AUSTRALIAN MONITOR IS1200 User manual

Clever Features, Contractor Friendly
IS600
IS1200
Stereo Professional Audio Amplifiers
Installation
&
Operation Manual

2
Introduction
The Australian Monitor Installation Series IS600 & IS1200 are 2 RU stereo power
amplifiers. The IS600 delivers 300 watts per channel @ 4 ohms & the IS1200
delivers 600 watts per channel @ 4 ohms. Designed for permanent
installations where high quality audio reproduction is required on a small
budget, the IS series deliver the sound quality & features contractors require.
The IS series continues the Australian Monitor tradition of delivering an
amplifier packed with clever features at a contractor friendly price.

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Features
•Custom 2RU design.
•High efficiency toroidal mains transformer.
•Binding post and 4 pole speaker output connection.
•Stereo or Parallel operation.
•Balanced inputs and buffered attenuators.
•Signal Present indication.
•Output clip indication.
•Efficient front to back cooling.
•Twin speed axial fans.
•Thermal fault indication.
•Signal ground lift switch.
Protection Features
•Short circuit protection.
•Overload protection.
•Soft Start.
•Thermal protection.

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Contents
Page
1. Introduction 2
2. Controls, Connectors & Indicators 5
2.1 Front Panel 5
2.2 Rear Panel 7
3.Installation 9
4.Operation 11
5. Maintenance 14
6. Specifications 15
IMPORTANT!
Please read carefully.
This operation manual contains important information regarding safety precautions,
installation, performance, operation and maintenance of your IS-Series power amplifier. You
should familiarize yourself with the contents of this manual before operating your amplifier
The user should not attempt to service the amplifier. Only qualified and knowledgeable
personnel familiar with the internal workings of the amplifier should attempt any repair,
servicing or authorized modification to the amplifier. The amplifier does not contain any parts
which the user can service or re-use in this or any other product.
If you are in need of special assistance and the information you require is outside the scope
of this manual, please contact your nearest service agent or Australian Monitor direct:
THE TECHNICAL OFFICER
AUSTRALIAN MONITOR
C/- AUDIO TELEX COMMUNICATIONS PTY LTD
PRIVATE BAG 149,
SILVERWATER. N.S.W. 1811
AUSTRALIA.
Phone Fax
Australia [phone] (02) 9748-2537
International 61-2-9647-1411 61-2-9748-2537
Email [email protected]
Internet www.australianmonitor.com.au

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Front Panel
1 Attenuator
There are 2 level controls on all IS models. Each control is labelled for the
channel which it controls. 0dB indicates minimum attenuation.
2 Clip Indicator
This LED displays the status of the output stage and displays two levels of
operation.
These levels are:
Below clip level (unlit)
Clipping & above (red)
The LED will change to red once the output exceeds the clipping point of
the amplifier’s output stage. The threshold is referred to the amplifier supply
rails and alters with changes in the mains supply, changes in the load and
duty cycle fluctuations.
The attack and decay time (ballistics) of the status circuit are those of a
Peak Programme Meter (P.P.M.)
1 2 4
5 6
3

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NOTE: The amplifier is not damaged by running into clipping, but speakers
may be. To maximise the life of your speakers, try to keep clipping
infrequent.
3 Power Switch
This switches AC power to the amplifier. Press the switch to up for power on
and down for power off. At start-up (turn-on), the input to the amplifier is
muted for approximately two seconds.
4 Protect Indicator
This red LED will illuminate when thermal shutdown occurs.
5 Active Indicator
This LED will illuminate blue and indicates that the amplifier is ON and
receiving AC mains power.
6 Signal Indicator.
This LED displays the status of the output stage and varies in intensity in
proportion to the output signal level.

