www.altronics.com.au
User manual revision number: 1.0 20/05/2015
Operating Manual
A 4906
Mic/Line/100V Input - Line +24V Switched Output
Redback® Proudly Made In Australia
Distributed by Altronic Distributors Pty. Ltd.
Phone: 1300 780 999 Fax: 1300 790 999 Internet: www.altronics.com.au
OVERVIEW
The A 4906 is a versatile unit which accepts either a line level signal, balanced microphone signal or 100V input signal.
The output signal is a line level signal suitable for feeding into an amplifier. Phantom power is available to the microphone
input, and a VOX circuit, with adjustable sensitivity is used to trigger output relays. The unit is powered from a 24V DC
source.
OPERATION
A signal is fed into any of the three inputs. Either a Balanced Mic Input with an input level of 3mV, a line level input with
an input level of 300mV or a 100V input directly from the output of a 100V PA amplifier. The three inputs are mixed inter-
nally and output to the Line Output with a level of 5V.
Any of the input signals will trigger the VOX circuit, which has an adjustable sensitivity. Once the VOX circuit has been
triggered, the VOX active LED will illuminate and the state of the relay outputs will change.
PHANTOM POWER
An internal jumper selects phantom power to the microphone input. This is 12V DC and is applied to the hot and cold
pins of the microphone input. The jumper is fitted as standard, ie Phantom power is “ON”. To turn the phantom power
“OFF” the jumper inside the unit will have to be removed. To do this, first remove all the screws from one side of the unit
and remove the panel. Then remove the four screws in the corners on the other side of the unit, and then slide the board
assembly out. The jumper position on the board is shown in Fig 1.
RELAY OUTPUTS
There are two sets of relay contacts available. The first set provide a Normally Closed (N/C) and a Normally Open (N/O) set
of contacts which are voltage free. These would be used when just a closing contact is required.
The second set provide a Normally Closed (N/C) and a Normally Open (N/O) set of contacts which have 24V DC present.
These would be used to operate an external 24V DC device. (Note the maximum current draw available at this output is
120mA).
FEATURES
• Mic, line or 100V input level.
• Line level output.
•Phantom power to Mic Input (12V DC).
• Controls for master volume and VOX sensitivity.
• VOX operated relay outputs.
• 24VDC switched output. (120mA Max).
• 24VDC operation via 2.1mm DC power jack.
• Dimensions 133W x 30H x 80D mm.
Fig 1
