Extron electronic MLS 406, MLS 406SA, MLS 406MA User Manual

MLS 304MA, MLS 304SA, MLS 406,

MLS 406MA, MLS 406SA

MediaLink™ Switchers

68-775-01 Rev. C

06 06

Precautions

Safety Instructions • English

This symbol is intended to alert the user of important operating and maintenance
(servicing) instructions in the literature provided with the equipment.

This symbol is intended to alert the user of the presence of uninsulated dangerous
voltage within the product’s enclosure that may present a risk of electric shock.

Caution

Read Instructions • Read and understand all safety and operating instructions before using the equipment.
Retain Instructions • The safety instructions should be kept for future reference.
Follow Warnings • Follow all warnings and instructions marked on the equipment or in the user

information.

Avoid Attachments • Do not use tools or attachments that are not recommended by the equipment

manufacturer because they may be hazardous.

Consignes de Sécurité • Français

Ce symbole sert à avertir l’utilisateur que la documentation fournie avec le matériel
contient des instructions importantes concernant l’exploitation et la maintenance
(réparation).

Ce symbole sert à avertir l’utilisateur de la présence dans le boîtier de l’appareil
de tensions dangereuses non isolées posant des risques d’électrocution.

Attention

Lire les instructions• Prendre connaissance de toutes les consignes de sécurité et d’exploitation avant

d’utiliser le matériel.

Conserver les instructions• Ranger les consignes de sécurité afin de pouvoir les consulter à l’avenir.
Respecter les avertissements • Observer tous les avertissements et consignes marqués sur le matériel ou

présentés dans la documentation utilisateur.

Eviter les pièces de fixation • Ne pas utiliser de pièces de fixation ni d’outils non recommandés par le

fabricant du matériel car cela risquerait de poser certains dangers.

Sicherheitsanleitungen • Deutsch

Dies es Symbol soll dem Benut zer in der im Liefer umfang ent haltenen
Dokumentation besonders wichtige Hinweise zur Bedienung und Wartung
(Instandhaltung) geben.

Dieses Symbol soll den Benutzer darauf aufmerksam machen, daß im Inneren des
Gehäuses dieses Produktes gefährliche Spannungen, die nicht isoliert sind und
die einen elektrischen Schock verursachen können, herrschen.

Achtung

Lesen der Anleitungen • Bevor Sie das Gerät zum ersten Mal verwenden, sollten Sie alle Sicherheits-und

Bedienungsanleitungen genau durchlesen und verstehen.

Aufbewahren der Anleitungen • Die Hinweise zur elektrischen Sicherheit des Produktes sollten Sie

aufbewahren, damit Sie im Bedarfsfall darauf zurückgreifen können.

Befolgen der Warnhinweise • Befolgen Sie alle Warnhinweise und Anleitungen auf dem Gerät oder in der

Benutzerdokumentation.

Keine Zusatzgeräte • Verwenden Sie keine Werkzeuge oder Zusatzgeräte, die nicht ausdrücklich vom

Hersteller empfohlen wurden, da diese eine Gefahrenquelle darstellen können.

Warning

Power sources • This equipment should be operated only from the power source indicated on the product. This

equipment is intended to be used with a main power system with a grounded (neutral) conductor. The
third (grounding) pin is a safety feature, do not attempt to bypass or disable it.

Power disconnection • To remove power from the equipment safely, remove all power cords from the rear of

the equipment, or the desktop power module (if detachable), or from the power source receptacle (wall
plug).

Power cord protection • Power cords should be routed so that they are not likely to be stepped on or pinched by

items placed upon or against them.

Servicing • Refer all servicing to qualified service personnel. There are no user-serviceable parts inside. To

prevent the risk of shock, do not attempt to service this equipment yourself because opening or removing
covers may expose you to dangerous voltage or other hazards.

Slots and openings • If the equipment has slots or holes in the enclosure, these are provided to prevent

overheating of sensitive components inside. These openings must never be blocked by other objects.

Lithium battery • There is a danger of explosion if battery is incorrectly replaced. Replace it only with the

same or equivalent type recommended by the manufacturer. Dispose of used batteries according to the
manufacturer’s instructions.

Avertissement

Alimentations• Ne faire fonctionner ce matériel qu’avec la source d’alimentation indiquée sur l’appareil. Ce

matériel doit être utilisé avec une alimentation principale comportant un fil de terre (neutre). Le troisième
contact (de mise à la terre) constitue un dispositif de sécurité : n’essayez pas de la contourner ni de la
désactiver.

Déconnexion de l’alimentation• Pour mettre le matériel hors tension sans danger, déconnectez tous les cordons

d’alimentation de l’arrière de l’appareil ou du module d’alimentation de bureau (s’il est amovible) ou
encore de la prise secteur.

Protection du cordon d’alimentation • Acheminer les cordons d’alimentation de manière à ce que personne ne

risque de marcher dessus et à ce qu’ils ne soient pas écrasés ou pincés par des objets.

Réparation-maintenance • Faire exécuter toutes les interventions de réparation-maintenance par un technicien

qualifié. Aucun des éléments internes ne peut être réparé par l’utilisateur. Afin d’éviter tout danger
d’électrocution, l’utilisateur ne doit pas essayer de procéder lui-même à ces opérations car l’ouverture ou le
retrait des couvercles risquent de l’exposer à de hautes tensions et autres dangers.

Fentes et orifices • Si le boîtier de l’appareil comporte des fentes ou des orifices, ceux-ci servent à empêcher

les composants internes sensibles de surchauffer. Ces ouvertures ne doivent jamais être bloquées par des
objets.

Lithium Batterie • Il a danger d’explosion s’ll y a remplacment incorrect de la batterie. Remplacer uniquement

avec une batterie du meme type ou d’un ype equivalent recommande par le constructeur. Mettre au reut les
batteries usagees conformement aux instructions du fabricant.

Vorsicht

Stromquellen • Dieses Gerät sollte nur über die auf dem Produkt angegebene Stromquelle betrieben werden.

Dieses Gerät wurde für eine Verwendung mit einer Hauptstromleitung mit einem geerdeten (neutralen)
Leiter konzipiert. Der dritte Kontakt ist für einen Erdanschluß, und stellt eine Sicherheitsfunktion dar. Diese
sollte nicht umgangen oder außer Betrieb gesetzt werden.

Stromunterbrechung • Um das Gerät auf sichere Weise vom Netz zu trennen, sollten Sie alle Netzkabel

aus der Rückseite des Gerätes, aus der externen Stomversorgung (falls dies möglich ist) oder aus der
Wandsteckdose ziehen.