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Rear Panel
7 Balanced XLR Input
A female 3-pin XLR type connector is provided for each input:
Pin 1 = Signal Ground;
Pin 2 = Hot (non-inverting or in phase);
Pin 3 = Cold (inverting or reverse phase).
8 Balanced 6.35mm TRS Input
A female 6.35mm TRS connector is provided for each input.
Tip = Hot (non-inverting or in phase);
Ring = Cold (inverting or reverse phase);
Sleeve = Signal Ground.
9Input Sensitivity Switch
This switch allows the amplifiers input sensitivity to be correctly matched to
the equipment providing the amplifiers input signal. See the Operation
section (page 12) for more details.
10 Parallel/Stereo Switch
This switch determines whether channels A & B are receiving separate signals
(i.e. Operating in stereo mode) or whether the input signal from channel A
is being fed through to channel B.
78910 11
13
12
14 15

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Note: This is not Bridge mode.
11 Ground Lift Switch
When this switch is engaged, it disconnects signal ground from the input
connectors on both channels. It is intended to be used when “hum” is
caused by earth loops (due to different ground potentials between source
equipment and the amplifier) or stray magnetic field pick up on the input
ground/shield wiring. The amplifier should be turned off before engaging this
switch!
12 Speaker Output Connector
A 4 pole speaker connector is provided as an additional speaker output. This
standard of loudspeaker-to-amplifier connection allows access to both
channels of the amplifier via the one connector for bi-amp applications.
Channel-A is considered the dominant channel and has both channels wired
to the speaker connector. See the installation section of this manual for
detailed information on speaker connector wiring.
13 Mains Fuse
The IS600 is fitted with a 8 amp slow blow fuse & the IS1200 is fitted with a 15
amp slow blow fuse.
14 Mains Connection
Your amplifier is fitted with an internationally recognised IEC mains inlet
connector. Please ensure that the connecting mains lead for use with the IEC
connector is of an approved type and is of sufficient current carrying
capacity.
NOTE: Your unit must always be earthed!
15 Binding Post Outputs
Touch-proof binding posts (banana jacks) are provided for speaker output
termination with banana plugs or bare wire. The red post is used as positive
and the black post is used as negative.

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Installation
Power Requirements
Ensure that your mains voltage is the same as the rear panel mains voltage
marker (+/- 10%).
Mounting
Your amplifier is designed for standard 19” rack mounting and occupies 2 EIA
rack units.
Cooling
Each channel of your IS Series amplifier is cooled by an axial fan which draws
cool air from the front of the amplifier and expels heated air out the rear of
the amplifier. These amplifiers include two-speed fans which normally run at
half speed, switching to full speed when the internal heatsink temperature
exceeds 500C. An unrestricted airflow into and out of the amplifier must be
provided. Any restriction of the air flow will cause heat to build up within the
amplifier and possibly force the amplifier into its thermal shutdown mode. If

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the amplifiers are to be operated in an environment where the airflow is
restricted, such as sealed racks, cooling should be supplemented by extra
cooling fans to evacuate the heated air and aid the flow of cool air through
the amplifier.
Input Wiring
IMPORTANT
Do not directly connect pin 1 on the amplifier’s input XLR or TRS jack, to the
amplifier’s chassis, speaker ground or power ground!
NOTE: Input signal ground is not to be used as a safety ground (earth).
The input to your amplifier is a balanced 3-pin configuration and requires all
three pins to be connected. Only high quality twin-core shielded cable
should be used. When wiring for a balanced source, the connector going to
the input of your amplifier should be wired as follows:
Pin 1 = GROUND / SHIELD.
Pin 2 = HOT (In Phase - non inverting).
Pin 3 = COLD (Reverse Phase - inverting).
When wiring for an unbalanced source you must ensure that pin 3 is
connected to pin 1 (input ground), either by linking the pins in the input
connector or by the source equipment’s output wiring.
When wiring for an unbalanced source:
Pin 1 = GROUND/SHIELD
Pin 2 = HOT (in phase with the amplifier’s output),
Pin 3 = GROUND/SHIELD (joins to pin 1).
NOTE:
In-line XLR connectors often have a termination lug that connects directly to
the chassis of the connector. Do not link this lug to pin 1 at the amplifier’s
input as it will defeat the amplifier’s input grounding scheme. This lug is often
referred to as a ”drain” and is used to provide a termination to the chassis for
shielding purposes when a floating signal ground is required between the
source and destination, or when disconnecting the signal ground is required
to reduce earth loop noise, or noise induced into signal grounds from stray
magnetic fields.
Output Wiring
When wiring to your speakers, always use the largest gauge wire your
connector will accept. The longer the speaker lead, the greater the losses will
be, resulting in reduced power and less damping at the load. We
recommend using a heavy-duty, two core flex (four core flex if bi-amping) 10
to 12 gauge (2mm2to 2.5mm2or 50/0.25 or equivalent) as a minimum.