Ecler NPA SERIES - Manual (Page 4)

4
1. IMPORTANT NOTE
Congratulations! You are the owner of a carefully designed and manufactured equipment. We thank you
for trusting on us and choosing our amplifier NPA SPM (Networked All purpose Switching Power Mosfet).
In order to obtain maximum operativity and perfect functioning order, it is most important to carefully read
all considerations taken into account in this manual before connecting this amplifier.
We recommend our authorised Technical Services if any maintenance task should be needed so that
optimum operation shall be achieved.
1.1. Precautions
The amplifier should have an earth connection in good conditions (earth resistance, Rg=30
Ω or less).
The environment must be dry and dustless. Do not expose the unit to rain or water splashes, and do not
place liquid containers or incandescent objects like candles on top of the unit. Do not obstruct the
ventilation grilles 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.
Do not manipulate the output terminals to the loudspeakers when the amplifier is switched on, there are
voltages up to 400Vpp. The output cabling should be connected by a qualified technician. Otherwise only use pre-
made flexible cables. There are no user serviceable parts inside the amplifier.
2. INTRODUCTION
With the PAM amplification series, ECLER introduced in early 90's a new concept to the world of
professional audio: The use of switching field effect transistors. The integration 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 controlled bass; conventional Mosfets have a 4 to 7 times higher 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.
The SPM-Technology (Switching Power Mosfet) has been developed and patented by ECLER Laboratorio
de Electro-Acústica, S.A. NPA line of amplifiers is a new step forward in the development of SPM amplification
technology, following in the successful DPA series footsteps.
SOA Contour following protection: the SOA is the safe operating area of transistors. A good protection
system should respect this area and its shiftings, as the SOA changes as a function of the operating temperature.
So, at 80°C it is considerably narrower than at 25°C, the start-up temperature. Some manufacturers decide to use
protection systems which compromise on the performance of the components. You get a fair protection, but the
performance remains mediocre. Others prefer to leave "dark" areas between the safe operating area and the
activation of protection, which is very risky indeed.
The new SOA contour following protection systems built into the NPA amplifiers guarantees total protection
of the amplifier at any output power, load or operating temperature, as the intelligent electronic circuitry
permanently watches for changes in the safety area, adapting itself to any situation.
Maximum damping factor: In NPA series traditional output relays have been replaced with a CROWBAR
electronic system. This device short-circuits the signal if surges that can damage the loudspeakers connected to
the amplifier are detected. On the contrary, any type of relay used in the conventional method introduces a
mechanical contact in the audio signal path to the speaker, contact that is exposed to wear and a significant
decrease in the amplifier damping factor.