Studio Technologies 50 User Manual

Model 50 Central Controller,

Model 51 Control Console,

and Related Components

User Guide

Issue 4, July 2000

This User Guide is applicable for systems consisting of:

Model 50, serial number M50-00133 and later;
Model 51, serial number M51-00336 and later;

or Model 51 units upgraded to software

part number 7946, version 1.01 and higher

© 2000 by Studio Technologies, Inc., all rights reserved

5520 West Touhy Avenue

Skokie, Illinois 60077 U.S.A.

Telephone [phone]

Fax [phone]

www.studio-tech.com

50060-700, Issue 4

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Table of Contents

Foreword...................................................................... 5

Introduction .................................................................. 7

What This User Guide Covers ................................. 7

System Overview ..................................................... 7

System Features ...................................................... 8

Installation .................................................................... 12

Advanced Installation Topics....................................... 17

Configuration ............................................................... 20

Model 51 Configuration ChartMain Functions..... 22

Model 51 Configuration Chart

Alternate Functions ............................................. 23

Alternate Configure Functions ................................. 24

Operation ..................................................................... 26

Model 50 Central Controller .................................... 26

Model 51 Control Console....................................... 26

Talent Amplifiers ...................................................... 29

Troubleshooting ........................................................... 30

Technical Notes ........................................................... 32

Specifications............................................................... 37

Appendix A .................................................................. 40

MIDI Messages ........................................................ 42

Block Diagrams

Model 50 Central Controller

Model 51 Control Console

Model 35/Model 38 Talent Amplifiers

Model 70 Interface/Model 71 Mic Module

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Issue 4, July 2000 Model 50/51 User Guide
Page 4 Studio Technologies, Inc.

Foreword

I am pleased to present the StudioComm series of products. As both president and owner
of Studio Technologies, I take a very personal approach when designing products. Getting
older has increased my appreciation of the more subtle things in lifebe they a part of
nature or the nuances contained in a well-designed piece of electronic equipment. Do
the technical and operational aspects of a product work together to feel right? A Studio
Technologies design is ready to go only when I am completely satisfied. My entire focus
for the StudioComm series was to make a system that youd really enjoy using, and one
that would perform reliably for years. I hope you share my enthusiasm.

Many fine people worked toward making the StudioComm happen. Mitch Budniak (ace
consulting engineer) designed many of the circuits. Jim Cunningham contributed to the
analog design. Carrie Loving provided engineering support. Barbara Govednik coordi­nated the marketing communications aspects. Ben Kamen designed the automatic testing
routines. Larry Leviton wrote the excellent micro-controller software. Al Lux designed
the printed circuit boards. Jim McGuire designed the graphics. Fred Roeck performed the
mechanical design. Joe Urbanczyk coordinated the safety testing and agency approvals.
J.C. Utter wrote and electronically illustrated the technical manual, with extensive input
from me.

Many thanks to Bob Tjarks, professional audio sales manager at Gand Music & Sound,
Northfield, Illinois. Bob brought to my attention the need for a product to serve digital
audio workstations. His product idea evolved into the StudioComm series. Additional
thanks to Timothy Powell of Metro Mobile Recording, Glenview, Illinois, who provided his
excellent ears when issues of sonic quality arose. His extensive field and studio experience
was extremely helpful in keeping me on the audio straight and narrow.

Please contact me with your questions, comments, and suggestions. I can be
reached by voice at [phone], fax at [phone], or via the e-mail at
[e-mail].

Sincerely,

Gordon K. Kapes
President

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Issue 4, July 2000 Model 50/51 User Guide
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Introduction

The Model 50 Central Controller, along
with the companion Model 51 Control
Console, are members of the
StudioComm family of products. The
Models 50 and 51 are specifically de­signed to work in conjunction with digital
audio workstations to provide a full set of
monitoring and communications functions.
Features include control room and studio
monitoring, an integrated headphone
system, dubbing, and communications
functions that include talk to studio, talk to
phones, and slate. All StudioComm func­tions perform to a level that rivals even the
largest recording consoles. Many of the
functions are user configurable, allowing
unmatched flexibility.

