CX242 Zone Mixer
Installation & User Guide
Cloud Electronics Limited
140 Staniforth Road, Sheffield, S9 3HF England
Tel +44 (0) 114 244 7051
Fax +44 (0) 114 242 5462
V4.0
CX242: I
NSTALLATION AND OPERATION MANUAL
CX242 Zone Mixer
Installation and operation manual
1
Contents
1 Introduction ...............................................................................2
2 Schematic Diagram...................................................................2
3 Zone Configuration Controls .....................................................3
4 Music Inputs..............................................................................4
4.01 Sensitivity & Gain Control .........................................................4
4.02 Music Control - Local or Remote ..............................................4
4.03 Priority.......................................................................................4
4.04 Mono Operation ........................................................................4
5 Microphone Inputs ....................................................................6
5.01 Mic Inputs .................................................................................6
5.02 Gain Control..............................................................................6
5.03 Front Panel Level Controls. ......................................................6
5.04 Microphone Priority...................................................................6
6 Zone Outputs ............................................................................6
6.01 Equalisation ..............................................................................7
6.02 Switch-on Mute .........................................................................7
6.03 Remote Control Requirements .................................................7
7 Remote Music Mute - Fire Alarm Interface ...............................7
8 Expansion Connector................................................................8
9 General notes ...........................................................................9
9.01 Earthing ....................................................................................9
9.02 Unbalanced Mode..................................................................... 9
10 Controlling the music functions using external DC control........9
10.01 Level Control.............................................................................9
10.02 Source Select ...........................................................................9
11 Technical Specifications .........................................................10
12 General Specifications ............................................................ 11
Section
Page
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1 Safety Notes
• Do not expose the unit to water or moisture
• Do not expose the unit to naked flames.
• Do not block or restrict any air vent
• Do not operate the unit in ambient temperatures above 35
• Do not perform any internal adjustments unless you are qualified to do so and fully
understand the hazards associated with mains operated equipment.
• The unit has no user serviceable parts. Refer any servicing to qualified service
personnel.
• If the moulded plug is cut off the lead for any reason, the discarded plug is a
potential hazard and should be disposed of in a responsible manner.
For more detailed information refer to the rear of the manual.
2 Schematic Diagram
2
o
C
LINE 4
LINE 3
LINE2
LINE 1
MIC 1
MIC 2
GAIN
GAIN
GAIN
GAIN
GAIN
GAIN
For clarity only one channel shown
MIC 2
ZONE 1
MIC 2
ZONE 2
DC CONTROLLED
SOURCE SELECT
LINE 4 PRIORITY
DC CONTROLLED
SOURCE SELECT
MIC 1
ZONE 1
MIC 1
ZONE 2
REMOTE OR LOCAL
SOURCE SELECT + LEVEL
EQ VCA
EQ
REMOTE OR LOCAL
SOURCE SELECT + LEVEL
ZONE 1
MICROPHONE
AUTO PRIORITY
EQ
EQ
ZONE 2
MICROPHONE
AUTO PRIORITY
VCA
FIRE ALARM
MUSIC MUTE
LEVEL
ZONE 1
OUTPUT
ZONE 2
OUTPUT
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3 Zone Configuration Controls
Pre-set switches and controls protected by the anti-tamper panel:
1
PR M1
Z1 MICS
REM
9
1 Mic 1 priority on/off in Zone 1 - Button out = off, button in = on
2 Mic 2 priority on/off in Zone 1 - Button out = off, button in = on
3 Treble control for Zone 1 mic signals - Horizontal position gives flat a response.
4 Bass control for Zone 1 mic signals - horizontal position gives a flat response.
5 Treble control for Zone 2 mic signals - horizontal position gives a flat response.
6 Bass control for Zone 2 mic signals - horizontal position gives a flat response.
7 Mic 1 priority on/off in Zone 2 - Button out = off, button in = on.
8 Mic 2 priority on/off in Zone 2 - Button out = off, button in = on.
9 Remote/local control of Zone 1 music signals. Button out = local,
button in = remote.
