www.altronics.com.au
Operating Manual
Redback® Proudly Made In Australia
OVERVIEW
The Redback A 4264 is a 4 x 60 Watt power amplier for installations requiring four ampliers in a small rack space. The
amplier is ideally suited for use with multi zone audio systems using 100V line speaker systems only.
FEATURES
• 4 independent 60W ampliers
• Very Low noise and distortion
• 100V outputs
• 240V AC or 24V DC operation
• Output Peak Limited
• Thermal Overload protected
• Power Status Indicators
• Peak Limit Indicators
• Overload Indicators
• 2RU Rack Mountable (suits 19 inch racks)
POWER SUPPLY
The amplier operates on 230V AC or 24V DC primarily for battery backup operation. Ensure power is switched OFF at
the front panel before connecting either mains power to the IEC socket or 24V DC to the screw terminal input. As high
currents may be drawn when operating from a 24V DC supply conrm the capacity of the DC power supply used.
AUDIO CONNECTIONS
Audio input is via 3 pin balanced XLR sockets with input sensitivities of 300mV. Pinout details are printed on the rear of
the amplier. The amplier output level controls are rear mounted to prevent tampering or accidental adjustment.
User manual revision number: 1.1 25/11/2015
A 4264 4 x 60Watt Power Amplier
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Fig 1
A 4264 4 x 60 Watt Power Amplier
REAR PANEL CONNECTIONS
230V AC @ 50Hz
FUSE 7.5 A M205
CH4
100V
OUT
INPUT
24V DC
+
–
RISK OF ELECTRIC SHOCK
OPEN BY QUALIFIED
PERSONNEL ONLY
!
CAUTION
+
_
12
3
1 • Shield
2 • Hot
3 • Cold
LINE IN
CHANNEL 4
RESETTABLE
DC FUSE
Made in Australia by
Altronic Distributors Pty Ltd
www.altronics.com.au
CHANNEL 3
RESETTABLE
DC FUSE
CHANNEL 2
RESETTABLE
DC FUSE
CHANNEL 1
RESETTABLE
DC FUSE
+
_
CH3
100V
OUT
CH2
100V
OUT
+_+
_
CH1
100V
OUT
VOLUME
CHANNEL 1
LINE IN
VOLUME
CHANNEL 2
LINE IN
VOLUME
CHANNEL 3
LINE IN
VOLUME
CHANNEL 4
12
3
1 • Shield
2 • Hot
3 • Cold
12
3
1 • Shield
2 • Hot
3 • Cold
12
3
1 • Shield
2 • Hot
3 • Cold
0
2
4
6
8
10
0
2
4
6
8
10
0
2
4
6
8
10
0
2
4
6
8
10
2 1
3
2 1
3
2 1
3
2 1
3
2
3
4
5
6
7 8
9
10
11
12
13
14
15
16
17
18
1
Fig 1 shows the layout of the A 4264 rear panel.
1 240V AC power socket (Australian standard)
Connects to 240V AC mains power with the included IEC lead.
2 Channel 4 100V Out
This is a 60W output for driving speakers tted with 100V line transformers.
3 Channel 3 100V Out
This is a 60W output for driving speakers tted with 100V line transformers.
4 Channel 4 DC Fuse
This is a resettable fuse for channel 4. If the fuse is tripped, press the red button to reset.
5 Channel 3 DC Fuse
This is a resettable fuse for channel 3. If the fuse is tripped, press the red button to reset.
6 Channel 4 volume
Use this to adjust the output level of channel 4.
7 Channel 4 input
This is a balanced line input with a sensitivity of 300mV.
8 Channel 3 volume
Use this to adjust the output level of channel 3.
9 Channel 3 input
This is a balanced line input with a sensitivity of 300mV.
10 24V DC Battery Backup
This is a 24V DC input used primarily for backup power.
11 Channel 2 volume
Use this to adjust the output level of channel 2
12 Channel 2 input
This is a balanced line input with a sensitivity of 300mV.
13 Channel 1 volume
Use this to adjust the output level of channel 1.
14 Channel 1 input
This is a balanced line input with a sensitivity of 300mV.
15 Channel 2 DC Fuse
This is a resettable fuse for channel 2. If the fuse is tripped, press the red button to reset.
16 Channel 1 DC Fuse
This is a resettable fuse for channel 1. If the fuse is tripped, press the red button to reset.
17 Channel 2 100V Out
This is a 60W output for driving speakers tted with 100V line transformers.
18 Channel 1 100V Out
This is a 60W output for driving speakers tted with 100V line transformers.
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SPEAKER CONNECTIONS
Speakers fitted with 100V line transformers may be connected to the corresponding terminals on the rear of the amplifer.
Always ensure the total load of the fitted speakers does not exceed the rated output of the amplifier (ie 60 watts)
otherwise damage may result. When fitting speakers with line transformers the impedance of the load cannot be
measured using a standard multimeter. An impedance meter is required. Fig 2 lists the impedance at certain loads of
speakers fitted with 100V line transformers. So for a total load of 60 watts using 100V line transformer fitted speakers the
impedance of the speaker load should be 166Ω.
i
Wiring speakers in parallel for 70/100V line: Where several speakers are to
be used at one time, on one circuit, it becomes necessary to use speakers tted
with line-matching transformers. This is to overcome the effects of connecting
speakers in parallel and cable losses. The amplier generally has an output
voltage of 100 volts (70 volts is typically used in North America, however
operation is similar). In this conguration the total wattage load on the amplier
is derived from adding all the line transformer primary tap ratings together. For
example, 70 one watt speakers will have a total speaker load of 70 watts. Or
alternatively, it is conceivable to connect 100 one watt speakers to a 100 watt,
100 volt line amplier.
