Martin Audio – MA1.3s Amplifier
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bandwidth.
Be sure to use balanced inputs on all measuring equipment (including oscilloscope probes) if
you are bench testing.
Reverse operation of Channel B.
5.3.3
Tandem mode
In tandem mode channel A input is linked to channel B input, either input socket may then be used to provide the
input signal. Tandem mode is activated by placing the two central switches (4 and 5) in the “ON” position (UP).
Both input attenuator’s are active, allowing you to set different levels for each channel. Note that only the inputs are
connected in parallel. This is NOT a parallel output mode.
Never connect either output terminal to ground or in
parallel.
You can use the remaining input connectors to parallel off “Daisy – chain” signals to other amplifiers.
NOTE: Always turn off the Link switch when using the amplifier for Bi-amping.
5.3.4
Bridge mono mode
Bridge mono mode is used to deliver increased power to the loudspeakers. Using
the MA1.3s in bridge mode reduces the number of channels from two to one. The
nominal impedance of the load must be more than 3 ohms. Set the Link/bridge
switches to the “ON” position (UP) and use either of the input connectors A or B.
You can use the remaining input connectors to carry a parallel signal to other
amplifiers. Both A and B level attenuators must be in the same position. We
recommend they are used in the 0dB fully clockwise position.
The loudspeaker should now be connected to channel A output Speakon. (+1
should be connected to the [+] terminal of the loudspeaker, and –2 to the [-]
terminal of the loudspeaker)
5.3.5
Bridge mono mode features
Bridged mono mode combines the power of two output channels into one. This
results in twice the voltage swing, four times the peak power and just less than
three times the full power of a single channel.
This is because the coil is driven with positive voltage at one pole and an equivalent negative voltage at the other
pole. So, if an 8 ohms load is connected in bridged mode, one channel shares one 4 ohms part of the load, and the
other channel shares the other 4 ohms part. The power into 4 ohms from an MA 1.3s is 650W. So, the total bridged
power into the 8 ohms load will be 2 x 650W = 1300W.
All material © 2007. Martin Audio Ltd. Subject to change without notice.
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