L-Acoustics LA4 User manual

LA4 AMPLIFIED CONTROLLER
LA4 CONTROLEUR AMPLIFIE
VERSION 1.1
www.l-acoustics.com
EN
F
R
USER MANUAL
MANUEL UTILISATEU
R

www.l-acoustics.com

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1SAFETY WARNINGS
All information hereafter detailed applies for the L-ACOUSTICS®LA4 Amplified Controller, designated in this
section as ‘‘the product’’.
1.1 Symbol Description
1.1.1 Symbols employed in this manual
Throughout this manual the potential risks are indicated by the following symbols:
The VOLTAGE symbol indicates a potential risk of electric shock that could be life threatening
and/or seriously damage the product.
The WARNING symbol indicates a potential risk of physical harm to the user or people within close
proximity to the product.
In addition, the product may also be damaged.
The CAUTION symbol notifies information to the user which can prevent possibly damaging the
product.
The IMPORTANT symbol notifies an important recommendation of use.
1.1.2 Symbols indicated on the product
As the product is an electrical device, it represents potential hazard for the user. For this reason the user may pay
particular attention to the symbols that are indicated on the product’s cover:
The lightning flashes symbols next to the NL4FC Speakon connector sockets indicates that the
product can produce high output voltages that can potentially be life threatening !!!
Connections between the product and a speaker should always be done with an all ready-made lead.
Never attempt to touch any exposed speaker wiring whilst the amplifier is operating without
disconnecting the Speakon connector first from the product.
!
CAUTION
RISK OF ELECTRIC SHOCK
D
O
N
O
T
O
PEN
W
ARNING:
RISK OF HAZARDOUS ENERGY
SEE OPERATING MANUAL
CLASS 2 PERMITTED
!
IMP
O
RTANT
!
CAUTION
!
WARNING
V
OLTAGE

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1.2 Important safety instructions
1. Read this manual
2. Heed all safety warnings
3. Follow all instructions
4. The user should never incorporate equipment or accessories not approved by L-ACOUSTICS
5. Environments
Use the product only in E1, E2, E3, or E4 environments according to EN55103-2 standard.
6. Radio interference
A sample of this product has been tested and complies with the limits for the EMC (European Electro
Magnetic Compatibility) directive. These limits are designed to provide reasonable protection against
harmful interference from electrical equipment. However, there is no guarantee that interference will
not occur in a particular installation.
7. Power cord caution
Do not use the product if the power cord is broken or frayed.
Protect the power cord from being walked upon or pinched - particularly at the plugs and the point
where the power cord exits from the apparatus.
8. Mains supply
Connect the product only to AC power outlets rated 120 / 230 V, 50 - 60 Hz.
A specific 100 V, 50 - 60 Hz version exists for Japan.
9. Grounding
The product may only be connected to mains power supplies tied to ground.
Always operate the product with the chassis ground wire connected to the electrical safety earth of
the mains supply outlet. Do not defeat the safety purpose of the grounding-type plug. A grounding-
type plug has two pins and a third grounding prong. The third prong is a safety feature. If the provided
plug does not fit into the local outlet, consult an electrician for replacement of the obsolete outlet.
10. Lightning storm
During lightning storms, disconnect the product from the mains power supply.
Switching the product off does not disconnect the product from the mains power supply. Therefore,
disconnecting can only be achieved by removing the plug from the mains outlet.
VOLTAGE
VOLTAGE
VOLTAGE
VOLTAGE
!
IMPORTANT
!
IMPORTANT

