Ecler MPA4-150R, MPA6-150R User Manual

USER MANUAL
MANUAL DE INSTRUCCIONES
NOTICE D'UTILISATION
BEDIENUNGSANLEITUNG

2

3

INSTRUCTION MANUAL

1. IMPORTANT REMARK 04

2. INTRODUCTION 04

3. INSTALLATION 07

3.1. Placement and mounting 07

3.2. Mains connection 07

3.3. Ground Link switch 07

3.4. Multi-function 08

3.5. Input connections 09

3.6. Input options 10

3.7. Limiter circuit 11

3.8. Output connections 11

3.9. Output options 12

4. OPERATION AND USAGE 12

4.1. Start up 12

4.2. Input attenuation 13

4.3. Remote control 13

4.4. Connection of the VCA control 14

4.5. Indicators 14

5. CLEANING 15

6. DIAGRAMS 16

6.1. Function list 16

6.2. Function diagram 17

6.3. Configuration diagram 60

6.4. Technical characteristics 61

6.5. Block diagram 62

All numbers subject to variation due to production tolerances. ECLER SA reserves the right to make changes or
improvements in manufacturing or design which may affect specifications.

4

1. IMPORTANT REMARK
Congratulations! You are the owner of a carefully designed and manufactured equipment. We

thank you for having purchased our MPA R power amplifier.

It is VERY IMPORTANT that you read this manual before connecting the amplifier in order to

obtain its maximum performance.

We recommend our authorised Technical Services whenever any maintenance task should be

needed so that optimum operation shall be achieved.

2. INTRODUCTION
This multichannel power amplifier has been designed using the same technology as the PAM

amplification series. With this technology, ECLER introduced a new concept to the world of professional
audio: The use of switching field effect transistors. The SPM-Technology (Switching Power Mosfet) has
been developed and patented by ECLER S.A. The use of these parts for audio applications represents a
firm and spectacular enhancement comparing to conventional amplifiers.

These advantages can be outlined as follows:
a) Lower internal resistance than bipolar transistors, which leads to less heating of the amplifier

and more powerful and controllable bass.

Conventional Mosfets have a 4 to 7 times bigger internal resistance than switching Mosfets.
b) The extremely high speed of these devices gives a transparency to the upper frequencies till

now only achieved by tube amplifiers. This fact also reduces TIM (transitory intermodulation) to very low
levels.

c) All MPA-R models have an independent VCA control for each input channel, which can be

used to connect, for example, a remote potentiometer to adjust the corresponding signal level (ECLER
accessories are recommended for this use). Any other device which generates a DC voltage from 0 to
10V can be used to adjust the input signal level. It is also possible to use relays or any dry contact to
create a remote “MUTE” function for any of the input channels. This allows the user to remotely and
independently fix the attenuation/MUTE of the input signal, which will be send to the amplifier selected
with the switches on the rear panel of the unit.

A single potentiometer (o control signal) can be used for more than one or even all input

channels if suitable wiring is used (see detailed information in section 4.4.).

The VCA circuit is disabled by default. If using this circuit is desired, it has to be activated using

internal jumpers (see configuration diagram).

d) All MPA-R models have “STACK” connectors for “INPUT1, INPUT2” to send these signals to

other amplifiers or sound systems.

5

MPA4-150R

The MPA4-150R amplifier station consists of four 160W/4Ω amplifiers which can be configured

through a set of switches found on the rear panel. This allows multiple amplification setups useful in
many situations, for example:

• Four mono amplifiers for four different mono inputs.
When setup this way, the MPA R is able to amplify four different audio signals, each one having a
dedicated volume control.

• Four mono amplifiers for one common mono input.
The amplifier operates now with just one input signal for all amplifiers, but preserves the ability to control
each channels volume independently. This setup is useful when distributing signals to different zones.

• Four mono amplifiers for one common stereo input.
This setup is similar to the previous example but the input is now a stereo signal. The amplifier adds
both stereo channels together converting them into a mono signal.

• Two stereo amplifiers for two different stereo inputs.
Each stereo channel offers a dedicated volume control. Useful for addressing two zones with two
different stereo signals.

• Two stereo amplifiers for one common stereo input.
This setup is similar to the previous example but the input is now a single stereo signal which is fed to
both amplifiers.

• Two bridged amplifiers for two different mono inputs.
Now you get a typical stereo amplifier configuration. With a bridged amplifier you obtain doubled output
power with a load of at least 8Ω.