Measuring 70/100V Line Speaker Impedance: To measure amplier system
load, you must use an impedance meter in order to measure the ac resistance
of the connected speaker network. Impedance cannot be measured with a
standard multimeter, as this measures the dc resistance. Use the Altronics
Q 2001 or similar impedance meter.
About 70V & 100V Line Speaker Systems
Load 70V 100V
0.5W 9.4kΩ 20kΩ
0.66W 7.12kΩ 15kΩ
1W 4.7kΩ 10kΩ
1.25W 3.76kΩ 8kΩ
2W 2.35kΩ 5kΩ
2.5W 1.88kΩ 4kΩ
3W 1.56kΩ 3.3kΩ
5W 940Ω 2kΩ
7.5W 626Ω 1.3kΩ
10W 470Ω 1kΩ
15W 313Ω 666Ω
20W 235Ω 500Ω
30W 156Ω 333Ω
40W 117Ω 250Ω
60W 78Ω 166Ω
100W 47Ω 100Ω
125W 37Ω 80Ω
250W 19Ω 40Ω
500W 9.4Ω 20Ω
TROUBLE SHOOTING
If the REDBACK Phase 4 amplier fails to deliver the rated performance, check the following:
No Power, No Lights
Make sure amplier power switch is on. Make sure mains power switch is on at the wall. Check the mains and
DC fuse. Replace with only the correct type and rating. Over rated fuses will invalidate warranty.
Distorted Output
Check that the speaker type is correct for the output that you are using (ie. 4-16Ω, 70V or 100V line). Check for
any short circuits on the speaker line.
Very Low Output Volume
Make sure that the input is the correct level (check for shorted connectors). Check for any short circuits on the
speaker line.
Check if power LED’s on the front panel is lit to indicate there is signal. If it is not lit there is no signal present.
Continually Blows Fuses
Make sure that the speaker line is not shorted. Check speaker types, ratings and if on correct output.
Amplier Keeps on Cutting In & Out
Make sure that there is adequate ventilation around the amplier. Check the vent slots on the front,top and sides
are not covered or blocked and the fan on the rear is functioning correctly. Check also speaker types, ratings and
for any short circuits on the speaker line.
No Output From 24V DC
Make sure the 24V DC Out connector is wired correctly.
Fig 2
A 4264 4 x 60 Watt Power Amplier
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REDBACK is a registered trademark of Altronic Distributors Pty Ltd
Since 1976 Redback ampliers have been manufactured in Perth, Western Australia by Altronics. With over 35 years
experience in the commercial audio industry, we offer consultants, installers and end users reliable products of high build
quality with local product support. We believe there is signicant added value for customers when purchasing an
Australian made Redback amplier or PA product
Australian Made Status
All Redback house products made by Altronics will now be sporting the ofcial Australian Made logo. Since starting manufacturing of commercial audio equipment in the mid 70’s we have always taken pride in producing a quality local product.
The new adoption of the Australian Made logo will help us get the word out to local and export markets that our
products carry the ofcial compliance seal of the Australian Made campaign. We have always pushed our ‘local is better’
line in all of our marketing efforts, it’s always an added boost when you are backed up by a widely recognised and
respected icon.
Industry leading 10 year warranty.
There’s a reason we have the industry leading DECADE warranty. It’s because of a long tried and tested history of bulletproof reliability. We’ve heard PA contractors tell us they still see the original Redford amplier still in service in schools that’s over 37 years of operation - and still going strong!
Should a product become faulty please contact us to obtain a return authorisation number. Please ensure you have all the
relevant documentation on hand. We do not accept unauthorised returns. Proof of purchase is required so please retain
your invoice.
Distributed by Altronic Distributors Pty. Ltd.
Phone: 1300 780 999 Fax: 1300 790 999 Internet: www.altronics.com.au
A 4264 4 x 60 Watt Power Amplier
*Specications subject to change without notice
SPECIFICATIONS
Typical Specications per channel
Power Output: ............................60 watts RMS
Distortion: ...............................< 0.5%, @ 1kHz
Output line: ...............................................100V
Frequency Response: ............50Hz - 15kHz, -3dB
Sensitivity: ..............................................300mV
Signal to Noise Ratio: ..............................>90dB
OUTPUT CONNECTORS
Speakers: ....................................Screw terminals
INPUT CONNECTORS
Inputs: .....................................3 pin XLR balanced
24V DC power: .............................Screw terminals
240V AC power: ...................IEC power connector
CONTROLS
Line inputs:......................................................Volume
Power: ...................................................On/off switch
Indicators:...........................Power, Peak Limit,overload
Power Supply: ..............................240V AC or 24V DC
FUSE PROTECTION: ..........................7.5A AC , 5A DC
DIMENSIONS .............................≈483W x 410D x 88H
WEIGHT: ............................................................≈15kg
Colour:.................................................................Black
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