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Redback® A 4395A 500W Mixer Amplier
www.redbackaudio.com.auRedback® Proudly Made In Australia6
SPEAKER CONNECTIONS
Speakers with a total impedance or 4-16Ω may be connected to the terminals marked 4-16Ω on the rear of the amplifier.
Speakers fitted with line transformers (either 70V or 100V) 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 500 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 3 lists the impedance at certain
loads of speakers fitted with 70V and 100V line transformers. So for a total load of 500 watts using 100V line transformer
fitted speakers, the impedance of the speaker load should be 20Ω.
Fig 3
AUDIO CONNECTIONS
The amplier has two audio inputs, with input 1 either a balanced XLR input or dual RCA line input which is internally
mixed to create a mono signal. Input 2 is a dual RCA which is internally mixed to create a mono signal. Both inputs have
adjustable input sensitivities of 100mV or 1V set by the DIP switches on the rear of the unit.
A music input on the front of the amplier is also provided for connection of portable devices. This input when
connected, over-rides the rear input 2 audio source and is adjusted via the volume 2 level control.
A VOX function is also included which when enabled will allow input 1 to mute input 2.
Fig 4 shows a typical install where the A 4395A has a balanced microphone connected to input 1 and a Line level source
connected to input 2. If DIP switch 2 is set to “ON”, the microphone will VOX mute the CD player connected to input 2.
Fig 4
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.
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
Redback Q 2004
Speakers fitted with
100V line transformers.
4 -16Ω
70V
230V AC @ 50Hz
(Fuse 10A M205)
100V
12
3
1 • Shield
2 • Hot
3 • Cold
Input 1
Made in Australia by
Altronic Distributors Pty Ltd
www.altronics.com.au
INPUT
24V DC
+
–
RISK OF ELECTRIC SHOCK
OPEN BY QUALIFIED
PERSONNEL ONLY
!
CAUTION
OUTPUTS
+
–
+
–
+
–
+
_
24V DC
OUT
(1A Max)
LINK TO
CHARGE
BACKUP
BATTERY
RESETTABLE
FUSE 20 AMP
RESETTABLE
FUSE 20 AMP
Input 2
Balanced Mic
Line
L
L R
R
Line
DIP Switches
1 2 3 4
DIP Switch Settings
SW Item On Off
1
2
Input 1 Sensitivity
1V
3
VOX Enable
4
0.1V
Phantom Power Mic
Input 2 Sensitivity 1V 0.1V
On Off
On Off
Balanced
Mic Wiring
1 2 3 4
2 1
3
CD
REDBACK