• Two bridged amplifiers for a common mono input.
The MPA R operates now with a single mono signal for two mono amplifiers, each one with its own
volume control.

• Two bridged amplifiers for two different stereo inputs.
You can obtain two zones with independent volume control and two different stereo signals, but these
stereo signals are internally converted to mono in each bridged amplifier.

• Two bridged amplifiers for a common stereo input.
This setup is similar to the previous example but the input is now a stereo signal. The amplifier adds
both stereo channels together converting them into a mono signal.

• One stereo amplifier and one bridged amplifier for a common stereo input.
Useful for setups where a stereo amplifier drives the mid-range and high frequency speakers while a
second, bridged amplifier drives a subwoofer. This multichannel amplifier features a low-pass filter to
operate on a subwoofer system and a high-pass filter for the mid-range speakers and tweeters.

6

MPA6-150R

The MPA6-150R amplifier station consists of six 170W/4Ω amplifiers which can be configured
through a set of switches found on the rear panel. This allows multiple amplification setups useful in
many situations, for example:

• Six mono amplifiers for six different mono inputs.
When setup this way, the MPA R is able to amplify six different audio signals, each one having a
dedicated volume control.

• Six mono amplifiers for one common mono input.
The amplifier operates now with just one input signal for all amplifiers, but preserves the ability to control
each channel volume independently. This setup is useful when distributing signals to different zones.

• Six mono amplifiers for one common stereo input.
This setup is similar to the previous example but the input is now a stereo signal. The amplifier adds
both stereo channels together converting them into a mono signal.

• Three stereo amplifiers for three different stereo inputs.
Each stereo channel offers a dedicated volume control. Useful for addressing three zones with three
different stereo signals.

• Three stereo amplifiers for one common stereo input.
This setup is similar to the previous example but the input is now a single stereo signal which is fed to all
three amplifiers.

• Three bridged amplifiers for three different mono inputs.
Useful for addressing three zones with three different mono signals. Each bridged channel offers a
dedicated volume control. With a bridged amplifier you obtain doubled output power with a load of at
least 8Ω.

• Three bridged amplifiers for a common mono input.
The MPA operates now with a single mono signal for three mono amplifiers, each one with its own
volume control.

• Three bridged amplifiers for a common stereo input.
This setup is similar to the previous example but the input is now a stereo signal. The amplifier adds
both stereo channels together converting them into a mono signal.

• Four mono amplifiers and one bridged amplifier for one common mono input.
Useful for setups with four amplifiers for mid-range speakers and tweeters and an extra (bridged)
amplifier for a subwoofer. This multichannel amplifier features a low-pass filter to operate on a
subwoofer system and a high-pass filter for the mid-range speakers and tweeters.

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3. INSTALLATION

3.1. Placement and mounting

The amplifier is presented as a 2 unit high 19'' rack module. It is supplied with plastic washers in
order not to damage the unit when tightening the screws.
It is important that the amplifier, as a heat source, is not placed next to other equipment nor exposed to
high temperatures.

3.2. Mains connection

The amplifier operates on alternate currents, depending on the country 110-120, 220-240V
50/60Hz (see characteristics in the back of the unit). The power consumption at maximum performance
is 1095VA for the MPA4-150 R and 1590VA for the MPA6-150 R. It's important that your mains
installation is adequately rated to these power demands.
The amplifier should have an earth connection in good conditions (earth resistance, Rg=30Ω or
less). The environment must be dry and dustless. Do not expo se the un it to rai n or wate r splas hes, and
do not place liquid containers or incandescent objects like candles on top of the unit. Do not obstruct the
ventilation grids with any kind of material.
In case there is some type of intervention and/or connection-disconnection of the amplifier, it is most
important to previously disconnect the mains power supply. There are no user or serviceable parts inside
the amplifier.
You should avoid that the supply cable twists with the shielded signal cables, as this could lead to
unwanted hum.

In order to protect the unit from an eventual electrical overload or momentary power peaks from
the internal circuits it carries a fuse. Should it ever blow up, unplug the unit from mains and replace it
with an identical one. If the new fuse blows again contact immediately with our Authorized Technical
Service.

CAUTIO N: THE FUSE IS INTERNAL AND SHOULD ONLY BE MANIPULATED BY QUALIFIED
SERVICE PERSONNEL. YOU MUST NEVER USE A HIGHER VALUE FUSE.

