www.altronics.com.au
Redback® Proudly Made In Australia
2
* Specifications subject to change without notice.
Distributed by Altronic Distributors Pty. Ltd. Perth. Western Australia. Phone: 1300 780 999 Fax: 1300 790 999
SPECIFICATIONS
Output Power: ...................................................250W RMS
Current Draw: .............................................17A at full load
................................................................360mA Quiescent
Freq. Response: .............................................40Hz - 13kHz
Distortion: ...............................................................< 0.6%
Signal to Noise Ratio:................................................. -91dB
Sensitivity: .......................................................600mV RMS
Fuse Rating and Type: .........................................20A Blade
Dimensions (mm): ...............................300W x 240D x 95H
TROUBLESHOOTING
Fuse blows:
Check speaker loads and replace fuse with 20
Amp blade fuse.
Fuse continually blows:
Disconnect load, apply power. If
fuse blows again, refer unit to authorised service centre.
Overload LED illuminates:
Check speaker types and
ratings to ensure the amplifier is not overloaded, and that
there are no shorts on the speaker line.
Temp LED illuminates:
In this condition check the unit for
adequate ventilation. Check also speaker types and ratings
to ensure the amplifier is not overloaded, and that there are
no shorts on the speaker line.
20A
OUTPUT TRANSFORMER
HEATSINK
FAN
DC FUSE
(20 Amp)
+ - 24V DC
IN
+ - 24V DC OUT
(1A M
AX)
+ -
SPEAKER
OUT (100V
)
+ GND -
INPUT
+ GND -
LOOP OUT
PROTECT LIMIT OVERLOAD TEMP FAULT POWER
LED INDICATORS
AUDIO INPUT
POWER INPUT
SPEAKER
OUTPUT
VOLUME
SIGNAL
SIGNAL PRESENT INDICATOR
LINK GND & -VE INPUTS FOR
AN UNBALANCED
INPUT
+ GND -
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 fitted
with line-matching transformers. This is to overcome the effects of connecting
speakers in parallel and cable losses. The amplifier generally has an output
voltage of 100 volts (70 volts is typically used in North America, however
operation is similar). In this configuration the total wattage load on the amplifier
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 amplifier.
Measuring 70/100V Line Speaker Impedance:
To measure amplifier 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
Fig 2
Fig 1
