Studio Technologies 81 - Manual (Page 9)

Model 81 User Guide Issue 1, January 2000
Studio Technologies, Inc. Page 9
Installation
In this section you will be installing the
Model 81 in an equipment rack. Audio
input, audio output, and AC mains power
connections will be made.
System Components
The shipping carton contains a Model 81,
User Guide, and warranty card. Units
destined for North America are shipped
with an AC mains cord. Your dealer or
distributor will provide an AC mains cord
for non-North American destinations.
Mounting the Model 81
The Model 81 requires one space in a
standard 19-inch (48.3cm) equipment
rack. It is desirable to locate the Model 81
to allow easy access to both the front and
the back panels. The back panel contains
the input and output connectors. The front
panel is used to access the calibration
controls and output-level switches. The
front panel also contains four LED level
indicators. The Model 81 is secured to
the equipment rack using two mounting
screws per side.
Audio Input
The Model 81 provides one stereo line-
level input. It is electronically balanced,
and compatible with balanced or unbal-
anced signals that have a nominal level
range of –12 dBV to +6dBu. The ExactCal
section allows precise level calibration
with the connected input signal. The
configuration section of this guide pro-
vides details on using the trim pots.
It is anticipated that in most cases a stereo
signal will be connected to the input. The
Model 81 can also be used as a 1-input/
16-output monaural distribution amplifier,
or as a dual 1-input/8-output monaural
distribution amplifier.
Two 3-pin female XLR-type connectors
are used to interface with the input source.
Prepare the mating connectors (males) so
that pin 2 is signal high (+ or hot), pin 3 is
low (– or cold), and pin 1 is shield. With an
unbalanced source, connect pin 2 to high
(+ or hot), and pins 1 and 3 to shield. If
connecting to an unbalanced source in
this manner results in hum or noise, try
connecting pin 2 to high (+ or hot) and
pin 3 to shield; leave pin 1 unterminated.
Audio Outputs
The Model 81 contains eight independent
stereo line-level outputs. The outputs can
be individually configured for a nominal
output level of –10dBV or +4dBu, so you
can connect to all line-level inputs with no
hassle.
Two 25-pin D-subminiature (D-sub) con-
nectors (female) provide access to the
eight outputs. The connector labeled
OUTPUTS 1-4 provides access to outputs
1-4. The connector labeled OUTPUTS 5-8
provides access to outputs 5-8. Please
refer to Figures 1 and 2 for details on the
exact “pin out” of the D-sub connectors.
The outputs are electronically balanced
and capable of driving balanced or unbal-
anced loads of 600 ohms or greater. While
balanced operation is preferred, unbal-
anced operation does not pose a prob-
lem. To connect to an unbalanced load
connect the + terminal of the D-sub as
signal high, and both the – and shield as
the signal low/shield. For optimal unbal-
anced operation, it is important to connect
both – and shield together directly on the
D-sub, and not at the other end of the
harness.