30W Public
Address Amplifier
®
www.altronics.com.au
Proudly Assembled in Australia
Operating Instructions
A 4020A: 30W Desk Mount Amplifier
Distributed by Altronic Distributors Pty. Ltd. Perth. Western Australia.
Phone: 1300 780 999 Fax: 1300 790 999
Internet: www.altronics.com.au
Features
• 1 balanced microphone input
• 2 auxiliary inputs
• Bass and treble controls (on both microphone and
auxiliary inputs).
• Full 30W RMS output (100V).
• Protection against over-voltage, over current, thermal
run-away and short circuit load.
• Internationally accepted IEC mains socket (240V AC
operation only).
• Stereo RCA sockets for all auxiliary inputs (configured to
mono internally allowing standard stereo equipment to
be directly connected).
• Ten year warranty.
Connecting Up the Unit
Microphone One
Microphone inputs are connected via balanced XLR 3 pin
socket. For connection to the 3 pin XLR sockets refer to
Fig 1.
Auxiliary Inputs
Both auxiliary inputs are connected via standard RCA
sockets.
Speaker Outputs
Screw terminals are provided for 100V outputs. Minimum
impedance for 100V loads is 333
Ω
(When only the 100V
output is used).
If more than 30W is used then the unit may shut down
due to overloading.
VOX Muting Adjustments
VOX can be selected ON or OFF on the board via the
internal jumper. This is factory set in the OFF position.
VOX sensitivity is adjusted via trimpot on rear of unit.
Once VOX muting is activated input 1 will override input 2.
Both mic 1 and aux 1 inputs will activate the vox muting.
Operation
Once all inputs and outputs are connected:
1
Turn bass and treble to midway point.
2
Turn all volume controls to zero.
3 Turn power switch on. Power indicator should
illuminate.
4
Turn on microphone or auxiliary input source and
adjust appropriate volume control to desired level.
The microphone and auxiliary for input 1 are mixed
together. Both the mic and auxiliary inputs can be run
together but note there is only the one volume control for
both of these.