10 Stereo/mono switch for Zone 1 music signals. Button out = stereo, button in = mono.
11 Line 4 priority switch for Zone 1. With button in, line 4 overrides other signals.
12 Treble control for Zone 1 music signals. Horizontal position gives flat response.
13 Bass control for Zone 1 music signals. Horizontal position gives flat response.
14 Treble control for Zone 2 music signals. Horizontal position gives flat response.
15 Bass control for Zone 2 music signals. Horizontal position gives flat response.
16 Line 4 priority switch for Zone 2. With button in, line 4 overrides other signals.
17 Stereo/mono switch for Zone 2 music signals. Button out = stereo,
button in = mono.
18 Remote/local control of Zone 2 music signals. Button out = local,
button in = remote.
MONO
Z1 MUSIC Z2 MUSIC
10
2
PR M2
L4 PR
11
3
HF
++++
0000
++
0
HF
12
4
LF
000
LF
13
+
5
HF
HF
14
6
LF
+
LF
15
7
PR M1
Z2 MICS
L4 PR
16
8
PR M2
MONO
17
REM
18
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4 Music Inputs
The unit has four stereo line inputs which are suitable for most music sources such as
compact disc players, tape players and tuners etc. All inputs are unbalanced and use
RCA phono sockets. The input impedance is 100k ohms.
4.01 Sensitivity & Gain Control
All four stereo line inputs have a pre-set gain control on the rear panel adjacent to the
respective input sockets. The nominal input sensitivity is 0dBu (775mV) and this can be
varied from -12dBu (195mV) to +12dBu (3.08V). The pre-set gain controls should be set
so that all the input signals are operating at the same level and the front panel level
control has an optimum range of control.
4.02 Music Control - Local or Remote
The music source and music level control functions can be operated from the front panel
or remotely by using the optional remote source/level plate RSLC-1. This plate can be
positioned up to 100 metres from the CX242 and two core cable with overall screen
should be used. The front panel mounted anti-tamper panel should be removed by using
the allen key provided; depress the switch marked 'REM' to select remote control
operation of the desired zone (see Figure 1). Self adhesive labels are provided to identify
the signal source on the front panel.
4.03 Priority
When a Juke Box or Spot Announce Player is connected to the CX242, fully automatic
priority over any selected line input can be achieved by using the Line 4 input and
activating the 'L4 PR' switch concealed behind the anti-tamper panel.
When this mode of operation is selected, the unit will operate normally until a signal is
detected on channel 4 and this causes the selected signal (usually background music) to
mute, allowing the signal on line 4 to operate with priority.
Once the signal on line 4 ceases, the selected music signal will smoothly restore to its
former level. The time taken for the selected signal to be restored can be set at 3, 6 or 12
seconds by fitting the appropriate jumper (J1) on the printed circuit board. The factory
default release time is 3 seconds. The line 4 priority option can be switched to operate on
either or both zone outputs.
4.04 Mono Operation
When the mono mode of operation is selected, use the left output socket. A mono music
signal is present on both the left and right output sockets but the signal level of the two
outputs is controlled independently.
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When local control is selected, the front panel signal source switch is operative and the
front panel music level control adjusts the level of the left output socket; the signal level of
the right output socket can be controlled by a remote level control plate. With no plate
fitted, the right output operates with mic signals only. When the remote mode of
operation is selected, the source select control on the remote plate is operative and the
remote level control adjusts the signal level of the left output socket; in this mode, the
front panel level control adjusts the music signal level on the right output. See the
illustrations below for more details:
LEFT
RIGHT
5
FRONT PANEL CONTROLS
LEFT
OUTPUT
SELECT
LEVEL
REMOTE CONTROL
MONO MODE
WITH LOCAL CONTROL SELECTED
LEFT
RIGHT
REMOTE CONTROL
SELECT
LEVEL
RIGHT
OUTPUT
LEVEL
RIGHT
OUTPUT
LEVEL
FRONT PANEL CONTROLS
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MONO MODE
WITH REMOTE CONTROL SELECTED
LEFT
OUTPUT
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NSTALLATION AND OPERATION MANUAL
5 Microphone Inputs
5.01 Mic Inputs
Two microphone inputs are provided and the microphone amplifier is an electronically
balanced, transformerless design configured for optimum low noise performance.
The input impedance is greater than 2k and is suitable for microphones in the 200 to 600
ohm range. Inputs are via gold plated 3 pin XLR type connectors with latch, which are
positioned on the rear panel. For balanced microphones, connect the cable screen to Pin
1, the in phase signal to pin 2 and reverse phase to pin 3.
