Studio Technologies 40 User Manual

Model 40 Central Controller

and Related Components

User Guide

Issue 1, July 1994

© 1994 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

50065-794, Issue 1

Tab le of Contents

Introduction ................................................................. 5

What This User Guide Covers ................................ 5

System Overview .................................................... 5

Model 40 Central Controller .................................... 5

Model 35 Talent Amplifier ....................................... 7

Model 38 Talent Amplifier ....................................... 7

Installation................................................................... 9

Configuration............................................................... 13

Operation .................................................................... 13

Model 40 Central Controller .................................... 1 3

Talent Amplifiers ..................................................... 1 4

Troubleshooting .......................................................... 15

Technical Notes .......................................................... 15

Circuit Description ....................................................... 17

Specifications .............................................................. 2 3

Appendix ..................................................................... 25

Block Diagrams

Model 40 Central Controller

Model 35/Model 38 Talent Amplifiers

Model 40 User Guide Issue 1, July 1994
Studio Technologies, Inc. Page 3

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Issue 1, July 1994 Model 40 User Guide
Page 4 Studio Technologies, Inc.

Introduction

The Model 40 Central Controller, along
with related components, are part of the
StudioComm series. StudioComm prod­ucts provide monitoring and communica­tions functions for professional audio
applications. The Model 40 Central
Controller, along with up to eight Model 35
or Model 38 Talent Amplifiers, allow the
creation of sophisticated headphone (cue)
systems for use in recording, broadcast,
film, and specialized applications. With a
totally unique, proprietary design, a spe­cialized, high-quality headphone system
is easily configured and installed.

What This User Guide Covers

This User Guide is designed to assist
you when installing, configuring, and
using the Model 40 Central Controller,
Model 35 Talent Amplifier, and Model 38
Talent Amplifier. It also contains detailed
service information, including block and
schematic diagrams.

System Overview

cables to up to four Model 35 or Model 38
Talent Amplifiers. Two pairs of head­phones can be connected to each talent
amp. By placing the final output stage in
the talent amplifiers, superior audio quality
can be delivered directly to the user.

The highlight of a StudioComm head­phone system is the sonic quality; low
distortion, low noise “high fi” audio with an
output level loud enough for “rock ‘n roll.”
The entire audio path is optimized for one
thing: making headphones sound great.

The design and implementation of a
StudioComm headphone system is simple.
Cables terminated with standard 3-pin
XLR-type connectors link the Model 40
Central Controller with the talent amplifi­ers. For assistance, both input and loop­through connectors are provided on
each talent amp. For the first time, cable
length simply stops being an issue.
Locating talent amplifiers over 500 feet
(164m) away from a Model 40 is perfectly
acceptable.

The underlying concept of a StudioComm
headphone system is distributed amplifica­tion. The Model 40 Central Controller
provides two stereo line inputs, each
which can be assigned to two output
groups. Each output group distributes line­level stereo audio and DC power over
standard 3-conductor microphone-type

Model 40 User Guide Issue 1, July 1994
Studio Technologies, Inc. Page 5

Model 40 Central Controller

The Model 40 is the connection point for
the audio inputs, and provides the talent
amplifier outputs which connect to the
talent amplifiers. The unit mounts in one
standard rack space.

Two Stereo Line Inputs

Talent Amplifier Output Groups

The analog outputs of consoles, worksta­tions, off-air receivers, or virtually any
analog source can be connected to the
Model 40’s line inputs. The inputs accept
balanced or unbalanced signals, with an
acceptable input level range of –10dBV to
+10dBu. Signal Present LEDs provide
assistance when adjusting the input level
controls.

Model 40 Front Panel

POWER

INPUT LEVEL

INPUT 1

SIGNAL

PRESENT

LR

INPUT LEVEL

INPUT 2

SIGNAL

PRESENT

LR

MODEL 40 CENTRAL CONTROLLER

Each of the two output groups is designed
to feed up to four StudioComm talent
amplifier modules. The physical output
of each group is a 3-pin male XLR-type
connector that provides power and left
and right audio to the talent amplifiers.
The talent amplifier output groups are
short circuit protected. Error conditions
are displayed by the Over Current LEDs
on the Model 40’s front panel.

INPUT 1
INPUT 2

CURRENT

OUTPUT GROUP A

OVER

INPUT 1
INPUT 2

CURRENT

OUTPUT GROUP B

OVER

SKOKIE, ILLINOIS U.S.A.

Power

present LED

Input level adjustable

over –10dBV to

+10dBu range

Model 40 Back Panel

SEE INSTRUCTION MANUAL

!

100V

0.4A
120V

0.2A

220/240V

50/60Hz

AC mains

connection

Mains voltage

configuration chart

CAUTION:

TO PREVENT ELECTRICAL
SHOCK, DO NOT REMOVE

COVER OR BACK.

NO USER SERVICEABLE

PARTS INSIDE. REFER

SERVICINGTO QUALIFIED

SERVICE PERSONNEL.

Signal

Present LEDs

5520 WEST TOUHY AVE.
SKOKIE, IL 60077 U.S.A.

[phone]

MADE IN U.S.A.

