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REDBACK® A 2387 6 Zone 100W Speaker Switcher/Attenuator
This speaker selector and volume control unit enables you to use up to six pairs of speakers throughout
your home. The volume for each speaker pair can be controlled individually. The output from the amplifi-
er/receiver is wired directly to the A 2387. From there, speaker wire is run to speakers located in various
rooms throughout the house. Music for each location is selected by pushing the front panel ON/OFF but-
tons, and adjusting the appropriate volume control to the desired level.
FEATURES:
• Manual impedance matching adjustment for high acoustic quality
• 4Ω or 8Ω speaker compatible.
• Speaker power: 100W/channel (RMS).
• Removable connector can handle 12-22 AWG capacity speaker cable.
• Recessed areas on front panel for labeling the room/zones. (labels not included)
• 19' rack mounting option.
• Requires no power to operate.
1. Impedance Matching protection functions:
A 2387 is provided with selectable impedance compatible design and high acoustic quality for enjoyment.
No matter whether you are using 4Ω or 8Ω speakers, the A 2387 can be set manually for impedance
matching using the impedance pair selector located on the back of the unit. While multiple speakers are
connected to the amplifier at the same time, the reducing impedance of the speakers may adversely
affect the amplifier. Therefore, it is important to select the correct impedance-pair setting. Set the number
of the speaker pairs that you propose to install on the speaker output, and use a flat-head screw driver to
make the adjustment for impedance matching on the back of unit.
Note: The unit is factory preset to have the impedance-pair rotary switch set on '6'. The number should be
selected accurately in accordance with the quantity of the speaker pairs that have been connected to the
unit, in order to optimize sound quality. For example, if using four speakers, connect speakers to any out-
puts and set the impedance pair switch to "2", referring to the two pairs of speakers being used.
Figure 1: Rear panel connections
Impedance pair selector
(factory preset at 6)
Figure 2: Front panel controls
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REDBACK® A 2387 6 Zone 100W Speaker Switcher/Attenuator
2. Independent Amplifier Input Control
A 2387 has two sets of amplifier inputs – A and B – on the rear panel. There is a push-button switch on
the front panel beside each speaker volume control knob that allows a user to choose which input source
will feed into which speaker pair. Thus, a user can have either amplifier's audio feeding into speakers in
one room or all rooms, or a combination of different sources in different rooms.
3. Switching Speaker pairs ON/OFF.
A 2387 has ON/OFF switches for each independent speaker pair control. A user can therefore turn the
audio off or on for a given room. Note: For safety reasons it is recommended for each speaker output be
set to the 'OFF' position before commencing speaker installation.
4. Volume Control:
The A 2387 sound volume control knob has 12 steps which applies up to -42dB attenuation on the audio
signal (as shown in the table below). The frequency response is 30Hz-20kHz with ±2dB of deviation. The
first position is OFF. Turn the knob clockwise to increase the volume for each speaker pair.
Switch Steps
1
2
3
4
Attenuation
OFF -42dB -36dB -30dB -24dB -18dB -15dB -12dB -9dB
INSTALLATION
Remember that the left and right audio channel circuits are separated in this device. Therefore, it is
important to make sure that the input connections (+ and - , L and R) are wired correctly from each
source (A and B), and to each speaker pair.
OPERATION
This device is easy to operate. It is effectively a two into six audio matrix switcher with impedance match-
ing capability for speaker pairs.
1. Firstly, connect the source amplifiers to the A and B inputs.
2. Then install the speaker pairs where they are required inside the home or office. Connect the speaker
wires into the unit's rear panel.
3. Switch the source amplifiers on. Assign 'A' source input to chosen speakers and 'B' input to the
remainder. Press A/B source switch down to select source 'B' input for a channel.
4. Turn on the speakers you wish to listen to (press the ON/OFF button in) and turn up the volume to a
desired level suitable for that room.
Figure 3: Wiring diagram
5
6
7
8
9
10
-6dB
-3dB
11
12
0
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