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GR8A

 

U

SER 

G

UIDE

 

 

REMOTE STANDBY

   9-pin D-type female connector can be wired to 

external switches to remotely mute individual channels. Any combination 
of channels can be muted at the same time.  Putting a channel into 
standby mutes its output driver stage.  To mute a channel simply switch its 
connector pin to the common (+15V) pin.  Do not connect the common pin 
to any other equipment.  The front panel STANDBY indicator lights to warn 
that the channel is muted.  Use shielded cable for long cable runs. 

 

SIGNAL OUTPUTS

   These are the amplifier outputs that connect to the 

speaker terminals.  Each has a 2-way Phoenix type pluggable screw 
terminal connector.  Mating plugs are provided with the unit.  Use suitable 
gauge speaker wire, ensure reliable connections and observe the correct 
polarity according to the legend printed above the connector.  The 
following connections are typical. 

 

OUTPUT MODE switches

   The 

GR8A

 amplifier outputs can operate non-

bridged (independently) or be bridged in pairs according to the setting of 
the tamperproof underpanel mode switches.  Press the switch to select 
bridge mode using a pen or similar pointed object.  This configures two 
amplifiers to work together into one speaker.  Use bridge mode when you 
need a lot more amplifier power to drive a single speaker. 

BRIDGE MODE

  Use the odd numbered channel input and controls.  The 

even numbered input is disabled.  You should blank off the unused level 
controls using the plugs provided.  The front panel BRIDGE indicator lights 
to show the pair of channels is bridged.  If you are using remote standby 
switching for the bridged pair make sure you switch them both together. 

 

TRANSFORMER OPTION

   The high quality 

GR8X

 transformer option is 

available separately from Allen & Heath to convert the amplifier outputs to 
drive 70V or 100V speaker lines.  Alternatively, any standard 70V or 100V 
line transformer of suitable power rating and quality to match the amplifier 
may be used. 

 

 

To avoid damage to the amplifier make sure you do not 

connect a combined speaker impedance of less than 4 ohms in 
single mode, or less than 8 ohms in bridge mode.

 

 

To avoid damage to the speakers do not drive the amplifier 

into clipping or feed it with a previously clipped signal.

 

 

Do not use bridge mode when using the amplifier with a 70V 

or 100V line transformer.

 

NORMAL                    70V or 100V TRANSFORMER OPTION                BRIDGED 

Содержание GR8A

Страница 1: ...8 Channel Amplifier GR8A USER GUIDE Publication AP4298 ...

Страница 2: ... of performance and reliability for which this equipment has been designed and manufactured read this User Guide before operating In the event of a failure notify and return the defective unit to ALLEN HEATH or its authorised agent as soon as possible for repair under warranty subject to the following conditions Conditions Of Warranty The equipment has been installed and operated in accordance wit...

Страница 3: ... remove this connection CONTENTS Warranty 2 Safety Warnings 3 Welcome to the Allen Heath GR8A 4 General Precautions 4 Specifications 5 Front Panel Controls 6 Rear Panel Controls and Connectors 7 Installation 9 Operation 10 Block Diagram 11 SAFETY WARNING Mains electricity is dangerous and can kill Mains voltage is present within the GR8A Do not remove the top cover There are no user serviceable pa...

Страница 4: ... Remote output standby control per channel Service And Technical Support Under normal operating conditions the GR8A does not require user maintenance or calibration apart from occasional vacuuming of the air intake filter should it become ingrained with dust To avoid damage to internal components by mishandling and or misconnection service work should be referred only to technically competent pers...

Страница 5: ... into 8 ohms Peak transient power Unbridged 130W into 4 ohms Bridged 250W into 8 ohms Slew rate 10V uS Frequency response 20Hz to 20kHz 0 0 5dB Total Harmonic Distortion 6W into 8 ohms 1kHz 0 03 Signal to noise ratio Relative to 60W into 4 ohms 100dB Stand by Separate control per channel Control Switch common 15V to channel pin Attenuation 80dB Inter channel Crosstalk relative to 60W into 4 ohms 1...

Страница 6: ...ontrol that adjusts its level from fully off to maximum sensitivity In bridged mode the odd numbered channel control sets the overall level and the even numbered control is not used Use the level controls to match the amplifiers to the connected source equipment set maximum volume allowed or adjust the balance between different outputs Blanking plugs are provided for situations where tamper proof ...

Страница 7: ...d and wired pin 2 hot Input sensitivity is 4dBu for rated power output Good quality 2 core screened signal cable should be used for these inputs to avoid signal degradation or interference pickup over long cable runs Use balanced connections where possible INPUT MODE switches Three tamperproof underpanel switches configure the inputs to allow different combinations of common input sourcing Use the...

Страница 8: ...o select bridge mode using a pen or similar pointed object This configures two amplifiers to work together into one speaker Use bridge mode when you need a lot more amplifier power to drive a single speaker BRIDGE MODE Use the odd numbered channel input and controls The even numbered input is disabled You should blank off the unused level controls using the plugs provided The front panel BRIDGE in...

Страница 9: ...nd screened cables for the inputs If you have problems with ground loops lift the screen connection at one end of the input cables or operate the source equipment ground lift switches Use adequately rated speaker wire for the outputs Input cables may be run together but outputs should be separated to avoid interaction between the amplifiers Route all input and output cables away from mains compute...

Страница 10: ...amplifier level controls to correct the signal matching These controls can also be used to preset the maximum volume allowed for each output or to balance the volume between different outputs Remove the knobs and fit the blanking plugs provided with the unit if you wish to lock the controls and make them tamperproof Metering A 3 colour signal meter indicator is provided for each channel to monitor...

Страница 11: ...GR8A USER GUIDE 11 BLOCK DIAGRAM ...

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