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Martin Audio – MA900 Amplifier

E

NGLISH

9

O nce  co n ne cte d  to   a   su ita ble  AC   su pp ly,  the   am plifier  ca n  be   starte d   w ith   the   p o we r  switch.  Wh en   yo u po w er  u p   the 
a mp lifie r  it  ta ke s  a   cou p le   o f  secon d s  to   se lf  ch eck  (th is  is  kno wn   as  th e  "soft  sta rt"  o r  "slow   start"  se qu e nce), the  fa ns
the n  blo w  at  high   sp ee d  b efore  g oing   in to   "idle".  T he   tw o  bo tto m  gre en   L E D’s  th e n  illum in ate   to  sho w  th e   a mp lifie r  is
o pe ra tio na l.

6.4

 

Grounding

T he re   is  n o  g ro un d  lift  switch  o n  th is  am plifier.  T he   sign al  grou nd   is  a lwa ys  floa tin g  (lifted ),  with   re sp ect  to ch a ssis
g ro un d  via   a   grou nd   lift  re sisto r.  If  a   p ote ntia l  d iffe ren ce   ab ove  0 .6 V  is  de te cte d  b etwe en   sign a l  grou n d  an d   cha ssis
e arth ,  a   sho rt  circu it  is  a utom a tica lly  introd uce d  be tw e en   th e  tw o,  en su rin g  ele ctrical  p ro tectio n.  If  o th er  eq uipm e nt  o r
a mp lifie rs  w ith in   a   syste m  sh ou ld  de velop   a n   e le ctrical  fa ult  to  ea rth ,  the   m ain s  fu se  on   th at  e q uipm en t  sho u ld   rup ture
d ue   to this a utom atic  syste m  allow in g   a n  ea rth   fa ult  cu rre nt  to   flo w   for  protectio n  p urpo se s.
If  ho we ver  yo u  wish   to   p e rm an en tly  co nn ect  the   sign al  g rou nd   to   cha ssis  e arth ,  con ne ct  th e  X LR -co nn ecto r’s  sh ell  lu g 
to  pin  1 .  In   th e  in terest  o f  sa fety  n ever  d iscon n ect  th e   e arth  pin  o n  th e   m ains  ca ble .
T o  co mp ly  with  CE   a p prova l  (rad io  in terfe re n ce ),  th ere  is  an   AC   m ain s  filte r.  T h is  filter  n e ed s  the   cha ssis  e arth   fo r
referen ce,  o th erw ise  a   curre n t  lo o p  is  fo rm ed   via  th e   sig n al  g ro u nd .
N ever  d iscon n ect  (lift)  the   m ain s  sa fety  ea rth .

6.5

 

Power consumption

There are three ways to determine the power/current consumption of the amplifier:

First, the peak current draw at full power output. Under this condition the amplifier will operate for less than 2
minutes before thermally limiting or blowing the mains fuse.

Second, the maximum expected average current under worst case program material, which is 1/3 of full power
according to the FTC-standard. At this level the music will be in the state of constant clip and is therefore the
highest power level one can obtain without completely obliterating the program material.

Lastly, the "normal operating power", as defined by EN 60065 as a measurement level for approval and testing to
this standard. The normal operating power is measured using pink noise, with an average output power equal to
1/8 of full power. The one-eighth power is the maximum volume music can be re- played without continuous
amplifier clipping this corresponds to headroom of only 9dB's, which is very low for normal program material.

6.5.1

 

Calculation

The current draw can be calculated by dividing the mains input power by the mains voltage.
We recommend that you design the power distribution for at least the required current at 1/8 power, and 1/3 power
for heavy-duty demands such as concert touring and Industrial music etc.

The heat power can be calculated as follows:
If a headroom figure of 9dB is used with a 4 ohms load on each output of the amplifier. The 1/8 power per channel
is 320 / 8 = 40 watts, and the total output power = 2 x 40 = 80 watts.
The mains power consumption from the chart above is then 370 watts.

Power

1/3 Power

1/8 Power

Idle

[W]

note 1

note  2

MA900

8 ohms

2x

200

345

235

60

4 ohms

2x

320

570

370

60

2 ohms

2x

470

930

585

60

note 1

Average power with music as program source. The amplifier driven to clip level.

note 2

Normal music power with 9dB headroom, IEC standard power rating.

