
the
reading
of
meter
14
the
needle
should
be
as
n.ear
as
possible
to
the
+20
dB
PEAK
or
+10
dB
RMS
values,
without
exceeding
them.
If
the
signal
is
too
weak when
attenuator
7
is
on
+20
dB,
turn
the
knob
to
the
right;
if
the
readi
ng
is
sti
II
too
low
when the
attenuator
is
on
o
dB,
turn
gain selector 39
from
+60
dB
to
+40
dB.
If
necessary, readjust main
attenuator
7.
If
the
signal
is
too
strong when
attenuator
7
is
on
+20 dB,
turn
its
knob
to
the
left;
if
the
reading
is
sti
II
too
high when
the
attenuator
is
on
+40
dB
(marked
with
an
arrowhead), move gain selector 39
from
+60 dB
to
+80
dB.
IK = K
o
- G - X I
Same
as
below
The preamplifier gain
"G"
is
the
same
as
for
Bruel & Kjaer 2619 preamplifier.
K
o
=
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
2
reference value, in accor-
dance
with
the
following
table:
3.6.3.2.
Limits
and Corrections
with
Bruel &
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
+60
dB;
when
the
latter
is
on
+80
dB (+90 dB
for
a
1/
4
"
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:
Limits
and Corrections
with
the QJPA
Preamplifier and
OSJA-BK
Amplifier
3.6.3.1.
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.
Type
of
cartridge
X in dB
1"
Ih"
1/
4
"
1/
4
"
1/
8
"
4135
4136*
4138**
0
+12
+22
+30 +34
*With
the
1/
4
"
cartridge
4136,
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 1J4"; add 12 dB
to
the calculated value
to
obtain
the sound level.
Example
1J2" cartridge
4133
with
preamplifier
2619:
K
o
= +12.2 dB G =
0.4
dB X = +12 dB
Value
to
which
the
potentiometer
of
the
QSJP
adapter should
be
adjusted:
K
= 12.2 +
0.4
- 12 =
+0.6dB
3.6.3.3.
Limits
and Corrections
with
the
M
KH
110
Microphone
and
the
OSJA-MKH
Amplifier
TheOSJA-MKH
amplifier
does
not
in any way alter
the performance
of
the
microphone
and its elec-
tronic
circuit'; reference should
be
made
to
the
sound level
limits
indicated
by
the manufacturer
for
saturation
'and
background noise.
Correction: With the
MKH
110
microphone
add
60 decibels
to
the value set on main
attenuator
7
and
to
the value shown
by
meter 14.
With
the
MKH
110-1
microphoneadd80dB.
3.6.3.4.
Limits
and Corrections
with
the
1560-P42
GENERAL
RADIO
Amplifier
As
the
OSJA-BK
amplifier
is
being used, the
same
limits
and corrections
as
those given in paragraph
3.6.3.2.
are
valid.
The G value,
which
represents
preamplifier
gain in
relation
to
the
type
of
cartridge,
is
shown in the
following
table.
Type
of
cartridge
G in dB
IMPORTANT
-2.5
%"
-6
In all
cases
where there
is
uncertainty
about
the
sensitivity, the K correction
factor
of
the
cartridge,
or
the gain
of
the
input
circuits, we recommend the
use
of
a calibration device. This device
is
applied
to
the cartridge and produces a calibrated sound level
of
a precisely
known
value. The BrLiel & Kjaer
pistonphone and the acoustic
calibrator
produce a
fixed frequency signal;
with
calibration
equipment
using
an
electrostatic
actuator
for
condenser
micro-
phones
it
is
possible
to
calibrate at
different
frequencies.
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
re-
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"/s
(3.8
cm/s):
25
Hz
to
3.5
kHz
±1
dB
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
:.:
••••
.
~
•••
~
Push lever
32
backwards
to
its
fu
lIest
extent.
Ra
ise
the
head shield.
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Nagra IV-SJ Manuel utilisateur
- Catégorie
- Amplificateurs audio de voiture
- Taper
- Manuel utilisateur
dans d''autres langues
- English: Nagra IV-SJ User manual
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