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11. Interconnections
When connecting the product to other equipment, turn off the power and unplug all of the equipment
from the supply source. Failure to do so may cause an electric shock and serious personal injury. Read
the user manual of the other equipment carefully and follow the instructions when making the
connections.
Do not connect a speaker output in parallel or series with any other amplifier’s output. Do not
connect the speaker outputs to any other voltage source, such as a battery, mains source, or power
supply, regardless of whether the product is turned on or off.
12. Over power risks
The product is very powerful and can be potentially dangerous to both loudspeakers and humans alike.
Even when using the product’s front panel attenuator to reduce the gain, it is still possible to reach full
output power if the input signal level is high enough.
13. Ventilation
Openings in the product’s cabinet are provided for ventilation to ensure reliable operation of the
product by protecting it from overheating. These openings must not be blocked or covered. This
product should be installed in accordance with the manufacturer instructions given in this manual.
14. Heat
Do not operate the product near any heat source, such as radiators or other devices.
15. Water and moisture
To prevent fire or shock hazard, do not expose the product to rain or moisture.
Do not use the product near water.
Do not operate the product while wet.
16. Interference with external objects and/or liquids
Never push objects of any kind into the product through openings as they may touch dangerous
voltage points or short out parts that could result in a fire or electric shock. Never spill liquid of any
kind on the product.
17. Cleaning
Unplug the product from the mains power supply before cleaning.
Do not use liquid or aerosol cleaners.
Clean only with dry cloth.
18. Mounting instructions
Do not place the product on an unstable cart, stand, tripod, bracket, or table. The product may fall,
causing damages or serious injuries. Any mounting of the product should follow the manufacturer’s
instructions, and should use the mounting accessories recommended by the manufacturer, as
described in this manual.
VOLTAGE
VOLTAGE
VOLTAGE
!
CAUTION
!
CAUTION
!
CAUTION
!
CAUTION
!
WARNING

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19. Causes that require immediate service
Refer all servicing to qualified service personnel. Servicing is required when the product has been
damaged in any way such as:
•Power supply cord or plug is damaged,
•Liquid has been spilled or an object has fallen into the product,
•The product has been exposed to rain or moisture,
•The product was dropped or the housing is damaged,
•The product does not operate normally.
20. Servicing and replacement parts
Do not attempt to service this product as removing covers may expose to dangerous voltage or other
hazards.
The use of unauthorized replacement parts may result in injury and/or damage through fire, electric
shock, or other electricity-related hazards.
All service and repair work must be carried out by an L-ACOUSTICS authorised dealer. When
replacement parts are required, ensure that the dealer/distributor only uses replacement parts
specified by the manufacturer.
21. Shipping
Use the original packaging for shipping the product, unless it is mounted in a rack with the front and
rear panels fixed to the rack, as described in this manual.
22. Manual
Keep this manual in a safe place during the lifetime of the product. This manual forms an integral part
of the product. Reselling of the product is only possible if the user manual is available. Any changes
made to the product have to be documented in writing and passed on to the buyer in the event of
resale.
VOLTAGE
!
CAUTION
!
IMPORTANT
!
CAUTION

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1.3 EC declaration of conformity
L-ACOUSTICS
13 rue Levacher Cintrat
Parc de la Fontaine de Jouvence
91462 Marcoussis Cedex
France
State that the following product:
Amplified Controller, LA4
Are in conformity with the provisions of:
EN60065 (Electrical safety)
EN55103-1 (Emission)
EN55103-2 (Immunity)
Applied rules and standards:
Electro-magnetic compatibility 89/336/EEC
Low voltage electrical equipment 73/23/EEC
Established at Marcoussis, France, the 06/21/2007
Christophe Pignon