What This User Guide Covers

This User Guide is designed to assist
you when installing, configuring, and
using the Model 50 Central Controller,
Model 51 Control Console, Model 35
Talent Amplifier, Model 38 Talent Ampli­fier, and related components. A limited
amount of troubleshooting and back­ground technical information is also pro­vided. Should you require detailed
technical information please refer to the
StudioComm Service Guide covering the
Models 50, 51, 35, and 38. The Service
Guide contains detailed service informa­tion, including schematic diagrams. The
Service Guide is not shipped with each
StudioComm system, but is available from
the factory upon request. It is free of
charge to purchasers of StudioComm
equipment. Give us a call or send an
e-mail if you need this highly exciting
document!

System Overview

The StudioComm system is designed
to provide control over monitor and dub
sources, communication from the control
room to the studio, and a headphone
monitoring (cue) system. A complete
StudioComm system consists of a rack­mounted central controller, a desktop
control console, and one or more portable
talent amplifier units.

The Model 50 Central Controller and the
Model 51 Control Console work together
to provide performance and features for
use in advanced applications. The units
interconnect using a standard 5-pin MIDI­style cable. Circuitry in the Model 50
separately routes any of seven stereo
inputs to the control room, studio, head­phone, and dub outputs, with commands
provided by the Model 51 Control Con­sole. If you have MIDI software that sup­ports the StudioComm system, you can
even, in lieu of the Model 51, control the
Model 50 with your computer.

The Model 51 Control Consoles built-in
microphone lets you talk to the studio or
headphone outputs. It also allows you
to talk to the dub output, or to the dub
and headphone outputs using the slate
function.

The Model 35 Talent Amplifier is a por­table amplifier unit capable of driving one
or two pairs of high-impedance stereo
headphones. A single microphone-type
cable links the Model 35 with the Model 50
Central Controller. The Central Controller
provides power and left and right audio
over just three wires.

The Model 38 Talent Amplifier takes the
basics from the Model 35 and adds a

Model 50/51 User Guide Issue 4, July 2000
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unique stereo preamplifier section. This
allows each Model 38 user to create an
individual headphone mix, solving the
classic problem of wanting more me
in the phones! Like the Model 35, the
Model 38 is linked to the Model 50 Central
Controller by a single microphone-type
cable.

Studio Monitoring

The studio monitoring source is config­ured to follow the selected control room
source or headphone source. A push
button, along with an associated LED,
provides the studio on/off function. A
rotary potentiometer is used to set the
level.

System Features

Stereo Line Inputs

The Model 50 contains seven stereo line­level inputs which are compatible with
both balanced and unbalanced signals.
Each input is independently software
configurable for a nominal input level of
10dBV or +4dBu. This allows direct
connection with virtually any audio source.
Each input can also be configured to
operate as a mono input. In this manner,
a signal connected to the left input is
routed to both the left and right outputs.
For convenience, input 7 is located on
the front panel of the Model 50; inputs 1
through 6 are located on the back panel.

Control Room Monitoring

The control room section provides two
stereo line-level outputs for driving two
power amplifiers associated with monitor
loudspeakers. Seven buttons are used to
select the input source to be monitored.
The control room level is adjusted using a
smooth-feeling rotary potentiometer. The
Dim button allows the control room level
to be temporarily reduced. The Control
Room A/B button allows the control room
A or B outputs to be activated. The Mono
button allows the sum (L+R) of the se­lected source to be sent as the control
room output.

Dub Output

A stereo line-level output is provided as
a dub (copy) output. Any of the seven
inputs can be assigned to the dub output.
The dub output can also be configured to
follow the source selected for the control
room output. The slate function allows
communications (voice) audio to be sent
out the dub output. For convenience, the
dub output is available from both the front
and back panels of the Model 50.