3.3. Ground Link switch

The “GND LINK” switch (53) purpose is to avoid ground loops caused when several devices in
the same amplification chain are connected to earth simultaneously. This switch disconnects the
electrical ground from the mechanical ground on the housing. In case of a ground loop (humming noise)
operate this switch or alternatively the corresponding switches on the other devices connected to the
chain.

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3.4. Multi-function

Depending on the input switches on the MPA R (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
located on the rear panel, four different amplification configurations can be achieved:

MPA4-150R MPA6-150R

- 4 mono amplifiers with following possibilities: - 6 mono amplifiers with following possibilities:
4 different mono inputs 6 different mono inputs
1 common mono input for all 1 common mono input for all
1 common stereo input for all 1 common stereo input for all

- 2 stereo amplifiers with following possibilities: - 3 stereo amplifiers with following possibilities:
2 different stereo inputs 3 different stereo inputs
1 single stereo input for both 1 single stereo input for both

- 2 bridged amplifiers with following possibilities: - 3 bridged amplifiers with following possibilities:
2 different mono inputs 3 different mono inputs
1 common mono input 1 common mono input
1 common stereo input 1 common stereo input

- Combinations between mono, stereo and bridged - Combinations between mono, stereo and bridged

On the rear panel you can also activate the high-pass and low-pass filters:

High-pass filter ON/OFF switch (27, 31). The cut-off frequency lies at 160Hz for amplifiers 3 and
4 (5 and 6) simultaneously or when operating in bridged mode. This filter cuts out all frequency
components under 160Hz and passes the rest, being specially suited for connecting the mid-range and
high frequency speakers.

Low-pass filter ON/OFF (23). Filter with 160Hz cut off frequency for amplifiers 1 and 2 together or
when working in bridge mode, which eliminates audio signals with frequencies higher than 160Hz and
lets through those signals with frequencies lower than 160Hz.

Combining one bridged amplifier with switched on low-pass filter together with a stereo amplifier
with switched on high-pass filter turns your multichannel power amplifier into an ideal equipment for
clubs and other locations with a subwoofer, mid-range speakers and tweeters.

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3.5. Input connections

The signal input connections (41, 42, 43, 44, 45, 46) are electronically balanced XLR-3 sockets,
with input impedance higher than 20kΩ and a nominal sensitivity of 0dBV(1V). Pin assignment:

1. GROUND

2. PHASE (in phase with the output)

3. NON PHASE (inverted phase)

The following diagram shows the connection of balanced and non-balanced audio sources:

The “STACK” (39, 40) are in parallel with the inputs and are used to supply the same "INPUT 1,
INPUT 2" input signal to other amplifiers or sound systems. This signal output connectors are of jack 1/4"
type. The pin assignment is as follows:

HOT or direct signal > Tip
COLD or inverted signal > Ring
GROUND > Body

Some of the connection options and the corresponding switch settings are described later in
paragraph 3.6.

Depending on the chosen option, the "SP" indicators will only light for the active channels.

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3.6. Input options

OPTION MPA4-150R MPA6-150R

1

mono

4 mono amplifiers for 4 different mono
signal

6 mono amplifiers for six different mono signal

2

mono

4 mono amplifiers for a common mono
input

6 mono amplifiers for a common mono input

3

mono

4 mono amplifiers for a common stereo
input

6 mono amplifiers for a common stereo input

4

stereo

2 stereo amplifiers for 2 different stereo
inputs

3 stereo amplifiers for three different stereo
inputs

5

stereo

2 stereo amplifiers for a common stereo
input

3 stereo amplifiers for a common stereo input

6

bridged

2 bridged amplifiers for 2 different mono
signals

3 bridged amplifiers for three different mono
signals

7

bridged

2 bridged amplifiers for a common mono
signal

3 bridged amplifiers for a common mono signal

8

bridged

2 bridged amplifiers for a common stereo
signal

3 bridged amplifiers for a common stereo signal

9

combination

1 bridged amplifier and 2 mono amplifiers
for a common mono input

1 bridged amplifier and 4 mono amplifiers for a
common mono input

10

combination

1 bridged amplifier and 1 stereo amplifier
for 2 different stereo inputs

1 bridged amplifier and 2 stereo amplifier for
three different stereo inputs

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combination

1 bridged amplifier and 1 stereo amplifier
for a common stereo input

1 bridged amplifier and 2 stereo amplifiers for a
common stereo input

MPA6-150R

MPA4-150R - - MPA4-150R - - MPA4-150R -

INPUT SIGNALS INPUT SELECTORS MODE ST-BR

N.

