Ecler DPA2500T User Manual

Also see for DPA2500T: Service manual

Contents

63.3. Signal input connectionsThe signal input connectors are of XLR-3 type (11), electronically balanced. The pin assignment is asfollows:HOT or direct signal > Pin 2COLD or inverted signal > Pin 3GROUND > Pin 1For unbalanced connection short-circuit pin 3 to pin 1.The "STK OUTPUT" (10) are in parallel with the inputs and are used to supply the same input signal toother amplifiers or sound systems.The input impedance is 20KΩ (balanced) with a nominal input sensitivity of 0dBV(1V). This impedancemakes possible to parallel several amplifiers without loosing audio quality.3.4. Subsonic filterThis filter cuts off inaudible frequency components which when amplified suppose a risk of damage to thelow frequency speakers as they generate excessive excursions of the woofer's diaphragm. The DPAs feature aswitchable, Butterworth shaped Subsonic Filter located inside the unit (see fig.) with a 25Hz cut-off frequency and18dB/oct slope.Subsonic filters are very important when playing back vinyl records because the phono cartridges arespecially sensitive to feedback and acoustic coupling at very low frequencies.DPA amplifiers are delivered with switched ON Subsonic Filter.CAUTION: Changes on the Subsonic Filter have to be performed by a qualified technician.3.5. Limiter circuitThe high output power models DPA2500T/4000T additionally feature the A2SP –System (AnalogueAutogain Signal Processor), that consists in an VCA (Voltage controlled Amplifier) controlling the Input Signal gainin high stress situations at very low load impedances (2Ω or lower). As opposed to conventional compression orlimiting techniques, the side-effects are not noticeable and most important, neither dynamic range is reduced norTHD is increased. For transients shorter than 150 ms, it limits so that 10% THD is allowed, while for transientslonger than 150 ms, a maximum THD of 0.1% is allowed. Furthermore, these models include a thermal sensorinside the transformer that also contributes in controlling the A2SP in case of reaching a critical temperature thatcould be dangerous to any of the two power transformers.3.6. Output connectionsThe "OUTPUT" section on the back panel is provided with Speakon® connectors (13).To operate the amplifier on "BRIDGE" mode, place the "STEREO BRIDGE" switch (12) to the "BRIDGE"position. The correspondent Led on the front panel will lit. The input signal must be connected to the channel Iconnector while the output signal will be present on the Speakon® connector labelled as "BRIDGED".Please make sure that the resulting impedance of your installation, when the amplifier is operating inBRIDGE mode, is never lower than 4 Ohm (8 Ohm recommended).The connection cable that joins the amplifiers outputs and the loudspeakers must be of good quality,sufficient section and as short as possible. This is most important when the distances to cover are long ones i.e. upto 10 meters it is recommended to use a section not inferior to 2.5mm2 and for superior distances 4mm2.