Studio Technologies 742 2005 - Manual (Page 8)

Issue 2, May 2005 Model 742 User Guide
Page 8 Studio Technologies, Inc.
Model 742
When configured for “pre +4” operation,
the monitor outputs are again “pre” the
level controls, but this time with a nomi-
nal level of +4 dBu. This can be used for
various applications, including providing
an additional set of main bus outputs. In
certain cases this may eliminate the need
for an external distribution amplifier to be
included as part of the installed system.
Metering
As previously discussed, dual-color signal
present/peak LEDs are associated with
each of the eight input channels. In addi-
tion, two 10-segment LED meters provide
an indication of audio-signal levels on the
main output buses. The meters use three
LED colors: green, yellow, and red. The
LEDs are calibrated such that the actual
output level, in dBu, is indicated.
Reference Tone
A sine-wave audio tone is provided for
alignment and reference use. From the
factory the tone is configured for 400 Hz.
If required, a technician can revise the
frequency to be 1 kHz. A button on the
Model 742’s front panel allows the tone
to be connected to the main output buses.
In addition, a dedicated reference tone
output is also provided. This continuous
source of sine-wave signal is accessed by
means of a balanced line-level output on
the back panel. The dedicated reference
tone output is intended to provide a setup
or test signal that is available at all times,
without interfering with normal operation
of the main output buses.
Mounting, Connectors, and
Mains Power
The Model 742 requires one space in a
standard 19-inch rack. Industry-standard
XLR-type and ¼-inch 3-conductor connec-
tors are used for all audio interconnections.
To maximize reliability, all connectors were
carefully selected from among premium-
grade models. For example, the XLR-type
connectors feature metal shells and are
manufactured by Neutrik®. AC mains
power is connected directly to the Model
742 by way of a standard 3-pin detachable
IEC cord set; no external power supply is
used. AC mains power is factory configured
for 100, 120, or 220/240 volts, 50/60 Hz.
Configuration
Review
In this section you will be reviewing the
configuration of the Model 742. Configura-
tion changes will be made if required. Any
changes should be made prior to installing
the unit.
As previously mentioned in this guide, four
Model 742 operating parameters can be
configured to meet the exact needs of spe-
cific applications. These include phantom
power, compressor mode, monitor output
mode, and reference tone frequency. While
simple to perform, all changes do require
the skill of an experienced technician. This
person must ensure that AC mains power
is disconnected prior to removing the unit’s
cover. Then the locations of the configura-
tion jumpers can be identified and changes
made as required. In the case of revising
the reference tone frequency, a calibration
trim pot must also be adjusted.