Schutz des Netzkabels • Netzkabel sollten stets so verlegt werden, daß sie nicht im Weg liegen und niemand

darauf treten kann oder Objekte darauf- oder unmittelbar dagegengestellt werden können.

Wartung • Alle Wartungsmaßnahmen sollten nur von qualifiziertem Servicepersonal durchgeführt werden.

Die internen Komponenten des Gerätes sind wartungsfrei. Zur Vermeidung eines elektrischen Schocks
versuchen Sie in keinem Fall, dieses Gerät selbst öffnen, da beim Entfernen der Abdeckungen die Gefahr
eines elektrischen Schlags und/oder andere Gefahren bestehen.

Schlitze und Öffnungen • Wenn das Gerät Schlitze oder Löcher im Gehäuse aufweist, dienen diese zur

Vermeidung einer Überhitzung der empfindlichen Teile im Inneren. Diese Öffnungen dürfen niemals von
anderen Objekten blockiert werden.

Litium-Batterie • Explosionsgefahr, falls die Batterie nicht richtig ersetzt wird. Ersetzen Sie verbrauchte

Batterien nur durch den gleichen oder einen vergleichbaren Batterietyp, der auch vom Hersteller
empfohlen wird. Entsorgen Sie verbrauchte Batterien bitte gemäß den Herstelleranweisungen.

Instrucciones de seguridad • Español

Este símbolo se utiliza para advertir al usuario sobre instrucciones importantes
de operación y mantenimiento (o cambio de partes) que se desean destacar en el
contenido de la documentación suministrada con los equipos.

Este símbolo se utiliza para advertir al usuario sobre la presencia de elementos con
voltaje peligroso sin protección aislante, que puedan encontrarse dentro de la caja
o alojamiento del producto, y que puedan representar riesgo de electrocución.

Precaucion

Leer las instrucciones • Leer y analizar todas las instrucciones de operación y seguridad, antes de usar el

equipo.

Conservar las instrucciones • Conservar las instrucciones de seguridad para futura consulta.
Obedecer las advertencias • Todas las advertencias e instrucciones marcadas en el equipo o en la

documentación del usuario, deben ser obedecidas.

Evitar el uso de accesorios • No usar herramientas o accesorios que no sean especificamente recomendados

por el fabricante, ya que podrian implicar riesgos.

安全须知 • 中文

这个符号提示用户该设备用户手册中有重要的操作和维护说明。

这个符号警告用户该设备机壳内有暴露的危险电压，有触电危险。

注意

阅读说明书 • 用户使用该设备前必须阅读并理解所有安全和 使用说明。
保存说明书 • 用户应保存安全 说明书以备将来使用。
遵守警告 • 用户应遵守产品和用户指南上的所有安全和操作说明。
避免追加 • 不要使用该产品厂商没有推荐的工具或追 加设备，以避免危险。

Advertencia

Alimentación eléctrica • Este equipo debe conectarse únicamente a la fuente/tipo de alimentación eléctrica

indicada en el mismo. La alimentación eléctrica de este equipo debe provenir de un sistema de distribución
general con conductor neutro a tierra. La tercera pata (puesta a tierra) es una medida de seguridad, no
puentearia ni eliminaria.

Desconexión de alimentación eléctrica • Para desconectar con seguridad la acometida de alimentación eléctrica

al equipo, desenchufar todos los cables de alimentación en el panel trasero del equipo, o desenchufar el
módulo de alimentación (si fuera independiente), o desenchufar el cable del receptáculo de la pared.

Protección del cables de alimentación • Los cables de alimentación eléctrica se deben instalar en lugares donde

no sean pisados ni apretados por objetos que se puedan apoyar sobre ellos.

Reparaciones/mantenimiento • Solicitar siempre los servicios técnicos de personal calificado. En el interior no

hay partes a las que el usuario deba acceder. Para evitar riesgo de electrocución, no intentar personalmente
la reparación/mantenimiento de este equipo, ya que al abrir o extraer las tapas puede quedar expuesto a
voltajes peligrosos u otros riesgos.

Ranuras y aberturas • Si el equipo posee ranuras o orificios en su caja/alojamiento, es para evitar el

sobrecalientamiento de componentes internos sensibles. Estas aberturas nunca se deben obstruir con otros
objetos.

Batería de litio • Existe riesgo de explosión si esta batería se coloca en la posición incorrecta. Cambiar esta

batería únicamente con el mismo tipo (o su equivalente) recomendado por el fabricante. Desachar las
baterías usadas siguiendo las instrucciones del fabricante.

警告

电源 • 该设备只能使用产品上标明的电源。 设备必须使用有地线的供电系统供电。 第三条线

（地线）是安全 设施，不能 不用或跳过 。

拔掉电源 • 为安全地从设备拔掉电源，请拔掉所有设备后或 桌面电源的电源线，或任何接到市

电系统的电源线。

电源线保护 • 妥善布线， 避免被 踩踏，或重物 挤压。
维护 • 所有维修必须由认证的维修人员进行。 设备内部没有用户可以更换的零件。为避免出现

触电危险不要自己试图打开设备盖子维修该设备。

通风孔 • 有些设备机壳上有通风槽或孔，它们是用来防止机内敏感元件过热。 不要用任何东

西挡住通风 孔。

锂电池 • 不正确的更换电池会有爆炸的危险。必须使用与厂家推荐的 相同或相近型号的电池。

按照生产厂的建议处 理废弃电池。

Quick Start — MLS 304MA, MLS 406, MLS 406MA

NOTE Both the toggle switch

position and the
wiring must match the

down = 4 ohm or 8 ohm

direct connection

up = 70 V or 100 V

transformer

Installation

Step 1

Remove power from the switcher and the input,
output, and control devices.

Step 2

Install the rubber feet on the bottom corners or
rack mount the switcher.

Step 3

Connect input devices to the switcher. See
chapter 2 for details and wiring diagrams.

MLS 304MA

Inputs 1 and 2: composite video and audio
Inputs 3 and 4: RGB computer video or

composite video and audio

MLS 406, MLS 406MA

Inputs 1, 2, 3: S-video or composite video

and audio

Inputs 4, 5, 6:

or composite video and audio

Aux/Mix audio input

Connect a mono audio source to mix a line­level audio signal with the selected input’s
audio. This channel is always active.

See chapters 3 and 4 for details on setting up the
audio and configuring video.

Step 4

Connect cables from the MLS’s RGB, S-video,
and video output connectors to the inputs on the
display device.

Connect a cable between the Monitor Output
port and the local monitor.

