Studio Technologies 2A 2013 - Manual (Page 13)

Model 2A User Guide Issue 1, October 2013
Studio Technologies, Inc. Page 13
Typically interference from outside signals
will not be an issue. But precautions were
taken in the Model 2A’s circuit designs to
limit bandwidth, minimizing the chance that
EMI and RF pickup problems will occur.
Mounting
The Model 2A is intended for mounting in a
standard 19-inch rack, requiring one 1.75-
inch rack space (1U). The unit is secured
to the rack’s front mounting rails using two
mounting screws per side.
Program Inputs
The Model 2A allows four line-level pro-
gram audio sources to be connected. The
input circuitry is designed for compatibility
with signals that have a nominal level in
the range of –10 to +8 dBu, although it’s
expected that most connected signals will
have a nominal level of +4 dBu. A level ad-
justment trim potentiometer (“trim pot”) is
associated with each program input. These
trim pots are not intended for precise
calibration, but strictly to allow the program
input signals to be adjusted to the same
relative level. A little attention when setting
the trim pots will give optimal operational
performance. Correctly setting the trim
pots will allow an operator, using the front-
panel program select switches, to rapidly
change the selected program sources
while not presenting large changes in level
to users listening to the IFB outputs. It is
intended that the trim pots will be adjusted
only upon initial installation or during main-
tenance; they are not considered an op-
erator function. Refer to the Configuration
section of this guide for details on setting
the trim pots.
Connections to the program audio inputs
are made by way of the four 3-pin female
XLR connectors that are located on the
Model 2A’s back panel. They are labeled
A, B, C, and D, corresponding to label-
ing on the program selection switches on
the front panel. The input circuitry is direct
coupled, electronically balanced with an
input impedance of 24 k ohms. Prepare
cable-mounted 3-pin male XLR connectors
such that pin 2 is positive (+ or hot), pin 3
is negative (– or cold), and pin 1 is shield.
With unbalanced signals connect pin 2 to
positive and pins 1 and 3 to shield.
Auxiliary Audio Input
The Model 2A allows a line-level audio
source to be connected and used by the
voice operated (VOX) interrupt function.
The input circuitry is designed for com-
patibility with signals that have a nominal
level over a range of –10 to +8 dBu. A level
adjustment trim pot is associated with the
auxiliary input. The pot is not intended for
precise calibration, but strictly to allow the
AUX input level to be adjusted for correct
VOX operation. The trim pot is intended to
be adjusted only upon initial installation or
during maintenance and is not considered
an operator function. Refer to the Configu-
ration section of this guide for details on
adjusting the trim pot.
A connection to the auxiliary audio input
is made via a 3-pin female XLR connector
on the Model 2A’s back panel. It is labeled
AUX. The input circuitry is direct coupled,
electronically balanced with an input im-
pedance of 24 k ohms. Prepare the cable-
mounted 3-pin male XLR connector so that
pin 2 is positive (+ or hot), pin 3 is negative
(– or cold), and pin 1 is shield. With an un-
balanced signal connect pin 2 to positive,
and pins 1 and 3 to shield.