1 2 3 4 5 6 CH1 CH2 CH3 CH4 CH5 CH6 CH1-2 CH3-4 CH5-6

1 I1 I2 I3 I4 I5 I6 IN1 IN2 IN3 IN4 IN5 IN6 ST ST ST
2 I - - - - - IN1

LINK

CH1

LINK

CH1

LINK

CH2

LINK

CH3

LINK

CH4

ST ST ST

3 L R - - - - IN1+IN2

LINK

CH1

LINK

CH1

LINK

CH2

LINK

CH3

LINK

CH4

ST ST ST
4 L1 R1 L2 R2 L3 R3 IN1 IN2 IN3 IN4 IN5 IN6 ST ST ST
5 L R - - - - IN1 IN2

LINK

CH1

LINK

CH2

LINK

CH3

LINK

CH4

ST ST ST
6 I1 - I2 - I3 - IN1 - IN3 - IN5 - BR BR BR
7 I - - - - - IN1 -

LINK

CH1

-

LINK

CH3

- BR BR BR

8 L R - - - - IN1+IN2 -

LINK

CH1

-

LINK

CH3

- BR BR BR

9 I - - - - - IN1

LINK

CH1

LINK

CH1

LINK

CH2

LINK

CH3

LINK

CH4

BR ST ST

10 L1 R1 L2 R2 L3 R3 IN1+IN2 - IN3 IN4 IN5 IN6 BR ST ST
11 L R - - - - IN1+IN2 IN2

LINK

CH1

LINK

CH2

LINK

CH3

LINK

CH4

BR ST ST

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3.7. Limiter circuit
This system is an always active protection inside the MPA R series of amplifiers. The ANTICLIP

circuitry constantly analyses harmonic distortion caused by excessive signal excursion at the power
amplifier's output and automatically reduces the input level in order never to reach distortion.

The great convenience of such a circuit in any kind of installation has to be remarked: The clear
advantage of a limiting system in front of conventional compressors is that the former does practically not
alter the dynamic range, acting only when the distortion threshold is reached.

3.8. Output connections

The OUTPUTS section at the rear panel has screwable terminals (47, 48, 49, 50, 51, 52), one for

each amplifier.

The attenuation controls and the output configurations are described later in paragraph 3.9.

The cable which connects the speakers to the amplifier should be high quality and as short and
thick as possible. This is important when covering long distances; For up to 10m we recommend a cable
section not smaller than 2.5mm². For longer distances we recommend 4mm².

Remember that the minimum load impedance for stereo or mono amplifiers is 4Ω. In bridged
mode the impedance must be not less than 8Ω. For a reliable operation under any circumstance connect
lower load impedances than just specified.

Attention: use only the indicated terminals when using the amplifiers in bridge mode.

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3.9. Output options

OPTION MPA4-150R MPA6-150R

1 mono 4 mono amplifiers 6 mono amplifiers

2 stereo 2 stereo amplifiers 3 stereo amplifiers

3 bridged 2 bridged amplifiers 3 bridged amplifiers

4 combination 1 bridged amplifier and 2 mono amplifiers

for a common mono input

1 bridged amplifier and 4 mono amplifiers for a
common mono input

5 combination 1 bridged amplifier and 1 stereo

amplifiers for 2 different stereo amplifiers

1 bridged amplifier and 2 stereo amplifiers for
3 different stereo amplifiers

4. OPERATION AND USAGE

4.1. Start up

To switch the unit on just push the switch labelled POWER (20) and the integrated pilot-light will
light up. We highly recommend the "safe power-up sequence": First the sound sources, then mixer,
equalizers and active filters and, finally, power amplifiers. Powering off should be done by following the
exact reverse sequence in order to avoid any possible peaks reaching the next device, and
consequently protecting the loudspeakers, which are specially sensitive to these peaks.

