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
accesories are recomended 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.