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2CONTENTS
1SAFETY WARNINGS 1
1.1 Symbol Description ................................................................................................................................................. 1
1.1.1 Symbols employed in this manual ............................................................................................................ 1
1.1.2 Symbols indicated on the product ........................................................................................................... 1
1.2 Important safety instructions................................................................................................................................... 2
1.3 EC declaration of conformity .................................................................................................................................. 5
2CONTENTS 6
3INTRODUCTION 8
3.1 Welcome to L-ACOUSTICS ................................................................................................................................... 8
3.2 Unpacking................................................................................................................................................................ 8
4SYSTEM CONCEPT 9
4.1 Presentation............................................................................................................................................................. 9
4.2 System Configurations............................................................................................................................................. 9
5LA4 AMPLIFIED CONTROLLER 11
5.1 Front and rear panel.............................................................................................................................................. 11
5.2 Main features ......................................................................................................................................................... 12
5.2.1 Simplified Block diagram........................................................................................................................ 12
5.2.2 DSP Architecture................................................................................................................................... 12
5.2.3 A/D Converters ..................................................................................................................................... 13
5.2.4 Amplifier section .................................................................................................................................... 13
5.2.5 User interface ........................................................................................................................................ 14
5.2.6 L-NET Remote Control Network ......................................................................................................... 14
5.2.7 Digital Audio Network........................................................................................................................... 14
5.2.8 LA NETWORK MANAGER PC Software.............................................................................................. 14
6INSTALLATION 15
6.1 Mounting................................................................................................................................................................ 15
6.2 Cooling .................................................................................................................................................................. 16
6.3 Operating voltage.................................................................................................................................................. 16
6.4 Connecting to AC mains........................................................................................................................................ 16
6.5 On/Off Switch........................................................................................................................................................ 17
6.6 Wiring .................................................................................................................................................................... 18
6.6.1 XLR input connectors............................................................................................................................ 18
6.6.2 SPEAKON output connectors ............................................................................................................... 19
6.6.3 L-NET Wiring......................................................................................................................................... 20
6.7 Power consumption .............................................................................................................................................. 20
6.8 Heat power calculation.......................................................................................................................................... 20
7OPERATION 21
7.1 Quick access.......................................................................................................................................................... 21
7.1.1 Output channel Mute control ................................................................................................................ 21
7.1.2 Input & Output Gain control.................................................................................................................. 22
7.1.3 Front panel Lock / Unlock control......................................................................................................... 22
7.2 Main Screen ........................................................................................................................................................... 22
7.3 User interface menu.............................................................................................................................................. 24
7.3.1 Introduction ........................................................................................................................................... 24
7.3.2 LOAD PRESET (user: 1 to 10, manufacturer: 11 to 99)........................................................................ 25
7.3.3 STORE PRESET (User memories 1 to 10)............................................................................................. 26
7.3.4 DELETE PRESET (User memories 1 to 10)...........................................................................................27
7.3.5 PRESET PARAMETERS.......................................................................................................................... 28
7.3.6 CLEAR GROUP PARAMETERS............................................................................................................. 29
7.3.7 OPTIONS .............................................................................................................................................. 30

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7.4 On screen messages.............................................................................................................................................. 33
7.4.1 Start-up sequence .................................................................................................................................. 33
7.4.2 Warning messages.................................................................................................................................. 33
7.5 LED display............................................................................................................................................................ 34
7.5.1 Bargraph display..................................................................................................................................... 34
7.5.2 L-NET LED............................................................................................................................................ 34
7.5.3 Routing and input signal display.............................................................................................................. 35
7.6 Amplified controller protection systems ............................................................................................................... 36
7.6.1 Thermal Protection................................................................................................................................ 36
7.6.2 DC Protection........................................................................................................................................ 36
7.6.3 Mains supply Under & Over-voltage Detection.....................................................................................36
7.6.4 Mains supply Failure Detection.............................................................................................................. 36
7.6.5 Peak Over-Current Protection.............................................................................................................. 36
7.6.6 Mean Over-Current Protection - Fuse Protection................................................................................ 36
7.6.7 DSP & Operating system Error.............................................................................................................. 36
7.7 L-Drive – Transducer protection system .............................................................................................................. 37
8CARE AND MAINTENANCE 38
8.1 Maintenance information....................................................................................................................................... 38
8.2 Filter cleaning......................................................................................................................................................... 38
8.3 Troubleshooting .................................................................................................................................................... 39
8.3.1 No power, no sound, or sound is too low............................................................................................. 40
8.3.2 Bad sound .............................................................................................................................................. 41
8.3.3 Overheating ........................................................................................................................................... 41
9SPECIFICATIONS 42
10 APPENDIX 43
10.1 LA4 factory preset library (version 1.1)................................................................................................................. 43

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3INTRODUCTION
3.1 Welcome to L-ACOUSTICS
Thank you for purchasing the L-ACOUSTICS®LA4 Amplified Controller.
This manual contains important information on installing and operating the product correctly and safely. Read this
manual carefully in order to familiarize yourself with these procedures.
As part of a continuous evolution of techniques and standards, L-ACOUSTICS reserves the right to change the
specifications of the product and the content of this manual without prior notice. Please check the L-ACOUSTICS web
site @ www.l-acoustics.com on a regular basis for latest update.
If the product requires repair or if information upon warranty is needed, please contact an approved L-ACOUSTICS
distributor. In order to obtain the address of the nearest distributor go to the internet site @ www.l-acoustics.com.
3.2 Unpacking
Carefully open the shipping carton and check the product for any noticeable damage. Each L-ACOUSTICS product is
tested and inspected before leaving the factory and should arrive in perfect condition.
If found to be damaged, notify the shipping company or the distributor immediately. Only the consignee may institute a
claim with the carrier for damage incurred during shipping. Be sure to save the carton and packing materials for the
carrier's inspection.
Figure 1: Unpacking of the LA4 amplified controller

