Studio Technologies 46A - Manual (Page 9)

Model 46A User Guide Issue 1, September 2014
Studio Technologies, Inc. Page 9
Simple Installation
The Model 46A uses standard 3-pin XLR
connectors to allow convenient intercon-
nection in most broadcast and general
audio environments. For flexibility, access
to the 2-wire party-line intercom interfaces
can be made using the connectors pro-
vided on both the front and back panels.
In permanent installations the back-panel
connectors will typically be utilized. In other
settings, such as field television produc-
tion, front-panel-access allows intercom
beltpacks to be rapidly connected, without
requiring access to the inside of a rack
enclosure or necessitating the use of a sec-
ondary input/output (I/O) panel.
The Model 46A is housed in a rugged alu-
minum and steel enclosure that is designed
to be “road tough.” It mounts in one space
of a standard 19-inch rack enclosure. The
mains input source can range from 100
to 240 volts, 50/60 Hz allowing direct op-
eration virtually anywhere in the world.
A switch-mode power supply, contained
within the Model 46A’s enclosure, provides
conversion of the mains input power into
the DC voltage required by the intercom
power supply circuits. Also contained
within the unit is a DC-to-DC converter that
creates the voltages required by the analog
and digital circuitry. These efficient power
supplies help to ensure cool, reliable op-
eration in a variety of settings.
Design Philosophy
While the “bits and pieces” that make up
the Model 46A have been described in
conventional terms, the real strength of the
unit rests in how it integrates and performs
in the “real world.” Before beginning the
Model 46A’s design process, conversa-
tions with industry experts quickly made
it apparent that installing and configuring
existing 2-wire-to-4-wire interface units was
invariably a time-consuming, aggravating
process that required the talent of an expert
to achieve reasonable results. And even
under those constraints the resulting
audio performance was often mediocre.
Any new design had to look at the ap-
plication in a different way. This led to the
over-riding Model 46A design goal: create
a “new breed of cat,” fundamentally chang-
ing how broadcast 2-wire-to-4-wire interface
equipment fit into actual applications.
An important first step was to eliminate the
requirement that a senior technician, along
with a screwdriver, be present during every
installation. (It was universally acknowl-
edged that their time can be better spent
elsewhere!) The need to adjust trim potenti-
ometers, fabricate special cabling and con-
nector straps, use nulling earpieces, etc.,
had to be eliminated. For example, in virtu-
ally all instances, input and output levels fall
within just a few dB of their nominal values
and, as such, could be supported with a
limited number of configurable choices.
In addition, it was acknowledged that in
this application analog audio circuitry was
capable of providing excellent audio perfor-
mance, but that the required manual nulling
process was operationally taxing. By add-
ing digital control to the analog circuitry,
automatic nulling could be performed—the
best of both worlds!
The next step was to identify resources that
would improve the installation process and
make operation more reliable. This led to
the inclusion of multiple LED level meters,
allowing continuous monitoring of the input
and output signals. It also turned out that
in many applications only a small number
of user devices, such as beltpacks, are