Marantz 3800 - Page 24

C.
ENCODE
LOOP
GAIN
(1)
(2)
(3)
(4)
(5)
Ensure
controls
are
set
as
listed
in
Para-
graph
3B.
Set
oscillator
frequency
to
1
kHz
and
apply
signal
at
the
AUX
INPUT
Jack.
Adjust
amplitude
for
a
580
mV
signal
measured
at
the
TAPE
1
or
TAPE
2
OUT-
PUT
Jack.
Measure
amplitude
of
the
input
signal
(at
the
SCOPE
OUTPUT
Jack).
Calculated
gain
should
be
between
85
mV
and
245
mV.
D,
DECODE
LOOP
GAIN
(1)
(2)
(3)
(4)
(5)
(6)
(7)
Reset
Mode!
3800
controls
to
include:
(a)
DOLBY
Switch
set
to
REC
1,
(b)
VOLUME
Control
rotated
to
maxi-
mum (cw),
(c)
RECORD
LEVEL
Controls
rotated
fully
cew,
(d)
PLAY
CAL
Controls
rotated
fully
cw.
Set
oscillator
frequency
to
1
kHz
and
apply
a
signal
to
the
AUX
INPUT
Jack.
Adjust
oscillator
amplitude
for
a
0
VU
indication
on
the
Dolby
VU
Meter.
If
Dolby
VU
Meter
is
calibrated,
signal
amplitude
measured
at
the
PREAMPLI-
FIER
(PREAMP)
OUTPUT
Jack
should
be
approximately
6.3
V
rms.
NOTE:
A
580
mV
value
is
equal
to
Dolby
Level
or
0
VU
display
on
the
Dolby
VU
Meter.
When
the
signal
is
applied
to
the
X10
amplifier,
the
output
signal
level
measured
at
the
PREAMP
OUTPUT
Jack
will
be
approximately
6.3
V
rms.
Measure
amplitude
of
output
signal
at
PREAMP
OUTPUT
Jack.
Measure amplitude of input signal at
SCOPE OUTPUT Jack.
Calculated
gain
should
be
between
32
mV
and
100
mV.
E.
DOLBY
RECORD
MODE
FREQUENCY
RESPONSE
(
Figures
2-8
through
2-10
)
(1)
(2)
(3)
When
encoder
functions
as
a
flat
amplifier:
(a)
Ensure
all
controls
are
set
as
listed
in
Paragraph
3B.
(b)
Apply
a
1
kHz
signal
to
the
AUX
INPUT
Jack
and
adjust
amplitude
for
580
mV
measured
at
TAPE
1
or
TAPE
2
OUTPUT
Jack.
(c)
Check
frequency
response
at
this
level
and
at
18
mV
INPUT
for
oscillator
frequencies
20
Hz,
100
Hz,
1
kHz,
10
kHz,
and
15
kHz,
(here-
after
referred
to
as
from
20
Hz
to
15
kHz).
Response
should
be
flat
(+
1
dB).
When
encoder
functions
as
an
encoder:
(a)
Ensure
all
controls
except
DOLBY
Switch
are
set
as
listed
in
Paragraph
3B.
Reset
DOLBY
Switch
to
REC
I.
(b)
Apply
a
100
Hz
signal
to
the
AUX
INPUT
Jack
and
adjust
amplitude
for
a
580
mV
signal
measured
at
TAPE
!
or
TAPE
2
OUTPUT
Jack.
(c)
Check
frequency
response
for
oscil-
lator
frequencies
from
20
Hz
to
15
kHz.
Response
should
be
fiat
(+
1.5
dB).
(d)
Reset
frequency
to
100
Hz
and
|ower
amplitude
30
dB.
The
signal
level
measured
at
the
TAPE
OUTPUT
Jacks
should
be
approximately
18
mV
rms.
(e)
Reset
frequency
to
5
kHz
and
observe
the
amplitude
of
the
output
signal.
Amplitude
should
increase
by
9
dB
(+
2
dB)
or
to
a
level
between
41
mV
and
65
mV.
When
encoder
functions
as
a
decccler:
(a)
Ensure
all
controls
except
Dolby
Switch
are
set
as
listed
in
Paragaph
3B.
Reset
Dolby
Switch
to
REC
II.
(b)
Apply
a
100
Hz
signal
at
AUX
IN.
PUT
Jack
and
adjust
amplitude
for
a
580
mV
signal
at
TAPE
|
or
TRPE
2
OUTPUT
Jack.
2-9