To operate the channel in the unbalanced mode, connect pin 3 to pin 1 (ground) inside
the XLR cable plug. Use pin 2 as hot and pin 1 as screen (ground).
5.02 Gain Control
Pre-set gain controls are provided adjacent to the respective XLR input connector. The
gain can be adjusted from 0dB to 60dB and this wide range of gain allows direct
connection of high output devices such as radio microphones without the need for
additional attenuation. A high overload margin is maintained at all gain settings.
5.03 Front Panel Level Controls.
Separate controls for Mic 1 level and Mic 2 level are provided for both Zone 1 and Zone 2
and these provide the user with a convenient means to operate either microphone at a
suitable level in the zone of their choice.
The microphone signals are routed directly to the respective output stage and are
unaffected by the operation of the music controls. The gain control on the rear panel
should be set at a level where it is not possible to have excessive gain even when the
front panel level controls are fully clockwise.
Self adhesive labels are provided to customise the controls.
5.04 Microphone Priority
Fully automatic, voice operated priority is provided for both microphone inputs on both
zones. Priority on/off switches are positioned behind the anti-tamper panel. With the
priority function selected, when a microphone signal is detected, the music signal is
attenuated by 20dB allowing the message to be clearly heard; normal music operation is
restored smoothly after the announcement has been made. See Figure 1 for priority
switch location details.
6 Zone Outputs
The two output zones have balanced output stages using 3 pin XLR type connectors and
can operate into loads as low as 600Ω. The nominal output level is 0dBu (775mV) but the
CX242 can operate with a wide range of signal levels up to a maximum output of +20dBu
(7.7V). A 3 pin XLR connector is required for each output. For balanced interconnections,
2 core screened cable should be used. Connect the cable screen to pin 1. Pin 2 is the in
phase signal (normally red) and pin 3 is the reverse phase signal (normally blue or black).
If you plan to connect any zone output to an unbalanced load, see section 9.02
'Unbalanced Mode'.
6
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6.01 Equalisation
Both Zone 1 and Zone 2 have separate treble and bass controls for the music signals and
the microphone signals. These pre-set controls are protected by the front panel mounted
anti-tamper panel. The music treble control has a range of ±10dB at 10kHz and the music
bass control operates with a range of ±10dB at 50Hz. The microphone tone controls
operate at ±10dB at the frequencies of 8kHz and 100Hz.
6.02 Switch-on Mute
When the CX242 is switched on, a two stage mute circuit operates. The music signals are
fully muted for a period of two seconds, followed by a five second period when the music
level smoothly changes to the level set by the controls. During this switch-on mute cycle,
the red 'Music Mute' LED will illuminate.
6.03 Remote Control Requirements
The CX242 is fitted with VCA control of the music level as standard but if remote control
of the signal source and level is required, then the optional 'Remote Source/Level Plate'
(RSL-1) is required. Both Zone 1 and Zone 2 can be operated remotely or by local control
as required.
The RSL-1 can be fitted directly onto a standard UK electrical single gang mounting box
(recessed or surface) with a minimum depth of 25mm (not supplied). Two core screened
cable must be used to link the remote plate to the CX242. Connect the cable screen to
terminal 1 on both the mixer connector and the remote plate. Terminals 2 & 3 on the
mixer connector should connect to terminals 2 & 3 respectively on the remote plate.
When the mono mode is selected and the front panel source select switch is used, a
remote plate with a level control only is available (RLC- 1) for installations where separate
control of the mono signal present on the right output socket is required. Single screened
cable can be used for the RL-1, connect the screen to terminal 1 and the core to terminal
2, with no connection to terminal 3.
7 Remote Music Mute - Fire Alarm Interface
In certain circumstances, there may be a Local Authority or Fire Service requirement to
mute the music signals via a fire alarm control panel in an alarm condition. The CX242
provides a facility to attenuate the music signals only, by using a fully isolated pair of
contacts (usually a relay mounted close to the CX242 which is powered by the fire alarm
control panel) which should close during an alarm condition.
