Studio Technologies 200 User Manual
User Guide
Issue 3, August 2004
This User Guide is applicable for serial numbers:
M200-00161 and later
Copyright © 2004 by Studio Technologies, Inc., all rights reserved
www.studio-tech.com
50316-0804, Issue 3
Table of Contents
Introduction ................................................................... 5
System Features ........................................................... 5
Installation and Setup ................................................... 8
Configuration ................................................................ 13
Operation ...................................................................... 15
Technical Notes ............................................................. 16
Specifications ................................................................ 26
Appendix A .................................................................... 27
Block Diagram
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Introduction
What This User Guide Covers
This User Guide is designed to assist you
when installing, configuring, and using
the Model 200 Announcer’s Console.
Additional background technical information is also provided. A product block diagram is included at the end of this guide.
System Overview
The Model 200 Announcer’s Console is
specifically designed for television sports
broadcasting applications, serving as the
audio control center for on-air talent. The
unit integrates on-air, talkback, and cue
audio signal routing and control into one
compact package. Highlights of the Model
200 include ease of installation and use,
reliability, and sonic excellence. Whether
used for professional, amateur, or entertainment-only broadcast events, “pro” quality performance is always maintained.
Figure 1. Model 200 front panel
The Model 200 is optimized to directly
interface into the broadcast environments
typically used for events such as football,
baseball, basketball, and motor sports.
Standard connectors are used for the microphone, headphone, talkback, and IFB
signals. This allows setup to be fast and
consistent. A limited number of configuration options are provided. Once selected,
no event-to-event configuration changes
should be required. For ease of use, the
on-air talent is presented with a simple
set of controls and indicators. Whether
it’s mic preamplifier, audio switching,
talkback output, or headphone cue feed,
excellent audio performance is maintained
throughout.
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Figure 2. Model 200 back panel
System Features
Microphone Input and
Configuration
A high-performance microphone preamplifier circuit provides low-noise/low-distortion
amplification over a 20 to 60 dB gain range.
The gain is adjustable in 10 dB steps. The
input is compatible with balanced dynamic
or condenser microphones. The microphone
power source is 48 volts nominal and meets
the worldwide P48 phantom standard.
The output of the microphone preamplifier
is used by the main and talkback output
circuits.
One 8-position DIP-type switch array is
used to set the gain of the microphone
preamplifier and the on/off status of the
phantom power. These switches are
accessible via the bottom of the Model
200’s enclosure; the unit does not have
to be disassembled. To prevent access to
the configuration switches a security panel,
included with each unit, is attached to the
bottom of the enclosure.
Main and Talkback Outputs
The Model 200 provides one main and
one talkback output. The main output is
intended to serve as the on-air audio feed.
It is designed as a fully professional interface with high output capability, low distortion, and low noise. It features an output
transformer that is well suited for driving
long broadcast cable runs. The talkback
output is intended to provide production
trucks, control rooms, or support personnel
with a talent-originated cue signal. The talkback output is transformer-coupled with
a +4 dBu nominal signal level. It contains
resistors in series with its output connections, allowing the talkback output from
multiple Model 200 units to be directly
“summed.”
User Controls and Status
Indicators
Two pushbutton switches, three LED indicators, and two rotary controls provide
the user with a clear, easy-to-use interface.
One of the pushbutton switches controls
the status of the main output. This is the
audio output intended for on-air use.
The main output button performs a
“push-to-mute” function that momentarily
mutes the main output. This “cough” function is typically required for on-air applications. Two LEDs display the on/off status
of the main output.
A second pushbutton switch controls the
talkback output. This is the audio output
used to communicate with producers,
directors, or other behind-the-scenes production personnel. The talkback button
provides a “push-to-talk” function. When
active, the talkback function routes the
microphone signal to the talkback output
while muting the main output. A status LED
is associated with the talkback button. Two
rotary controls allow the user to adjust the
level of the headphone output.
IFB Input
A broadcast-standard “wet” (DC with
audio) IFB circuit can be directly connected
to the Model 200’s IFB input. Originated by
sources such as the RTS™ 4000-series IFB
system or IFB interface devices from Studio
Technologies, the connected IFB circuit can
provide DC power to operate the Model 200
as well as two channels of cue audio.
Cue Sources and Headphone
Output
The two audio sources associated with the
IFB input are routed, by way of interface,
level controls, and output circuitry, to the
headphone output. Originating in production trailers, control rooms, or remote locations, these cue sources typically provide
program-with-interrupt audio on one channel and program-only audio on the other.
The Model 200 doesn’t perform any cue
source channel rerouting, summing, or
muting. Channel 1 (pin 2 of the IFB connector) serves as the headphone output’s left
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channel source. Channel 2 (pin 3 of the
IFB connector) serves as the source for
the headphone’s right channel output.
Some applications may benefit by being
able to connect standard line-level audio
signals to the Model 200. To meet this
need one or two optional line input cards
can be installed in the unit’s back panel.
Each card provides a 3-pin female XLRtype connector and transformer-isolated
+4 dBu nominal input circuit. One card
is assigned to the left headphone output,
the other to the right.
