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10

SPECIFICATIONS 

Safety approvals
MARTIN AUDIO MA Series amplifiers are designed to meet EN60065
electrical safety standards. 

EMC approvals
EMC stands for Electro Magnetic Compatibility. This implies that the
equipment should have low emission of radio frequencies, directly as
electromagnetic fields in the air and as conducted from the cables from and to
the unit. The unit should also be able to handle electromagnetic fields, high
voltage flashes and radio interference, coming into the unit via the air or
cables.

Emission
The regulations now cover the frequency range from 150kHz to 300MHz. The
maximum level radiated from a unit has to be below 100µV (0.0001V).

Immunity
The equipment should be able to handle three different types of interference:

Electrostatic discharges up to 8kV, hitting the chassis or cables.

•  Transients and bursts up to 1kV conducted through the cables to the 

unit.

•  Electromagnetic fields up to 3V/m, radiated on the unit and the cables in 

the frequency range of 27 - 500 MHz.

We have extended the tests in two cases and chosen a standard used for
heavy industrial situations. First, we have tested conducted disturbances in
the frequency range 150kHz - 80MHz, by injecting 3V amplitude modulated
(80%) signals into all the cables (inputs, outputs and mains). This covers
noise from AM transmitters, which are still in use in some areas. Secondly, we
have extended the range for electromagnetic fields to 26 - 1000MHz, with a
level of 6V/m and 80% AM modulated. 
In the range 895 - 905MHz, we test with field strength of 35V/m and 100%
pulse modulation. This emulates the signals from a mobile phone close to the
unit. In all cases the noise plus distortion is below 1%, at normal operation
level, (normal operation level is 1/8 of full power or -9dB under clip point
according to EN60065).

Martin Audio – MA4.2 Power Amplifier

E

NGLISH

21

CONTENTS

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GUIDES

APPLICATIONS GUIDE

Содержание MA4.2

Страница 1: ...ections 9 5 7 Connecting speakers 11 5 8 Impedance matching MLS switch 12 6 OPERATION MODES 13 6 1 Stereo operation 13 6 2 Tandem mono 13 6 3 Bridged mono 13 6 4 Stereo reverse 14 7 OPERATION 15 7 1 O...

Страница 2: ...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 Do not blo...

Страница 3: ...es radio frequency energy and if not used or installed in accordance with these operating instructions may cause interference to other equipment Compliance with the EMC directive does not automaticall...

Страница 4: ...es 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 input level or check the cooling arrangements af...

Страница 5: ...on section See page 11 2 Minimum load selector MLS switch This switch is used to select the minimum nominal speaker impedance the amplifier is going to drive see page 12 3 Clip limiter switch Turns th...

Страница 6: ...w see Design features on page 19 Should the heat sink get too hot its sensing circuit will mute the hot channel If the power supply overheats another sensing circuit will mute all output channels unti...

Страница 7: ...a unit in the system is faulty its mains fuse will blow due to this automatic ground system If however you wish to tie the signal ground to chassis connect the XLR connector s shell lug to pin 1 In th...

Страница 8: ...g example If we consider a headroom of at least 9dB and a 4 ohm load on an amplifier producing 2100 watts per channel The 1 8 power per channel is then 2100 8 263 watts total output 2 x 263 525 watts...

Страница 9: ...gh 20kohms balanced to allow daisy chaining or multiple parallel input connections To daisy chain use the TRS jacks provided on each channel The input circuits also have high enough headroom to accept...

Страница 10: ...to the shield at the source The hum and noise rejection for the cable is equivalent to that for a balanced line To minimize hum in the audio use balanced inputs whenever possible Figure 8 Balanced lin...

Страница 11: ...output or input terminal see warning on page 2 For normal two channel operation connect each speaker load across the outputs positive and ground terminals Pay attention to speaker polarity loudspeaker...

Страница 12: ...ation using table 3 for initial starting positions The amplifier is very well protected even down to 0 3 ohms but where speed is of essence stick to the fixed positions The MA4 2 amplifier is a power...

Страница 13: ...ctors for mixing or other purposes Both level attenuators are active allowing you to set different levels for each channel Never connect either output terminal to ground or in parallel 6 3 Bridged mon...

Страница 14: ...reo reverse This mode is similar to the Tandem mono mode Apart from depressing the Link switch you also depress the Phase reverse switch as in the Bridge mono Channel B is now phase reversed To compen...

Страница 15: ...ly if there is a high level signal at the input 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 sequ...

Страница 16: ...it LED indicates when the amplifier output is clipping or limiting It has two different indication states When the clip limiter is engaged it has a short time constant and illuminates briefly When the...

Страница 17: ...the clip limiting is inaudible The limiter can be turned On or Off by depressing the relevant clip limit switch 2 Some manufacturers of loudspeaker processors do not recommend the use of clip limiter...

Страница 18: ...t can do during sustained high power sine wave testing the AFS limiter will restrict the mains current to a safe level consequently reducing the amplifier output If the AFS limiter circuit is activate...

Страница 19: ...ieved not only by the design of the power supply and heatsink but also by the use of an alloy chassis making rear rack supports unnecessary in most applications Switch mode power supply SMPS Switch mo...

Страница 20: ...ss of speaker demands and AC line conditions Minimum Load Switches MLS Thanks to the regulated SMPS the maximum power available for the output stages can be adjusted without increased heat dissipation...

Страница 21: ...sts up to 1kV conducted through the cables to the unit Electromagnetic fields up to 3V m radiated on the unit and the cables in the frequency range of 27 500 MHz We have extended the tests in two case...

Страница 22: ...ation only For use on 115 Volts AC internal modifications to the power supply board must be made Warning This modification should only be carried out by an experienced service technician Please contac...

Страница 23: ...remove possible high frequency oscillations from the relevant input Fault The amplifier goes into thermal protection when driven at low level Check that your loudspeaker has not got a short circuit in...

Страница 24: ...ts act of God war civil insurrection misuse abuse operation with incorrect AC voltage operation with faulty associated equipment exposure to inclement weather conditions and normal wear and tear Units...

Страница 25: ...kHz at 500W 4 ohms 0 04 POWER MATRIX MLS SWITCH SETTING LOAD CONFIGURATION 5dB 4dB 2dB 0dB 16 ohms Stereo 2 channel 220W 260W 410W 650W 8 ohms Stereo 2 channel 430W 520W 820W 1300W 4 ohms Stereo 2 cha...

Страница 26: ...ire 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 MARTIN AUDIO L O N D O N Please Click here to ret...

Страница 27: ...MARTIN AUDIO L O N D O N The Martin Experience ENGLISH MA4 2 Power Amplifier User s Guide CONTENTS PRINT GUIDES APPLICATIONS GUIDE...

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