Marantz 4230 - Balance Control; Dolby Unit; 400 Hz Tone; Dolby Switch

DIMENSION Control Setting
Minimum (FCCW)
Center
Maximum (FCW)
LR Output
LE + RE
LF
LF — RF
RR Output
RF+LF
RF
RF —LF
When
the
DIMENSION
control
is
set
to
the
minimum
position
the
LR
and
RR
channel
signals
become
monophonic,
to
the
center
are
stereophonic,
and
to
the
maximum:
are
out
of
phase,
thus
providing
vanished
sound
image
positioning.
In
the
SQ
DECODER
position,
signal
sources
encoded
by
the
CBS
SQ
system
are
ideally
decoded
into
4-channel
signals.
Required
for
this
operation
is
incorporation
of
the
SQ
Adaptor,
Model
SOA-1,
into
the
Model
4230.
4.2 Balance Control
Signals
from
the
buffer
amplifiers
are
fed
into
the
balance
control
circuit,
in
which
the
signals
are
controlled
by
three
balancers:
FRONT
L-R,
REAR
L-R,
and
FRONT-REAR.
By
setting
the
FRONT-REAR
balancer
to
the
“FRONT”
side
and
the
FRONT
L-R
balancer
to
the
“L’
side,
for
example,
only
the
front
left
channel
is
drived.
The
balance
control
circuit
is
provided
with
the
REMOTE
CONTROL
switch
which
makes
the
Model
RC-4
Remote
Control
Box
operative
when
set
to
the
“REMOTE”
position.
In
the
“REMOTE”
position
the
BALANCE
and
VOLUME
controls
on
the
Model
4230
become
in-
effective
since
signals
are
led
to
the
Model
RC-4.
Balance
and
volume
can
be
adjusted
by
the
Model
RC-4.
Balanced
and
volume
controlled
signals
are
led
to
the
tone
control
amplifier.
5. DOLBY UNIT
The
Dolby
unit
built
in
Model
4230,
which
is
a
switchable
processor,
is
inserted
in
each
of
both
FRONT
R
and
L
channels.
The
attached
“DOLBY
PROCESSING
CHART”
will
facilitate
you
to well
understand
the
operation
of
the
Dolby
circuit.
An
input
signal
coming
to
J601
is
amplified
by
H601,
and
its
output
signal
is
led
to
the
filter
which
cuts
off
the
tape
bias.
The
signal
passed
through
the
filter
is
further
amplified
and
comes
‘to
the
mixing
circuit
of
resistors
R623
and
R625
and
to
the
phase
inverting
circuit
of
H6O7
and
H609.
The
output
signal
is
fed
out
from
J607.
_In
the
recording
mode
of
operation,
the
signal
is
fed
out
from
J605
preceding
the
mixing
circuit
and
applied
at
J611.
The
signal
is
then
discriminated
in
the
frequency
and
level
by
the
dynamic
filter
consisting
of
H611,
H613,
H615
and
H617,
and
is
fed
back
to
the
mixing
circuit.
In
the
playback
mode
of
operation,
a
part
of
the
output
signal
(at
J607)
is
fed
to
J611
and
discriminated
in
the
frequency
and
level
by
the
dynamic
filter
consisting
of
H611,
H613,
H615
and
H617
and
fed
back
to
the
mixing
circuit.
6.
400Hz
TONE
The
400Hz
tone
signal
which
is
a
580mV,
400Hz
sine
wave
is
available
at
the
FRONT
and
REAR
TAPE
MONITOR
OUT
terminals
at
any
position
of
the
DOLBY
switch
(with
the
excep-
tion
of
the
RECORD
[i
position)
and
the
SELECTOR
switch.
The
output
signal
of
the
400Hz
oscillator
consisting
of
HLO1
and
HLO2
is
fed
to
JLO2
and
JLO3
through
the
emitter
follower
HLO3.
The
output
levels
at
JLO2
and
JLO3
are
adjusted
to
580mV
and
approximately
25mV,
respectively.
The
signal
fed
from
the
Dolby
P.W.
Board
(P600)
comes
to
JLO4
and
is
rectified
through
HLO6.
The
rectified
output
at
JLO6
is
led
to
the
meter
M004.
7. DOLBY SWITCH
This
switch
sets
the
Dolby
noise-reduction
circuit
for
record
or
playback
and
also
switches
the
Meter
Mode
from
AM
or
FM
SIGNAL
STRENGTH
to
DOLBY
CAL
LEVEL,
or
vice-versa.