N

There are three modes (selectable only via

RGB computer video, S-video,

RS‑232 control) for determining which
input signal, if any, is sent to the
Monitor Output port. For an explanation
of modes and video routing, see Video
Signal Routing on page 3‑7. For
selecting the mode, see chapter 4, Serial
Communication.

Step 6

Adjust the audio (sensitivity) level for each input.
See Making adjustments on page 3-6.

Step 7

Connect audio devices to the Lineout and
Preamp audio outputs

• Lineout outputs a fixed, line level audio

signal not affected by Volume knob
adjustments.

• Preamp outputs a variable, line level audio

signal for use with powered speakers or an
amplifier. The volume can be attenuated via
the Volume knob or RS-232.

Lineout and Preamp outputs can be set up as

• -10 dBV (-8 dBu, 0.316 Vrms, default),

unbalanced, for consumer level devices
such as VCRs or stereo receiver-amplifiers

or

• +4 dBu (+6 dBV, 1.23 Vrms), balanced, for

professional level devices such as mixers

and power amplifiers
depending on how the connector is wired and
how the MLS is set up via RS-232 control.
Selecting mono or stereo (via RS-232) affects both
of these ports. See Audio outputs on pages 2-9
through 2-10.

Step 8

Connect a host computer, control system,
MediaLink Controller (MLC) and/or an Extron
IR Link to the RS-232/MLC/IR control port. See
Control Connection on pages 2-7 through 2-8.

Step 7 — MLS 304MA, MLS 406MA

Connect speakers to the amplified output
(MLS 304MA, MLS 406MA) for mono audio out-

put. See pages 2-11 through 2-13 for diagrams.
Set the rear panel toggle switch to the desired

amplifier output type: transformer (Xfmr) (for a
70 V or 100 V system) or Direct (4 or 8 ohms).

Step 5

Connect a host computer to the RS-232/MLC/IR
control port (see Control Connection on page 2-6),
load and start the control software, set up the
video, select a Monitor Output mode, and select a
Lineout/Preamp output level.

This output provides a mono signal even if the
input is a stereo signal. For stereo output, use
the non-amplified Lineout and Preamp outputs
instead. See chapter 2, Installation.

Quick Start — MLS 304MA, MLS 406, MLS 406MA, cont’d

R

S

-2

32

/M

L

C

/IR

Tx

RxIR 12V

A

B

C

P

R

E

A

M

P

1

0

0

-

2

4

0

V

1

.

0

A

M

A

X

.

5

0

-6

0

H

z

INPUT 4

AUDIO INPUTS

LIN

E LEVEL
MONO

AUD

IO

AUDIO

LINEOUT

AUX/MIX

ADJUST

-42dB
TO

+24dB

L

R

L

R

L

R

1

2

3

IN

PUTS

OUTPUTS

VIDEO

H

V

B

G

R

Y

1

2

3

INPUTS

MON

ITOR O

UT

4

5

6

C

D

IRECT

X

F

M

R

C

O

M

4/8 ohm

100V

70V

AMPLIFIED OUTPUT

20 WATTS MONO

System
Control

Mono Amplified Output

Projector Control

Extron
MLS 406MA

MediaLink Switcher

VCRDVD

Projector

Speakers

PC

Laptop

w/ Audio

or

Document Camera

Extron

MediaLink
Controller

MAX

MID

MIN

MAX

MID

MIN

Signal: when lit, this indicates that a signal of at

least -20 dBV (-18 dBu) is detected at the input.

Clip: a blinking/lit LED indicates that the

level is set too high.

Normal: a blinking LED indicates that the level

is set properly for maximum power output.

NOTE Increasing the audio level beyond the point at

which the Mid/normal LED blinks may result in
a distorted output signal.

NOTE In setup mode a blinking or lit Mid/normal LED

indicates that the power amplifier is capable of
delivering maximum power output.

NOTE You may not need to adjust the per-input gain,

because the default input gain adjustment is set
for consumer audio sources such as VCRs, DVD
players, and laptop computers.

MLS 304MA, MLS 406MA, MLS 304SA, and
MLS 406SA

(amplified models)

Signal: when lit, this indicates that a signal of at

least -20 dBV (-18 dBu) is detected at the input.

Peak: if blinking/lit, the level is set too high.

Normal: if blinking/lit, the output level at the

Lineout and Preamp connectors is near the
specified output level of -10 dBV or +4 dBu.

MLS 406 (nonamplified model)

-10 dBV
sensitivity

Step 8

Connect all the devices’ power cords, and power
on the system.

Video Configuration

Step 1

Via RS-232, configure the MLS: select the video
type for 15-pin HD inputs; See chapters 2,

Installation and 4,

Serial Communication.

Step 2

Select a Monitor Output mode via the control
software. See Monitor Output Modes on page 3-7
and chapter 4,

Serial Communication.

Audio Configuration

Step 1

For the Lineout and Preamp outputs, select mono
or stereo audio, and select -10 dBV (unbalanced)
or +4 dBu (balanced) via RS-232 control.
Default: -10 dBV.

4a. Enter setup mode: press and hold an in-

put button for 3 seconds. The input’s LED
blinks.

Adjust audio levels: while still holding the

4b.

input button, rotate the Volume knob until
the Mid/normal LED lights or blinks.

Step 2

Via RS-232, set Aux/Mix to on
or off. If the Aux/Mix input will
be used, use a small screwdriver to
adjust the Aux/Mix input level.

Step 3

Disconnect audio output devices.

Step 4

Select an input and set audio input sensitivities.

N

Audio input sensitivity levels must be

adjusted with an active audio signal.

4c. Release the input button to save the setting

for that input.

Repeat steps 4a through 4c for each input.

4d.

Step 5

Reconnect the output devices, and via RS-232
set the global treble and bass levels and turn on
loudness control, if desired.