MPA4-150R

N. ACTIVE VOL CH 1 CH 2 CH 3 CH 4

1 CH1,2,3,4 + - + - + - + ­2 CH1,2,3,4 + - + - + - + ­3 CH1,3 + BRIDGED - + BRIDGED ­4 CH1,3,4 + BRIDGED - + - + ­5 CH1,3,4 + BRIDGED - + - + -

MPA6-150R

N. ACTIVE VOL CH 1 CH 2 CH 3 CH 4 CH 5 CH 6

1 CH1,2,3,4,5,6 + - + - + - + - + - + ­2 CH1,2,3,4,5,6 + - + - + - + - + - + ­3 CH1,3,5 + BRIDGED - + BRIDGED - + BRIDGED ­4 CH1,3,4,5,6 + BRIDGED - + - + - + - + ­5 CH1,3,4,5,6 + BRIDGED - + - + - + - + -

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4.2. Input attenuation

These are rotary trimmers located on the front panel (1, 4, 7, 10, 13, 16).

These attenuators allow the connection of different mixers, an independent volume control and
the connection of speakers not able to handle the amplifiers maximum output power, thus avoiding the risk
of damaging them with the mixers or preamps volume control.
Inside the device's packaging you will find a little plastic bag containing transparent caps, which
protect the input attenuation settings from unwanted manipulation. These caps are transparent in order
to let you visualize the current settings.

Once inserted, they cannot be removed with bare fingers, for this purpose, a small screwdriver is

needed.

4.3. Remote control
The MPA R rear panel offers one terminal per amplifier to remotely control the volume, using the

built-in “VCA” circuit.
The combined usage of the rotary potentiometers located at the front panel and the remote VCA
control determines the final value of the signal’s attenuation for each input channel. Therefore, a certain
value can be fixed for the signal attenuation
using the rotary so that the remote control via
VCA will not exceed this value and viceversa,
that is, the two controls are connected in
series.
This functionality can be useful in
installations where users with little experience
are in charge of volume adjustment.

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4.4. Connection of the VCA control
As already mentioned in the introduction of this manual, the signal attenuation level for each of the

input channels can be set using the following methods:

a) Using a remote potentiometer with nominal resistance between 10kΩ and 50kΩ.
b) Using a device that generates a control voltage from 0 to 10V DC.
c) Using remote relays/dry contacts.

NOTE

: it is possible to connect a maximum of 16 inputs to one control potentiometer. It is

necessary that the ground terminals of all amplifiers are connected.

The connection cables can be up to 500m long if a section of 0,5mm

2

is used.
Consult the available accessories at your ECLER dealer or at www.ecler.com.
Remember that the VCA circuit is disabled by default. If you need to use it, you have to activate it

using the internal jumpers (see configuration diagram).

4.5. Indicators
The SP signal presence indicators (3, 6, 9, 11, 14, 17) light up when the input signal reaches

approximately -40dBV.

The CLIP indicators (2, 5, 8, 12, 15, 18) light up when the output signal for the speakers is -1,5dB

below the actual clipping threshold. This clipping system watches for eventual supply voltage variations,
thus giving always an accurate clipping indication, regardless of mains voltage deviations. It is normal
that when operating at high output power, the CLIP indicators light up in synchronisation with the low
frequencies, which carry the most energy. Nevertheless, you should avoid that the CLIP indicators are lit
continuously.

Thermal protection indicator “THERMAL” (19), it shines when the cooling tunnel temperature
reaches 90ºC. The amplifier will automatically restart when the temperature lessens to 80ºC.

15

5. CLEANING

The front panel should not be cleaned with dissolvent or abrasive substances because
silk-printing could be damaged. To clean it, use a soft cloth slightly wet with water and neutral liquid
soap; dry it with a clean cloth. Be careful that water never gets into the amplifier through the holes of the
front panel.

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6. DIAGRAMS 6.1. Function list

