Studio Technologies 2A 2015 - Manual (Page 7)

Model 2A User Guide Issue 2, March 2015
Studio Technologies, Inc. Page 7
50/60 hertz is connected via a detachable
mains cord and provides power for the
Model 2A.
IFB Channels
The Model 2A contains two independent
IFB channels. Each channel has individual
controls and indicators, including program
source select switches, program level
control, 5-segment LED level meter, and
LED status indicators. The features of one
of two identical channels will be highlighted
in this paragraph. Six switches allow the
four program audio inputs and audio com-
ing from the two telephone interfaces to
be selected as program audio sources. A
rotary level control allows adjustment of
the program audio level relative to that of
the non-adjustable interrupt audio level. A
5-segment LED meter displays the level of
the composite IFB audio signal. (The com-
posite audio signal is the combination of
the selected program audio source(s) and
the interrupt audio source(s).) The level
meter facilitates the rapid setting of the
program level control, as well as providing
a general indication of the IFB channel’s
signal level.
Each channel’s composite IFB audio signal
(a mix of program and interrupt audio)
is sent to four places: a line-level output,
the talent amplifier output, telephone in-
terface 2, and the monitor output section.
Each line output provides an electronically
balanced, line-level signal that interfaces
with external equipment via a 3-pin XLR
connector. The talent amplifier output
provides IFB channel 1 and 2 audio, along
with 24 volts DC power on one 3-pin XLR
connector. Any combination of up to six
Model 32A or Model 33A units can be con-
nected to the talent amplifier output. For
application flexibility, the talent amplifier
output provides 200 ohm line impedances
on both of its output channels. This allows
direct connection of not just listen-only
devices, such as the Models 32A and 33A,
but party-line (PL) user beltpacks as well.
In this way popular PL beltpacks, from sup-
pliers such RTS® and Clear-Com®, can
be connected and used to create a small
PL intercom system that includes IFB
listen. A selector switch associated with
telephone interface 2 can be used by an
operator to send either IFB channel 1 or 2
out the connected phone line. The monitor
output section allows loudspeaker moni-
toring of audio from either IFB channel 1
or 2. (An optional external loudspeaker is
required.)
Program Inputs
The Model 2A contains four line-level
program inputs. Each can be individu-
ally assigned to the two IFB channels,
with the ability to assign multiple program
inputs to an IFB channel. Program signals
enter the unit via four 3-pin XLR connec-
tors located on the unit’s back panel. The
program inputs are electronically balanced
and feature low noise, low distortion, and
high common mode signal rejection. Each
program input has a trim potentiometer as-
sociated with it. The trim pots, accessible
from the back panel, allow source signals
with a nominal level of –10 to +8 dBu to be
correctly utilized.
Program audio is muted whenever inter-
rupt activity is taking place. Solid-state
circuitry is used to provide noise-free audio
switching with essentially no “clicks” or
“pops” added. If desired, a program “dim”
rather than a full mute can be implemented
by adding two resistors to the Model 2A’s
circuit board.