Table of Contents

Chapter 1 • Introduction ............................................................................................................ 1-1

About this Manual .................................................................................................................... 1-2

About the MLS 304 Series and the MLS 406 Series .............................................. 1-2

Features ........................................................................................................................................... 1-2

All models .................................................................................................................................. 1-2

MA models ................................................................................................................................ 1-2

SA models ...........................................................................................................................1-2

Chapter 2 • Installation ................................................................................................................ 2-1

UL/Safety Requirements ..................................................................................................2-2

Important safety instructions

Mounting the Switcher ....................................................................................................2-2

Tabletop use
Rack mounting

.......................................................................................................................2-2

...................................................................................................................2-2

Rear Panels and Cabling .......................................................................................................2-3

Power, input, and control connections ................................................................................. 2-3

Power connection
A/V input connections
Control connection

Video output, local monitor, and audio output connections .........................................2-7

Video outputs ..................................................................................................................... 2-9

Audio outputs

Wiring for 4 ohm or 8 ohm speakers (MA models)
Wiring for a 70 volt or 100 volt distributed speaker system (MA models)
Wiring for 4 ohm or 8 ohm speakers (SA models)
Speaker arrangement examples

Examples of speaker layouts

............................................................................................................... 2-3

..................................................................................................................... 2-9

.............................................................................................2-2

........................................................................................................ 2-3

.............................................................................................................. 2-6

.................................................. 2-11

............. 2-12

.................................................... 2-13

................................................................................ 2-14

................................................................................ 2-14

PRELIMINARY

Application Diagrams ........................................................................................................... 2-15

Chapter 3 • Operation and Setup ........................................................................................ 3-1

Front Panel Features and Operation ............................................................................. 3-2

Front panel security lockout (executive modes) .................................................................. 3-3

Enabling/disabling executive mode 1; disabling executive mode 2

Resetting the switcher ............................................................................................................. 3-4

Setting Up and Optimizing the Audio .......................................................................... 3-4

Configuring Lineout and Preamp output levels .................................................................. 3-5

Adjusting audio input levels .................................................................................................. 3-5

Making adjustments

........................................................................................................... 3-6

Video Signal Routing .............................................................................................................. 3-7

Monitor Output Modes ........................................................................................................... 3-7

Standard mode (mode 3)
DA (distribution amplifier) mode (mode 2)

RGB follow mode (mode 1)................................................................................................. 3-7

.................................................................................................... 3-7

....................................................................... 3-7

MLS 304 Series, MLS 406 Series • Table of Contents

................................ 3-4

i

PRELIMINARY

Table of Contents, cont’d

Remote Control .......................................................................................................................... 3-8

Troubleshooting ......................................................................................................................... 3-9

If the image does not appear or there is no sound ............................................................ 3-9

If the switcher does not respond to controls ....................................................................... 3-9

If you are unable to configure the MLS via the Windows®-based software ................... 3-9

Chapter 4 • Serial Communication ..................................................................................... 4-1

RS-232 Programmer’s Guide ...............................................................................................4-2

Host-to-MLS communications ................................................................................................ 4-2

MLS-initiated messages
Error responses

Using the command/response tables ................................................................................. 4-3

Symbol definitions

Command/response table for SIS commands ....................................................................... 4-4

Command/response table for special function SIS commands .......................................... 4-7

...................................................................................................................4-2

Control Software for Windows

Installing the software ............................................................................................................ 4-8

Using the control program ..................................................................................................... 4-8

User Mode screen

Special features

Switcher (MLS) Config screen

File menu options .................................................................................................................. 4-12

Saving and restoring configurations
Updating firmware

Using the help program ........................................................................................................ 4-14

Key to file names ................................................................................................................... 4-14

...................................................................................................... 4-2

.............................................................................................................. 4-3

®

...................................................................................... 4-8

................................................................................................................ 4-9

............................................................................................................. 4-9

........................................................................................... 4-10

............................................................................... 4-12

........................................................................................................... 4-12

Appendix A • Reference Material ........................................................................................A-1

Specifications ..............................................................................................................................A-2

Part Numbers and Accessories ..........................................................................................A-6

Included parts ...........................................................................................................................A-6

Optional accessories ................................................................................................................A-6

Frequency Response Graph for the Loudness Feature ......................................A-7

Audio Reference Levels .........................................................................................................A-7

Audio Block Diagrams ..................................................................................................... A-8

MLS 304MA audio block diagram
MLS 304SA audio block diagram
MLS 406, MLS 406MA audio block diagram
MLS 406SA audio block diagram

All trademarks mentioned in this manual are the properties of their respective owners.

.................................................................................... A-8

..................................................................................... A-9

.................................................................. A-10

................................................................................... A-11

68-775-01 Rev. C

06 06

ii

MLS 304 Series, MLS 406 Series • Table of Contents

MLS 304 Series and MLS 406 Series

Chapter One

1

Introduction

About this Manual

About the MLS 304 Series and MLS 406 Series

Features

Introduction

About this Manual

This manual covers the installation, setup, programming, and use of the Extron
MLS 304MA, MLS 304SA, MLS 406, MLS 406MA, and MLS 406SA MediaLink™
switchers. The three models share many features, and instructions apply to
all three unless otherwise stated. Throughout the manual these switchers are
interchangeably referred to as MLS, MediaLink switcher, and switcher. Procedures
or explanations that are model-specific mention the model name (e.g. MLS 406MA).

About the MLS 304 Series and the MLS 406 Series

The Extron MLS 304MA, MLS 304SA, MLS 406, MLS 406MA, and MLS 406SA
are four- and six-input, active switchers. They accept RGB computer video (all
models), S-video (MLS 406 Series), composite video inputs (all models), stereo
audio inputs, and a line level mono audio auxilliary/mixer input.

Each switcher has a local monitor loop-through/output in addition to the RGB
and video projector/plasma display output and balanced or unbalanced lineout
and preamp audio outputs. If desired, the monitor output can be used as a second
RGB display output instead of for a local monitor. Additionally, the MA models
offer amplified mono audio output for 4 ohm, 8 ohm, or distributed 70 V or 100 V
speaker systems. The SA models offer amplified stereo audio output for 4 ohm or
8 ohm speaker systems.

These switchers can all be set up and controlled via the front panel buttons or via
an RS-232 connection from a computer, a control system, or an Extron MediaLink
Controller. Some setup options are available only via the included Windows-based
MediaLink Control Program. With the addition of an optional Extron IR Link
infrared signal repeater, an Extron MediaLink IR remote control can be used for
input selection and volume adjustment.

Features

All models

MA models

SA models

• High RGB video bandwidth (280 MHz at -3 dB)

• Triple-Action Switching™ (RGB delay switching)

• Video format versatility: the switchers accept RGB computer video, S-video
(MLS 406, MLS 406MA, MLS 406SA), and composite video

• Monitor Output for local monitor loop-through or for an additional RGB output

• Aux/Mix audio input for mixing mono line level audio with the switchable
audio input

• Adjustable audio bass, treble, and volume

• Individually adjustable audio input levels

• Balanced or unbalanced preamp audio output

• Loudness control

• Ability to lock the front panel to prevent unauthorized access (executive mode)

• Control and configuration via RS-232

• Ventilated 1U, rack mountable, metal enclosure

• Integrated 20 watt mono audio amplifier for 4 ohm or 8 ohm, or 16 watts for 70 V
or 100 V distributed output

• Integrated 24 watt audio amplifier for stereo or dual mono 4 ohm output or
16 watts for stereo or dual mono 8 ohm output

1-2

MLS 304 Series, MLS 406Series • Introduction

MLS 304 Series and MLS 406 Series

Chapter Two

2

Installation

UL/Safety Requirements

Mounting the Switcher

Rear Panels and Cabling

Application Diagrams

PRELIMINARY

Installation

UL/Safety Requirements

The Underwriters Laboratories (UL) requirements listed below pertain to the safe
installation and operation of a MediaLink Switcher.