In the mute mode, a music gain reduction of between 20dB and 70dB (full mute) is
effective and the desired mute level can be set by adjusting the small pre-set level control
adjacent to the 2 pole remote music mute connector on the rear panel. The front panel
mounted 'Music Mute' LED will illuminate to indicate the operation of the mute circuit.
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8 Expansion Connector
Two CX242's can be linked by fitting the optional 'Expansion Connector Kit'. The multicore link duplicates the two mic and four line signals derived from the source CX242 onto
the respective input stages of a second CX242. This simplifies the interconnection of two
units which are required to control the same input signals and distribute these to four
stereo zones.
It is possible by utilising a custom interconnection cable to link more than two CX242’s
together. If required only the signals that are to be shared can be linked and other signal
sources or microphones can be connected directly, to achieve the desired configuration;
refer to the following wiring chart for further details:
When using a customised interconnecting cable the appropriate number of 15 way D
connector cable assemblies (part number wj960319) should be obtained from our spares
department. One cable assembly fits inside each CX242 in the system to facilitate the
connection of the link cable.
Pin 1 Line 2 – left Pin 2 Line 2 - right
Pin 3 Line 1 – right Pin 4 Line 1 - left
Pin 5 0V Pin 6 0V
Pin 7 0V Pin 8 Mic 2
Pin 9 Line 3 – left Pin 10 Line 3 - right
Pin 11 Line 4 – right Pin 12 Line 4 - left
Pin 13 0V Pin 14 0V
Pin 15 Mic 1
Installation of standard “Expansion Connector Kit”:
The kit comprises two 15 way 'D' connector assemblies and a screened link cable. Fit the
cable assemblies as follows:
Disconnect the power lead prior to commencing any work.
Remove the top panel from the mixer which will be connected to the signal sources.
Remove the blanking cover from the expansion connector mounting holes.
Fit one of the 15 way female connectors to the rear panel using the supplied retention
pillars. The connector must be positioned on the inside surface of the rear panel.
Connect the ribbon cable connector to CON2 marked ‘OUTPUTS'.
Replace the top panel and mark the unit so as to identify it as the signal source.
Remove the top panel from the destination mixer.
Remove the blanking cover from the expansion connector mounting holes.
Fit the second 15 way female connector to the rear panel.
Connect the ribbon cable connector to CON1 marked ‘INPUTS'.
Replace the top panel and mark the CX242 so as to identify it as the destination unit.
The two units can now be connected together and the input signals from the source
CX242 will be connected to the second unit. To achieve matching microphone signal
levels, the rear panel mounted mic gain pre- set controls on the destination CX242 should
be positioned fully anti- clockwise. The line input pre-set gain controls do not interact and
should be set as required.
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9 General Notes
9.01 Earthing
The 0V rail of the CX242 is coupled to the chassis ground by a parallel resistor/capacitor
network and no interconnection problems should be encountered.
When several mains powered units are connected together via their signal cables, there
is a risk of one or more earth loops which may cause an audible hum on the system even
with the gain controls set to minimum.
The 'hum' can be remedied in several ways; the preferred method is to operate the output
links to the power amplifiers in the balanced mode, with the cable screen only connected
at the receiving end (amplifier input). The signal source units should be located as close
as possible to the CX242 and the metal housing of the various units should not be
electrically connected together through the equipment rack.
If this is a problem, rack isolating kits are available from specialist hardware suppliers. If
the problem persists, try to connect all the interconnected units, including the power
amplifiers to a common power source to ensure that a common ground is provided.
9.02 Unbalanced Mode
If the zone outputs are required to operate in the unbalanced mode, the unused pin of the
XLR type connector should be left with no connection.
The nominal output signal in this mode is -6dBu (387mV). The input gain controls may
require to be adjusted to provide the extra 6dB of gain.
10 Controlling the music functions using external DC control.
The CX242 can be used as part of an automated sound system by controlling the music
level and music source by an external 0-10V DC voltage. The 3 pole connector normally
used to terminate the RSL-1 control plate, can be used to feed two separate control
voltages into the CX242. Pin 1 is a ground (0V) termination common to both control
voltages; this should be connected to the technical ground (0V) of the voltage source. Pin
2 is the control voltage input for the music level and pin 3 is used to control the music
signal source selection.