Output to talent

TO TALENT AMPLIFIERS

OUTPUT B

amplifiers—

Group B

Switch between

Input 1 and 2 for the

Output Groups

TO TALENT AMPLIFIERS

OUTPUT A

Output to talent

amplifiers—

Group A

LEDs display

error conditions

MODEL 40 CENTRAL CONTROLLER

L

R

INPUT 2

Stereo line inputs

1 and 2

L

R

INPUT 1

Issue 1, July 1994 Model 40 User Guide
Page 6 Studio Technologies, Inc.

Model 35 Talent Amplifier

Model 38 Talent Amplifier

The Model 35 Talent Amplifier is a por­table amplifier unit capable of driving 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. A single microphone­type cable links the Model 35 with the
Model 40 Central Controller.

Model 35 Front Panel

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 40. This allows the Model 38
user to create an individual headphone

1

STEREO
MONO (L+R)

2

OUTPUTLEVELPOWER

HEADPHONE

OUTPUT

Model 35 Back Panel

Power present

LED

MODEL 35 TALENT AMPLIFIER

5520 W. TOUHY AVE.

SKOKIE, IL. 60077

U.S.A.

Connects to additional

talent amplifiers

Headphone output

level control

Connects to the Model 40 or another talent

Switch between stereo

and mono (L+R) output

SN

PUSH

INPUTLOOP THRUMADE IN U.S.A.

amplifier’s loop thru connector

Two headphone

outputs

Model 40 User Guide Issue 1, July 1994
Studio Technologies, Inc. Page 7

mix, solving the classic problem of wanting
“more me” in the phones! Like the Model
35, the Model 38 is linked with a Model 40
Central Controller by a single cable.

Model 38 Front Panel

MIC

LINE

POWER

Power

present LED

Mic/Line button switches

the talent input between

microphone and line level

Model 38 Back Panel

MODEL 38 TALENT AMPLIFIER

CUE MIX (FROM CENTRAL CONTROLLER)

LEVEL LEVEL

STEREO
MONO (L) MONO (L+R)

TALENT

Talent level

to phones

Switch between

stereo and mono

(L only) for the

talent input

STUDIO TECHNOLOGIES, INC., SKOKIE, IL U.S.A. [phone]

PUSHPUSH

MADE

IN

U.S.A.

LOOP THRU

CUE MIX

Cue mix level

to phones

TALENT

STEREO

LOOP THRUIN LEFT/MONO IN RIGHTLOOP THRU IN

1

2

HEADPHONE

OUTPUT

Two headphone

Switch between stereo

and mono (L+R) for

the cue mix

SN

PUSH

outputs

Connects to additional

talent amplifiers

Connects to the Model

40 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

Issue 1, July 1994 Model 40 User Guide
Page 8 Studio Technologies, Inc.

Installation

In this section you will be installing the
Model 40 Central Controller in an equip­ment rack. Audio input connections will be
made. Wiring will be installed to allow
Model 35 or Model 38 Talent Amplifiers to
be connected. AC mains power will be
connected to the Model 40.

System Components

The main StudioComm shipping carton
contains a Model 40 Central Controller,
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
will be contained in separate cartons.
Please check to ensure you have every­thing you need.

Sample Installation

Please refer to the following page for a
diagram detailing a possible Model 40 and
talent amplifier installation.

Mounting the Model 40

The Model 40 requires one space in a
standard 19-inch (48.3cm) equipment
rack. It is desirable to locate the Model 40
to allow easy access to both the front and
the back panels. The back panel contains
the input and output connectors, while the
front panel contains several controls,
switches, and LED indicators. The Model
40 is secured to the equipment rack using
two mounting screws per side.

Audio Inputs

The Model 40’s line-level audio input
connections are made using ¼-inch
3-conductor phone jacks. Don’t be con-

cerned about damage to your audio quality,
the jacks we use are manufactured by
Neutrik of Switzerland and feature gold­plated contacts for excellent performance.

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.

Stereo Line Inputs

The Model 40 allows two stereo line input
sources to be connected. During operation
either talent amplifier output group can
select either of the stereo inputs as its
source. This allows flexibility in routing the
desired source to the desired group of
talent amplifiers. In some installations only
one stereo source may be available. In this
case the one stereo source should be
connected to input 1. For future use it may
be wise to connect input 2 to points on a
patch bay. This will allow rapid connection
of another audio source should the need
arise.

The input circuitry is electronically balanced,
and is compatible with balanced or unbal­anced signals that have a nominal level
range of –10dBV to +10dBu. The input
impedance is 50K ohms so that compatibil­ity with virtually every source is assured.

Prepare the input plugs so that tip is posi­tive (+ or hot), ring is negative (– or cold),
and sleeve is shield. The input jacks will
also accept unbalanced ¼-inch 2-conductor
phone plugs. With unbalanced phone plugs,
tip is positive (+ or hot) and sleeve is shield.
If 3-conductor phone plugs are used to
connect unbalanced input signals, connect
positive (+ or hot) to tip and shield to ring
and sleeve.

Model 40 User Guide Issue 1, July 1994
Studio Technologies, Inc. Page 9

Example Installation

Recorder/Reproducer

Model 40 Central Controller

Model 35 Talent Amplifiers

Model 38 Talent Amplifier

Output Group 1

Output Group 2

Total of eight headphones per group

Issue 1, July 1994 Model 40 User Guide
Page 10 Studio Technologies, Inc.