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4SYSTEM CONCEPT
4.1 Presentation
The L-ACOUSTICS®LA4 Amplified Controller is at the heart of the L-ACOUSTICS integrated system approach. It
offers cutting edge loudspeaker Amplification, DSP, Network Control, and comprehensive System Protection in a single
ergonomic package. The performance level delivered by the LA4 allows for full optimization of all L-ACOUSTICS
speaker resources and deliver outstanding audio quality combined with the best possible transducer protection.
All L-ACOUSTICS loudspeaker systems will now benefit from the advanced and exclusive properties of the LA4 and
LA8 control platforms. As a result of the integrated approach all L-ACOUSTICS loudspeaker systems will be enhanced
by the superior performance of high end electronic platforms, allowing for perfect power matching combinations across
the entire product range.
Packaged in a compact 2U lightweight format chassis, the LA4 platform has the following characteristics:
•A 4 channel high efficiency amplifier section fed by two inputs that can deliver up to 4 x 1000 Watts
into 4 ohms yielding perfect power matching for a selected range of L-ACOUSTICS speakers.
•A DSP section featuring advanced filter algorithms (IIR and IFR) and an exclusive L-DRIVE protection
system for the transducers allowing for optimum system performance.
•A complete on board preset library stored in 99 memory locations to cover all principal
L-ACOUSTICS loudspeaker system configurations for a selected range of L-ACOUSTICS speakers.
•An intuitive and ergonomic user interface plus display for all configuration settings and status
information all fully accessible from the front panel.
•Two I/O Ethernet ports for networking up to 253 units in multiple network topologies via the
proprietary L-NET network.
•A complementary PC-based LA NETWORK MANAGER software (Windows®compatible) with
remote network monitoring and control of the LA4 units.
•4 NEUTRIK® NL4FC Speakon connector for loudspeaker outputs.
•A rear-panel plug-in card slot also allowing the LA4 to be ready for multi-channel digital audio
networking implementation (this option will be available as a future development).
4.2 System Configurations
Driving four amplifier output channels through a DSP offers a wide range of options when it comes to system
configuration possibilities. The LA4 and LA8 onboard DSP preset libraries allow the Sound Engineer a high degree of
flexibility through the use of 6 system template configurations, as follow:
•4 Way active mono system driven by a single input
•4 Channel mono subwoofer system driven by a single input
•2 Way active stereo system for the active speaker range
•2 Channel stereo system for the passive speaker range
•Hybrid mono system
•Hybrid stereo system
Please refer to annex 10.1 for a complete preset library description of the LA4.

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The LA4 on board factory preset library covers L-ACOUSTICS loudspeaker systems that require up to 800 Watts into
8 ohms or 1000 Watts into 4 ohms in twin parallel transducer configurations. The products supported by the LA4 are
the following:
•KIVA & KILO, ARCS
•115XT HiQ, 12XT, 8XT
•SB118
•MTD and XT older series are also supported
Figure 2: LA4 amplified controller & supported products
KIV
A
12XT
LA4
LA NETWORK MANAGER
8XT
115XT HiQ
ARCS
SB118
KILO

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5LA4 AMPLIFIED CONTROLLER
5.1 Front and rear panel
Figure 3: LA4 amplified controller front & rear panel
1 On/Off Switch
2 Anti-Dust Cover
3 Input selection + Menu keys
4 Output selection keys
5 LED load
LED Signal presence
LED clip and level Bargraph
6 LED Control L-NET Network
7 LCD Screen
8 Nav/Edit Encoder wheel
9 XLR Send Input Link connector
10 XLR Input connector
11 RJ45 L-NET network socket
12 Digital Audio Network socket
(available as a future development)
13 SPEAKON output connectors
14 Fan Grill
15 AC power cord