10.01 Level Control
A maximum gain reduction of 60dB can be achieved with a control voltage of +10V; the
rate of attenuation is approximately 165mV per dB. A control voltage of zero realises unity
gain (full volume), however, with no external connection to pin 2, an internal 4k7 resistor
connected to the +15V power will ‘pull up’ the control voltage to provide maximum
attenuation. The output impedance of the control voltage source should be low enough to
overcome the influence of this resistor.
10.02 Source Select
Here are details of the source select control voltages (pin 3) required to switch the four
line input signals:
Line 1 +8.50V
Line 2 +7.00V
Line 3 +4.50V
Line 4 0.00V
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With no external connection to pin 3, an internal 15k resistor connected to the +15V
power will ‘pull up’ the source select control voltage and the ‘off’ position will be selected.
The output impedance of the control voltage source should be low enough to overcome
the influence of this resistor. If you require to fix the music signal to the Line 1 input, wire
a 20k resistor between pins 1 & 3 on the remote control connector.
If the control voltages are not isolated, there is a small risk of creating a ‘ground loop’ by
linking the CX242 ground with the ground of the equipment providing the control voltages;
we suggest that all pieces of equipment be positioned in close proximity.
11 Technical Specifications
Stereo Line Inputs
Frequency Response 20Hz-20kHz ±0.5dB
Distortion <0.05% 20Hz-20kHz
Nominal input level 0dBu/775mV
Input impedance
Input gain ±12dB
Headroom >20dB
Noise -90dB A weighted (0dB gain)
Microphone Inputs
Frequency Response 100Hz-20kHz ±0.5dB
Distortion <0.03% 20Hz-20kHz
Gain range 0dB-60dB
Input impedance
Common mode rejection >70dB 1kHz
Headroom >20dB
Noise
Zone outputs
Nominal output level 0dBu balanced, -6dBu unbalanced
Minimum load impedance
Maximum output level +26dBu balanced, +20dBu unbalanced
100kΩ
HF ±10dB 10kHz Equalisation
LF ±10dB 50Hz
>2kΩ (balanced)
-122dB EIN 22Hz-22kHz (150Ω)
HF ±10dB 5kHz Equalisation
LF ±10dB 100Hz
600Ω
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12 General Specifications
Remote music mute attenuation Adjustable -20dB to -70dB
Remote music mute connection 2 core cable to isolated relay contacts
Line 4 priority release time Adjustable 3, 6 or 12 seconds
Power consumption 15VA
Power requirements 230V±10% or 115V±10%
T100mA H for 230V input Fuse rating
T200mA H for 115V input
Fuse type 20mm x 5mm class 3 T 250V
Width 482.60mm
Height 44mm
Depth 160mm
This product conforms to the following European EMC Standards:
BS EN 55103-1:1997
BS EN 55103-2:1997
This product has been tested for use in commercial and light industrial environments. If the equipment
is used in controlled EMC environments, the urban outdoors, heavy industrial environments or close to
railways, transmitters, overhead power lines etc. the performance of the unit may be degraded.
The product conforms to the following European electrical safety standard.
BS EN 60065:1998
Weight 3.50kg including packing
Safety Considerations and Information
The unit must be earthed. Ensure that the mains power supply provides an effective earth
connection using a three-wire termination.
When the mains switch is in the off position the live and neutral conductors of the mains
transformer are disconnected.
CAUTION – Installation
Do not expose the unit to water or moisture
Do not expose the unit to naked flames.
Do not block or restrict any air vent
Do not operate the unit in ambient temperatures above 35
o
C
CAUTION - Mains Fuse
Replace the mains fuse only with the same type and rating as marked on the rear panel. The
fuse body size is 20mm x 5mm.
CAUTION – Servicing
The unit contains no user serviceable parts. Refer servicing to qualified service personnel. Do
not perform servicing unless you are qualified to do so.
Disconnect the power cable from the unit before removing the top panel and do not make any
internal adjustments with the unit switched on.
Only reassemble the unit using bolts/screws identical to the original parts
In the interest of continuing improvements Cloud Electronics Limited reserves the right to alter
specifications without prior notice.
Cloud Electronics Limited 140 Staniforth Road Sheffield S9 3HF England
Telephone +44 (0) 114 244 7051 Fax +44 (0) 114 242 5462 E-mail: Info@cloud.co.uk
15/07/02 V4
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