Communications Functions

The Model 51 Control Console contains
an internal microphone that is used in
conjunction with the three communica­tions functions. The talk to studio function
interrupts the studio source and sends
communications audio. The talk to
phones function either interrupts the
phones source or adds (sums or mixes)
communications audio with the phones
source. The slate function interrupts the
dub source and, if configured, the head­phone source and connects communica­tions audio. The slate function can be
configured to send a 50Hz sine wave
along with communications audio. The
audio level of each communications func­tion is individually adjustable.

MIDI Control

All Model 50 Central Controller functions
are controlled using system-exclusive MIDI

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messages. The Model 51 Control Console
speaks this language, and in most
applications a Model 51 will be utilized. In
special applications the Model 50 Central
Controller can be connected directly to a
MIDI bus, allowing the creation of a fully
automated recording or audio routing
system. (For more information on MIDI
support, refer to Appendix A.)

Configuration

the left and right outputs. The dub output
level can be set for a nominal 10dBV or
+4dBu output level.

Unique to the system is the ability to
configure the dim level to one of six val­ues, ranging from full mute to a modest
10dB reduction. The auto dim off function,
when configured, allows any change in
the control room level potentiometer to
automatically turn off an active dim state.

The Model 51 Control Console can be
configured to make the system meet a
users exact operating environment. As
previously discussed, each of the seven
stereo line inputs can be independently
set for 10dBV or +4dBu operating levels.
They also can be set for either mono or
stereo operation. In the mono mode a
signal connected to the left input is sent to

Model 50 Front Panel

Power

present LED

Model 51

Control Console

over current LED

Talent Amplifier

over current LED

Input data

present LED

Model 50

input data LED

The talk to phones function can be config­ured to either interrupt the source selected
for headphone audio and connect com­munications audio, or to have the commu­nications audio added (summed or mixed)
with the headphone audio.

The slate function can be configured to
talk to the dub output, or talk to both the

Stereo line input 7;

LED indicates

+4dBu configuration

Dub output;

LED indicates +4dBu

configuration

Model 50 Back Panel

AC mains

connection

Mains voltage

configuration

chart

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To/from Model 51

Control Console

Mic Module

input

Output to talent

amplifiers

Dub

output

Studio output

Control room

A & B outputs

Stereo line

inputs 1-6

Model 51 Front Panel

Source selection

for control room (CR),

studio, headphones, and

dub; three columns of

LEDs show the currently

selected sources

Configure button

switches between

normal operation

and configure mode

Studio on/off button

and level control

Built-in microphone for

communications functions

(talk to studio, talk to

phones, slate)

Change the control
room level; listen in
mono (L+R); select
output A or B; or reduce
the level by a preset
amount

Talk to the studio or
headphones; slate; set
communications levels

Model 51 Back Panel

Connection

to the Model 50

Central Controller

Connection for

external talk to studio

and talk to phones

switches

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dub and headphone outputs. Slate can
also be set to generate a 50Hz sine wave
when activated. This provides an audible
marker for analog tapes, and a visual
indication on a wave form display screen.

Four functions can be set for push-to-latch
operation if desired: talk to studio, talk to
phones, slate, and control room mono.

Headphone Monitoring

The StudioComm system contains an
integrated, full-featured headphone (cue)
system. Up to four Model 35 or Model 38
Talent Amplifiers can be connected to
the Model 50s talent amplifier output. A
single 3-conductor microphone-type cable
carries power and stereo audio.

The studio output is set to follow the
control room source or the headphone
source. The headphone source is set for
independent selection or to follow the
control room source. The dub source is
set for independent selection or to follow
the control room source.

All configuration parameters, along with
power down operation conditions, are
stored in nonvolatile memory.

