< CONTENTS > PRINT APPLICATIONS GUIDE CONTENTS (ENGLISH) 1 2 3 3.1 3.2 3.3 4 4.1 4.2 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 6 6.1 6.2 6.3 6.4 7 7.1 7.2 7.3 7.4 7.
> PRINT APPLICATIONS GUIDE GUIDES This equipment conforms to the requirements of the EMC Directive 89/336/EEC, amended by 92/31/EEC and 93/68/EEC and the requirements of the Low Voltage Directive 73/23/EEC, amended by 93/68/EEC. Standards Applied EMC Emission Immunity Electrical Safety 1 EN55103-1:1996 EN55103-2:1996 EN60065:1993 UNPACKING Each Martin Audio MA Series amplifier is built to the highest standard and thoroughly inspected before it leaves the factory.
> PRINT APPLICATIONS GUIDE GUIDES USER RESPONSIBILITY 3.1 Speaker damage Many loudspeakers can be easily damaged or destroyed by overpowering, especially with the high power available from a bridged amplifier. Always check the speakers continuous and peak power capabilities. Even if the gain is reduced by using the amplifier's front panel attenuator, it is still possible to reach full output power, if the input signal level is high enough. 3.
> PRINT APPLICATIONS GUIDE GUIDES INTRODUCTION Thank you for purchasing a MARTIN AUDIO power amplifier. This manual contains important information on operating your amplifier correctly and safely. Please take some time to read this manual and familiarize yourself with the advanced features of this amplifier. 4.1 The front panel ➄ ➀ ➂➃ ➁ ➁ Figure 1. Front panel ➄ ➇ ➆ ➅ 1.
< > PRINT ENGLISH CONTENTS GUIDES APPLICATIONS GUIDE 5. Fan grille filter A foam filter is located behind the front panel grille to prevent dust entering the amplifier. 6. Power switch This is used to power up the amplifier. (See page 7 and 15) 7. AC idicator Indicates if AC voltage is present. 8. AFS indicator Indicates if the adaptive fuse saver is activated (see page 18). 4.2 The rear panel ➃ ➃ ➀ ➁ ➀ ➁ Figure 2. Rear panel ➂ ➄ ➈ ➂ ➅ ➆ 1.
> PRINT APPLICATIONS GUIDE GUIDES 8. Gain select switch Allows amplifier gain to be switched between 32dB (2.26Vrms input sensitivity) and 41dB gain (0.775mV input sensitivity). (See page 15). 9. AC power cable (See page 6) 5 INSTALLATION 5.1 Mounting The amplifier is two rack units high (2U) and will mount in a standard EIA 19'' rack. Amplifiers may be stacked directly on top of each other. There is no need for spacing between units.
< > PRINT APPLICATIONS GUIDE GUIDES MARTIN AUDIO switch mode amplifiers use primary switching, i.e. the mains is rectified directly before the transformer, which means that the power supply is insensitive to the mains frequency and will operate from DC to 400Hz. The amplifier is supplied with an approved European AC line connector.
< > PRINT APPLICATIONS GUIDE GUIDES 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. It also corresponds to headroom of 9dB, which is very low for normal program material. If operating the amplifier into a sustained 2 ohm load, protection circuits within the amplifier will limit the long-term current draw, and thermal protection may occur. MAX OUTPUT POWER Power MA4.
< > PRINT APPLICATIONS GUIDE GUIDES 5.6 Input connections Both inputs are balanced on 3 pin XLR type connectors and wired pin 2 hot, pin 3 cold, pin 1 ground/shield: PIN 1 PIN 2 PIN 3 - SIG. GROUND/SHIELD HOT (+) COLD (-) + – 2 1 3 SIG. GND. Figure 3. XLR input connector pin-out. There are TIP RING SLEEVE also TRS jacks for linking etc. They are wired as follows: HOT (+) COLD (-) SHIELD/SIG. GROUND SIG.GND – + Figure 4.
> PRINT APPLICATIONS GUIDE GUIDES Do not use XLR and TRS jacks on the same channel simultaneously for mixing or other purposes. Balanced Output Signal Grounded Shield 1 Amplifier Input 2 2 3 Amplifier Input Balanced Output Chassis Grounded Shield 1 1 3 2 2 3 1 3 Figure 6. Balanced line To use an unbalanced source, connect pin 3 (ring on TRS jack) to the shield of the connector. If you leave one pin disconnected, you will lose 6dB in gain.
< > PRINT APPLICATIONS GUIDE GUIDES 5.7 Connecting speakers Speaker connections are made via the two Neutrik NL4FC Speakon connectors (1). These connectors meet the EC safety requirements. They are wired as follows: Pin Pin Pin Pin -1 +1 -2 +2 Speaker ground. Speaker positive. No connection. No connection. 21+ 2+ 1- Figure 9. Speakon connector Please note that this is the standard wiring convention for Speakon connectors adopted worldwide.
< > PRINT GUIDES APPLICATIONS GUIDE 5.8 Impedance matching (MLS switch) The MLS™ switches (2) are located on the rear panel. The MLS (Minimum load select) switches offer impedance matching, so you can drive the MA4.2 into 2 ohms without increased heat loss. As stated earlier the MA4.2 can produce at least 2000 watts into any impedance between 2 and 8 ohms. Utilise higher MLS™ positions when connecting to lower impedances as shown in Table 2. As can be seen from Table 2, The MA4.
