Fm Quadradial Output Jack; Fm De-Emphasis Switch; Dolby Fm Preset Level Controls; Muting Level Control - Marantz 4270 Instructions Manual

antenna will provide better reception. Two single
wires are required to make an AM outdoor
antenna. First, connect one end of a single
wire to the AM ANTENNA terminal on the rear
panel, and the other end at a very high position
outdoors. Next, connect the other single wire
between the "G" terminal and an earth ground
(such as a water pipe).
(Refer to Figure 11.)
FM QUAD RADIAL OUTPUT JACK
In anticipation of discrete 4-channe l stereo broad­
casts, your Model 4270 is equipped w ith an FM
QUAD RADIAL OUTPUT jack. The signal avail­
able at this jack is the unequalized output of the
FM discriminator. It's frequency response cha­
racteristics and signal level are ideal to drive any
4-channel adaptor. This jack can also be used as
a simple white-noise generator for frequency
response check of loudspeakers or amplifiers.
For this application, release FM MUTII\lG Switch
of the Model 4270 in FM mode and tune off
from any FM signal.
FM DE-EMPHASIS SWITCH
Selects 75J.LS or 25J.LS FM DE-EMPHASIS for
accurate reception of Dolbyized FM signals.
DOLBY FM PRESET LEVEL CONTROLS
These factory-adjusted controls govern FM out­
put level to the DOLBY circuit. These controls
are for the use of a qualified technician only.
MUTING LEVEL CONTROL
Adjusts the threshold of the inter-station muting
circuit. Turning this control counter-clockwise
w ill lower the threshold to permit reception of
weak signals.
POWER MODE SWITCH
Switches from 25 watts x 4 operation to 70 watts
x 2. In the 2-channel mode, only the front
speaker terminals are used.
BE CERTAIN THAT THE UNIT'S POWER
SWITCH IS OFF BEFORE OPERATING THE
POWER MODE SWITCH.
NOTE: When operating the unit in the 70W x 2
mode, all speaker terminals are "above ground".
Consequently, the use of any switching or testing
system which employs a common ground will
activate the limiting circuits and should therefore
be avoided.
PRE OUT, MAIN IN JACKS
For normal operation, these jacks are inter­
connected with the supplied jumpers. When
connecting an external unit (equalizer, reverbera­
tion unit, etc.), remove the jumpers and connect
the PRE OUT jacks to the external unit's inputs.
In turn, connect the external unit's outputs to the
MAIN IN jacks.
It is possible to create a higher powered 4-channel
system by adding an external amplifier. If the
external amplifier has less than 70 watts x 2, it
should be used to drive the rear speakers. If the
external amplifier has more than 70 watts x 2, it
should be used to drive the front speakers. In
each case, the rear panel POWER MODE Switch
should be set to the 70Wx2 position.
CONNECTING AN EXTERNAL AMPLIFIER
FOR REAR CHAI\II\IELS
To use an external amplifier for the rear chan­
nels, connect the REAR PRE OUT jacks to
the inputs of the external amplifier. In turn,
connect the rear speakers to the output terminals
on the external amplifier. The 4270 will then
supply the power for the front speakers and the
external amplifier will supply the power for the
rear speakers.
CONNECTING AN EXTERNAL AMPLIFIER
FOR FRONT CHANNELS
To use an external amplifier for the front chan­
nels, connect the REAR PRE OUT jacks to the
FRONT MAIN IN jacks. Connect the rear speak­
ers to the FRONT speaker terminals on the 4270.
Then, connect the FRONT PRE OUT jacks to the
inputs of the
external
amplifier. In turn, connect
the front speakers to the output terminals on the
external amplifier. The 4270 will then supply
the power for the rear speakers and the external
amplifier will supply the power for the front
speakers.
CHASSIS GROUND BINDING POST
Permits connection of the ground wire from a
turntable or other component to reduce hum.
MAIN AND REMOTE SPEAKERS
Sixteen quick-connect terminals are provided
eight for main speakers and eight for remote
speakers. (Refer to "CONNECTING THE 4270"
and "REMOTE SPEAKERS".)
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