1. Channel 1 volume, CH1

2. Channel 1 Clip indication, CLIP

3. Input 1 Signal presence, SP

4. Channel 3 volume, CH3

5. Channel 3 Clip indication, CLIP

6. Input 3 Signal presence, SP

7. Channel 5 volume, CH5

8. Channel 5 Clip indication, CLIP

9. Input 5 Signal presence, SP

10. Channel 2 volume, CH2

11. Input 2 Signal presence, SP

12. Channel 2 Clip indication, CLIP

13. Channel 4 volume, CH4

14. Input 4 Signal presence, SP

15. Channel 4 Clip indication, CLIP

16. Channel 6 volume, CH6

17. Input 6 Signal presence, SP

18. Channel 6 Clip indication, CLIP

19. Thermal protection indication, TH

20. Power switch and pilot light, POWER

21. Channel 1 / Channel 1+ 2, IN1/IN1+IN2

22. Channel 2 / link channel 1, IN2/LINK CH1

23. Low-pass filter switch, LP FILTER

24. Stereo / bridge channel 1 switch, 1+2

25. Channel 3 / link channel 1, IN3/LINK CH1

26. Channel 4 / link channel 2, IN4/LINK CH2

27. High-pass filter switch, HP FILTER

28. Stereo / bridge channel 3 switch, 3+4

29. Channel 5 / link channel 3, IN5/LINK CH3

30. Channel 6 / link channel 4, IN6/LINK CH4

31. High-pass filter switch, HP FILTER

32. Stereo / bridge channel 5 switch, 5+6

33. Screwable terminal for remote control 1, CH 1

34. Screwable terminal for remote control 2, CH 2

35. Screwable terminal for remote control 3, CH 3

36. Screwable terminal for remote control 4, CH 4

37. Screwable terminal for remote control 5, CH 5

38. Screwable terminal for remote control 6, CH 6

39. Jack connector to other amplifiers, STACK INPUT 1

40. Jack connector to other amplifiers, STACK INPUT 2

41. XLR input connector 1, INPUT 1

42. XLR input connector 2, INPUT 2

43. XLR input connector 3, INPUT 3

44. XLR input connector 4, INPUT 4

45. XLR input connector 5, INPUT 5

46. XLR input connector 6, INPUT 6

47. Output terminals channel 1, CH1

48. Output terminals channel 2, CH2

49. Output terminals channel 3, CH3

50. Output terminals channel 4, CH4

51. Output terminals channel 5, CH5

52. Output terminals channel 6, CH6

53. Electrical ground / mechanical ground disconnection switch, GND LINK

54. Ground terminal, GND

55. Mains socket

17

6.2. Function diagram

18

MANUAL DE INSTRUCCIONES

1. NOTA IMPORTANTE 19

2. INTRODUCCIÓN 19

3. INSTALACIÓN 22

3.1. Ubicación y montaje 22

3.2. Conexión a red 22

3.3. Conmutador “Ground Link” 22

3.4. Multifunción 23

3.5. Conexiones de entrada 24

3.6. Opciones de entrada 25

3.7. Circuito limitador 26

3.8. Conexiones de salida 26

3.9. Opciones de salida 27

4. OPERACIÓN Y USO 27

4.1. Puesta en funcionamiento 27

4.2. Atenuadores de entrada 28

4.3. Control remoto 28

4.4. Conexionado del control VCA 29

4.5. Indicadores 29

5. LIMPIEZA 29

6. DIAGRAMAS 30

6.1. Lista de funciones 30

6.2. Diagrama de funciones 31

6.3. Diagrama de configuración 60

6.4. Características técnicas 61

6.5. Diagrama de bloques 62

Todos los datos están sujetos a variación debida a tolerancias de producción. ECLER S.A. se reserva el derecho de
realizar cambios o mejoras en la fabricación o diseño que pudieran afectar las especificaciones.

19

1. NOTA IMPORTANTE

¡Enhorabuena!. Vd. posee el resultado de un cuidadoso diseño y una esmerada fabricación.
Agradecemos su confianza por haber elegido nuestra etapa de potencia MPA R.
Para conseguir la máxima operatividad del aparato y su máximo rendimiento, es MUY
IMPORTANTE antes de su conexión, leer detenidamente y tener muy presentes las consideraciones que
en este manual se especifican.
Para garantizar el óptimo funcionamiento de este aparato, recomendamos que su mantenimiento
sea llevado a cabo por nuestros Servicios Técnicos autorizados.