Important Safety Instructions

1. Read these instructions.

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not use this apparatus near water.

6. Clean only with a dry cloth.

7. Do not block any ventilation openings. Install in accordance with the

8

9

10

11

12. Use only with the cart, stand, tripod, bracket, or table specified by the

13

14. Refer all servicing to qualified service personnel. Servicing is required when

manufacturer’s instructions.

. Do not install near any heat sources such as radiators, heat registers, stoves,

or other apparatus (including amplifiers) that produce heat.

. Do not defeat the safety purpose of the polarized or grounding type plug. A

polarized plug has two blades with one wider than the other. A grounding
type plug has two blades and a third grounding prong. The wide blade or the
third prong are provided for your safety. If the provided plug does not fit into
your outlet, consult an electrician for replacement of the obsolete outlet.

. Protect the power cord from being walked on or pinched particularly at

plugs, convenience receptacles, and the point where they exit from the
apparatus.

. Only use attachments/accessories specified by the manufacturer.

manufacturer, or sold with the apparatus. When a cart is used, use caution
when moving the cart/apparatus combination to avoid injury from tip-over.

. Unplug this apparatus during lightning storms or when unused for long

periods of time.

the apparatus has been damaged in any way, such as power-supply cord
or plug is damaged, liquid has been spilled or objects have fallen into the
apparatus, the apparatus has been exposed to rain or moisture, does not
operate normally, or has been dropped.

2-2

MLS 304 Series, MLS 406 Series • Installation

Rack Mount MLS 304MA.eps

MLS 304MA

MediaLink Switcher

CON

TROL

PEAK

C

LIP

SIGNAL

IN

PUT SELEC

T

1

2

3

4

Mounting the Switcher

Tabletop use

Each MLS switcher comes with rack mounting brackets and rubber feet. For table­top use, attach a self-adhesive rubber foot to each corner of the bottom of the unit.

Rack mounting

For rack mounting, do not install the rubber feet. Attach the provided rack
mounting brackets to the switcher with machine screws, then fasten the switcher to
the rack using the supplied machine screws.

Although it is not required, for the models with audio amplification (MLS 304MA,
MLS 304SA, MLS 406MA, MLS 406SA) Extron recommends allowing one rack unit
of space (1.75"/4.5 cm) above and below the switcher for air circulation to prevent
overheating.

C

The MA and SA models contain a class AB amplifier, which gets hot.

There is no cooling fan in the MLS switcher.

PRELIMINARY

Rack mounting the MediaLink Switcher

MLS 304 Series, MLS 406 Series • Installation

2-3

Installation

AUDIO INPUTS

LINE LEVEL

MONO

AUDIO

AUDIO

AUX/MIX

ADJUST

-42dB
TO

+24dB

L

R

L

R

1

2

INPUTSOUTPUTS

VIDEO

H

V

B

G

R

1

2

INPUTS

3

4

MONITOR OUT

100-240V

1.0A MAX.

50-60Hz

RL

AUDIO INPUTS

LINE LEVEL

MONO

AUDIO

AUDIO

AUX/MIX

ADJUST

-42dB

TO

+24dB

L

R

L

R

L

R

1

2

3

INPUTS

OUTPUTS

VIDEO

H

V

B

G

R

Y

1

2

3

INPUTS

MONITOR OUT

4

5

6

C

100-240V

1.0A MAX.

50-60Hz

RS-232/MLC/IR

Tx

Rx IR 12V

A B C

PREAMPLINEOUT

4

RL RL

RS-232/MLC/IR

Tx

Rx IR 12V

A B C

PREAMPLINEOUT

RL RL

2 4 5

3a

3b

61

MLS 304MA and MLS 304 SA Rear Panel

MLS 406, MLS 406MA, and MLS 406SA Rear Panel

Sleeve (Gnd )

Tip (+)

Sleeve ( )

Audio RCA connector color_2.eps

Right Channel
(Red Jacket)

Left Channel
(White Jacket)

Tip (Signal)

Rear Panels and Cabling

Power, input, and control connections

N The MA and SA models differ only by amplifier output type and connection.

Power connection

a

All other A/V, power, and control connections are the same.

AC power connector — Plug a standard IEC power cord into this connector to

connect the switcher to a 100 to 240 VAC, 50 Hz or
The front panel power LED (

) lights while the MLS is receiving power.

60 Hz power source.

A/V input connections

b

PRELIMINARY

Ñ

N

2-4

MLS 304 Series, MLS 406 Series • Installation

B Video inputs —

MLS 304MA MLS 304SA: connect a composite video source device to each of

these female RCA (tip-ring) connectors for video inputs 1 and 2.

MLS 406, MLS 406MA, MLS 406SA: connect either an S-video source (using

the 4-pin mini DIN connector) or a composite video source (using the
BNC connector) for input 1, 2, or 3.

RCA audio inputs — These audio inputs correspond to the like-numbered

video inputs. These inputs accept line level audio signals from consumer
and professional audio sources. Consumer devices such as PCs, VCRs, and
DVD players typically output an unbalanced -20 dBV to -10 dBVsignal.
Professional products such as mixers and signal processing gear typically
output a balanced 0 dBu to +4 dBu (+6 dBV) level signal.
To adjust input levels, see pages 3-5 and 4-10 through 4-11.

Connect an unbalanced stereo audio source to each pair of RCA jacks. Use
the red sheathed cable/connector for the right channel, and use the white
sheathed cable/connector for the left channel as shown below.

Wiring RCA connectors for unbalanced stereo audio input

After the audio inputs and outputs are connected, see chapter 3 for

instructions on how to adjust the per-input audio input levels and optimize
audio input and output.

L R

L R

L R

L R

Unbalanced Stereo Input

Tip

Sleeve

Tip

Sleeve

Balanced Stereo Input

Tip

Ring

Sleeve (s)

Tip

Ring

(high impedance)

(high impedance)

Unbalanced Mono Input

Tip

Sleeve

Tip

Sleeve

Balanced Mono Input

Tip

Ring

Sleeve (s)

Tip

Ring

(high impedance)

(high impedance)

0.2” (5 mm) max.

The length of exposed wires is critical.
The ideal length is 0.2" (5 mm).

• If the stripped section of wire is
longer than 0.2", the exposed
wires may touch, causing a
short circuit between them.

