Studio Technologies IFB Plus 2001 - Manual (Page 13)

Model 2 User Guide Issue 7, November 2001
Studio Technologies, Inc. Page 13
Precautions were taken to limit the Model
2’s bandwidth, minimizing the chance for
RF pickup problems.
Mounting
The Model 2 is intended for rack mount-
ing, requiring one 1.75-inch (4.5cm) rack
space. It weighs a bit over 10 pounds
(4.7kg), and operates on either 120 or
220/240V, 50/60Hz. The unit is secured to
the front mounting rails of an equipment
rack using two mounting screws per side.
In addition to the front mounting “ears,”
we encourage you to secure the Model 2
from the back. Provision has been made
for this to be easily accomplished. On
each side of the Model 2’s chassis are
two threaded fasteners intended to secure
user-fabricated mounting bars or brackets.
Use standard 8-32 screws to secure the
mounting brackets to the Model 2’s chas-
sis. To prevent damage to the Model 2’s
“guts,” limit the screw length so that the
threads extend into the chassis a maxi-
mum of ¼-inch. Refer to Figure 1, located
at the end of this guide, for a mechanical
drawing detailing the fastener locations.
This drawing will assist you in fabricating
the mounting brackets.
Program Inputs
The Model 2 allows four line-level program
audio sources to be connected. The input
circuitry is designed for a nominal input
level of +4dBu. A trim potentiometer is
associated with each input, giving a ±8dB
adjustment range. The 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 to setting the trim pots will give
better operational performance. It will
allow an operator, using the front-panel
program switches, to rapidly change pro-
gram inputs, while not giving large changes
in level to users listening to the IFB chan-
nel. It is anticipated that the trim pots will be
adjusted only upon initial installation or
during maintenance, and are not consid-
ered an operator function. Refer to the
Technical Notes section of this guide for
details on setting the trim pots.
Program audio connections are made via
four 3-pin female XLR-type connectors
located on the back panel. The program
input circuitry on the Model 2 is direct
coupled, electronically balanced with an
input impedance of 24k ohms. External
load resistors must be added if your facility
terminates all audio lines, e.g., with 600
ohms. Studio Technologies discourages
terminating audio lines—but if you have to,
you have to! Prepare the mating connec-
tors so 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 2 allows an auxiliary line-level
audio source to be connected for use with
the voice operated (VOX) interrupt function.
Identical to the program inputs, the auxil-
iary input circuitry is designed for a nominal
signal level of +4dBu. A trim pot is associ-
ated with the auxiliary input, giving a ±8dB
adjustment range. The pot is not intended
for precise calibration, but strictly to allow
the AUX input level to be adjusted for cor-
rect VOX operation. It is anticipated that
this pot will be adjusted only upon initial
installation or during maintenance, and is
not considered an operator function. Refer
to the Technical Notes section of this guide
for details on setting the trim pot.