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5.2 Main features
5.2.1 Simplified Block diagram
The LA4 combines in a 2U lightweight chassis the resources of a 2 IN / 4 OUT DSP engine driving four channels of
amplification, a flash memory for preset storage and management, a front panel user interface, a Fast Ethernet device
for network remote control, high performance A/D-D/A converters for audio signals, and an optional digital audio card
(this option will be available as a future development).
The administration of the LA4’s resources is performed by an embedded Operating System (Linux) while the auto-
sensing SMPS (Switched Mode Power Supplies) of the LA4 allows for weight and size reduction.
Figure 4: LA4’s simplified block diagram
5.2.2 DSP Architecture
The new proprietary algorithms are allowing optimum performance and protection of each individual transducer of the
L-Acoustics system in use for an even more natural, transparent and realistic sound experience.
•The engine is a SHARC 32 bit floating point DSP at 96 kHz sampling rate that offers an enhanced dynamic
range by not generating calculation clips like other fixed point DSPs.
•A specialised engineering approach combining IIR and FIR filters generates a perfect linearization of phase
curves and therefore a significant improvement of the system impulse response.
•The 2 x 4 matrix architecture offers flexibility and allows for adapted system configuration.
•The L-DRIVE transducer protection system offers ultimate protection by monitoring both excursion and
temperature of the transducer (for more information about the L-Drive see section 7.7).
•With 89 factory presets and 10 user memory locations, the engineer is offered fingertip access to all the usual
L-ACOUSTICS speaker system configurations (please refer to appendix 10.1 for a complete preset library
description of the LA4).

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Figure 5: DSP Architecture
5.2.3 A/D Converters
The LA4 amplified controller is fitted with two cascaded 24 bit A/D converters with a sampling rate of 96kHz allowing a
ground-breaking encoding dynamic of 130 dB.
5.2.4 Amplifier section
The amplifier section of the LA4 uses a Class H technology supporting the wide dynamic range encountered in live
audio productions. The 4 amplifier channels can deliver up to 4 x 1000 Watts into 4 ohms yielding perfect power
matching for a selected range of L-ACOUSTICS speakers.
The auto-sensing SMPS (Switched Mode Power Supply) offers better stability by associating two symmetrical power
supplies. The power supply architecture allows an optimized distribution of the power resources with respect to each
amplifier output channel requirements.

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5.2.5 User interface
The front panel user interface features quick access functions for the 2 inputs and 4 outputs. The encoder wheel gives
instant access to the user menus and the LCD display offers real time visualization of the system parameters.
Navigation through the menu pages is fast and intuitive. Beside the standard on board factory preset library the
engineer can design and store his own settings (initialised from a standard preset template) in one of the 10 available
user locations (see part 7).
5.2.6 L-NET Remote Control Network
The proprietary L-NET network uses a high speed data transfer of 100 Mbit/sec for real time monitoring and control of
each individual LA controller within a network of up to 253 units. Multiple network topologies such as daisy-chaining,
star, and hybrid, are quickly and easily configurable allowing for total flexibility in achieving the required system
architecture. The physical connection between the PC and the controllers is managed with CAT5e STP cable and the
I/O Ethernet sockets located on the rear panel of the controller require industry standard RJ45 connectors. The use of
a universal Ethernet switcher is recommended for specific network topologies.
Note: Please refer to the ‘‘LA NETWORK MANAGER’’ software manual for detailed operating instructions.
5.2.7 Digital Audio Network
A slot located on the rear panel is designed to accept an optional L-DGA card (digital audio network). The slot allows
for the provision of an additional digital input module consisting of a 64 audio channel bus plus one extra channel
dedicated to control and monitoring. The extremely low and predictable latency of this technology combined with
proven real world reliability delivers stable and predictable results in all sound reinforcement applications. The L-DGA
card also allows for cascading of several LA4 (and LA8) using the same type of cable as for the L-NET remote control
network. The signal routing on the digital audio bus into any LA controller can be operated from the LA NETWORK
MANAGER application.
This option will be available as a future development.
5.2.8 LA NETWORK MANAGER PC Software
L-ACOUSTICS®LA NETWORK MANAGER provides network control and monitoring of both LA4 (and LA8)
controllers from a PC Windows®-operating system. The multiple window display gives an overall visualization of the
network status, number and groups of controllers, and all the information related to the control and monitoring of the
networked units.
Access to all settings such as mute, gain, delay, and preset can be done via the remote software interface. An EQ
contour is also available allowing quick and easy tonal balance of the loudspeaker system.
LA NETWORK MANAGER also features system stand-by and initialization control in addition to comprehensive visual
monitoring of the audio signal paths and quick detection of any faults in the attached network.
Note: Please refer to the ‘‘LA NETWORK MANAGER’’ software manual for detailed operating instructions.
!
IMP
O
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6INSTALLATION
6.1 Mounting
The LA4 is two rack units high (2U) that can be mounted in an EIA-standard 19’’ rack (see Figure 6 for amplifier
dimensions).Four mount points are provided on the front panel of the amplifier for rack mounting. Use four screws and
washers when mounting the amplified controller to the front rack rails.
Figure 6: Controller dimensions
When transporting or for touring applications it is essential that LA4 controllers are rear supported
in addition to front panel mounting. Use the rear rack support brackets provided with the
controller as described in Figure 7.
Any mechanical damage to LA4 controllers used in portable applications without rear support will
not be covered by warranty.
Figure 7: Controller and rear rack support brackets
!
CAUTION

