Studio Technologies IFB Plus 2007 - Manual (Page 11)

Model 2 User Guide Issue 9, January 2006
Studio Technologies, Inc. Page 11
has been made for this to be easily ac-
complished. 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 se-
cure the mounting brackets to the Model 2’s
chassis. To prevent damage to the Model
2’s “guts,” limit the screw length so that the
threads extend into the chassis a maximum
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 +4 dBu. A trim potentiometer is associ-
ated with each input, giving a ±8 dB adjust-
ment 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 opera-
tional performance. It will allow an operator,
using the front-panel program switches, to
rapidly change program inputs, while not
giving large changes in level to users listen-
ing to the IFB channel. It is anticipated that
the trim pots will be adjusted only upon ini-
tial installation or during maintenance, and
are not considered 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 lo-
cated on the back panel. The program input
circuitry on the Model 2 is direct coupled,
electronically balanced with an input imped-
ance of 24 k ohms. Prepare the mating con-
nectors (male XLRs) so that pin 2 is positive
(+ or hot), pin 3 is negative (– or cold), and
pin 1 is shield. With unbalanced signals con-
nect 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 +4 dBu. A trim pot is associ-
ated with the auxiliary input, giving a ±8 dB
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 instal-
lation 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.
The auxiliary audio connection is made via
a 3-pin female XLR-type connector on the
back panel. The auxiliary audio input circuit-
ry is direct coupled, electronically balanced
with an input impedance of 24 k ohms.
Prepare the mating connector (male XLR)
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 posi-
tive, and pins 1 and 3 to shield.
The VOX interrupt function is quite special-
ized and may not be used regularly in your
facility. For maximum flexibility, it may be
best to terminate the auxiliary audio input to
a patch point in the audio patch bay. In this
way, a variety of audio sources can quickly
be selected as the VOX interrupt input
source. The VOX feature may sit unused
for months or years, but when you need it
there’s no substitute! The Model 2’s VOX