Ecler NPA2500T User Manual

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Ecler NPA2500T User Manual Manual pdf 4 page image

41. IMPORTANT NOTECongratulations! You are the owner of a carefully designed and manufactured equipment. We thank youfor 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 readall 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 thatoptimum operation shall be achieved.1.1. PrecautionsThe amplifier should have an earth connection in good conditions (earth resistance, Rg=30Ω or less).The environment must be dry and dustless. Do not expose the unit to rain or water splashes, and do notplace liquid containers or incandescent objects like candles on top of the unit. Do not obstruct theventilation grilles with any kind of material.In case there is some type of intervention and/or connection-disconnection of the amplifier, it is mostimportant to previously disconnect the mains power supply.Do not manipulate the output terminals to the loudspeakers when the amplifier is switched on, there arevoltages 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. INTRODUCTIONWith the PAM amplification series, ECLER introduced in early 90's a new concept to the world ofprofessional audio: The use of switching field effect transistors. The integration of these parts for audio applicationsrepresents a firm and spectacular enhancement comparing to conventional amplifiers. These advantages can beoutlined as follows:a) Lower internal resistance than bipolar transistors, which leads to less heating of the amplifier and morepowerful and controlled bass; conventional Mosfets have a 4 to 7 times higher internal resistance than switchingMosfets.b) The extremely high speed of these devices gives a transparency to the upper frequencies till now onlyachieved 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 Laboratoriode Electro-Acústica, S.A. NPA line of amplifiers is a new step forward in the development of SPM amplificationtechnology, following in the successful DPA series footsteps.SOA Contour following protection: the SOA is the safe operating area of transistors. A good protectionsystem 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 useprotection systems which compromise on the performance of the components. You get a fair protection, but theperformance remains mediocre. Others prefer to leave "dark" areas between the safe operating area and theactivation of protection, which is very risky indeed.The new SOA contour following protection systems built into the NPA amplifiers guarantees total protectionof the amplifier at any output power, load or operating temperature, as the intelligent electronic circuitrypermanently 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 CROWBARelectronic system. This device short-circuits the signal if surges that can damage the loudspeakers connected tothe amplifier are detected. On the contrary, any type of relay used in the conventional method introduces amechanical contact in the audio signal path to the speaker, contact that is exposed to wear and a significantdecrease in the amplifier damping factor.