Model 35 Front Panel

Using the Model 51 Control Console,
any of the seven stereo inputs can be
assigned to the talent amplifier output.
The talk to phones and slate functions
allow communications (voice) audio to be
sent to the talent amps. The talent amplifi­er output is short circuit protected. Error
conditions are displayed by the Talent
Amplifier Over Current LED on the Model
50s front panel.

Power present

LED

Model 35 Back Panel

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Headphone output

level control

Connects to additional

talent amplifiers

Switch between

stereo and mono

(L+R) output

Connects to the Model 50 or another talent

amplifiers loop thru connector

Two headphone

outputs

Each Model 35 and Model 38 Talent
Amplifier can drive two sets of high-

impedance headphones (>150Ω). The

audio output is loud, and very clean.
The units feature a built-in level control,
a stereo/mono switch, and a power
present LED.

The Model 38 Talent Amplifier takes the
basics from the Model 35 and adds a
unique stereo preamplifier section. This
allows a musicians microphone or line­level signal to be looped through the
Model 38, boosted by its preamp, and
then combined with the stereo cue mix
supplied by the Model 50. This provides

Model 38 Front Panel

each Model 38 with an individual head­phone mix, solving the classic problem
of wanting more me in the phones! Like
the Model 35, the Model 38 is linked with
a Model 50 Central Controller by a single
cable.

Installation

In this section you will be installing the
Model 50 Central Controller in an equip­ment rack. Audio input and output con­nections will be made using the Model
50s multitude of phone jacks. One or

Two headphone outputs

Power present

LED

Mic/Line button switches

the talent input between

microphone and line level

Talent level

to phones

Switch between

stereo and mono

(L only) for the

talent input

Cue mix

level to

phones

Switch between

stereo and mono

(L+R) for the cue mix

Model 38 Back Panel

Connects to additional

talent amplifiers

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Connects to the

Model 50 or another

talent amplifiers loop

thru connector

Loop thru connectors parallel the

talent inputs for routing to a digital

audio workstation, effects device,

microphone preamp, etc.

Connects to talent

sources such as key-

boards or microphones

more Model 35 or Model 38 Talent Amplifi­ers will be connected. A location will be
selected for the Model 51 Control Con­sole, and it will be connected to the Model

50. AC mains power will be connected to
the Model 50.

System Components

The main StudioComm shipping carton
contains a Model 50 Central Controller,
Model 51 Control Console, 5-conductor
MIDI-style cable, User Guide, and war­ranty card. Units destined for North
America are shipped with an AC mains
cord. Your dealer or distributor will provide
an AC mains cord for non-North American
destinations. Model 35 and Model 38
Talent Amplifiers, along with accessories,
will be contained in separate cartons.
Please check to ensure you have every­thing you need.

Balanced Connection

(Input & Output)

Ring ()

Tip ( + )

Sleeve

(Shield)

(Switchcraft No. 297, Neutrik NP3C, or equivalent)

Unbalanced Connection

(Input & Output)

Tip ( + )

Sleeve

(Shield)

(Switchcraft No. 280, Neutrik NP2C, or equivalent)

Mounting the Model 50

The Model 50 requires one space in a
standard 19-inch (48.3cm) equipment
rack. Select a location near where the
Model 51 Control Console will be located.
A cable is provided to connect the Model
50 to the Model 51. If required, you can
supply a longer cable, however 50 feet
(15.3m) is the recommended maximum
length. It is desirable to locate the Model
50 to allow easy access to both the front
and the back panels. The back panel
contains most of the input and output
connectors, while the front panel is used
to access line input 7 and a multiple (mult)
of the dub output. In addition, the front
panel also contains several LED indica­tors. The Model 50 is secured to the
equipment rack using two mounting
screws per side.

Audio Inputs and Outputs

The Model 50s line-level audio input
and output connections are made using
¼-inch 3-conductor phone jacks. The
choice of phone jacks was simply a matter
of real estate21 XLR connectors dont
quite fit on the back of a one rack-space
unit! Dont be concerned about your audio
quality, the jacks we use are manufac­tured by Neutrik of Switzerland and fea­ture gold-plated contacts.

