Studio Technologies 41 2004 - Manual (Page 4)

Model 41 User Guide Issue 1, October 2004
Studio Technologies, Inc. Page 5
Introduction
The Model 41 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 41 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 41’s audio quality is excellent;
little hiss, hum, or other artifacts are pres-
ent. To ensure optimal operation, the unit
provides extensive resources for visually
and audibly monitoring the audio and DC
output signals.
Installation of the Model 41 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 opera-
tion virtually anywhere in the world.
Model 41 Back Panel
Model 41 Front Panel
There may be persons not familiar with the
term IFB. That’s not unreasonable as it’s a
somewhat obscure acronym for interrupt-
ible foldback. On its own, the term fold-
back is an alternate way of describing a
cue or monitor function. Adding “interrupt-
ible” before it means that the cue source
can be temporarily replaced with an audio
signal originating from a producer, direc-
tor, or other production personnel. IFB
circuits are often used in the broadcast in-
dustry for talent cueing applications, both
in studio and field settings. Both “dry”
and “wet” IFB circuits can be deployed
and their characteristics are worth review-
ing. The term “dry” IFB typically refers to
a transformer-balanced line-level audio
circuit with a +4 dBu nominal level. This
is essentially a standard 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 –10 dBu. The Model 41 imple-
ments wet IFB circuits. As such, in this
user guide the term IFB will always repre-
sent this type of circuit.