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Technics SH-9020 - Page 4

Technics SH-9020
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h
permits
the
meters
to
num
peak
value
detected
m
is
designed
so
that
it
r
the
indication
to
return
gnal
conditions.
e
advantage
of
the
peak
snecessary
to
be
able
to
Im
peak
value
of
the
pro-
ture,
therefore,
makes
it
ain
the
maximum
peak
~with
constantly
chang-
te
value
for
along
period
to
pre-set
to
the
correct
j
to
record.
yeak-hold
feature
can
be
n
of
the
maximum
peak
for
25
minutes
or
more.
he
indication
of
only
the
in
which
there
are
com-
>
J
6
sponse
ynal
waveform
>
above,
it
is
possible
to
stermine
the
maximum
le
peak
value
indicated
sd
until
a
higher
peak
SH-9020
mg
ABOUT
THE
INDICATED
VALUES
49
30
2010
9
-0
0
dB
SCALE
0,007
0.01
01
1
10
100
1000;
W
SCALE
dB
peak
/average
Indication
of
decibels
(dB)
e
The
outer
(upper)
scale
is
calibrated
in
dBm
units
and
defines
the
signal
level
of
0.775V
(1
mW)
at
600
to
be
OdB.
When
the
meter
sensitivity
selection
push-
button
is
set
to
OdB,
the
meters
will
indicate
—20dB
at
an
input
of
OdBm.
When
the
pushbutton
is
set
to
+20dB,
the
meters
will
indicate
OdB
at
an
input
of
OdBm.
For
VU
meters,
an
indication
of
0
VU
indicates
a
signal
level
of
1.228V
at
600.
For
this
unit,
how-
ever,
the
—
16dB
point
becomes
equivalent
to
0
VU
(when
the
meter
sensitivity
selection
pushbutton
is
set
to
OdB).
The
relationships
between
dBm,
dBs,
VU
and
voltage
are
shown
below.
*
At
the
level
usually
used,
a
1V
signal
level
is
de-
fined
to
be
OdBs.
Value
indicated
by
meters
(meter
sensitivity:
0
dB)
+10
[4]
SH-9020
e¢
In
addition
to
being
used
for
checking
the
recording
level
and
the
Output
level,
the
dB
scale
can
also
be
used,
by
playing
a
frequency-check
record,
to
check
the
frequency
response
of
a
phonograph
cartridge
or
to
check
channel
separation,
etc.
W
indication
When
this
unit
is
used
as
a
power
meter,
the
inner
(lower)
scale
of
the
meters
should
be
used.
The
W
scale
is
calibrated
in
output
values
at
a
pure
resistance
load
which
is
equivalent
to
nominal
resist-
ance.
When
the
meter
sensitivity
selection
pushbutton
is
set
to
the
OdB
position,
power
is
indicated
in
the
range
shown
(1mW
~1000W)
on
the
meters.
When
itis
set
to
+20dB,
the
actual
value
of
the
power
is
0.01
of
the
indicated
value
(thus,
a
range
of
0.01
mW
~
10W).
Impedance
correction
Because
the
values
indicated
on
the
meters
(when
they
are
used
as
power
meters)
are
different
depend-
ing
upon
the
impedance
of
the
speakers
used,
it
is
necessary
to
use
the
speaker
impedance
selector
(on
the
rear
panel)
to
make
the
impedance
correction.
If
the
speakers
to
be
used
have
an
impedance
of
8
ohms,
set
the
switch
to
the
8
position.
For
speakers
with
a
6-ohm
impedance
set
to
6,
and
for
a
4-ohm
impedance
set
to
49.
Note
that
meter
readings
will
be
incorrect
if
the
correct
setting
is
not
made
to
correspond
with
the
impedance
of
the
speakers.
Speaker
impedance
selector
“
If
the
speakers
have
an
impedance
different
from
any
of
those
indicated,
set
the
selector
to
the
closest
approximate
value.
Actual
output
is
then
calculated
in
the
following
way:
(Value
indicated
on
meters)
x
(Selector
set-
ting
+
Impedance
of
speakers
used).
If,
for
example,
the
selector
is
set
to
8
for
speak-
ers
of
16-ohm
impedance,
multiply
the
value
indi-
cated
on
the
meters
by
1/2
to
determine
the
actual
output.
When
the
Technics
models
SE-9060
Is
used
for
Balanced-Transformerless
operation,
set
the
speak-
er
impedance
selector
to
a
value
which
is
1/2
of
the
impedance
of
the
speakers
to
be
used.
If,
for
example,
the
speaker
impedance
is
82,
set
the
selector
to
the
“49”
position.
m
METER
RESPONSE
CHARACTERISTICS
FOR
VARIOUS
SIGNAL
WAVEFORMS
Because,
as
explained
previously,
the
response
characteristics
of
peak-level
meters
and
of
average
meters
are
different,
the
two
types
of
meters
would
indicate
two
completely
different
values
when
the
waveform
and
the
duration
are
different.
In
the
figures
below,
the
indicated
values
for
the
two
types
of
meters
are
shown.
The
pake
value
is
held
constant,
and
the
waveform
or
the
duration
are
varied.
®@
When
the
duration
is
changed
e
These
figures
shown
the
indicated
values
for
3
types
of
signal
levels
with
different
waveform
durations.
The
peak-level
meter
is
shown
at
the
left,
and
the
average
meter
at
the
right.
®
When
the
waveform
is
changed
e
These
figures
show
the
indicated
values
for
3
types
of
signal
levels
with
different
waveforms.
The
peak-
level
meter
is
shown
at
the
left,
and
the
average
meter
at
the
right.
|'@
Continuous
wave
@
Sine
wave
average
peak
/avgrage
peak
/avefage
average
@
Square
wave
average
peak
average
©
Single-wave
peak
/averAge
©
Music
signal
average
average
e
Peak-level
meters
have
a
fast
response...with
an
“attack’’
time
of
100
sec
or
less,
so
that
the
indi-
cated
value
doesn’t
change
even
for
signals
of
short
duration,
because
the
value
is
indicated
after
being
held
for
a
short
time.
For
average
meters,
however,
the
deflection
of
the
indication
needles
is
almost
e
As
you
can
understand
from
the
above,
in
order
to
detect
the
peak
value,
the
indicated
value
of
peak-
level
meters
doesn’t
change
even
if
the
waveform
is
changed,
but,
for
average
meters,
the
indicated
value
is
completely
different
in
order
to
fulfill
their
function
of
indicating
the
average
value.
exactly
equivalent
to
the
perceived
‘‘feeling’’
of
the
sound
volume.
Because
the
“‘attack”’
time
is
set
to
be
330
msec,
therefore,
average
meters
cannot
properly
respond
to
signals
of
short
duration,
and
their
indi-
cation
is
lower
than
that
of
peak-level
meters.
SH-9020

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