Studio Technologies 76DBA V.3.00 - Manual (Page 12)

Issue 1, November 2010 Model 76DBA/77B User Guide
Page 12 Studio Technologies, Inc.
for Surround
signal level are compatible with the require-
ments of AES3id interfacing. These signals
are typically interconnected using coaxial
cable terminated with BNC connectors. For
details on how a Model 77B 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 con-
nectors on the other end will be used for
connecting to the digital monitor outputs.
The D-subminiature connector follows the
TASCAM® 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 sup-
port for 16 audio channels; eight interfaces
each supplying two audio channels.
A wiring assembly prepared for the Model
76DBA’s digital monitor outputs, when con-
figured for AES3 (110 ohms/5 Vpp), would
be identical to that of a DA-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 76DBA’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 + termi-
nal would go to pin 2 of the XLR, the – termi-
nal 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 connections
should go to the “body” of the BNC plug.
To clarify, for optimal operation it is best
to connect both the – and shield connec-
tions 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 DA-88-style assembly, the two thread-
ed fasteners associated with the Model
76DBA’s D-sub connectors use 4-40
threads. This complies with the original
TASCAM® Signal Signal
Connections Channel High (+) Low (–) Shield
Pre-Fader L/R 1 24 12 25
Pre-Fader C/LFE 2 10 23 11
Pre-Fader LS/RS 3 21 9 22
Stereo Input C Direct 4 7 20 8
Post-Fader L/R 5 18 6 19
Post-Fader C/LFE 6 4 17 5
Post-Fader LS/RS 7 15 3 16
Auxiliary Stereo 8 1 14 2
Notes: 1) All signals transformer-coupled digital audio;
selectable for AES3 or AES3id compatibility.
2) Connector type on Model 76DBA is 25-pin
D-subminiature female (DB-25F). Installer must
provide male (DB-25M). Connector uses 4-40
threaded inserts for locking with mating plug.
3) Wiring scheme follows TASCAM DA-88 convention.
Standard DA-88-type wiring harnesses are directly
compatible, with the possible exception of 4-40 screw
threads being required.
Figure 4. Connections for Digital Monitor
Outputs