Studio Technologies 780-03, 790 User's Guide
for Surround
Model 780-03 Central Controller and
Model 790 Control Console
User Guide
Issue 1, April 2015
This User Guide is applicable for systems consisting of:
Model 780-03: serial number M780-03-00151 and later
software version 1.00 and higher and FPGA version 4.15 and higher;
Model 790: serial number M790-00151 and later with software version 1.00 and higher
with
© 2015 by Studio Technologies, Inc., all rights reserved
www.studio-tech.com
50394-0415, Issue 1
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for Surround
Table of Contents
Revision History ............................................................ 4
Introduction ................................................................... 5
Installation .................................................................... 9
Configuration ................................................................17
Operation ...................................................................... 36
Technical Notes ............................................................42
Specifications ...............................................................46
Appendix A—Connection Pin-Out Charts ....................48
Appendix B—Sync Input Sources ................................50
Appendix C—Downmix Formulas .................................51
Model 780-03/790 User Guide Issue 1, April 2015
Studio Technologies, Inc. Page 3
Revision History
Issue 1, April 2015:
1. Initial release.
for Surround
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Introduction
What This User Guide Covers
This User Guide is designed to assist
you when installing and using the Model
780-03 Central Controller and one or more
associated Model 790 or Model 71 Control
Consoles.
Overview
Creating and distributing eight channel
(7.1) surround audio material has become
common for entertainment, cinema, and
allied applications. As such, the ability
to simply and effectively monitor these
sources is imperative during the recording and post-production process. Studio
Technologies has addressed these needs
with the StudioComm for Surround Model
780-03 Central Controller and the Model
790 and Model 71 Control Consoles. With
digital audio inputs, digital and analog
monitor outputs, support for multiple user
control surfaces, and an extensive set of
resources it’s a simple task to integrate a
monitoring system into virtually any facility.
The carefully selected group of features,
including two surround (7.1) and one stereo input, configurable input-source time
delay, LFE low-pass filter, multiple pre- and
post-fader surround outputs, configurable
downmix and mute/solo functions, and
bass management, along with a multi-format sync input, make the system powerful
yet simple to operate. And by using the
best of contemporary technology, as well
as following rigorous design practices, the
system’s audio quality is excellent.
A StudioComm for Surround system starts
with the Model 790 Control Console. It’s
the system’s “command center” and is designed to reside at a user’s location,
allowing fingertip selection of all monitoring
functions. Numerous LEDs provide com
plete status information. A 4-digit numeric
display indicates the level of the post-fader
digital and analog monitor outputs. A major
strength of the Model 790 is its ability to
configure, under software control, many
important operating parameters. Intended
for secondary monitoring locations that
don’t require all of the Model 790’s features, the Model 71 Control Console is a
compact user control surface. It provides
three of the most basic functions: a rotary
level control, dim on/off button, and reference level on/off button.
Most installations will use only one Model
790 Control Console. However, up to three
additional Model 790 or Model 71 Control
Consoles can also be connected. This
provides multiple users with control over
a facility’s monitor system. And to make
installation simple, the Model 780-03 provides power for all connected Model 790 or
Model 71 units.
The core of this StudioComm for Surround system is the Model 780-03 Central Controller. The one-rack-space unit
contains circuitry that supports balanced
digital audio inputs, balanced digital and
analog monitor outputs, digital audio and
control processing, and interfacing for the
user control surface(s). The Model 780-03
provides two surround (7.1) and one stereo digital audio inputs. These balanced
digital inputs are AES3-compliant; sources
of this type are ubiquitous in many postproduction and audio facility environments.
The inputs allow a sample rate of 44.1,
48, 88.2 or 96 kHz and a bit depth of up to
24 to be supported. Circuitry associated
with the stereo input provides sample rate
conversion (SRC) capability, allowing a
wide range of digital audio sources to be
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for Surround
monitored. To compensate with processing
delays (latency) associated with associated
video displays up to 340 milliseconds of
input delay can be selected. For flexibility,
two delay values can be configured, allowing real-time selection as desired. A number
of different signals can serve as the Model
780-03’s digital audio timing reference. For
synchronization with a master timing reference a dedicated source of word clock,
DARS (AES11), bi-level video, or tri-level
video can be connected. Alternately, the L/R
connection of the actively selected surround
or stereo input source can serve as the timing reference.
