Allen&Heath GL3000 User Manual

AUDIO MIXING CONSOLE

USER

GUIDE

PUBLICATION AP2366

LIMITED ONE YEAR WARRANTY

This product has been manufactured in the UK by ALLEN & HEATH and is warranted to
be free from defects in materials or workmanship for a period of one year from the date of
purchase by the original owner.

To ensure the high level of performance and reliability for which this equipment has been
designed and manufactured please read this User Guide before use.

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:

1. The equipment has been installed and operated in accordance with the instructions in the User Guide.

2. The equipment has not been subject to misuse either intended or accidental, neglect, or alteration
other than as described in the User Guide or Service Manual, or approved by ALLEN & HEATH.

3. Any necessary adjustment, alteration, or repair has been made by ALLEN & HEATH or its authorised
agent.

4. The defective unit is to be returned carriage prepaid to ALLEN & HEATH or its authorised agent with
proof of purchase.

5. Units to be returned should be packed to avoid transit damage.

These terms of warranty apply to UK sales. In other territories the terms may vary according to legal

requirements.

This product complies with the European Directives for
Electromagnetic Compatability 89/336/EEC & 92/31/EEC.

ALLEN & HEATH AGENT:

U.K. FACTORY:

ALLEN & HEATH.
Kernick Industrial Estate,
Penryn.
Cornwall. TR10 9LU.

copyright © 1995 ALLEN & HEATH. All rights reserved Publication ............. AP2366 Issue 1

INTRODUCTION

The GL3000 continues ALLEN & HEATH’s commitment to provide high quality audio mixing consoles
engineered to meet the exacting requirements of today’s audio business. It brings you the latest in high
performance technology and offers the reassurance of over two decades of console manufacture and
customer support.

This user guide presents a quick reference to the function, application and installation of the GL3000. For
further information on the basic principles of audio system engineering please refer to one of the specialist
publications available from bookshops and audio equipment dealers.

Whilst we believe the information in this guide 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.

SERVICE AND TECHNICAL SUPPORT

Under normal conditions the GL3000 does not require user maintenance or internal calibration. Any service
work required should be carried out by qualified service personnel only.

We are able to offer further product support through our worldwide network of approved dealers and
service agents. To help us provide the most efficient service please keep a record of the console serial
number, and date and place of purchase to be quoted in any communication regarding this product.

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Mains electricity is dangerous and can kill. Mains voltage is present within the
power supply unit provided with the console. Do not remove the power unit cover with
mains connected. The correct mains voltage setting is indicated on the rear of the
power unit. Check your mains wiring and earthing before switching on.

SAFETY WARNING !

DO NOT REMOVE THE MAINS EARTH CONNECTION!

The console chassis is connected to mains earth to ensure your safety. Audio

0V connects to the console chassis internally. Should problems be encountered with
ground loops operate the audio ground lift switches on connected equipment
accordingly or disconnect the cable screens at one end. Refer to the section on
'EARTHING' later in this User Guide.

PRECAUTIONS.

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z AC POWER: Check the power unit for correct AC mains voltage setting before switching on.

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Allow adequate space around the unit for ventilation.

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z CONNECTIONS: Use audio connectors and cables only for their intended purpose. Do not

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connect any source of AC or DC power to the console audio connectors. Do not
connect the output of power amplifiers directly to the console.

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z CLEANING: Avoid the use of chemicals, abrasives and solvents. The control panel is best

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cleaned with a soft brush and lint-free cloth. To remove stubborn marks (such
as chinagraph pencil) isopropyl alcohol may be used.

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z LUBRICATION: The faders, switches and potentiometers are lubricated for life. The use of

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electrical lubricants on these parts is not recommended.

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z DIRT, DUST, SMOKE and MOISTURE: Prevent damage to the moving parts, such as faders

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and potentiometers, and cosmetics by avoiding drinks spill age, tobacco ash and
smoke, and exposure to rain and condensation. Protect from excessive dirt, dust,
heat and vibration.

GL3000 USER G UIDE ISS.1

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INSTALLING THE POWER SUPPLY UNIT

Refer to the SAFETY WARNING on the first page of this User Guide.

Power supply type RPS9 is provided with the GL3000 to convert AC mains voltage to the regulated
positive and negative DC voltages required to power the console. It also supplies the +48V phantom power
voltage for use with certain microphones.

The RPS9 may be operated free standing or 19" rack mounted (2U height) up to 2 metres away from the
console. As with any power supply unit it is recommended that it is positioned slightly away from the console
or other signal processing equipment containing sensitive low level audio signals to avoid any possible hum
pickup. It connects to the console by means of a 2.5 metre DC power cable fitted with a 5 pin locking XLR
plug. Mains input to the RPS9 is via a standard 3 pin IEC mains connector with integral AC mains fuse.
A mains cable with moulded plug suitable for the local supply is provided.