Caution: For reliable audio interconnec­tion, the plugs you use must comply with
industry standard RS-453. Switchcraft No.
297, Neutrik NP3C, or equivalent will work
correctly. Refer to the Technical Notes
section for details.

For all input and output phone plugs,
tip is positive (+ or hot), ring is negative
( or cold), and sleeve is shield. The

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Model 50 will also accept unbalanced
¼-inch 2-conductor phone plugs for inputs
and outputs. With unbalanced phone
plugs, tip is positive (+ or hot) and sleeve
is shield. If 3-conductor phone plugs are
used to connect unbalanced input or
output signals, connect positive (+ or hot)
to tip and shield to ring and sleeve.

Studio Output

The Model 50 contains a stereo line-level
output for connection to an audio power
amplifier. This audio amplifier serves the
pair of loudspeakers that is located in the
studio area. (Of course the studio output
can be connected to loudspeakers that
contain integral power amplifiers.)

Stereo Line Inputs

The Model 50 provides seven stereo line­level inputs. Inputs 1 through 6 are located
on the back panel; input 7 is on the front.
Each input is electronically balanced, and
can be configured for compatibility with
10dBV or +4dBu signal levels. The
Model 51 Control Console gives you push­button control, so you can easily change
input sensitivities at any time (refer to the
Configuration section under Input Sensitiv­ity). Monaural sources should be con­nected to the left (L) input and configured
for mono operation (refer to the Configura­tion section under Stereo/Mono Input).

Control Room Outputs

The Model 50 contains two stereo line­level outputs for connection to two audio
power amplifiers. These audio amps
serve two pairs of loudspeakers that are
located in the control room. (Of course the
control room outputs can be connected to
loudspeakers that contain integral power
amplifiers, such as the products from
Genelec.)

The outputs, labeled A and B, are elec­tronically balanced and capable of driving
loads of 600 ohms or greater. In most
situations best performance will be ob­tained if the audio amplifiers input sensi­tivity is set to near maximum. Refer to the
Technical Notes section for details on
setting amplifier sensitivity.

The output is electronically balanced and
capable of driving loads of 600 ohms or
greater. In most situations best perfor­mance will be obtained if the audio
amplifiers input sensitivity is set to near
maximum. Refer to the Technical Notes
section for details on setting amplifier
sensitivity.

Dub Output

The Model 50 contains a stereo line-level
output which is intended for connection
to a variety of analog audio devices. The
dub output is electronically balanced and
capable of driving 600 ohm loads or
greater. With the input impedance of most
audio devices at 10k ohms or greater, the
dub output can easily drive 10 or more
devices simultaneously. The dub output
can be configured for a nominal level of
10dBV or +4dBu, so you can connect
to all line-level inputs with no hassle (refer
to the Configuration section under Dub
Output Level ).

The dub output is available on phone
jacks located on both the front and back
panels of the Model 50. The phone jacks
are connected in parallel, being a multiple
or mult of each other; one set of dub
output circuits drive both outputs. The
design intention was that permanent
connections would be made to the back
panel dub output, while the front panel
dub output would remain available for
on the spot use.

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Mic Module Input

A ¼-inch 3-conductor phone jack, labeled
Mic Module, is located on the back panel.
In most cases the Mic Module input will not
be used, and no plug should be inserted.
For details on using the Mic Module input,
refer to the Advanced Installation Topics
section later in this guide.

Warning: Do not connect the Model
50s talent amplifier output to anything
but Studio Technologies talent amplifi­ers. Some audio equipment may be
damaged by the +23Vdc contained
on pin 2 of the talent amplifier output
connector.

