www.altronics.com.au
Redback® Proudly Made In Australia
12
Setup
Fig 2.1A
2.0 SETUP
2.1 Setup Guide
The A 4275 and A 4285 mixer amplifiers have a total of six inputs configurable as either Dual RCA (Line input) or 3 Pin
Male XLR (Mic inputs). Each Input includes an individual 4 way dip switch enabling selection of mic or line input operation,
adjustable line input sensitivity (100mV or 1V), Priority/VOX muting for inputs 1-3 and phantom power on/off. (Priority/
VOX muting is not available on inputs 4-6).
1. Prior to installation, set input configurations as desired via the DIP switches on the rear of unit. Section 2.3 shows the
various settings.
2. Plug in a low impedance microphone into the microphone input, or a music source (tape or Compact Disc or similar)
into the line input.
3. Turn all controls fully down and then switch the amplifier on.
4. Turn up the level control associated with the input that you are using to about half way. Talk into the microphone (or
play some music) and adjust the Master level control to achieve the required volume.
For the best sound performance turn the input level control to a high setting (say 3/4 ) and use the Master as the volume
control.
Use the other input level controls to set the required mixing ratios. Adjust the bass and treble controls to obtain the de-
sired sound. For best performance when using long lines between microphones/mixer and or amplifier use balanced lines.
These reduce noise or hum that may be induced into the cables. Note that a balanced line uses three wires (two signal
wires and one screened earth wire or shield) where an unbalanced cable uses only one signal wire and a screened earth.
Fig 2.1A shows illustrates a basic install with one microphone input on input 1 and five line level input sources connected
to inputs 2 -5. The DIP switches for each input must be set to suit the input type, the input sensitivity (for line level inputs),
whether the input is a priority input and whether phantom power is required. (see section 2.3 for DIP switch settings)
4 -16Ω
70V
100V
OUTPUTS
L
R
24V DC IN
Balanced Mic
+_
PTT
(short to
activate)
Power Fail
(Contacts
close on
power fail)
Send
Return
Tape Out
Preamp Out
Link To Charge
Backup battery
Input 1
Input 3
Input 2
Input 4
Input 5
Input 6
ALERT - EVAC MODULE
Output Levels
Voice Chime Alert
Over
& Evac
EV
COM
CAN
CH
AL
Triggers
L
R
+ –
Rem. Vol
Connect
to 1K
Ω
Pot
+
–
+
–
+
–
Line
24V DC
Switched
Output
DIP 5
Interface
DIP 4
DIP 1
DIP 2
DIP 3
Balanced Mic
Line
Balanced Mic
Line
Balanced Mic
Line
Balanced Mic
Line
Balanced Mic
Line
Balanced Line
L
R
L
R
L
R
L
R
L
R
2
1
3
2
1
3
2
1
3
2
1
3
2
1
3
2
1
3
2
1
3
1 2
3
4 5
6
7 8
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
230V AC @ 50Hz
w
w
w
.altr
onics
.com.au
RESETTABLE
DC FUSE
Made in Australia
by Altronic
Distributors
Pty Ltd
DIP 5
DIP 4
IMPORTANT NOTE
Ensure power is switched OFF when
adjusting DIP switches. New
settings will be effective when
power is switched back on.
DIP 3
SW
Item
On
Off
1
2
Input 6 Level 1V
100mV
3
Not USed
4 Input 5 Level 1V
100mV
Not USed
1
2
3
4
DIP 2
SW
Item
On
Off
Input 4 Level
1V 100mV
Not USed
Input 3 Level
1V 100mV
Input 3 Priority
On Off
*
DIP 1
SW
Item
On
Off
1
2
Input 2 Level
1V 100mV
3
Input 2 Priority
On Off
4 Input 1 Level
1V 100mV
Input 1 Priority
On Off
**
SW
Item
On Off
1
2
3
4
Not Used
Not Used
Not Used
Not Used
DIP 4
DIP 1
DIP 2
DIP 3
SW
Item
On Off
Switched 24VDC Out
On Off
Phantom Power Input 6
On Off
On Off
1
2
3
4
Phantom Power Input 5
On Off
5
Phantom Power Input 4
On Off
6
Phantom Power Input 3
On Off
7
Phantom Power Input 2
On Off
8
Phantom Power Input 1
Preamp Out
†
Post
Pre
†
Sets the Preamplifier output to
Pre or Post Master.
DIP 5
Priority or VOX muting is only
functional on inputs 1-3. When
VOX is enabled on input 1 it will
override all other inputs includ-
ing the Alert/Evac Module. VOX
enabled on input 2 will override
inputs 3-6. VOX enabled on input
3 will override inputs 4-6.
If the Alert/Evac module is fitted
it will override inputs 2-6.
*
Model 125W
5A
AC Fuse
250W
7.5A
AC Fuse Ratings
RISK OF ELECTRIC SHOCK
OPEN BY QUALIFIED
PERSONNEL ONLY
!
CAUTION
Speakers fitted with
100V line transformers.
CD
REDBACK
DVD 2
REDBACK
DVD 1
REDBACK
CD
REDBACK
TUNER
REDBACK