Check that the voltage indicated in the fuseholder window is

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the same as the mains supply in your area.

AC mains supply = 100 to 110 V.AC 100 T 3.15A 20mm fuse

AC mains supply = 110 to 125 V.AC 120 T 3.15A 20mm fuse

AC mains supply = 210 to 230 V.AC 230 T 1A 20mm fuse

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AC mains supply = 235 to 260 V.AC 240 T 1A 20mm fuse

To avoid the risk of fire replace the fuse only with the correct
type and value as specified on the unit.

It is normal for the power unit to dissipate heat. Ensure adequate
ventilation around the unit. Do not cover the unit or position it on

soft furnishings during operation. Do not position other equipment
known to generate significant amounts of heat below the unit. It is
recommended that rack units containing high power amplifiers and
other heat dissipating equipment are fitted with cooling fans.

Always switch the power unit off before connecting or
disconnecting the console power cable.

This unit contains no user serviceable parts. Do not remove
the cover. Refer servicing to qualified service personnel only.

Note: The RPS9 is fitted with a rear panel ground lift switch. This is for use when the unit powers certain
other Allen & Heath equipment. This switch is not operative on the GL3000 range. Refer to the section
on 'EARTHING THE AUDIO SYSTEM'.

The RPS9 power supply unit conforms to safety standard

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BS EN 60065

GL3000 USER G UIDE ISS.1

EARTHING THE AUDIO SYSTEM

The console chassis is connected to mains earth via the DC power cable. Audio 0V is connected to the
chassis and hence mains earth internally. In this way all signal returns and connector shields are connected
to mains earth at the console.

To ensure operator safety do not remove the earth connection

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For best performance it is important that the earth system is solid, clean and noise-free. To prevent mains
born and external interference pickup from lighting equipment, motors and other mains powered equipment
it is recommended that a separate 'clean' mains distribution outlet is used for the audio system.

All signal cables should have their screens connected to earth at the connector. If earth (ground) loop
problems result in audible hum or buzz then disconnect the cable screen connection at one end, usually the
destination end. This may be done within the cable plug or by operating the 'ground lift' switch if available
on the connected equipment. Many DI boxes and power amplifiers include this facility.

from the power supply mains plug.

PLUGGING UP THE CABLES

Where possible use balanced connections to prevent noise and interference pickup especially on long
microphone cable runs. Avoid running audio cables next to mains, computer or lighting cables, or near
thyristor dimmer units, power supplies etc. The use of low impedance sources such as good quality
microphones of 200 ohms or less significantly reduces interference pickup. Many problems can be avoided
by taking time to check that all cables are correctly wired (in-phase) with professional quality cable and
carefully soldered joints. The following wiring convention is used:

XLR pin 1 = 0V earth shield 1/4" jack tip = hot / signal / left / send

pin 2 = hot (in phase signal) ring = cold / 0V / right / return

pin 3 = cold (out of phase signal) sleeve = 0V earth shield

To connect an unbalanced source to a balanced console input, link the cold input (XLR pin 3 or jack ring)
to 0V earth (pin 1 or jack sleeve) at the console. To connect a balanced console output to an unbalanced
destination link the cold output to 0V earth at the console.

Switch off channel +48V when the inputs are connected to non-

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phantom powered, line or unbalanced sources.

ADJUSTING THE LEVELS

For best performance it is important that the connected source signals are matched to the "normal operating
level" of the console. Similarly the console outputs should be correctly matched to the operating levels of
the connected amplifiers and destination equipment. If too high the signal peaks will be clipped resulting
in a harsh distorted sound, and if too low the signal-to-noise ratio is reduced resulting in excessive
background hiss.

For best results operate the console with the meters averaging '0' or just below and allowing the loudest
passages and occassional peaks into the 'yellow'. Reduce the gain if the peak indicators flash (red). The
GL3000 produces a standard XLR output level of +4dBu for a meter reading of 0VU. It is advisable to
adjust the power amplifier input gain or fit an attenuator pad if normal console operation results in an output
level too high for the connected amplifier. Normal operation should result in fader levels around the '0' mark.

The GL3000 has an advanced PFL (pre-fade listen) / AFL (after-fader listen) and channel metering
system to let you listen to and check the level of signals at different points in the signal path without affecting
the main outputs. Use the channel PFL switches to set up the input GAIN controls to read an average
'0' (yellow LED). Signal activity is always shown on the channel meters regardless of fader position. The
green 'SIG' LED lights at -20dBu to indicate signal presence, the green '0' LED indicates normal level, and
the red 'PEAK' LED warns of potential overload 5dB before clipping.

GL3000 USER G UIDE ISS.1

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