Studio Technologies 780-03 V.4.15 - Manual (Page 11)

Model 780-03/790 User Guide Issue 1, April 2015
Studio Technologies, Inc. Page 11
for Surround
Digital Monitor Outputs
The 25-pin female D-subminiature con-
nector on the back panel labeled Digital
Monitor Outputs provides access to the
Model 780-03’s pre- and post-fader digital
audio monitor outputs. The channels are
organized as two 8-channel surround (7.1)
sources, one pre-fader (fixed level) and the
other post-fader (level adjustable by the
user). The pre-fader digital monitor output
channels are intended for connection to
metering or monitoring equipment that re-
quires uninterrupted full-level signals. The
post-fader digital monitor output channels
are intended to be connected to a loud-
speaker system that provides seven main
channels and one subwoofer channel.
The digital monitor outputs are transform-
er-balanced AES3 digital audio signals
with a source impedance of 110 ohms and
a nominal signal level of 5 Vpp. Signals
of this type are normally interconnected
to destination equipment using shielded
twisted-pair cable terminated with 3-pin
male XLR connectors.
A cable assembly with a 25-pin male
D-subminiature connector (DB-25M) on
one end and the desired connectors on
the other end will be used for connecting
to the digital monitor outputs. The D-sub-
miniature connector follows the TASCAM-
type 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 channels to be transported. But with
AES3 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
780-03’s digital monitor outputs would typi-
cally be identical to that of a TASCAM-type
output assembly. An assembly of this type
would often have a 25-pin male D-submin-
iature connector (DB-25M) on one end and
eight 3-pin male XLR connectors on the
other.
For compatibility with balanced AES3
digital audio signals connect the D-sub’s
+ terminal as signal high and the – terminal
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. Refer to
Figure 5 or Appendix A for the exact con-
nection details. Note that unlike a TASCAM-
type assembly, the two threaded fasteners
associated with the Model 780-03’s D-sub
connectors use 4-40 threads. This complies
with the original design standard for D-
subminiature connectors.
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 SL/SR 3 21 9 22
Pre-Fader BL/BR 4 7 20 8
Post-Fader L/R 5 18 6 19
Post-Fader C/SUB 6 4 17 5
Post-Fader SL/SR 7 15 3 16
Post-Fader BL/BR 8 1 14 2
Notes: 1) All signals transformer-coupled digital audio;
balanced AES3 (110 ohms, 5 Vpp) compatible.
2) Connector type on Model 780-03 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 AES59-2012 convention.
Standard TASCAM-type wiring harnesses are directly
compatible, with the possible exception of 4-40 screw
threads being required.
Figure 5. Connections for Digital Monitor Outputs