User manual DLS MRA31

[. . . ] There is one such list of material on the following page. Amplifier location Important Allow air circulation around the amplifier. The DLS Marine Audio amplifiers have a compact design that allows great flexibility in mounting. Safety Considerations: Your amplifier must be installed in a dry, wellventilated environment and in a manner which does not interfere with your vessel's factory installed electronic devices. You should also take the time to securely mount the amplifier so that it does not come loose in the event of a collision or a sudden jolt to the vessel. [. . . ] 3 If amplifier installation kits are available with different size of power cable, chose the most heavy power cable to improve sound quality and to allow more amplifiers to be installed now or later. These are the minimum sizes we recommend for the amplifiers: MRA22 10 mm2 (7 AWG) MRA31 21 mm2 (4 AWG) This is for cable lengths up to 5 meters. The ground cable must have the same size. MRA22, MRA31 Input and controls Input Wiring Inputs may be low level from the RCA output of the car stereo or high level from the car stereo speaker output. Important On MRA22 use either the low level or high level input, do not use both at same time. Low level input Use a pair of shielded stereo audio cables with RCA type jack. Avoid placing the RCA cable close to speaker cables, power cables and remote control cable. High Level Input Connect left and right speaker wires coming from the car stereo to the high level input as shown. You must connect both plus and minus as the inputs are balanced, connecting plus only gives lower level and bad sound quality. By changing the polarity of plus and minus, you can change the phase. RCA Output Input Output A A Use RCA Outputs to connect additional amplifiers (not available on MRA31). B B Hi / Low level input switch To ensure best possible performance from the amplifiers a switch is installed to select between Hi and Low input. When using High Level input: Push in the button to position Hi level "Hi Level" Low level When using Low level input: Push out the button to position "Low Level" If the switch is set to wrong position, the amplifier still works, but the risk for disturbances or distortion increases. Fuses MRA31 uses two 30 ampere ATC blade type fuses. MRA22 uses one 25 A fuse. MRA 22, MRA31 High Input (C/D Ch) White: A ch. + White/Black: A ch. Grey/Black: B ch. Grey: B ch. + Power Light / Protect light Power (Green) Protect (Red) The power light (green ) comes on when the amplifier is turned on. The protect light ( red ) comes on when the amplifier shuts down from overheating, or a short circuit ( speaker failure) Hi level input plug on amp. MRA31 On MRA31 the high level signal is fed internally to channel C when using high level input. With the Hi/Low input swich set to Hi, the amplifier turns on automatically on high input. You dont need to connect a separate remote wire from your head unit. Parallel input on MRA31 Parallel Input MRA31 Off PC On MRA31 the PC position internally connects the A/B input with the input for channel C. 4 MRA22, MRA31 Input Level control The input level control, 5V ­ 0, 25 V, Level matches the output of your radio to the input of the amplifier. After installation is complete, make sure the input of the amplifier is turned down all 5V 0, 25V the way ( counter-clockwise at 5V ). Play a tape or CD, make sure all bass or treble settings or equalizer are flat, and turn the volume of the radio up until you just start to hear distortion. On the amplifier increase the input level control ( clockwise or to the right ) until you just start to hear distortion, then back the level control just a bit. Now your radio and amplifier levels are matched. High Pass Filter (HPF) HPF 50Hz 220Hz 15Hz 500Hz Filter freq. range: MRA22: 15-150 Hz MRA31: 50 - 150 Hz Phase control MRA31 The phase control on MRA31 can be set continuously from 0 - 180 degrees. This is very useful when you want to adjust the bass sound for best front stage image. Start on 0 and turn the control slowly clockwise until you experience that the bass sound is coming from the front. If you dont get the result you want, also try to PHASE phase reverse the subwoofer connections and make 0 180 a new adjustment. [. . . ] If noise remains regardless of cable position, try to use so called Quasi-balanced signal cables. DLS PRO-cables are Quasibalanced. + Battery 1, 5 Volt + - 3. NOTE!Tweeters can not be tested this way, double check the connections instead. Professional Tip: Securing wires Use wire ties to bundle together when possible. (But never bundle speaker wires or signal cables together with power wires. Professional Tip: Crimp connections Purchase crimp connectors and crimping tool. [. . . ]