Studio Technologies 220 2013 - Manual (Page 34)

Issue 5, February 2013 Model 220 User Guide
Page 34 Studio Technologies, Inc.
This can be successfully done as long as
several limitations are taken into account.
The first limitation is that the 10 k ohm input
circuit presents an unbalanced load to the
source. In most cases this shouldn’t pose
a problem. If a balanced interconnection
scheme must be maintained an in-line iso-
lation transformer can be used. A second
limitation is that the audio level presented
must not exceed 0 dBu or signal “clipping”
may occur. Prepare a 3-pin male XLR con-
nector so that the line-level audio source
designated as IFB channel 1 is connected
with signal high on pin 2 and low/shield on
pin 1. The audio source designated as IFB
channel 2 should be connected with signal
high on pin 3 and low/shield on pin 1. With
this connection scheme the nominal input
level is –10 dBu, the same as with an IFB
circuit. This may require that an external
attenuator (“pad”) be used to reduce the
level of the connected signal. As expected,
powering the Model 220 in this scenario
will require an external source of 24 volt DC
to be connected.
Additional Connectors
Three spare connector locations are
provided on the Model 220’s back panel.
From the factory they contain blank plates
that can be readily removed and replaced
with a variety of XLR connectors. These
spare connector locations are specifically
included so that a Model 220 can be cus-
tomized to meet the many specific needs
that arise in broadcast and related audio
applications. Expected uses for these
locations include adding a 5-, 6-, or 7-pin
XLR connector to allow direct connection
of a broadcast headset. Other uses include
creating “loop through” or “mult” functions
for the talkback outputs or IFB input
connections.
The spare connector locations are com-
patible with the Neutrik DL-series of
connectors. For flexibility, versions are
available that provide from three to seven
contacts. For example, a compatible 3-pin
female connector would be Neutrik part
number NC3FD-L-1. To support headsets
the NC6FDS-L-1 is often used. This is a
6-pin female connector with the unique
Switchcraft 6-pin arrangement. The hard-
ware that secures the blank plates to the
Model 220’s back panel is also intended
to secure the replacement connectors.
If connectors are added to the Model
220’s spare connector locations adding
labels to those connectors can be helpful.
For a great look it is recommended that
Brother® P-Touch ¼-inch (6 mm) labels
be created. Tape material that prints white
text on a black background works out
well for the Model 220. The Brother label
cassette number TX-3151, white on black,
is appropriate for use with many of their
printers.
In addition to the spare connector loca-
tions on the back panel, provision has
been made to allow easy interconnection
with the Model 220’s printed-circuit-board-
mounted input and output connectors.
This was accomplished by including
numerous 3-position male “header” con-
nectors on the Model 220’s circuit board.
These headers, on 0.1-inch centers, are
wired in parallel with the Model 220’s con-
nectors. This “no solder” solution makes
customizing a Model 220 a simple pro-
cess. The headers, located on the Model
220’s printed circuit board, are Molex®
part number 22-23-2031. They mate with
Molex housing number 22-01-3037. To
make the inter-connection, separate crimp
terminals are attached to loose wires and
then “snapped” into the housing. Molex