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GR8A

 

U

SER 

G

UIDE

 

Welcome to the Allen & Heath GR8A 

The 

GR8A 

is one of a range of architectural sound products in the Allen & Heath Contractor Series.  It 

is an 8 channel audio power amplifier designed to work with multi-output zoning mixers such as the 
Allen & Heath 

GR05

GR1

DR128

 and 

DR66

.  Modern amplifier technology has enabled the 

GR8A 

to 

achieve multi-channel high power output in a relatively small case size. Much time and effort has been 
invested into making the 

GR8A

 an excellent performing, reliable and cost effective solution wherever 

multi-channel audio is required.  The 

GR8X

 transformer rack option is available from Allen & Heath to 

enable the amplifier to drive 70V or 100V loudspeaker systems.  

This user guide presents a quick reference to the function and application of the 

GR8A

.  We 

recommend that you read this guide fully before starting. Whilst we believe the information presented to 
be reliable, we do not assume responsibility for inaccuracies. We also reserve the right to make 
changes in the interest of further product development. 

 

Main Features 

 

8 Independent audio power amplifiers in a 2U chassis with removable rack ears 

 

60W per channel into 4 ohms, 40W into 8 ohms 

 

Outputs bridgeable for 120W into 8 ohms 

 

Balanced XLR inputs with common mono/stereo source switching in groups of four 

 

Speaker outputs on Phoenix type removable screw terminal connectors 

 

3 Colour input signal metering 

 

Selectable output monitoring on headphones or local speaker 

 

Full output protection and 3 speed fan cooled temperature management system 

 

Battery power backup facility 

 

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 personnel.

 

We are able to offer further product support through our world-wide network of approved dealers and 
service agents.  You can also access our Web site on the internet for information on our product range, 
assistance with your technical queries or simply to chat about audio matters. To help us provide the 
most efficient service please keep a record of the serial number, date and place of purchase to be 
quoted in any communication regarding this product. 

 

General Precautions 

Your 

GR8A 

is ruggedly constructed to give many years of reliable operation.  However, you will extend 

the life of the amplifier and preserve its cosmetics by applying these simple common sense 
precautions: 

Avoid storing or using the amplifier in conditions of excessive heat or cold, or in positions where it is 
likely to be subject to vibration, dust, smoke, dirt or moisture.  Do not use any liquids to clean the 
control surface of the unit.  Use a soft dry brush or dry lint-free cloth.  Check the air intake dust filter 
regularly and vacuum from the outside to remove dust build up as necessary.  Avoid using the amplifier 
close to strong sources of electromagnetic radiation such as video monitors, mains and high power 
electric cabling. 

Do not remove the service cover.  There are no user serviceable parts inside.  All the controls and 
installation settings for the unit are accessible from the outside. 

 

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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