Studio Technologies 42 - Manual (Page 4)

Model 42 User Guide Issue 1, July 2004
Studio Technologies, Inc. Page 5
Introduction
The Model 42 is designed to create
broadcast-standard IFB circuits from line-
level audio sources. The unit’s primary
application is to interface analog outputs
associated with digital matrix intercom
systems with broadcast IFB user devices.
The Model 42 provides four independent
IFB circuits. Each IFB circuit provides DC
power and two analog audio signals to
support the connected IFB user devices.
The Model 42’s audio quality is excellent;
little hiss, hum, or other artifacts are
present. Installation is very simple. Audio
input connections are made using a
25-pin D-subminiature connector. The
IFB output circuits interface using standard
3-pin XLR-type connectors. The compact,
one-rack-space package is constructed
using heavy-gauge steel components.
The unit’s mains power input can range
from 100 to 230 volts, 50/60 hertz. This
“universal input” ensures correct operation
virtually anywhere in the world.
Model 42 Back Panel
Model 42 Front Panel
Power present
LED
IFB output
circuit connections
AC mains
connection
Audio input
connections
There may be persons not familiar with
the term IFB. That’s not unreasonable
as it’s a somewhat obscure acronym for
interrupted foldback. (It can also be known
as interruptible foldback.) On its own,
the term foldback is an alternate way of
describing a cue or monitor function. Add-
ing “interrupted” before it means that the
cue source can be temporarily replaced
with an audio signal originating from a
producer, director, or other production
personnel. IFB circuits are often used in
the broadcast industry for talent cueing
applications, both in studio and field
settings. Both “dry” and “wet” IFB circuits
can be deployed and their characteristics
are worth reviewing. The term “dry” IFB
typically refers to a transformer-balanced
line-level audio circuit with a +4dBu
nominal level. This is essentially a stan-
dard audio circuit that is commonly used
to interconnect audio equipment. The term
“wet” IFB refers to a circuit that combines
DC power and one or two channels of
analog audio. The audio is unbalanced
with a typical nominal level of –10dBu. A