A range of digital and analog surround
(7.1) monitor outputs are provided. The
post-fader digital and analog monitor outputs are intended for connection to monitor
loudspeaker systems. The pre-fader digital
monitor output can be used with metering systems that require signals that aren’t
impacted by level control or other monitoring functions. The digital monitor outputs are
compatible with equipment that requires
balanced AES3 digital audio signals with an
output impedance of 110 ohms and a signal
level of 5 volts peak-to-peak (Vpp).
A sophisticated bass management function is integral to the Model 780-03’s design
and can be enabled if desired. It can apply
to both the post-fader digital and analog
monitor output channels. The overall goal
of bass management is very simple: ensure
that the entire audio bandwidth of all channels can be accurately monitored. Many
loudspeaker systems have inherent lowfrequency limitations, preventing a true
sonic “picture” of the source material from
being presented. To overcome this, the lowfrequency energy from the seven channels
associated with the surround inputs and
the two channels associated with the stereo
input can be separated and routed to the
subwoofer (SUB) channel of the monitor
outputs. Several of the bass management
functions can be configured to match the
requirements of specific installations.
Figure 1. Model 780-03 Central Controller Front Panel
Control console
status LED
Figure 2. Model 780-03 Central Controller Back Panel
AC mains input
Remote control inputs
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To /from
Models 790 &
71 Control
Consoles
Analog monitor outputs
Digital
monitor outputs
Sync
input
Stereo
input
Digital surround (7.1)
inputs A & B
Sync status
LED
for Surround
Mute/ solo
mode
Input source
select
Figure 3. Model 790 Control Console Front Panel
Channel mute/ solo
Downmix
Monitor output
level display
Post-fader surround
monitor output
• Surround/ stereo
• Reference level
• Mute all
• Dim
• Rotary level control
Great care was taken in designing the
system’s architecture, ensuring that the
character of the audio input signals was
preserved. All audio processing, including
bass management, is performed in 32-bit
logic using a high-speed field-programmable gate array (FPGA) integrated circuit.
High-performance integrated circuits are
used to perform input, output, and clocking
tasks.
The Model 780-03 occupies one space
(1U) in a standard 19-inch rack. Digital
audio sources are interfaced with the
Model 780-03 using one 25-pin female
D-subminiature connector and one 3-pin
female XLR connector. A BNC connector
is used to interface with an external sync
source. Digital and analog monitor output
signal connections are made using two
25-pin female D-subminiature connector.
One 9-pin female D-subminiature connector
is used to connect the Model 780-03 with
a maximum of four Model 790 or Model 71
Control Consoles. A second 9-pin “D-sub”
connector is used to interface with remote
control signals. AC mains power is con
nected directly to the Model 780-03, with an
acceptable range of 100 to 240 V, 50/60 Hz.
Additional Details
The Model 790 provides three buttons and
associated LEDs for selection of the source
to be monitored. The choices are the two
surround inputs and the stereo input; only
one source can be monitored at a time. It’s
interesting to note that while the surround
inputs have an LFE channel associated
with them, the corresponding post-fader
digital and analog monitor output channels
are designated as subwoofer (SUB), rather
than LFE. This terminology was selected
to highlight the fact that this output channel
may include more than just LFE content.
The bass management function, if enabled,
will redirect low-frequency energy from the
main channels, combine it with the contents
from the LFE input channel, and route the
combination to the subwoofer (SUB) channels of the post-fader digital and analog
monitor outputs.
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An LFE low-pass filter function is provided
as a means of checking the audio content
in the LFE channel of a selected surround
input. The user can enable and disable the
function as required, helping to ensure that
the proper signals are being mixed to the
LFE channel. Having the correct audio con
tent in the LFE channel can be critical as
the LFE channel is typically band-restricted
during distribution.
The post-fader digital and analog monitor
output levels can be controlled by way of a
large, easy-to-use rotary control. The control, actually a digital encoder, allows level
selection in precise 0.5-dB steps. The auto
mute all function causes the post-fader
digital and analog monitor output channels
to automatically mute whenever the output
level control reaches maximum attenua
tion. Using the reference level function,
the post-fader digital and analog monitor
output levels can be set to a pre-configured
value. This is provided for audio-with-picture applications that require a specific
monitor output level. The reference level is
easily configured by taking an electronic
“snapshot” of the desired monitor output
level. For user confirmation, the 4-digit LED
display will show the level of the post-fader
digital and analog monitor output channels.