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6.2 Cooling
The amplified controller uses a forced air cooling system to maintain a low and even operating temperature. All fan
cooled L-ACOUSTICS amplified controllers have front to rear airflow. Therefore when stacking more than one unit in a
rack, mount units directly on top of each other or close any open space in the rack with blank panels.
If the controller is rack-mounted, do not block front or rear air vents with front or back panels or
doors. If this cannot be achieved a forced ventilation system has to be used.
If the controller is installed in an enclosed rack the open area at the back of the controller must be
at least 140 cm3per controller.
Make sure that the controller’s front filter system is clean and dust free (see section 8.2).
6.3 Operating voltage
Operating voltage range and frequency are indicated on the controller back panel.
Only connect the controller to an appropriate AC circuit and outlet.
If you are unsure of the output voltage of your AC mains please consult your local electrician.
The following table gives the Power Supply Data for the LA4 amplified controller:
Table 1: LA4 Power supply data
Voltage (V) Mains Frequency (Hz) Current (A) Power Consumption (W)
100 50 - 60 26 1600
120 / 230 50 - 60 22 / 12 1600
6.4 Connecting to AC mains
The amplified controller is supplied either with a European, US, or Japanese AC power connector depending on the
country of use. If the power plug is not appropriate, it can be cut off and wired to a suitable connector in the following
manner:
Table 2: Power cord wiring colour code
Country Live Neutral Earth
Europe Brown Blue Green / Yellow
USA Black White Green
Japan Black White Green
Changing the connector must be done by qualified personnel only.
The specific safety regulations of the country of use must be strictly applied.
The connector must be approved for the specific voltage and current rating given in Table 1.
The ground connection of the supplied AC power cord is a safety feature. Do not attempt to disable
it by using an adaptor, or by other methods.
Note: Warranty will not cover damages caused by a wiring error.
VOLTAGE
VOLTAGE
!
CAUTION

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6.5 On/Off Switch
When the controller is switched on (Figure 8), it will go thru a 20 seconds start-up procedure of internal tests as
described in section 7.4.1. When the LCD shows the main screen the controller is ready for use (see section 7.2).
When the amplified controller is switched Off, the LCD flashes the following message ‘‘POWER OFF’’ for several
seconds until complete shut down.
Note: If the power is lost while the amplifier is switched on, it will restart automatically once the power has been
restored and reboot to the exact same state then prior the power loss.
If the On/Off switch is On and nothing is shown on the LCD display while the L-Net LED is lit, the controller is in
Stand-by Mode, under the control of the LA NETWORK MANAGER application, and cannot be operated via the front
panel. In this particular case rebooting the unit by switching it off and on again will cancel the Stand-by Mode.
The On/Off switch does NOT disconnect the amplified controller from mains.
Figure 8: The On/Off switch
On Of
f
VOLTAGE

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6.6 Wiring
6.6.1 XLR input connectors
Two 3 pin male XLR input connectors are provided for channel A & B respectively as well as two 3 pin female XLR
input link connectors wired in parallel on channel A & B (see Figure 9).
XLR Input connectors are active balanced and wired according to IEC 268 as below:
Pin 1 ÖGround (Shield)
Pin 2 ÖHot (pos. signal)
Pin 3 ÖCold (neg. signal)
Figure 9: Input XLR connectors cabling
The input impedance is high enough (22 kΩ, balanced) to allow ‘‘daisy-chaining” or multiple parallel input connections.
To daisy chain amplified controllers use the male XLR connector (‘’Link’’) to feed the input signal to the next unit in the
signal chain.
The headroom of the input circuits is high enough to accept the maximum output level from virtually any line level signal
source (up to 22 dBu).
Note: Symmetrical (balanced) shielded cables are highly recommended as balanced signals are less sensitive to AC hum
and radio interference. Unbalanced lines may result in noise especially over long cable runs.