Martin Audio MA1.3s, User Manual

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Martin Audio – MA1.3s Amplifier
E
NGLISH
12
Channel A and B into two separate
Speakons.
Channel A and B into one Speakon
(Stereo and Bi-amp)
Bridged mono
Never connect either output terminal to ground or to some other output or input terminal (see warnings in
chapter 1)
For normal two-channel operation, connect each speaker load across the output’s positive and negative terminals.
Pay attention to speaker polarity; loudspeakers connected out of polarity degrade sound quality.
Keep the loudspeaker cables as short as possible and use a good quality stranded cable. Do not use shielded wire,
such as microphone or guitar cable. The loudspeaker cable reduces the power of the amplifiers in two ways:
It increases the load impedance and introduces resistive power losses.
WARNING: To prevent electric shock, do not operate the amplifier with any of the loudspeaker
cable conductors exposed.
8 OPERATION
8.1 Operating precautions
•
Make sure that the power switch is set to “OFF” before connecting any input or output or operating the
switches on rear panel. See pages
8
about installation.
•
Make sure that the AC mains voltage is correct and the same as the one printed on the rear panel of the
amplifier. See pages
8
, about operating voltage and power consumption.
•
Make sure that the operating mode switches on the rear panel, gain,link/ bridge, and clip-limiters, are in
the correct position. See page
6
about operating modes, page 1
3
about clip limiters and
7
for the ML
•
It is always a good idea to turn down the gain controls during power-up, to prevent speaker damage in
case a high signal is present at the input.
8.2 Powering up – Soft start
When you power up the amplifier it takes a couple of seconds to check its circuits. 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.
8.3 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 help the setting up of 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.
8.4 Indicators
The two-bottom green ”ON” LED’s indicating that the output circuits are receiving the correct rail voltage.
The ”-40 dB” LED’s illuminate if the output signal is greater than -40dB (with 0dB as reference to full output power).
These LED’s also act as signal present indicators.
All material © 2007. Martin Audio Ltd. Subject to change without notice.
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