Impedance Matching (Mls Switch); Bridge Mono Mode; Bridge Mono Mode Features - Martin Audio MA4.2s User Manual

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CONTENTS
5.3.4
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 4.2s (MLS at 0dB) is 2300W. So,
the total bridged power into the 8 ohms load will be 2 x 2300 = 4600W.
5.4

Impedance matching (MLS switch)

The MLS switches are located on the rear panel of the amplifier. The MLS (Minimum Load Select) switches offer
impedance/power matching, so that you can drive the MA 4.2s into 2 ohms without increased heat loss. Th e MA
4 .2 s can d elive r 2 30 0 wa tts in to b oth 2 a n d 4 oh m s. U se h ig he r M LS sw itch p o sitio ns w he n con n ecting to lo we r
imp ed an ces a s sho wn in T a ble 1. As ca n be se en from T ab le 1, th e MA 4.2s ca n pro du ce ou tp ut po we rs in e xce ss of
2 00 0 wa tts.
M LS po sitio ns ca n be se t diffe re ntly fo r e ach cha nn e l, a nd a va rie ty o f com b in atio n s ca n b e ach ie ve d (se e T ab le 2).
T ab le 2 provide s th e sim p le st w a y to find th e be st ML S p osition for yo ur ap plica tion . T he re is n o risk o f da m ag in g the
a mp lifie r, a s it is we ll protected (e ve n do w n to 0.3 oh m s). If yo u a re u n su re , o r wh e re tim e d oe s n ot p e rm it
e xp erim e ntation , use the de fa ult p osition s.
T he M A4 .2s a m plifie r is a p ow er co nve rter, a nd b y selectin g M LS p osition s you a re allocatin g a p o rtio n o f th e 6 40 0
w atts o f p ow e r
All material © 2007. Martin Audio Ltd. Subject to change without notice.
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Bridge mono mode

Martin Audio – MA4.2s Amplifier
Bridge mono mode is used to deliver increased power to the
loudspeakers. Using the MA4.2s 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

8
GUIDES