To match the needs of a facility, the display
can be configured to show either the attenuation level or the sound pressure level
(SPL).
The dim function allows the post-fader
digital and analog monitor output levels
to be reduced by a fixed dB amount. The
dim level is configured from among four
available values. A mute all function allows
the post-fader digital and analog monitor output channels to be simultaneously
muted. The input mute/solo section allows
an input channel to be muted or monitored
as desired. Multiple channels can also
be simultaneously selected for muting or
“soloing.”
Two output mute functions are also provided. One button allows the seven main
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channels of the post-fader digital and analog monitor outputs to be muted. A second
button allows the subwoofer (SUB) channels of the post-fader digital and analog
monitor outputs to be muted. The output
mute functions, along with the input mute/
solo function, allow a user complete flexibility when checking an input source and its
path to the loudspeaker system(s). These
mute and solo resources are crucial in a
multichannel environment, especially when
signals are passing through the bass management function.
Three downmix functions allow the selected
input source to be checked for compatibility
with common audio channel formats. This
can help ensure that surround and stereo
mixes correctly “fold down” into formats
that utilize less channels than the original.
Errors can be quickly identified and then
corrected. The downmix functions, To 5.1
and To Stereo, apply only to the two surround (7.1) sources. The To Mono downmix
function applies to the surround and stereo
inputs. Several of the downmix parameters
can be configured to best meet the needs
of an application. The downmix functions
always impact the post-fader digital and
analog monitor outputs. A configuration
setting allows the pre-fader digital monitor
output to be selected for pre- or post-down
-
mix operation.
For flexibility, the StudioComm for Surround
system is designed to easily integrate with
equipment such as production intercom
systems, on-air or recording tally signals,
and audio consoles. Two remote-control
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inputs provide access to the mute all and
dim functions. By providing access to these
functions, talkback or slate activity from an
audio console or other communications
system can control the level of the postfader digital and analog monitor outputs.
Installation
In this section you will be installing the
Model 780-03 Central Controller in an
equipment rack. Connections to the surround and stereo audio inputs, digital monitor outputs, and analog monitor outputs will
be made. A dedicated digital audio timing
reference signal can be connected to the
sync input. If desired, external equipment
will be interfaced to the remote control inputs. A location will be selected for the first
Model 790 Control Console and it will be
connected to the Model 780-03. AC mains
power will be connected to the Model 780-
03. For advanced applications up to three
additional Model 790 or Model 71 Control
Console units can be connected to the
Model 780-03.
Mounting the Model 780-03
The Model 780-03 Central Controller
requires one space (1U) in a standard
19-inch (48.3 cm) equipment rack. Secure
the Model 780-03 into the equipment rack
using two mounting screws per side. Se
lect a location that is convenient for making
connections to the audio signals as well
as interfacing with the first (or only) Model
790 Control Console. A cable is supplied
to connect the Model 780-03 to the Model
790. If the needs of a specific installation
dictate, an alternate-length interconnecting
cable can be fabricated and used.
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Audio Connections
Audio connections are made by way of
three 25-pin female D-subminiature connectors and one 3-pin female XLR connector. Audio monitor output connections are
made by way of two 25-pin female D-sub
miniature connector. The connectors are
located on the Model 780-03’s back panel.
Refer to Figure 2 for a detailed view of
these connectors.
-
System Components
The main shipping carton contains one
each of the following: Model 780-03 Central Controller, Model 790 Control Console,
9-pin D-subminiature interconnecting cable
(approximately 20 feet (6 meters) in length),
and a user guide. Also included in the shipping carton is a North-American-standard
AC mains cord. Your dealer or distributor
should provide an AC mains cord appropriate for destinations outside of North America. Any additional Model 790 or Model 71
Control Consoles will be shipped in separate cartons.
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Audio Inputs
Two balanced digital surround (7.1) and
one balanced digital stereo audio source
can be connected. Users will be able to
monitor them, one at a time, using the preand post-fader monitor outputs. A one-toone relationship is maintained between the
input and output channels, i.e., left input to
left monitor output, right input to right monitor output, center input to center monitor
output, etc. (Of course this won’t be true in
the case where the user has enabled one
of the three downmix functions.)
for Surround
The audio inputs support digital audio
signals with sample rates of up to 44.1,
48, 88.2, and 96 kHz and a depth (word
length) of up to 24 bits. It’s recommended
that the connected signal sources maintain
a common sample rate and timing reference. Having all signals “locked” together
helps to ensure proper handling by the
Model 780-03’s all-digital signal path.