• If the stripped section of wire is
shorter than 0.2", wires can be
easily pulled out even if tightly
fastened by the captive screws.

Do not tin the wires!

Input Type

Signal (BNC Color)

15-pin HD Pin

S-video Y (green), C (blue) 2, 3

Composite video video (red) 1

V = vertical sync

R = red or video

G = green or S-video (Y)

B = blue or S-video (C)

H/HV = horiz. sync

MLS 406, MLS 406MA, MLS 406SA audio input 4 (captive screw) — This

Ö

input accepts line level audio signals from consumer and professional audio
sources. Consumer devices such as laptops, VCRs, and DVD players typically
output an unbalanced -20 dBV to -10 dBV signal. Professional products such
as mixers and signal processing gear typically output a balanced +4 dBu level
signal. To adjust input levels, see pages 3-5 and 4-10 through 4-11.

Wire the 3.5 mm captive screw connector as shown in the
following illustrations, depending on input signal type.

N After the audio inputs and outputs are connected, see chapter 3 for

instructions on how to adjust the per-input audio sensitivity levels and
optimize audio input and output.

Computer video (and audio) inputs — MLS 304MA and MLS 304SA inputs
3 and 4; and MLS 406, MLS 406MA, and MLS 406SA inputs 4, 5, and 6, all on
15-pin HD connectors; are individually buffered and provide ID bit
termination. They accept

• RGB computer video signals (default) or

• S-video (MLS 406 Series only) or composite video (all models)

For S-video or composite video, the switcher must be configured via RS-232
serial control (SIS commands or control software); see pages 4-4 and 4-10
through 4-11.

For RGB input, connect a standard VGA-style cable from the source computer
to the desired MLS input. For S-video or composite video input, you may
need to use an adapter cable such as an Extron SY 15HDM-RGBHV cable
(shown below). Connect the video or S-video source to the MLS as follows:

N Selecting S-video or composite video for these inputs limits the Monitor

Output mode options to Standard Mode.

MLS 304 Series, MLS 406 Series • Installation

PRELIMINARY

2-5

Installation, cont’d

Sleeve ( )

Ring (R)

Tip (L)

3.5 mm Stereo Plug
(unbalanced)

-10 dBV
sensitivity

LINE LEVEL

MONO

AUX/MIX

ADJUST

-42dB
TO

+24dB

+ Positive

– Negative

Ground

For these inputs (excluding input 4 on the
MLS 406/MLS 406MA/MLS 406SA), connect the
corresponding unbalanced stereo audio signal
to the 3.5 mm mini stereo (tip-ring-sleeve) jack.
Wire the stereo connectors as shown at right.

N

e

N

C

After the audio inputs and outputs are

Aux/Mix audio input and adjustment — To mix an auxiliary, mono,

line-level audio signal (from a wireless microphone
receiver, for example) with the selected input’s audio,
connect the cable from the mono source to this 3-pole
captive screw connector. The signal can be balanced
or unbalanced. See the diagram at right.

The Aux/Mix level can be changed ONLY via this rear

The Aux/Mix input accepts line level audio
signals from consumer and professional audio
sources. Consumer devices such as PCs, VCRs,
DVD players, and some wireless microphones
typically output an unbalanced -20 dBV to -10 dBV signal. Professional
products such as mixers and signal processing gear typically output a
balanced 0 dBu to +4 dBu level signal.

connected, adjust the per-input audio
sensitivity levels and optimize audio input and
output. See pages 3-5 and 3-6 for instructions.

panel control. It can not be controlled or adjusted by
RS-232 control, or by a MediaLink Controller.

The maximum auxiliary input signal level is +4 dBu. Do not exceed this

input level.

PRELIMINARY

This input’s audio channel is always active, and it is independent of the
selectable audio inputs (1-4 or 1-6). The Aux/Mix audio can be heard
throughout a presentation, whether or not another input is selected.

N

N If you mute audio input by selecting input zero (SIS commands 0! or 0$), only

N Aux/Mix input can be turned off (muted) via a separate RS-232 command

N The Aux/Mix level can be changed ONLY via this rear panel control. It can

N The optional MediaLink Audio Control Module (ACM-Level, part

If audio output is muted via the 1Z SIS command, all audio outputs are

muted. You are not able to hear audio from any source.

audio from the numbered inputs (1-4 or 1-6) is muted. The Aux/Mix audio
input stays active and is not affected by selection of audio input 0.

(0M). See chapter 4, Serial Communication for details.

To adjust the Aux/Mix input level, use a small screwdriver
to turn the control adjacent to the Aux/Mix connector.
The adjustment range is -42 dB to +24 dB. Setting the
potentiometer to the marked location sets the input level
sensitivity for an approximately -10 dBV consumer signal.

not be controlled or adjusted by RS-232 control, or by a MediaLink Controller.

#70-182-01, -02, -03) is not compatible with these switchers. The mix level
control is not supported.

2-6

MLS 304 Series, MLS 406 Series • Installation

RS-232/MLC/IR

Tx

Rx IR

12V

A

B

C

Transmit (Tx)
Receive (Rx)

Sleeve(s)

+12 V, 0.4 A power output

Ground ( )

RS-232
MLC/IR

MediaLink Switcher to an MLC

MediaLink

Switcher
rear panel
RS-232/MLC/IR port

NOTE

The switcher provides up to 12 VDC, 0.40 A power to an MLC 206.
Other MLC models may draw more current than the MLS can provide.
Extron recommends using a separate power supply for the MLC.

NOTE If you use cable that has a

drain wire, tie the drain wire
to ground at both ends.

RS-232_MLC-IR port wiring_MLS304_062404.eps

RS-232
MLC/IR

Tx RxIR+12V

Tx RxIR

+

12 V

MediaLink Switcher to an IR Link

MediaLink
Switcher
rear panel
RS-232/MLC/IR port

IR Link
port

A B C

A B C

MediaLink Switcher Rear Panel

RS-232
MLC/IR

TxRxIR+12V

AB C

MediaLink Switcher Rear Panel

RS-232
MLC/IR

TxRxIR +12V

AB C

Ground ( )

+12 VDC

Transmit (Tx)

B

Receive (Rx)

A

250 feet (76.2 m) maximum

150 feet (45.7 m) maximum

Ground ( )

+12 VDC

IR (IR Link)

C

IR Link

MLA-Remote

SIGNAL

IR

A B C D E

D

DVD

MLC
MLS/Power
port

A B

MLS / Power

Transmit (Tx)
Receive (Rx)

+12 VDC

Ground ( )

B
A

MediaLink
Controller

(MLC)

Control connection

RS-232/MLC/IR control port —You can control the MLS switcher via an

f

RS-232 connection directly from a host computer, a control system, or a
MediaLink Controller (MLC). Alternatively, you can use IR remote control
via an Extron IR Link connected to this port.

