Studio Technologies 2A 2013 - Manual (Page 21)

Model 2A User Guide Issue 1, October 2013
Studio Technologies, Inc. Page 21
SHLD is intended for the shield wire of the
microphone cable; it doesn’t carry signal.
A dynamic microphone must not be con-
nected to the mic terminals; it won’t provide
the correct signal level and damage to the
mic may occur.
The Model 11A Gooseneck Microphone is
an unbalanced electret type, requiring an
external source of DC power. The micro-
phone utilizes a ¼-inch 3-conductor plug
for interconnection. The tip lead brings DC
power to the microphone, as well as hav-
ing microphone audio superimposed on it.
The ring lead is microphone common. The
sleeve lead is a shield connection. Included
with the Model 11A is a mounting hardware
kit. This kit contains a ¼-inch 3-conductor
jack used to mate with the microphone’s
plug. At the factory a 3-conductor wiring
harness assembly is attached to the jack.
The wiring harness has a red-colored wire,
a black-colored wire, and a shield wire.
One end of the red wire is attached to the
tip connection on the jack. The other end
should be connected to the + terminal on
the Model 24’s microphone input. One
end of the black-colored wire is attached
to the ring lead of the jack. The other end
should be connected to the – terminal on
the Model 24’s microphone input. One end
of the shield connection is attached to the
sleeve of the jack. The other end should
be connected to the SHLD terminal on the
Model 24’s microphone input.
Setting the input select switch to the LINE
position activates the line input and the
associated input trim potentiometer. The
line input circuit is balanced, transformer
coupled, with an input impedance of 40 k
ohms. Balanced or unbalanced signals can
be connected. The input trim pot allows
signals with a nominal level over the range
–15 to +10 dBu to be correctly interfaced.
When connecting balanced signals the
audio should connect to the + and – ter-
minals. The shield wire can be connected
to the SHLD terminal associated with the
mic input. Unbalanced signals can be
connected so that the signal high lead is
connected to the + terminal and the signal
low/shield lead connects to the – terminal.
If this results in hum or noise it’s possible
that improvements will be found by con-
necting the low/shield lead to both the
– and the SHLD terminals. If you have con-
nected a signal to the line input terminals,
set the trim pot only after installing the en-
tire IFB system. Refer to the Configuration
section of this guide for details on setting
the trim pot.
The Model 24 contains a monitor mute
function, which is intended to prevent
acoustical feedback if the access station is
located close to a monitor loudspeaker as-
sociated with the Model 2A Central Con-
troller’s monitor output. When the monitor
mute switch is set to its ON position, the
monitor outputs mute whenever an inter-
rupt occurs from that access station. Set
the switch to its OFF position if muting of
the monitor output is not desired.
Monitor Output
The Model 2A contains a monitor amplifier
which is intended to drive a small, efficient
loudspeaker. A loudspeaker is not provided
with the Model 2A and one must be ob-
tained for each installation. A switch on the
front panel selects whether IFB channel 1
or 2 will be monitored. The monitor output
is accessible from the back panel using a
¼-inch 2-conductor jack. The output has
a maximum power of 4 watts RMS, can
drive 8 ohm or greater loads, and is quite