Two rotary controls are provided for user
adjustment of the headphone output
levels. They provide independent volumecontrol adjustment of the left and right
channels. To help minimize the chance of
broadcast cues being missed, both level
controls are configured so that a minimum
headphone output level is maintained.
The headphone output was designed
to meet the needs of contemporary
headphones and headsets. Specifically,
the output circuits act as voltage, rather
than power, drivers. This implementation
provides high output levels with very low
distortion and noise, along with minimal
current consumption. The output circuits
can safely drive stereo or mono loads,
ensuring that all types of headphones,
headsets, and earpieces can be directly
connected.
Audio Quality and Protection
The Model 200’s circuitry has been
carefully designed to provide excellent
audio performance. Pro-audio-quality
components are featured throughout. For
reliability all audio switching is performed
using solid-state devices. In the critical
main output and talkback output audio
paths, “clickless” electronic switches
provide noise-free control. All audio inputs
and outputs make extensive use of protection components. This limits the chance of
damage from ESD and other undesirable,
yet real-world, hazards.
Power Sources
The Model 200 can derive its operating
power from either the IFB input or an external 24 volt DC source. For redundancy,
both power sources can be connected
simultaneously. An internal switch-mode
power supply ensures that all Model 200
features are available, including phantom
power, when powered by either source.
The Model 200 is compatible with IFB
circuits provided by most standard broadcast systems. However, maximum performance can often be obtained by using the
IFB interface devices available from Studio
Technologies. Single-channel and fourchannel units are available, each providing
high-quality audio along with an excellent source of DC power. They’re directly
compatible with most matrix intercom systems, as well as standard line-level audio
signals. Refer to the Studio Technologies
website for details.
Connectors
The Model 200 uses standard connectors throughout. The microphone and IFB
inputs use 3-pin female XLR-type connectors. The main and talkback outputs use
3-pin male XLRs. The headphone output
utilizes a ¼-inch 3-conductor jack. The
external source of 24 volt DC power
is connected by way of a 2.1 x 5.5 mm
“locking” coaxial power jack.
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In the world of broadcast audio it’s fair
to say that applications vary widely. To
this end, one or two additional XLR-type
connectors can be easily mounted into
the Model 200’s back panel. Seven
3-position “headers” are located on the
Model 200’s circuit board and provide
technician-access to all input and output
connections. Using a factory-available interface cable kit, these allow a Model 200
to be optimized to meet the exact needs of
specific applications. For example, some
applications may prefer to use a multipin XLR-type connector to interface with
a headset. This could be easily accomplished by adding the appropriate 5-, 6-,
or 7-pin XLR-type connector and making
a few simple connections. Other applications may benefit from having “mult” or
“loop-through” connections, something
easily incorporated into a Model 200. One
or two optional line-input cards, as previously discussed, can also be mounted in
the spare XLR positions.
200-Series Announcer
Installation and
Setup
In this section interconnections will be
made using the input and output connectors located on the Model 200’s back
panel. Microphone input, IFB input, main
output, and talkback output signals are interfaced by way of 3-pin XLR-type connectors. A ¼-inch 3-conductor phone jack is
provided for the headphone output. A 2.1
x 5.5 mm coaxial jack allows connection of
an external 24 volt DC power source.
System Components
Included in the shipping carton are the following: Model 200 Announcer’s Console,
user guide, button label sheet, and 24 volt
DC power supply. For units shipped to
destinations in Japan and North America
the power supply will have a nominal AC
mains input of 120 volts. For all other destinations a power supply compatible with
220/240 volt AC mains will be included.
Console Products
The Model 200 is just one in a series of
announcer console products available
from Studio Technologies. The Model 200
was designed specifically for on-air television sports applications where the performance requirements were well defined.
The unit’s features and operating modes
were selected to provide excellent performance and rapid setup, along with limited
configuration flexibility. For applications
that require additional performance
enhancements the other products in the
200-series should be reviewed. Complete
information is available on the Studio
Technologies website.
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Microphone Input
The Model 200 is compatible with balanced dynamic and condenser microphones. Depending on the application,
the microphone may be part of a headset,
or be an independent handheld or standmounted model. The Model 200’s 48 volt
nominal power source will support essentially all phantom-powered microphones.
The quality of the Model 200’s microphone
preamplifier and associated circuitry is
such that special applications may benefit
from using “high-end” microphones. If
selected appropriately, models from manufacturers such as AKG, Beyer, Neumann,
Sennheiser, and Shure will perform very
well in Model 200 applications.
Microphone interconnection is made by
way of a 3-pin female XLR-type connector
which is located on the Model 200’s back
panel. The mating connector (male) should
be wired so that pin 2 is signal high (+ or
hot), pin 3 is signal low (– or cold), and pin
1 is shield. It’s possible that an unbalanced
microphone will also work correctly. In this
case, the mating connector (male) should
be wired so that pin 2 is signal high (+ or
hot), and signal common/shield is connected to both pins 1 and 3.
The Model 200 is not compatible with
unbalanced “electret”-type microphones
that require a source of low-voltage DC for
operation. These microphones, sometimes
found in low-cost headsets, are not generally suitable for on-air or other demanding
applications.