Connect a cable between this port and an optional

Extron MLC MediaLink Controller or an optional
IR Link IR signal repeater.

• The MLC provides remote control of input switching
and volume.

• The IR Link accepts modulated IR signals
from a remote control so the remote control
can be used for selecting the switcher’s
inputs.

Extron Comm-Link cable is recommended
for this connection. If you use Comm-Link
cable, the switcher and controller (MLC) can be up to 250 feet (76.2 m) apart.
Wire the captive screw connector for connection to an IR Link, an MLC, or a
computer or control system as shown in the following four diagrams.

MLS 304 Series, MLS 406 Series • Installation

PRELIMINARY

2-7

RS-232
MLC/IR

MediaLink Switcher to an MLC

MediaLink

Switcher
rear panel
RS-232/MLC/IR port

NOTE

The switcher provides up to 12 VDC, 0.40 A power to an MLC 206.
Other MLC models may draw more current than the MLS can provide.
Extron recommends using a separate power supply for the MLC.

Ground ( )

+12 VDC input

NOTE If you use cable that has a

drain wire, tie the drain wire
to ground at both ends.

RS-232
MLC/IR

MediaLink Switcher to an MLC
that has an external power supply

MediaLink
Switcher
rear panel
RS-232/MLC/IR port

NOTE

If using an external power
supply (instead of the MLS) to
power the MLC, you must
connect a ground wire
between the MLC and MLS.

NOTE If you use cable that has a

drain wire, tie the drain wire
to ground at both ends.

RS-232_MLC-IR port wiring_MLS304_062404.eps

RS-232
MLC/IR

Tx RxIR +12V

Tx RxIR

+12 V

Tx RxIR

+12V

MediaLink Switcher to an IR Link

MediaLink
Switcher
rear panel
RS-232/MLC/IR port

IR Link
port

A B C

A B C

A B C

MediaLink Switcher Rear Panel

RS-232
MLC/IR

TxRxIR+12V

AB C

MediaLink Switcher Rear Panel

RS-232
MLC/IR

TxRxIR+12V

AB C

MediaLink Switcher Rear Panel

RS-232
MLC/IR

TxRxIR+12V

AB C

RS-232
MLC/IR

RS-232 port

of a

computer or

control system

MediaLink Switcher to a
computer or control system

MediaLink
Switcher
rear panel
RS-232/MLC/IR port

NOTE

Connect a ground wire
between the MLC and the
computer or control system.

NOTE If you use cable that has a

drain wire, tie the drain wire
to ground at both ends.

Tx RxIR +12V

A B C

MediaLink Switcher Rear Panel

RS-232
MLC/IR

TxRxIR+12V

AB C

Host Computer Control System

or

Ground ( )

+12 VDC

Transmit (Tx)

B

Receive (Rx)

A

Ground ( )

Transmit (Tx)

B

Receive (Rx)

A

Ground ( )

Transmit (Tx)

B

Receive (Rx)

A

250 feet (76.2 m) maximum

150 feet (45.7 m) maximum

Ground ( )

+12 VDC

IR (IR Link)

C

IR Link

MLA-Remote

SIGNAL

IR

A B C D E

D

DVD

MLC
MLS/Power
port

MLC
MLS/Power
port

A B

MLS / Power

Transmit (Tx)
Receive (Rx)

+12 VDC

Ground ( )

B
A

A B

MLS / Power

Transmit (Tx)
Receive (Rx)

B
A

Transmit (Tx)
Receive (Rx)

3
2

Ground all devices

External

Power Supply

(12 VDC, 1A max.)

External

Power Supply

MediaLink
Controller

(MLC)

MediaLink
Controller

(MLC)

1

5

9

6

7
6
5
4
3
2
1

8

9

Purple

Blue

Green

Yellow

Orange

Red

Brown

Grey

Black

Connector Shell

Pin #Color

UC Cable

Shield

UC 50', 100', 200' Cable Color Codes

To the

computer

or
control
system

To the

MLS

switcher

Installation, cont’d

PRELIMINARY

You may use a male 9-pin D-to-bare-wire RS-232 cable or a universal
control cable (UC 50', UC 100', or UC 200') for the connection to a computer
or control system. One end of the UC cable is terminated with a female
9-pin D connector, and the other end is unterminated. The UC cable’s
pin assignments are as shown in the following illustration. Refer to the
computer/control system’s pin assignment guide to determine which of the
cable’s wires to connect to which of the MLS’s RS-232/MLC/IR port pins.

2-8

MLS 304 Series, MLS 406 Series • Installation

AUDIO INPUTS

LINE LEVEL

MONO

AUDIO

AUDIO

AUX/MIX

ADJUST

-42dB
TO

+24dB

L

R

L

R

1

2

INPUTSOUTPUTS

VIDEO

H

V

B

G

R

3

4

MONITOR OUT

OUTPUTS

VIDEO

H

V

B

G

R

Y

MONITOR OUT

C

RL

AUDIO INPUTS

LINE LEVEL

MONO

AUDIO

AUDIO

AUX/MIX

ADJUST

-42dB
TO

+24dB

L

R

L

R

L

R

1

2

3

INPUTS

OUTPUTS

VIDEO

H

V

B

G

R

Y

MONITOR OUT

4

5

6

C

RS-232/MLC/IR

Tx

Rx IR 12V

A B C

PREAMPLINEOUT

AUDIO INPUTS

LINE LEVEL

MONO

AUDIO

AUDIO

AUX/MIX

ADJUST

-42dB
TO

+24dB

L

R

L

R

1

2

OUTPUTS

VIDEO

H

V

B

G

R

3

4

MONITOR OUT

AUDIO INPUTS

AUDIO

AUDIO

L

R

L

R

L

R

1

2

3

INPUTS

4

5

6

LINE LEVEL

MONO

AUX/MIX

ADJUST

-42dB
TO

+24dB

INPUTS

AMPLIFIED OUTPUT

20 WATTS MONO

DIRECT

XFMR

COM

4/8 ohm

100V

70V

AMPLIFIED OUTPUT

20 WATTS MONO

DIRECT

XFMR

COM

4/8 ohm

100V

70V

4

RL RL

RS-232/MLC/IR

Tx

Rx IR 12V

A B C

PREAMPLINEOUT

RL RL

AMPLIFIED OUTPUT

4/8 ohm

RIG HT LEF T

STEREO OR DUAL MONO

CLASS 2 WIRI NG

RL

RS-232/MLC/IR

Tx

Rx IR 12V

A B C

PREAMPLINEOUT

4

RL RL

RS-232/MLC/IR

Tx

Rx IR 12V

A B C

PREAMPLINEOUT

RL RL

3a

3b

61

7 8 9 10 11

12

MLS 304MA Rear Panel

MLS 406MA Rear Panel

MLS 406SA Rear Panel
(amplifier output)

VIDEO

Y

C

H

V

B

G

R

H

V

B

G

R

H

V

B

G

R

RGBHV RGBS RGsB, RsGsBs

S-video

(MLS 406 Series)

Composite

video

Video output, local monitor, and audio output connections

Video outputs

Display outputs — Connect cables from the

g

appropriate port(s) on the projector or display
panel to these BNC connectors according to the
output signal type, as shown below.