There is, however, an exception worth
noting. Circuitry associated with the stereo
input has sample rate conversion (SRC)
capability, allowing virtually any stereo digital audio signal to be connected. A signal
connected to the stereo input can have an
independent sample rate and timing reference while still being monitored correctly.
Refer to the Technical Notes section of this
user guide for a detailed review of the SRC
capability.
Signal Signal
Connections Channel High (+) Low (–) Shield
Surround Input A L/R 1 24 12 25
Surround Input A C/LFE 2 10 23 11
Surround Input A SL/SR 3 21 9 22
Surround Input A BL/BR 4 7 20 8
Surround Input B L/R 5 18 6 19
Surround Input B C/LFE 6 4 17 5
Surround Input B SL/SR 7 15 3 16
Surround Input B 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 4. Connections for Surround A and
Surround B Digital Inputs
The Model 780-03’s audio inputs are intended for connection with balanced digital
audio sources that are compatible with the
AES3 standard. This type of signal has a
nominal impedance of 110 ohms and a
nominal signal level of 5 Vpp.
One 25-pin female D-subminiature connector (DB-25F) is used to interface with
the 16 channels associated with surround
input A and surround input B. Each of
the eight connections supports two audio
channels. Often a wiring assembly prepared for these digital audio inputs would
be identical to that of a TASCAM®-type
(AES59-compliant) input assembly. A typical assembly of this type will often have
eight 3-pin female XLR connectors on one
end and a 25-pin male D-subminiature
connector (DB-25M) on the other. Refer to
Figure 4 or Appendix A for details on connecting with the 25-pin female D-subminiature connector.
Note that unlike a TASCAM-type assem
bly, the two threaded fasteners associated
with the Model 780-03’s D-subminiature
connector use 4-40 threads. This complies
with the original design standard for D-sub
connectors.
On the Model 780-03 the stereo input uses
a 3-pin female XLR connector for interfacing with a digital audio source. The mating
cable should have a 3-pin male XLR connector wired such that the + signal goes
to pin 2, the – signal to pin 3, and shield to
pin 1.
Unbalanced AES3 digital audio signals
can also be used with the Model 780-03’s
inputs if external coupling transformers
(“baluns”) are utilized. These impedancematching (75 ohms to 110 ohms) and level
step-up transformer assemblies typically
provide a BNC connector on their input
and a 3-pin male XLR connector on their
output.
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Digital Monitor Outputs
The 25-pin female D-subminiature connector 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 requires uninterrupted full-level signals. The
post-fader digital monitor output channels
are intended to be connected to a loudspeaker system that provides seven main
channels and one subwoofer channel.
The digital 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 digital monitor outputs. The D-subminiature connector follows the TASCAMtype 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 support 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 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 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 connection details. Note that unlike a TASCAMtype 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 Dsubminiature 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
Pre-Fader
Post-Fader L/R 5 18 6 19
Post-Fader C/SUB 6 4 17 5
Post-Fader
Post-Fader
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.
SL/SR 3 21 9 22
BL/BR 4 7 20 8
SL/SR 7 15 3 16
BL/BR 8 1 14 2
Figure 5. Connections for Digital Monitor Outputs
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Pre-Fader Monitor Output
The pre-fader digital monitor output channels are intended to connect to metering,
measurement, or other signal monitoring
equipment that requires uninterrupted, fulllevel digital audio signal sources.
Post-Fader Monitor Output
The post-fader digital monitor output chan
nels are designed for connection to digital
inputs on audio amplifiers associated with
monitor loudspeakers. Alternately, they can
be connected to the inputs of loudspeakers
that contain integrated amplifiers with digital
audio input capability.
Analog Monitor Outputs
The 25-pin female D-subminiature connector on the back panel labeled Analog Monitor Outputs provides access to the Model
780-03’s post-fader analog surround (7.1)
monitor output. The eight output channels
are intended for connection with the inputs
on a loudspeaker system that provides
seven main channels and one subwoofer
channel.
The analog monitor output channels are
designed for connection to audio amplifiers
associated with monitor loudspeakers, or
to the inputs of loudspeakers that contain
integrated amplifiers. The analog monitor
outputs are electronically balanced and
will perform optimally when driving loads
of 2000 (2 k) ohms or greater. In most applications 3-pin male XLR connectors will
be used to interface with the inputs on the
associated amplifiers or amplified speakers.
