Studio Technologies 742A - Manual (Page 22)

Issue 1, July 2012 Model 742A User Guide
Page 22 Studio Technologies, Inc.
Audio Mixer
• If the factory-default compressor thresh-
old of +10 dBu is in effect, normal
audio content will cause each meter to
display a small to moderate amount of
dynamic range control. The yellow level
LEDs may light on peak signal levels,
along with the compressor active LED.
The red LED will essentially never light.
• If the thresholds are set for +6 dBu,
typically only a meter’s first yellow LED
will light. The second yellow LED will
rarely light; the red LED will probably
never light. With this configuration there
often may be a large amount of dynam-
ic range control being performed by the
compressors. Obviously the goal in this
case is for the operator to carefully set
the Model 742A’s controls so that the
signal level generally stays below the
compressor’s threshold. But with the
fairly low threshold of +6 dBu, it may
be difficult to not have the compressors
active almost all the time.
• If the compressors have been con-
figured not to function (disabled), the
meters will get their biggest workout.
Depending on the setting of the input
and master output controls, all ten
segments of each meter may often
come into play.
Reference Tone
A sine-wave tone can be connected to
the two output buses, serving as a refer-
ence signal for local and remote use. A
pushbutton switch selects its status; when
the switch is in its on (in) position tone is
connected to both output bus 1 and 2. A
dual-color LED indicator, which is located
directly below the switch, lights red when-
ever tone is being sent to the main buses.
(The LED lights green when the Model
742A is operating and the tone is not as-
signed to the output buses.) The level of
the tone generation circuitry is adjusted
at the factory to match the Model 742A’s
internal operating level. When the tone is
connected to the output buses, the master
level controls should be adjusted to give
+4 dBu indications on the level meters.
(Refer to Figure 16 for a detailed view.)
Figure 16. Detail of front panel showing
reference tone on/off button and reference tone
active LED
Monitor Section
The monitor section can assist an operator
in obtaining the best performance from the
Model 742A and associated equipment.
The monitor section supports the connec-
tion of both a loudspeaker system and a
headphone device. The two monitor out-
puts are line-level and designed to be con-
nected to audio power amplifier channels
and associated loudspeakers. Alternative-
ly, they can be connected to “amplified”
loudspeakers that contain internal power
amplifiers. The headphone output, located
on the back panel, is designed to support
stereo devices.
Monitor output 1 and the left channel of
the headphone output use output bus 1 as
their audio source. Monitor output 2 and
the right channel of the headphone output