User Guide

Model 780-01/790 User Guide Issue 4, December 2020
Studio Technologies, Inc. Page 11
for Surround
and the other post-fader (level adjustable
by the user). The pre-fader monitor output
channels are intended for connection to
metering or monitoring equipment that re-
quires uninterrupted full-level signals. The
post-fader monitor output channels are
intended to be connected to a loudspeaker
system that provides seven main channels
and one subwoofer channel.
The monitor outputs are transformer-
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 monitor outputs. The D-sub connec-
tor follows the TASCAM-type wiring con-
vention, organizing the 25 pins into eight
groups of three pins each; one pin remains
unused. Each set of three pins provides an
independent AES3 balanced signal. In the
analog world this would allow eight audio
channels to be transported. But with AES3
digital audio signals this allows support
for 16 audio channels; eight signals each
supplying the pre- and post-fader monitor
outputs.
A wiring assembly prepared for the Model
780-01’s monitor outputs would typically
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 AES3 balanced
digital audio signals connect the D-sub’s
+ connections as signal high and the
– connections as signal low. In most appli-
cations a 3-pin male XLR connector will be
used. In this case the + connections would
go to pin 2 of each XLR, the – connection
to XLR pin 3, and the shield connection to
XLR pin 1. Refer to Figure 5 or Appendix A
for the connection details.
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 780-01 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
Pre-Fader Monitor Output
The pre-fader monitor output channels are
intended to connect to metering, measure-
ment, or other signal monitoring equipment
that requires uninterrupted, full-level digital
audio signal sources.
Post-Fader Monitor Output
The post-fader monitor output channels
are designed for connection to digital
inputs on audio amplifiers associated with
monitor loudspeakers. Alternately, they can