Studio Technologies 740 - Manual (Page 8)

Issue 3, May 2004 Model 740 User Guide
Page 8 Studio Technologies, Inc.
Model 740
is connected directly to the Model 740
by way of a standard 3-pin detachable
IEC cord set; no external power supply is
used. AC mains power is factory config-
ured for 100, 120, or 220/240 V, 50/60 Hz.
Configuration
Review
In this section you will be reviewing the
configuration of the Model 740. Configura-
tion changes can be made if required. Any
changes should be made prior to install-
ing the unit.
As previously mentioned in this guide, four
Model 740 operating parameters can be
configured to meet the needs of specific
applications. These include compres-
sor mode, monitor output mode, meter
source, and reference tone frequency.
While simple to perform, all changes do
require the skill of a technician. This per-
son must ensure that AC mains power
is disconnected prior to removing the
unit’s cover. Then the locations of one
or more of the configuration jumpers can
be moved. In the case of the reference
tone frequency, a calibration trim pot
must also be adjusted.
Compressor Mode
The compressor can be configured to
operate from one of three modes:
• From the factory the compressor is
set to have an operating threshold of
6 dB above the main output’s nominal
+4 dBu operating level. In other words,
the compressor will begin to function
when the level of the main output reach-
es about +10 dBu. This is an excellent
general purpose setting that is appropri-
ate for most applications.
• Alternately, the compressor’s threshold
can be changed to be 2 dB above the
+4 dBu operating level. This may be
appropriate for applications where an
RF transmission chain places severe
restrictions on the audio signal’s
dynamic range.
• While not recommended for most
applications, the compressor can
also be configured to be disabled.
With this configuration, no dynamic
range control will take place. For most
on-air applications it’s unlikely that this
would be appropriate.
Monitor Output Mode
The monitor output can be configured
to operate from one of three modes:
• From the factory the monitor output is
set to follow the position of the front-
panel rotary level control. This mode
of operation is sometimes referred to
as being “post” the level control. In ad-
dition, plugging a pair of headphones
into the jack on the front panel will
cause the monitor output to mute.
• An alternate configuration is available
that makes the monitor output follow
the rotary level control’s setting. But
plugging headphones into the front
panel doesn’t cause muting of the
monitor output. This allows the monitor
output to be active, whether or not the
headphones are plugged in.
• A third mode is specifically provided
for use in applications where an ampli-
fied loudspeaker with built-in user level
control is connected. This “pre-level-
control” mode allows the user to select
the source to be monitored on the Mod-
el 740’s front panel. But only the level
control on the amplified speaker is used