Studio Technologies 76DA V.3.01 - Manual (Page 40)

Issue 2, April 2011 Model 76DA/77 User Guide
Page 40 Studio Technologies, Inc.
for Surround
Dim
The dim function allows the post-fader sur-
round and stereo digital and analog moni-
tor output levels to be reduced by a fixed
amount. Its operating characteristics are
identical to those of the Model 77 Control
Console, discussed earlier in this section.
Reference Level
The reference level button sets the post-
fader surround and stereo digital and
analog monitor output levels to their preset
values. The operating characteristics are
identical to those of the Model 77 Control
Console, discussed earlier in this section.
Technical Notes
Loss of Sync
The Model 76DA relies on an external
timing reference (sync) source for proper
operation. This can be in the form of an
AES3id, word clock, DARS (AES11),
bi-level video, or tri-level video reference
signal. In most cases the sync signal will
be connected to the sync input BNC con-
nector located on the Model 76DA’s back
panel. Alternately, a configuration choice
allows the L/R input of the AES3id source
currently selected for monitoring to also
serve as the system’s timing reference.
Whenever a valid sync signal has been
connected to the Model 76DA the sync
status LED, located on the unit’s front pan-
el, will light. The sample rate of the monitor
output channels will reflect the rate of the
sync input and, if a video sync source is
utilized, the configured rate.
If a valid sync signal is not present
several visual indications are provided.
On the Model 76DA the sync status LED
will flash. On all connected Model 77
Control Consoles the 4-digit LED display
will cease normal operation, instead alter-
nating between the words
no and sync.
When a valid sync signal is again con-
nected the Model 76DA’s sync status LED
will light steadily. On the Model 77 units the
word sync will momentarily be displayed
followed by a brief display of the digital
monitor output sample rate. The sample
rate will display as
32.0, 44.1, 48.0, 88.2,
96.0, 176.4, or 192.0, reflecting the impact
of the sync source rate and the Model
76DA’s configuration.
If during normal operation the sync source
changes from one valid rate to another a
visual indication is provided. On the Model
77 units the new sample rate—
32.0, 44.1,
48.0, 88.2, 96.0, 176.4, or 192.0—will
momentarily be displayed.
Any time that a valid sync signal is not
connected to the Model 76DA the digital
monitor outputs will automatically revert
to an internally generated sample rate of
48 kHz with no digital audio content pres-
ent. This audio “black” signal will allow
most connected equipment to continue
to function correctly, of course with no
meaningful audio signal present. The
analog monitor outputs will move to their
minimum output condition. As soon as a
valid sync signal is again connected to the
Model 76DA the digital monitor outputs will
automatically switch to their correct sample
rate and audio signals will again be pres-
ent. The analog monitor outputs will return
to their normal signal levels.
Power Down
Great care was taken in the Model 76DA’s
design to minimize the chance that clicks,
pops, or other objectionable audio signals
will be present on the digital and analog