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.
Balanced operation of the post-fader ana
log monitor outputs is the preferred connection method but unbalanced operation
does not pose a problem. To connect to an
unbalanced load connect the + terminal as
signal high, and only the Model 780-03’s
shield terminal as the signal low/shield.
Leave the – terminal unconnected. For correct unbalanced operation, it is important
not to connect – and shield together.
The wiring scheme used by the D-subminiature connector complies with AES592012, as made popular by TASCAM. A
wiring assembly prepared for the Model
780-03’s analog monitor outputs is identical to that of a TASCAM-type output assembly. Please refer to Figure 6 for the
exact connection details. Again note that
unlike a TASCAM-type assembly, the
Model 780-03’s D-sub connectors use
4-40 threads.
Signal Signal
Connections Channel High (+) Low (–) Shield
Left (L) 1 24 12 25
Right (R) 2 10 23 11
Center (C) 3 21 9 22
Subwoofer (SUB) 4 7 20 8
Surround Left (SL) 5 18 6 19
Surround Right (SR) 6 4 17 5
Back Left (BL) 7 15 3 16
Back Right (BR) 8 1 14 2
Notes: 1) 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.
2) 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 6. Connections for Analog Monitor
Outputs
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Sync Input
The Model 780-03 requires a timing reference (sync) source so that the digital audio
input and digital monitor output signals
will be handled correctly. A configuration
setting allows the source of sync to be
selected. The default setting uses the L/R
input of the currently selected digital input
source which can be either of the surround
inputs or the stereo input. While this is acceptable, audio artifacts (clicks or noise)
will typically occur when switching between
input sources. A better method is to connect a dedicated timing reference signal to
the Model 780-03’s sync input connector.
The connected sync source must maintain
a stable relationship between itself and the
digital audio inputs. The actual sync source
can be in one of several formats: word
clock, DARS (AES11), bi-level video, or
tri-level video.
An overview of the various compatible
timing reference signals might prove
worthwhile. Word clock is a digital signal
that is locked in phase and frequency to
the sample rate of the associated digital
audio sources. DARS (digital audio reference source) is a timing signal compliant
with the AES11 standard. It’s sometimes
referred to as “AES3-black.” Technically it is
similar to an AES3 signal but is generated
specifically as a timing reference signal.
Bi-level video sync signals were originally
provided to support NTSC (United States)
and PAL (European) analog broadcast
applications, although they continue to be
used by contemporary digital video equipment. Tri-level sync signals were primarily
associated with facilities that upgraded to
support high-definition (HD) video signals,
however the need for this type of sync signal seems to be waning. The Model 780-03
supports both bi-level and tri-level signals
at numerous rate combinations, allowing
for compatibility with various worldwide
video formats.
With the wide range of allowable sync
sources proper Model 780-03 operation
should be easy to obtain. Extensive testing
has been done using many different sync
source types and rates. Interested users
can refer to Appendix B of this user guide
for details.
An external sync reference source should
be connected to the sync input BNC connector located on the Model 780-03’s back
panel. For flexibility the Model 780-03’s
sync input can be configured to be terminated with an impedance of 75 ohms or
be high-impedance (“floating”) so as to
not load the source. A sync source that is
dedicated for use by the Model 780-03’s
sync input would typically want to have
the input termination enabled. If the sync
signal connected to the Model 780-03 is
being connected (“multed”) to other inputs
it may be desirable that the termination be
disabled. (A general “rule of thumb” is that
termination should be applied only at the
location of the last physical device using a
specific sync signal.)
Remote Control Inputs
Support is provided for two remote control
input functions: remote mute all and remote dim. These functions only impact
the post-fader digital and analog monitor outputs. The Model 780-03’s remote
control inputs use logic circuitry, “pulled
up” to 3.3 Vdc by way of resistors, which
are active whenever they are brought to
their logic low state. Inputs of this type are
commonly referred to as GPI inputs. While
the input circuitry is protected from overcurrent and static discharge (ESD), care
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for Surround
should be taken to prevent nasty signals
from reaching them. The inputs are active
only when held in the low state; they can’t
be configured to change state (“latch”) in
response to a logic pulse.
