User Guide

Model 76D/77 User Guide Issue 13, December 2020
Studio Technologies, Inc. Page 11
for Surround
A cable assembly with a 25-pin male
D-sub 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 inter-
face. In the analog world this would allow
eight audio signals to be transported. But
with AES3 digital audio signals this allows
support for 16 audio channels; eight inter-
faces each supplying two audio channels.
A wiring assembly prepared for the Model
76D’s monitor outputs, when configured for
balanced 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 25-pin male D-subminiature con-
nector (DB-25M) on one end and eight
3-pin male XLR connectors on the other.
A wiring assembly prepared for the Model
76D’s monitor outputs, when set for unbal-
anced AES3 (75 ohms/1 Vpp), would typi-
cally have eight BNC plugs attached.
For compatibility with balanced AES3
digital audio signals connect the D-sub’s
+ terminal as signal high and the – termi-
nal as signal low. In most applications a
3-pin male XLR connector 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 unbalanced AES3
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 con-
nections should go to the “body” of the
BNC plug. To clarify, for optimal operation
it is best to connect both the – and shield
connectors 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 threaded
fasteners associated with the Model 76D’s
D-sub connectors use 4-40 threads. This
complies with the original design standard
for D-subminiature connectors.
TASCAM® Signal Signal
Connections Channel High (+) Low (–) Shield
Pre-Fader L/R 1 24 12 25
Pre-Fader C/SUB 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/SUB 6 4 17 5
Post-Fader LS/RS 7 15 3 16
Post-Fader Stereo 8 1 14 2
Notes: 1) All signals transformer-coupled digital audio;
selectable for balanced or unbalanced AES3
compatibility.
2) Connector type on Model 76D is 25-pin female
D-subminiature (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