Talent Amplifier Output

Up to four Model 35 or Model 38 Talent
Amplifiers can be connected in any combi­nation to the Model 50s talent amplifier
output. The output connector is a 3-pin
male XLR-type. For best performance,
use low-capacitance shielded microphone­type cable to distribute the talent amplifier
signal. If you have a choice, select cables
with the heaviest wire gauge commonly
available. This will reduce voltage drop
when using long cable runs. Refer to the
Technical Notes section for additional
information.

The simplest installation would use a mi­crophone cable to connect the Model 50
to the first talent amplifier; the loop through
connector on that talent amp sending the
signal on to the next talent amp.

Several mounting options are available
for the Model 35 and 38 Talent Amplifiers.
For details refer to the Mounting Options
sections in the Advanced Installation
Topics section of this manual.

In special cases you may need to obtain
a stereo, balanced line level output signal
from the Model 50 talent amplifier output.
The Model 70 Interface is available for this
purpose. For details refer to the Advanced
Installation Topics section later in this
guide.

Locating the Model 51 Control Console

The Model 51 was designed for desktop
use, however provision has also been
made for microphone-stand mounting.
For details refer to Mounting Options in
this section.

For convenience, you may want to wire
your facility to allow easy access to the
talent amplifier signal at all locations where
talent amplifiers might be used. The talent
amplifiers connect to the Model 50 in
parallel, so the connectors on the distribu­tion panels or mult boxes must be wired
in parallel.

Connecting the Model 50 to the
Model 51

A standard 5-conductor MIDI-style cable
is used to connect the Model 50 to the
Model 51; a cable is included with your
system. Just connect the cable between
the female 5-pin DIN-type connectors on
the back of the Model 50 and 51, and
youre done.

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Studio Technologies, Inc. Page 15

Note: If you require a longer cable, be
certain to buy a MIDI cable that has all 5
pins wired. If they arent all connected, the
Model 51 will not operate. This is because
the Model 50 powers the Model 51 with
the pins that arent used for MIDI data.

The Model 50 uses an IEC standard con­nector to mate with the AC mains cord.
The wire colors in the AC mains cord
should conform to the internationally
recognized CEE color code and must
be wired accordingly:

For best performance, the cable that
connects the Model 50 with the Model 51
should be limited to 50 feet (15.3m).
Should you need to exceed this length,
refer to the Technical Notes section
of this guide for details on the cable
requirements.

For more information on MIDI, and using
controllers other than the Model 51,
please refer to Appendix A.

Remote Control Inputs

The Model 51 allows the connection
of two external switches or contact clo­sures. Refer to the Advanced Installation
Topics section of this guide for details.

AC Mains Power

The Model 50 is internally configured to
operate from either 100, 120, or 220/240V,
50/60Hz. In most cases, units shipped to
North America are factory selected for
120V operation. Units bound for Japan are
selected for 100V, while our friends down
under and in Europe receive units set for
220/240V. Before connecting the Model 50
to mains power, check that it is configured
to match the local mains voltage. Look on
the back panel, adjacent to the power
entry connector, for the configured
voltage(s). Note than an incorrect configu­ration could seriously damage the unit.
Should it be necessary to change the
units operating voltage it must be
performed only at the factory or by an
authorized service technician.

Connection Wire Color

Neutral (N) Light Blue
Line (L) Brown
Protective Earth (E) Green/Yellow

Safety Warning: The Model 50 does
not contain an AC mains disconnect
switch. As such the mains cord plug
serves as the disconnection device.
Safety consideration requires that
the plug and associated outlet be
easily accessible to allow rapid discon­nection of mains power should it prove
necessary.

As soon as mains power is applied, the
Model 50s power present LED will light.
The Model 51 will go through its power-up
sequence lighting each LED in a rapid
sequence. The power present LEDs on
the talent amplifiers will also light.

The two Over Current LEDs located on
the front panel of the Model 50 should not
be lit. If either or both are flashing, imme­diately refer to the Troubleshooting sec­tion of this guide. If everything appears to
be functioning properly you are now ready
to configure the system.

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Page 16 Studio Technologies, Inc.