2. INTRODUCCIÓN

Esta etapa de potencia multicanal ha sido diseñada con la misma tecnología que nuestra serie de
amplificación PAM. Con esta tecnología, ECLER introdujo un nuevo concepto en el audio profesional: el
empleo de los transistores de efecto de campo de conmutación. La tecnología SPM (Switching Power
Mosfet) fue desarrollada y patentada por ECLER S.A. La incorporación al audio de estos componentes
significa una firme y espectacular mejora con relación a los sistemas convencionales.
Estas ventajas pueden resumirse así:

a) Resistencia interna más baja que los transistores bipolares lo cual redunda en un calentamiento
inferior de la etapa y en unos graves poderosos y muy bien controlados.
Los mosfets convencionales de audio presentan una resistencia interna de 4 a 7 veces superior a
los de conmutación.

b) La enorme rapidez de estos dispositivos confiere a los agudos una transparencia hasta ahora
sólo lograda con amplificadores a válvulas, al tiempo que una TIM (distorsión por intermodulación de
transitorios) muy reducida.

c) Todos los modelos MPA-R incorporan un control independiente VCA en cada uno de los

canales de entrada que puede ser empleado para controlar el nivel de señal correspondiente mediante,
por ejemplo, un potenciómetro remoto. (Se recomienda el uso de accesorios ECLER a tal efecto).
Cualquier otro dispositivo que entregue una señal 0-10V DC puede ser empleado para el ajuste del nivel
de la señal de entrada. Asimismo actuadores remotos como relés o cualquier contacto seco pueden ser
usados para implementar un "MUTE" remoto en cualquiera de los canales de entrada. Esto permite al
usuario final el fijar de forma remota e independiente la atenuación/MUTE de la señal de entrada que
será enviada al amplificador correspondiente según el estado de los conmutadores ubicados en el panel
posterior de la unidad.

Un único potenciómetro (o señal de control) puede actuar sobre más de uno o todos los canales

de entrada mediante el cableado adecuado. (Ver información detallada en la sección 4.4).

El circuito VCA está desactivado por defecto, si necesita utilizarlo debe activarlo mediante

jumpers internos. (Ver diagrama de configuración).

d) Todos los modelos MPA-R incorporan conectores "STACK" en "INPUT 1, INPUT 2" para el

envío de las señales a otros amplificadores o sistemas de sonido.

20

MPA4-150R

La MPA4-150R está formada por cuatro amplificadores de 160W/4Ω configurables mediante los

conmutadores situados en el panel posterior, permitiendo múltiples posibilidades de trabajo de entre las
que destacamos:

• 4 Amplificadores en mono para 4 señales mono diferentes.
De esta forma el MPA R está preparado para trabajar con cuatro señales distintas disponiendo cada
una de ellas de su propio control de volumen.

• 4 Amplificadores en mono con una entrada en común.
El amplificador trabaja solamente con una señal de entrada pero conserva la posibilidad de ajustar de
forma independiente el nivel de cada uno de los cuatro canales, es una aplicación ideal para realizar
una distribución de sonido a distintas zonas.

• 4 Amplificadores en mono con una entrada en estéreo común.
Aplicación idéntica a la anterior pero teniendo como entrada una fuente de sonido estéreo, el
amplificador realiza la suma de los dos canales de la fuente para convertirla en una señal mono.

• 2 Amplificadores estéreo con dos entradas estéreo diferentes.
Disponiendo cada una de ellas del control de volumen de cada canal estéreo. Útil para sonorizar dos
zonas con dos señales estéreo diferentes.

• 2 Amplificadores estéreo con entrada estéreo común.
Aplicación idéntica a la anterior pero con la misma señal estéreo de entrada en los dos amplificadores.

• 2 Amplificadores en puente con dos señales mono diferentes.
Disponemos de un amplificador estéreo convencional. Con un amplificador trabajando en puente
obtendremos el doble de potencia con una impedancia de carga mínima de 8Ω.

• 2 Amplificadores en puente con una señal mono en común.
El MPA R trabaja con una sola señal de entrada para dos amplificadores mono con posibilidad de
controlar los volúmenes de forma independiente.

• 2 Amplificadores en puente con dos entradas estéreo diferentes.
Tendremos dos zonas con controles de volumen independientes con dos señales estéreo diferentes,
pero estas señales estéreo se convierten en señales mono internamente en cada amplificador en
puente.

• 2 Amplificadores en puente con un entrada estéreo común.
Aplicación idéntica a la anterior pero teniendo como entrada una fuente de sonido estéreo, el
amplificador realiza la suma de los dos canales de la fuente para convertirla en una señal mono.

• 1 Amplificador estéreo y 1 amplificador en puente con una entrada estéreo común.
Útil para instalaciones con un amplificador estéreo con cajas de medios y agudos y un segundo
amplificador en puente para una caja de subgraves. Este amplificador multicanal dispone de filtro paso
bajo para instalar cajón de subgraves y de filtros paso alto para las cajas de medios y agudos.