User manual MARTIN AUDIO MA1.3S SCHEMATICS

[. . . ] Always operate the amplifier with the chassis ground wire connected to the electrical safety earth. Do not parallel or series connect an amplifier output with any other amplifier output. Do not connect the amplifier output to any other voltage source, such as battery, mains source or power supply, regardless of whether the amplifier is turned on or off. Do not run the output of any amplifier back into another channel's input. [. . . ] To daisy-chain, use the TRS jacks provided on each channel. Never connect either output terminal to ground or to some other output or input terminal (see warning on page 2). For normal twochannel operation, connect each speaker load across the outputs positive and ground terminals. Pay attention to speaker polarity; loudspeakers connected out of polarity can degrade sound quality. Keep the speaker cables as short as possible and use a good quality stranded speaker cable. Do not use shielded wire, such as microphone or guitar cable. Remember that the speaker cable robs the power of the amplifiers in two ways: It increases the load impedance and introduces resistive power losses. 6 OPERATION MODES 6. 1 Stereo operation For stereo (dual channel) operation, leave the Link and Phase reverse switches in the un-depressed position. In this mode, both channels operate independently of each other, with their level attenuators controlling their respective levels. Never connect either output terminal to ground or in parallel. The recommended minimum nominal impedance for stereo or tandem operation, is 2 ohms per channel. 11 Martin Audio ­ MA1. 3S Power Amplifier CONTENTS < > ENGLISH PRINT GUIDES 6. 2 Tandem mono For tandem (dual channel-single input) operation, depress the Link switch. Both channels can now be driven by a signal at either input connector. · Make sure that the AC mains is correct and the same as that printed on the rear panel of the amplifier. See pages 6-8 about operating voltage and power consumption. · Make sure that the switches on the rear panel for operation modes and clip are in the correct position. See pages 11-13 about operation modes and page 15 about clip limiters. · It is always a good idea to turn down the gain controls during power up as this prevents speaker damage, especially if there is a high level signal at the input. 13 Martin Audio ­ MA1. 3S Power Amplifier CONTENTS < > ENGLISH PRINT GUIDES 7. 2 Powering up - Soft start When you power up the amplifier it takes a couple of seconds to self check. This is known as the "soft start" or "slow start" sequence. The fans then blow at high speed before going into "idle" and the two bottom green LED's illuminate to show the amplifier is operational. 7. 3 Input attenuators The two input level attenuators on the front panel adjust the signal level for their respective amplifier channel in all modes. They are calibrated in dB to assist setting up active loudspeaker systems. In bridged mode, both controls must be in the same position, so that the speaker load will be shared equally between the channels. 7. 4 Gain switch The gain switch located on the rear panel is for changing the input sensitivity of the amplifier. [. . . ] If you are using your amplifier for heavy-duty use i. e. concert touring or industrial music, it is recommended that you have your amplifier serviced every 3 years, purely as a preventative measure. Troubleshooting These are typical things to check if you think your amplifier is faulty: Fault: No output. If the -40dB LED is functioning there is nothing wrong with the amplifier and the likely cause is an unsecured Speakon. [. . . ]