User manual ALESIS MATICA 900 REFERENCE MANUAL

[. . . ] ALESIS Matica 500/900 Reference Manual Contents CONTENTS 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 About Alesis Matica Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Why Another Power Amplifier?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2: Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Unpacking and Inspection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Physical Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Electrical Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Audio Installation: Input Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Audio Installation: Output Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 System Setup and Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3: Amplifier Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] Note: Alesis amplifiers are pre-wired at the factory for the line voltage in the country where the amplifier is intended for sale and are supplied with appropriate line cords. Before connecting them to the power line, check to be certain that they are properly wired for use in your country. When wiring a rack, it is good installation practice to route all AC wiring along one side of the rack and all audio wiring along the other side to avoid coupling ACborne interference into the audio. Matica 500/900 Reference Manual 7 Installations Audio Installation: Input Wiring ALESIS CORPORATION, LOS ANGELES SOUND REINFORCEMENT DIVISION MATICATM POWER AMPLIFIER Patent Pending MOUNT IN RACK ONLY. INSTALLER SUR SUPPORT DE MONTAGE SEULEMENT. WARNING/AVIS: SHOCK HAZARD DO NOT OPEN RISQUE DE CHOC ELECTRIQUE NE PAS OUVRIR TO PREVENT ELECTRICAL SHOCK DO NOT REMOVE COVERS. TO REDUCE THE RISK OF FIRE OR ELECTRICAL SHOCK DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE. B OUTPUT BRIDGED MONO OUTPUT A MATICA INPUT MODEL POWER 600 VA 500 900 1200 VA OUTPUT POWER 250 W@4W 450 W@4W USE CLASS 2 WIRING DUAL CHANNEL AUDIO INPUT WIRING = TIP = PIN 2 = RING = PIN 3 = SLEEVE = PIN 1 120 V 60 Hz FOR BRIDGED MONO USE A INPUT Figure 2: Amplifier rear panel controls and connections. Warning: Be sure that the AC power is off prior to connecting or disconnecting any signal wiring. To use the amplifier in Bridged Mono mode, connect the input signal to Channel A only and move the recessed slide switch to the Bridged Mono position. See below for output wiring in Bridged Mono configuration. Audio Installation: Output Wiring Warning: Be sure that the AC power is off prior to connecting or disconnecting any signal wiring. Alesis amplifiers can reliably drive 2 W loads in Stereo mode and 4 W loads in Bridged Mono mode. However, the impedance of a loudspeaker varies with frequency, and its nominal rated impedance is not necessarily its minimum impedance. Some loudspeakers carry both nominal and minimum impedance specifications, and some are supplied with impedance curves. When connecting Matica 500/900 Reference Manual 9 Installations multiple loudspeakers or systems to any amplifier, care should be taken that the actual load impedance does not drop below the amplifiers rated output load. Alesis amplifiers will not be damaged by excessively low output load impedances, but they will not be able to provide full output power and their protection circuits may automatically cut off their outputs until the low load condition is removed. Gauge (AWG) 6 8 10 12 14 16 18 20 22 Diameter (Solid) 4. 12 mm 3. 26 mm 2. 59 mm 2. 05 mm 1. 63 mm 1. 29 mm 1. 02 mm 0. 81 mm 0. 64 mm DC Resist. / 30 m (100) 0. 08 W 0. 13 W 0. 20 W 0. 32 W 0. 52 W 0. 82 W 1. 32 W 2. 08 W 3. 30 W Cable Length Resulting in a 1 dB Power Loss 4 W Load Impedance 366 m 244 m 145 m 91 m 58 m 37 m 23 m 15 m 9m 1200 800 475 300 190 120 75 50 30 8 W Load Impedance 740 m 488 m 290 m 182 m 116 m 74 m 46 m 30 m 18 m 2400 1600 950 600 380 240 150 100 60 Table 2: Speaker Cable Losses. Values are calculated based on the sum of the length of both conductors. Note that a 1 dB power loss is equivalent to 12% of the amplifier power. The wire thickness or gauge should be chosen according to the load impedance and the length of the wire run from the amplifier to the loudspeaker terminals. Because the wires resistance to the flow of current is in series with the loudspeaker, a wire with lower resistance will deliver more power to the loudspeaker; also, the amplifier will be able to control the loudspeakers movement betterthis latter is called damping factor. Its interesting to observe that an amplifiers rated damping factor is essentially unrealizable unless the loudspeaker is connected directly to the amplifiers output terminals without any interconnecting cables. For example, a typical installation using 20 feet (6 m) of 16 AWG wire connecting an amplifier and an 8 ohm speaker will result in a damping factor of 23. 5 with a perfect amplifier; with a real world amplifier, the damping factor will be even lower. Many special cables are sold for use with audiophile and studio loudspeakers. We make no recommendations for cables other than that there be sufficient copper in them to keep the total resistance acceptably low. Loudspeaker outputs for both channels are on heavy-duty five-way binding posts which can accept single or dual banana plugs, bare wire or terminals. [. . . ] It is possible that the output signal from the source may be too high and, thus, distorted before it reaches the amplifier gain control, either because the source device is clipping or the amplifier input stage is overloaded. In either case, no amount of level control adjustment at the amplifier can remove this distortion, and the device feeding the amplifier should have its gain lowered until the level is within proper bounds. It is also possible, particularly when using very efficient loudspeakers, that the sound level from the loudspeakers may be too high when the amplifier is driven to full output. In such cases, leaving the amplifier gain at maximum and turning down the signal sources output level can result in audible noise products in the signal coming from the source device or wiring. [. . . ]