A 9-pin D-subminiature connector (DE-9F)
is used for the remote control inputs. Refer
to Figure 7 or Appendix A for connection
details. Note that pin 4 (remote common)
connects to the Model 780-03’s internal
circuit common connection as well as to
the Model 780-03’s chassis and mains
earth connections. Figure 7 also shows
two spare remote control inputs (pins 8
and 9). These are provided for future applications and should remain unconnected.
Signal Pin Direction
Data Shield 1 Shield
Remote Mute All 5 Input
Remote Dim 6 Input
Remote Spare 1 8 In
Remote Spare 2 9 Input
Remote Common 4 Common
Note: Connector type on Model 780-03 is 9-pin female
D-subminiature (DE-9F). Connector uses 4-40
threaded inserts for locking with mating plug.
Figure 7. Connections for Remote Control
Inputs
put
Connecting the Model 780-03
to the Model 790
A 9-pin female D-subminiature connector
(DE-9F), labeled To/From Control Consoles, is provided on the back panel of the
Model 780-03 Central Controller. This is
used to interface the unit with Model 790
Control Consoles. Refer to Figure 8 or Appendix A for details. A 9-pin female D-sub
connector (DE-9F) labeled To/From Central
Controller, is provided on the back panel of
each Model 790 Control Console. A cable
Signal Pin Direction
Data + (RS-485) 1 To/From Models 790/71
Data – (RS-485) 6 To/From Models 790/71
Data Shield 2 To/From Models 790/71
DC + (12 V) 4 To Models 790/71
DC – (12 V Return) 9 To Models 790/71
DC Power Shield 5 To/From Models 790/71
Note: Connector type on Model 780-03 is 9-pin female
D-subminiature (DE-9F). Connector uses 4-40
threaded inserts for locking with mating plug.
Figure 8. Connections between Model 780-03
and Model 790 and Model 71
with 9-pin male D-sub (DE-9M) connectors
on each end is used to interconnect the
Model 780-03 with the Model 790 units. A
cable, approximately 20 feet
(6 meters) in length, is included in the shipping carton. The cable implements all nine
connector pins in a one-to-one manner.
Should an interconnecting cable of a different length be required there’s no problem
for one to be fabricated and used. While
it can be wired in a one-to-one fashion
supporting all nine pins, only four connections are actually required: pin 1 (data +),
pin 6 (data –), pin 4 (DC +), and pin 9 (DC
–). The Model 780-03’s connector pin-out
scheme was designed to allow creation of
an interconnecting cable which uses commonly available 2-pair audio cable. This
cable, consisting of two twisted pairs each
with an individual shield, is typically small
in diameter, flexible, and available in many
colors. One pair and shield can be used for
the data connection (pins 1 and 6) while
the other pair and shield can be used for
the DC connections (pins 4 and 9). This
implementation has the advantages of
providing a shield for the data path and a
more robust common (return path) connection (two conductors including the shield)
for the DC power circuit.
Issue 1, April 2015 Model 780-03/790 User Guide
Page 14 Studio Technologies, Inc.
for Surround
A few simple calculations are required to
determine the maximum cable length when
fabricating a cable to be used when connecting a Model 780-03 to a Model 790.
The differential transmission scheme used
by the system’s RS-485 interface makes
an interconnection in excess of 1000 feet
(>300 meters) easily possible. The limiting
factor is typically the ability of the wiring to
pass the DC power supplied by the Model
780-03 to a Model 790. The Model 780-03
supplies 12 Vdc, 500 milliamperes (mA)
maximum.
The Model 790 requires a minimum of
9 Vdc, 100 mA maximum, for operation.
(The voltage must be measured directly at
the Model 790’s 9-pin D-subminiature con
nector.) So the maximum interconnecting
cable length is directly related to the resis
tive voltage losses associated with the two
DC-carrying conductors (supporting pins 4
and 9). As the Model 780-03 supplies 12 V
and the Model 790 requires 9 V minimum,
this leads to a 3 Vdc maximum drop due
to the interconnecting cable. Using Ohm’s
law it’s quite easy to determine if a desired
cable length can be supported. Calculate
the voltage drop by multiplying the total
resistance (in ohms) of the proposed cable
by 0.1 (the Model 790’s required current in
amperes). Remember to include the resistance in both conductors (DC + and DC –)
when calculating the voltage drop. If the
voltage drop in the cable is 3 V or less it
should function correctly. If it’s greater than
3 V the cable is too long or the wire gauge
is too small.