As of the writing date of this user guide, the
Sennheiser HMD25 headset is very popular for on-air sports broadcast use. A fine
product, it works very well with the Model
200. Note that adding the suffix “-XQ” to the
headset’s part number (HMD25-XQ) specifies a 3-pin male XLR- type connector for
the dynamic microphone and a ¼-inch 3conductor plug for the stereo headphones.
This configuration is very useful, allowing
the headset to work directly “out of the box”
with the Model 200.
If the writer may digress for a moment to
recount a story… an audio dealer once
shared a secret with me concerning
headsets. He loved selling name-brand
but “lower-end” (less expensive) headsets,
which he did by the veritable “boatload.”
Why? Because they usually broke soon
after going into service! He knew that on a
regular basis he’d receive orders for more of
them. Had these users, from the beginning,
purchased only premium-quality headsets,
their total cost of ownership would have
been much less. Enough said…
Headphone Output
The Model 200’s headphone output is compatible with stereo or mono headphones,
headsets, or earpieces. Connecting devices
with a nominal impedance of 100 ohms or
greater is preferred. This shouldn’t prove to
be an issue as essentially all contemporary
devices will meet this condition.
Devices are connected to the headphone
output by way of a ¼-inch 3-conductor
phone jack which is located on the Model
200’s back panel. As is standard for stereo
headphones, the left output is connected
to the “tip” lead of the ¼-inch headphone
jack. The right output is connected to the
“ring” lead of the jack. Common for both
outputs is connected to the “sleeve” lead.
Devices with ¼-inch 2-conductor “mono”
plugs can also be used with the Model
200’s headphone output. In this arrangement only the tip lead (left channel) will
be active. The 2-conductor plug will physically connect (“short”) the ring lead (right
channel) to the sleeve lead (common).
Technically this won’t damage the circuitry
associated with the right-channel headphone output. (51 ohm protection resistors
are electrically in series with the headphone
output circuits.) However energy will be
wasted if an audio signal coming out of
the right channel goes into a “dead short.”
There are several ways of limiting the
chance that this condition will occur. The
first way is to disconnect or “un-route”
any audio source going to channel 2 of
the connected IFB circuit. Channel 2 audio
is found on pin 3 of the IFB input XLR-type
connector. The second way is pretty obvious—keep the right channel level control
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in its fully counterclockwise position. A
third way is preferred, but unfortunately
might prove to be impractical out in the
field. It would mandate the use of ¼-inch
3-conductor plugs on all devices, stereo or
monaural, that are to be connected. Stereo
headphones or headsets would connect
in the usual way: left channel on tip, right
channel on ring, and common on sleeve.
But monaural devices would connect only
to the tip and sleeve leads; the ring lead
would remain unconnected. This would
ensure that the Model 200’s right-channel
headphone output would never be shorted.
Main Output
The main output is intended to be the
“on-air” signal that connects to the input of
an audio console. The output is transformer
balanced with a nominal signal level of
–2 dBu. The actual level will depend on the
gain setting of the microphone preamplifier, sensitivity of the microphone, and how
loudly the talent speaks into the microphone. The transformer used in the main
output is intended for professional broadcast applications. It has a low source impedance and can drive lengthy cable runs
with no difficulty. It is capable of driving 600
ohm loads but performs best with loads of
2 k ohms or greater. (This should not prove
to be an issue as virtually all contemporary
audio equipment has a relatively high input
impedance.) As the secondary winding of
the output transformer connects directly to
the main output connector, care should be
taken so that DC voltage is never present
on the interconnecting cable.
The main output is interfaced by means
of a 3-pin male XLR-type connector
located on the Model 200’s back panel. The
interconnecting cable’s mating connector
(female) should be wired so that signal high
(+ or hot) is on pin 2 and signal low (– or
cold) is on pin 3. The cable’s shield can
be connected to pin 1, but it will have no
function. To limit the chance of grounding
interaction between the Model 200 and
connected equipment, pin 1 on the main
output’s connector is isolated from any
point in the Model 200. The fact that pin 1
“floats” will minimize the chance of hums,
noises, or buzzes being present on the
equipment connected to the main output.
Talkback Output
The talkback output is intended for
connection to control rooms, production
trailers, or other locations where talentoriginated voice cues are required. The
talkback output is transformer-balanced
with a nominal level of +4 dBu. The actual
level will depend upon the output level
of the connected microphone and the
amount of gain selected for the microphone preamplifier.
For protection against accidental connection to cables that have DC power present,
the talkback output is capacitor coupled.
In series with the talkback output leads
are 300 ohm resistors, making the effective output impedance approximately
600 ohms. These resistors allow talkback
outputs on multiple Model 200 units to
be connected together, creating a passive
summing network.
The talkback output is connected by way
of a 3-pin male XLR-type connector which
is located on the Model 200’s back panel.
A mating connector (female) should be
prepared so that signal high (+ or hot) is
expected on pin 2. Signal low (– or cold)
should be expected on pin 3. The cable’s
shield can be connected to pin 1. But, like
the main output, to minimize the chance
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