MAX OUTPUT POWER

MAINS INPUT POWER

All material © 2007. Martin Audio Ltd. Subject to change without notice.

Summary of Contents for MA900 - SCHEMATICS

Page 1: ...R AMPLIFIER TESTING 7 5 3 3 TANDEM MODE 7 5 3 4 BRIDGE MONO MODE 7 5 3 5 BRIDGE MONO MODE FEATURES 7 6 INSTALLATION 8 6 1 MOUNTING 8 6 2 COOLING 8 6 3 OPERATING VOLTAGE 8 6 4 GROUNDING 9 6 5 POWER CON...

Page 2: ...e amplifier if liquid ingress is suspected 3 Do not stand water or any other liquid on or near the amplifier 4 Do not use this amplifier near water Do not operate the amplifier if wet or standing in l...

Page 3: ...reach full output power if the input signal level is high enough 3 5 2 Speaker output hazard Power amplifiers are capable of producing hazardous output voltages To avoid the risk of electric shock do...

Page 4: ...2 Protect indicator This indicator illuminates if the amplifier attempts to function above its maximum operating temperature 90 C The indicator first comes on as a warning to either turn down the inp...

Page 5: ...page 13 4 Input signal XLR The Neutrik Combo jack is used which also features a _ TRS phone jacks Pin 2 is hot see page 10 5 Link Input A Phoenix screw terminal connector connected in parallel to the...

Page 6: ...o obtain full output power As the output power varies with the load impedance 4 ohms is usually taken as the reference The table below gives input volts rms Versus gain for full output power 1 t h d 1...

Page 7: ...e Link switches 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 MA900 in bridge mode reduces the number...

Page 8: ...low the exhaust to escape If the amplifier is rack mounted do not use covers or doors on the front or rear of the rack Should a heat sink get too hot its sensing circuit will mute the hot channel If t...

Page 9: ...will operate for less than 2 minutes before thermally limiting or blowing the mains fuse Second the maximum expected average current under worst case program material which is 1 3 of full power accor...

Page 10: ...incorporate an XLR and _ 6 3mm jack They are active balanced and wired PIN 1 GROUND SHIELD PIN 2 HOT PIN 3 COLD XLR input connector XLR balanced TIP HOT RING COLD SLEEVE SHIELD GROUND _ TRS plug The...

Page 11: ...worldwide safety requirements The Speakons are wired Channel A output Pin 1 Pin 1 Output A Pin 2 Pin 2 Output B Channel B output Pin 1 Pin 1 Output B The right Speakon Channel A has both channel A an...

Page 12: ...input level attenuators on the front panel adjust the signal level for their respective amplifier channel in all modes They are calibrated in dB s to help setting up active loudspeaker systems In brid...

Page 13: ...hes 90 C 9 2 VHF protection If a signal of more than 12kHz at full power is detected which lasts for more than five seconds the VHF protection mutes the input signal This is indicated on the front pan...

Page 14: ...loudspeaker this can occur when the speaker coil gets warm Fault The amplifier goes into protection with power indicators off Check that the AC mains voltage is within the amplifier s operating range...

Page 15: ...quipment exposure to inclement weather conditions and normal wear and tear Units on which the serial number has been removed or defaced will not be eligible for warranty service 3 MARTIN AUDIO LTD sha...

Page 16: ...both channels driven 3 5Arms 7Arms 1 3rd Full power both channels driven 5 5Arms 11Arms Full power 1Khz 1 thd 9 5Arms 19 Arms DISTORTION THD 20Hz 20KHz 1W to full power 0 03 THD 1KHz 1dB below clip 0...

Page 17: ...x Red LED s Indicators Signal Present 2 x Green LED s REAR PANEL Input Connectors 2 x Neutrik Combo 3 pin Phoenix Output Connectors 2 x Neutrik Speakons Clip Limiters Push Switch ON OFF per Channel S...

Page 18: ...HP12 3SL England Telephone 44 0 1494 535312 Facsimile 44 0 1494 438669 Web www martin audio com E mail info martin audio com The Martin Experience Please Click here to return to main menu Please Click...

Page 19: ...The Martin Experience ENGLISH MA900 Amplifier User s Guide All material 2007 Martin Audio Ltd Subject to change without notice...

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