The output signal is in the same format (RGBHV, RGBS, RGsB, RsGsBs,
S-video, or composite video) as the input signal. The signal is switched,
but not processed. Cables can be connected between the projector and
one, some, or all of the switcher’s video outputs.

Monitor Output — This 15-pin HD connector serves as either a local

h

monitor loop-through port or an additional RGB output. Connect a cable
between this port and the local or additional display device.

There are three different options (modes) for determining which input

signal, if any, is sent to the monitor output. These modes are selectable
only via RS-232 control. For an explanation of modes and video routing,
see pages 3-7 and 3-8. See chapter 4, Serial Communication for details
on selecting the mode.

Audio outputs

Lineout audio output and Preamp audio output — These outputs are
simultaneously active and can be wired and configured for balanced or
unbalanced mono or stereo audio signal output. The switcher must also
be configured for the corresponding signal type (mono or stereo).

Selecting either mono or stereo (via RS-232 by way of the control software
or SIS commands) selects the output signal format for both the Lineout
and Preamp outputs. The switcher configuration (mono or stereo) and
the output wiring must match.

• The Lineout connector outputs a fixed, line level audio signal that is

not affected by front panel Volume knob adjustments. A recording
or assistive listening device would typically be connected here.

MLS 304 Series, MLS 406 Series • Installation

PRELIMINARY

2-9

Installation, cont’d

Unbalanced Stereo Output

Tip

NO GROUND HERE.

Sleeve(s)

Tip

NO GROUND HERE.

Balanced Stereo Output

Tip

Ring

Sleeve(s)

Tip

Ring

L R

L R

L R

L R

Unbalanced Mono Output Balanced Mono Output

Tip

NO GROUND HERE.

Sleeve

Tip

Ring

Sleeve

Left

Right

Left

Right

Left

Right

Left

Right

CAUTION

For unbalanced audio, connect the sleeve(s) to
the center contact ground. DO NOT connect
the sleeve(s) to the negative (-) contacts.

• The Preamp connector outputs a variable, line level audio signal for

Lineout and Preamp outputs can be set up as

• unbalanced, -10 dBV (-7.8 dBu, 0.316 Vrms, default) for consumer level

or

• balanced, +4 dBu (+1.8 dBV, 1.228 Vrms) for professional devices such

depending on how the connector is wired and how the MLS is set up (via the
control software). See the following wiring diagrams and chapter 4,
Communication.

use with a powered amplifier or self-powered speakers. The volume
can be controlled (attenuated) via the front panel knob or RS-232
communication. The volume range is 0 (mute) through 100.

devices such as VCRs, DVD players, and stereo receivers

as mixers, signal processors, and power amps

Serial

C Connect the sleeve to ground (Gnd). Connecting the sleeve to a negative

(-) terminal will damage the audio output circuits.

N For mono output, wire either the left or the right side, not both.

PRELIMINARY

2-10

MLS 304 Series, MLS 406 Series • Installation

C Do not bridge mono outputs. The left and right input signals are

summed, and each mono output channel carries the same combination
signal.

N

If the output is wired for balanced output, the level is +6 dB higher than the

level for unbalanced output wiring. The balanced/unbalanced level difference
occurs no matter which line level output setting is chosen via RS-232. See
page 4-10.

N After the audio inputs and outputs are connected, see chapter 3, Operation

and Setup for instructions on how to adjust the per-input audio sensitivity

levels and optimize Lineout and Preamp output.

N If the Loudness feature is turned on, the gains for bass and treble frequencies

are affected for all outputs whenever volume is adjusted.

Amplified output (MLS 304MA, MLS 406MA only) — Cable speakers to this
5-position screw terminal for a mono amplified audio output. This provides a
mono output signal even if the input is a stereo signal. For stereo output, use
the non-amplified Lineout and Preamp outputs instead.

The 4 ohm/8 ohm direct connection circuit and the 70 V/100 V transformer
connection are mutually exclusive: only one circuit (direct or transformer) can
be active at a time.

C

Do not short the terminals to ground or the amplifier will be damaged.

C Do not bridge mono outputs. Bridging could damage the amplifier.

Two 8 ohm speakers wired in
parallel equal a 4 ohm load.

4 Ohm Load or

8 Ohm Load

4 Ohm Total Load 4 Ohm Total Load

8 Ohm Total Load

Two 4 ohm speakers wired in
series equal an 8 ohm load.

8 Ohm Total Load

AMPLIFIED OUTPUT

20 WATTS MONO

DIRECT

XFMR

COM

4/8 ohm

100V

70V

AMPLIFIED OUTPUT

20 WATTS MONO

DIRECT

XFMR

COM

4/8 ohm

100V

70V

AMPLIFIED OUTPUT

20 WATTS MONO

DIRECT

XFMR

COM

4/8 ohm

100V

70V

4/8 ohm

4/8 ohm

Mono –

Mono +

Mono –

8
ohms

8
ohms

4 ohms

4 ohms

Mono +

Mono –

4
ohms

Mono +

Mono –

Mono +

4
ohms

4
ohms

4
ohms

Mono –

8
ohms

Mono +

8
ohms

8
ohms

8
ohms

The MA models’ amplifier power-up delays are approximately

• 10 seconds for 70 V or 100 V output, 8 seconds to hear the relay click

• 8 seconds for 4 ohm or 8 ohm output

Wiring for 4 ohm or 8 ohm speakers (MA models)

The maximum power output when an MLS 304MA or MLS 406MA is wired

for 4 ohm or 8 ohm speakers is 20 watts per channel.

1. Flip the toggle switch down (Direct) to select 4 ohm or 8 ohm connection.

2. Use the appropriate wiring for the load as shown in the following

illustrations.

PRELIMINARY

MLS 304 Series, MLS 406 Series • Installation

2-11