> PRINT APPLICATIONS GUIDE GUIDES dB MLS Switch OUTPUT CH.B 0 1+ CH.B+ 1– CH.B– -2 -4 -5 Figure 10. MLS switches on rear panel 6 OPERATION MODES 6.1 Stereo operation For stereo (dual channel) operation, leave the Link and Phase reverse switches in the un-depressed position. In this mode, both channels operate independently of each other, with their level attenuators controlling their respective levels. Never connect either output terminal to ground or in parallel.
< > PRINT GUIDES APPLICATIONS GUIDE The recommended minimum nominal impedance for bridged mono is 4 ohms (equivalent to driving both channels at 2 ohms). Driving bridged loads of less than 4 ohms may cause a thermal overload. 2 + 1 3 + – CH A + – + – I/P LINK – 2 1 PHASE INVERT 3 + + – CH B + – – Figure 11. Bridge mono connection Both level attenuators must be at the same position. We recommend that you put them in the 0dB (full) position. 6.
> PRINT APPLICATIONS GUIDE GUIDES Channel A output is connected as in the normal stereo mode. By having channel A and B operating in opposite polarity, the energy storage in the power supply is more efficient. This means that the amplifier can deliver up to 10% more power than in tandem mono mode. This is significant for signals below 100Hz (sub bass etc.). 7 OPERATION 7.
< 7.5 > PRINT APPLICATIONS GUIDE GUIDES Indicators Figure 13. Front panel indicators The two bottom green "ON" LED's indicate when the power supply and output stage is operating correctly. The "-40 dB" LED's illuminate when the output signal is greater than -40dB. 0dB is referenced to full output power. These LED's also act as signal present indicators. The ''Clip/limit'' LED indicates when the amplifier output is clipping or limiting.
8 > PRINT APPLICATIONS GUIDE GUIDES PROTECTION FEATURES Each MARTIN AUDIO MA Series amplifier has many advanced protection features that will protect both the amplifier and the speakers connected to it, should a fault condition arise. Under normal use these features are inaudible. All protection circuits are independent. Output limiter An output limiter is included to avoid amplifier clipping.
< > PRINT APPLICATIONS GUIDE GUIDES VHF protection If a signal of more than 12kHz, at full power, is detected at the amplifier outputs and lasts for more than five seconds, the VHF protection mutes the input signal. (This is indicated on the front panel (3) labelled “Protect”). After five seconds the outputs will un-mute and return to normal operation, unless the output signal has remained unchanged in which case the VHF protection will re-initiate.
9 > PRINT APPLICATIONS GUIDE GUIDES DESIGN FEATURES Cooling MARTIN AUDIO MA Series amplifiers run very cool due to a patented heat exchanger. The bi-polar output devices are mounted directly onto a copper heat sink thereby avoiding thermal losses normally found when using mica washers. The heat sink is mounted horizontally in front of a pressure chamber and the air flow is constant along the whole heat sink.
< > PRINT APPLICATIONS GUIDE GUIDES 90 80 70 Voltage [V] 60 50 2 40 30 20 1 10 3 0 0 5 10 15 20 25 30 35 40 45 50 Current [A] Figure 14. Current-voltage characteristic of different power supply topologies. 1) Conventional power supply shows voltage drop due to internal resistance. 2) Regulated power supply used by MARTIN AUDIO. 3) Unregulated switch mode power supply with current limiting.
< 10 > PRINT APPLICATIONS GUIDE GUIDES 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.
< 11 > PRINT APPLICATIONS GUIDE GUIDES APPENDIX A Mains voltage selection All Martin Audio MA Series amplifiers are normally shipped for 230 Volt AC operation 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 contact MARTIN AUDIO for information. 22 Martin Audio – MA4.
< 12 > PRINT APPLICATIONS GUIDE GUIDES MAINTENANCE Under normal use the amplifier should give years of trouble free service. The only user maintenance required from the user is to vacuum the front grille periodically. In some extreme cases it may be necessary for your supplier to clean the inside of the amplifier. These conditions usually occur after prolonged use in environments using "cracked-oil" smoke machines. If you are using your amplifier for heavy-duty use i.e.
< 13 > PRINT APPLICATIONS GUIDE GUIDES WARRANTY General The MA4.2 Powered Amplifier is warranted to be free from defects in components and factory workmanship under normal use and service, for a period of one year from the date of original purchase.
< > 14 PRINT APPLICATIONS GUIDE GUIDES TECHNICAL SPECIFICATIONS MA4.2 INPUT IMPEDANCE GAIN SELECT SWITCH CMRR@1kHz OUTPUT IMPEDANCE@1kHz POWER BANDWIDTH SLEW RATE HUM/NOISE CHANNEL SEPARATION MAINS OPERATING VOLTAGE PROTECTION 20kohms (balanced) 10kohms single ended 41dB (I/P sens 0.775V), 32dB (I/P sens 2.26V) >50dB < 0.06 ohms 5Hz - 20kHz 20V/us <-95dB 1kHz - 80dB 10kHz - 70dB 120 - 270 (minimum start voltage 190) full output power maintained 180 - 280V. Optional (65 - 135V) operation.
CONTENTS < > PRINT MA4.2 APPLICATIONS GUIDE GUIDES Power Amplifier Please Click here to return to main menu Please Click here to visit our website MARTIN AUDIO L O N D O N The Martin Experience Century Point, Halifax Road, Cressex Business Park, High Wycombe, Buckinghamshire HP12 3SL, England. Telephone: +44 (0)1494 535312 Facsimile: +44 (0)1494 438669 Web: www.martin-audio.com E-mail: info@martin-audio.
CONTENTS < > PRINT APPLICATIONS GUIDE MA4.
