Studio Technologies 220 2013 - Manual (Page 9)

Model 220 User Guide Issue 5, February 2013
Studio Technologies, Inc. Page 9
Audio Quality and Protection
The Model 220’s circuitry is carefully tai-
lored to provide excellent audio perfor-
mance. Professional-quality components
are featured throughout. For reliability all
audio routing is performed using solid-state
devices. In all critical audio paths, “click-
less” electronic switches provide noise-free
control. All audio inputs and outputs make
extensive use of protection components.
This limits the chance of damage from
ESD and other undesirable, yet real-world,
hazards.
Power Sources
The Model 220 can derive its operat-
ing power from either the IFB input or an
external nominal 24 volt DC source. For
redundancy, both power sources can be
connected simultaneously. An internal
switch-mode power supply ensures that
all Model 220 features, including phantom
power, are available when the unit is pow-
ered by either source.
The Model 220 is compatible with IFB
circuits provided by most standard broad-
cast systems. However, maximum perfor-
mance can often be obtained by using the
IFB interface devices available from Studio
Technologies. The provide high-quality
audio along with an excellent source of
DC power. They’re directly compatible with
most matrix intercom systems, as well as
standard line-level audio signals. Refer to
the Studio Technologies website for details.
Auxiliary Relay
The Model 220’s circuitry includes a gen-
eral-purpose relay, allowing specialized
configurations to be created. Under soft-
ware control, the relay can be configured
to follow the state of the mic, talkback 1, or
talkback 2 buttons. Taking advantage of the
locations provided for additional XLR con-
nectors, a technician may easily implement
a variety of functions such as mic active
indication, audio muting during talkback, or
audio insertion control. Several modes were
specifically included to allow direct control
of the relay using the talkback 2 button,
without impacting any of the audio signals.
The auxiliary relay is also used by the
optional direct microphone output card.
Configuration
Model 220 configurations are made using
a number of DIP switches and two trim
potentiometers. One 8-position switch as-
sembly is used to set the gain of the micro-
phone preamplifier and the on/off status of
phantom power. Another 8-position switch
assembly configures which of the cue audio
sources are routed to the headphone out-
put. Two additional 8-position switch
assemblies communicate the desired
operating modes to the microprocessor.
Two rotary trim pots are used to adjust
the input sensitivity of the line inputs. All
switches and trim pots are accessible via
the bottom of the Model 220’s enclosure;
the unit does not have to be disassembled.
Changes made to any of the configuration
parameters become active immediately. To
prevent access to the configuration controls
a security plate, included with each unit, is
attached to the bottom of the enclosure.
Connectors
The Model 220 uses standard connectors
throughout. The microphone, IFB, and line
inputs use 3-pin female XLR connectors.
The main and talkback outputs use 3-pin
male XLRs. The headphone output utilizes
a ¼-inch 3-conductor jack. The external
source of 24 volt DC power is connected
by way of a 2.1 x 5.5 mm “locking” coaxial
power jack.