Martin Audio Martin Audio - MA200Q Amplifier, English, There are two types of DC protection

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limiter reduces the input signal proportionally. Note that, if the signal is distorted or clipped before it reaches the amplifier, the clip limiter will not be activated.

Under normal operation the clip limiter is inaudible. The limiter can be turned “On” or “Off” by pressing the relevant clip limit switch. (3 see page 5)

Some manufacturers of loudspeaker processors do not recommend the use of clip limiters in amplifiers, as it can effect the tracking of the processor's limiters.

If the amplifier is being used without any external limiting, Martin Audio recommend leaving the clip limiters switched "ON" (button depressed).

9.2Thermal protection

When the amplifier is driven very hard into a low impedance load, the cooling fans will run at high speed. If these operating conditions continue, the Protect indicator(s) will illuminate indicating that the amplifier is about to go into thermal shutdown.

After five seconds the amplifier will go into thermal protect by muting the input signal. After 15-20 seconds the amplifier will have cooled down enough for the amplifier to come out of shutdown and operate as normal. If the load conditions remain unchanged the thermal protection will be re - initiated. Thermal protection occurs when the heatsink temperature reaches 90°C.

9.3VHF 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 panel (4) by the LED 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.

9.4Short circuit protection

All Martin Audio MA Series amplifiers are completely short circuit protected. The protection circuit permits very high peak currents, but still holds the output devices within the safe operating area. If a short circuit is maintained, the channel affected will eventually go into a thermal protect cycle until the short circuit has been removed.

9.5AC mains voltage protection

If the AC mains voltage is outside the operational window (over or under voltage), the power supply will automatically shut down. When the mains voltage is above the minimum start voltage and below its maximum operating voltage the amplifier will restart.

The four green ”ON” LED’s indicate when the power supply is operating correctly.

9.6DC protection

There are two types of DC protection:

•Fuses on the supply branches of each channel.

•DC crowbar protection that shorts the output if more than 10 volts DC is being detected on the outputs. Both these circuits come into effect once a DC level is detected on either channel.

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Martin Audio – MA200Q Amplifier