Studio Technologies 76DA V.4.00 - Manual (Page 11)

Model 76DA/77 User Guide Issue 3, July 2012
Studio Technologies, Inc. Page 11
for Surround
compatible with the requirements of AES3id
interfacing. These signals are typically inter-
connected using coaxial cable terminated
with BNC connectors. For details on how a
Model 77 Control Console is used to select
the digital monitor output types refer to the
Configuration section of this user guide.
A cable assembly with a 25-pin D-sub plug
(male) on one end and the desired connec-
tors on the other end will be used for con-
necting to the digital monitor outputs. The
D-subminiature connector follows the TAS-
CAM® wiring convention, organizing the
25 pins into eight groups of three pins
each; one pin remains unused. Each set
of three pins provides an independent
interface. In the analog world this would
allow eight audio signals to be transported.
But with AES3/AES3id digital audio signals
this allows support for 16 audio channels;
eight interfaces each supplying two audio
channels.
A wiring assembly prepared for the Model
76DA’s digital monitor outputs, when con-
figured for AES3 (110 ohms/5 Vpp), would
be identical to that of a D-88-style output
assembly. An assembly of this type would
have a male 25-pin D-subminiature connec-
tor (DB-25M) on one end and eight 3-pin
male XLR connectors on the other. A wiring
assembly prepared for the Model 76DA’s
digital monitor outputs, when set for AES3id
(75 ohms/1 Vpp), would typically have eight
BNC plugs attached.
For compatibility with AES3 balanced
digital audio signals connect the D-sub’s
+ terminal as signal high and the – terminal
as signal low. In most applications a 3-pin
XLR plug (male) will be used. In this case
the + terminal would go to pin 2 of the XLR,
the – terminal to XLR pin 3, and the shield
terminal to XLR pin 1.
For compatibility with AES3id unbalanced
digital audio signals connect the D-sub’s
+ terminal as signal high, and both the
– and shield terminals as the signal low/
shield. When terminating to a BNC plug the
D-sub’s + terminal should connect to the
center pin; the – and the shield connec-
tions should go to the “body” of the BNC
plug. To clarify, for optimal operation it is
best to connect both the – and shield con-
nectors together directly on the D-sub plug,
rather than at the BNC end of the interface
assembly. Note that the output circuitry is
transformer-coupled so it is possible to just
connect to the + and – terminals and still
experience correct operation. This would
leave the shield connection unterminated.
Refer to Figure 4 or Appendix A for the
exact connection details. Note that unlike
a D-88-style assembly, the two threaded
fasteners associated with the Model 76DA’s
D-sub connectors use 4-40 threads. This
complies with the original design standard
for D-subminiature connectors.
Pre-Fader Surround Digital Monitor
Output
The pre-fader surround digital monitor
output channels are intended to connect
to metering, measurement, or other
signal monitoring equipment that requires
uninterrupted, full-level digital audio signal
sources.
Stereo Input C Direct Digital Monitor
Output
The stereo input C direct digital monitor
output is intended for use in site-specific
applications. It provides an uninterrupted,
full-level digital audio signal source that
is post-SRC and input delay in the signal
chain.