Additional Control Consoles
Some installations may benefit from the
Model 780-03’s ability to be controlled by
additional control consoles. At least one
Model 790 Control Console must be connected to the Model 780-03 Central Controller. After this requirement has been met
a combination of up to three additional
Model 790 or Model 71 Control Consoles
can also be connected to and powered by
the Model 780-03.
When connecting multiple control consoles
to a Model 780-03 all nine pins of each
interconnecting cable can be connected
in parallel (“multed”). Using this arrangement the data and 12 Vdc power signals
between all the units will be connected in
parallel. A custom cable implementation
requires just four pins to be connected: pin
1 (data +), pin 6 (data –), pin 4 (DC +), and
pin 9 (DC –).
To make installation simple, a “bus” cable
assembly can be created using a short
length of ribbon cable with one 9-pin male
and multiple 9-pin female D-subminiature
insulation-displacement connectors attached. Then standard 9-pin cables can
link the control consoles with the connectors on the bus cable.
Refer to the previous paragraphs of this
user guide where the issues involving
Model 780-03 to Model 790 cable length
are discussed. Note the required current
for a Model 790 is 100 mA while a Model
71 requires only 35 mA. It’s important to
review this information prior to selecting or
fabricating the interconnection cables that
will be used when installing multiple Model
790 or Model 71 units.
AC Mains Power
The Model 780-03 operates directly from
AC mains power over a range of 100 to
240 V, 50/60 Hz. Being a “universal input”
device, there are no switches to set or
Model 780-03/790 User Guide Issue 1, April 2015
Studio Technologies, Inc. Page 15
for Surround
jumpers to install to match a location’s AC
mains voltage. The unit uses a 3-pin IEC
320 C14-type inlet connector to mate with
a detachable AC mains cord. All units are
supplied with an AC mains cord that has
a North-American-standard plug (NEMA
5-15L) on one end and an IEC 320 C13
socket on the other. Units bound for other
destinations will require that the appropriate
cord be used. The wire colors in the mains
cord must conform to the internationally
recognized color code and should be terminated accordingly:
Connection Wire Color
Neutral (N) Light Blue
Line (L) Brown
Protective Earth (E) Green/Yellow
Safety Warning: The Model 780-03
does not contain an AC mains discon
nect switch; the AC mains cord plug
serves as the disconnection device.
Safety considerations require that the
plug and associated outlet be easily accessible to allow rapid disconnection of AC mains power should it
prove necessary.
As soon as AC mains power is applied
the Model 780-03 will perform a power-up
sequence. The two LEDs on the right side
of the front panel will momentarily light in a
test sequence. Then the two LEDs will flash
in cadence while the firmware loads into
the Model 780-03’s main logic device. After
a few seconds initial system operation will
commence and the two LEDs will perform
their intended functions. Once operating
data is being interchanged with the one or
more connected Model 790 or Model 71
Control Consoles the control console status
LED will light. The sync status LED will light
if a valid sync source has been recognized.
The sync status LED will flash if a valid sync
source is not recognized.
Also upon application of AC mains power,
all connected Model 790 units will go
through a power-up sequence, lighting
each of its LEDs in succession. Using its
4-digit display, each Model 790 will then
momentarily display its address, its software version, and the main and logic device
software versions of the associated Model
780-03.
All connected Model 71 units will also go
through a power-up sequence after AC
mains power is applied to the Model 780-
03. Each of the Model 71’s three LEDs will
light momentarily. After these LEDs have
lit, the device address will be shown briefly
using the dim and reference level LEDs, as
shown in Figure 9 in the Configuration sec
tion. When this is complete the Model 71 will
begin normal operation. Its status LED will
light if communication is established with
the Model 780-03. If the Model 71’s status
LED does not light check to see if there is a
device address conflict among all connected control consoles and that all cables are
implemented properly. Refer to the Configuration section of this user guide for details
on selecting the device address.
Should an error be detected during the
start-up process the two LEDs located on
the right side of the Model 780-03’s front
panel will remain flashing in cadence. On
the Model 790 units a diagnostic code may
be displayed. Refer to the Technical Notes
section of this user guide for details.
Only after the Model 780-03 and all connected Model 790 and Model 71 units have
correctly powered up will full system operation begin.
Issue 1, April 2015 Model 780-03/790 User Guide
Page 16 Studio Technologies, Inc.
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