BL2074
A 4075 125W
A 4085 250W
6 Input Mixer Amplifiers
®
www.altronics.com.au
Congratulations on purchasing a
REDBACK
Phase 4
Public Address Mixer Amplifier.
Engineered and manufactured to high standards this
unit will provide you with many years of trouble
free use.
A 4075
125 Watt Mixer Amplifier
A 4085
250 Watt Mixer Amplifier
F
EATURES
:
• Latest design and technology
• Very low noise and distortion
• 70V, 100V and 4-16 Ohm outputs
• 240V AC or 24V DC operation
• Rack mountable
• Thermal overload protection
• Thermally cued forced fan cooling
Inputs and Outputs
Inputs 1-6 can be configured for balanced microphone or line
use as desired. 3 pin XLR
and dual RCA sockets are provided
for each of these inputs. Outputs are 600
Ω
/0dBm 3 pin
balanced XLR or dual RCA sockets for record/tape out.
Input Configuration
Inputs 1-6 include 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
(see below for priority details) and phantom power on/off.
Priority/VOX muting is not available on inputs 4-6.
Note, when the Priority/VOX muting function is selected (inputs
1-3) it will operate with the input set for either microphone or
line operation.
Speaker Connections
Speakers with total impedance of 4 to 16 ohms, or speakers fit-
ted with a 70V/100V line transformer may be connected. Always
ensure that the total load of the speakers does not exceed the
rated output of the amplifier ie either 4
Ω
minimum for the 4-16
Ω
terminals or 80
Ω
minimum at 100V for the A 4075 (125W) and
40
Ω
minimum at 100V for the A 4085 (250W). Otherwise either
the DC or mains fuse could blow or the fault led activate and the
amp will shut down. Always be careful to avoid short circuits
and connection to the wrong terminals.
Power Supply
Ensure power is switched off at the front panel of the amplifier.
Connect either mains power to the IEC socket with the supplied
power lead, or 24V DC to the screw terminals on the rear of the
amplifier. High currents may be drawn (8.5 amps for the A 4075
and 18 amps for the A 4085). Therefore when operating from a
24V DC power supply, confirm the capacity of the DC power
supply used.
Optional Modules
Alert, evacuation and chime tones are available with the
installation of the optional A 2073 tone generator.
Front Panel LED Display
There are six indicators on the front panel, they are ;
1) A ten point LED
VU
display to indicate output level.
2) A signal LED
to indicate any signal present at any of the
inputs (1 to 6).
3) Overtemperature LED
indicating if there is a fault such as the
amplifier overheating or a short circuit on the speakers.
4) Peak LED. See below for more details on peak limiting
5) Overload LED indicates when the wattage of connected
speakers exceeds the rated wattage of the amplifier.
6) Power on LED
indicates that there is power (24VDC or
mains) to the amplifier.
Operating Instructions
