PROTECTION FEATURES. Optimus MT-3500, MT-1500

MT-1500 / MT-3500

Power Amplifiers

7. PROTECTION FEATURES

Each power amplifier incorporates several circuits to protect both themselves and the loudspeakers against short and open circuits, DC voltages and overheating. When the protection mode is activated, the channel’s output relay disconnects the speaker load until the problem is corrected or the amplifier cools down.

7.1 Overheat

The internal fan will keep the amplifier operating well within its intended temperature range under all normal conditions. When a channel’s heat sink temperature reaches 90 ºC, which may indicate an obstructed air supply, clogged air filter, etc, the channel will disconnect its load. Normal operation will resume automatically once it cools to 80 ºC. During this time, the channel’s

PROTECT LED will light.

If an output is shorted, the protection circuit will be more sensitive than in the normal protection situation and will protect the channel’s output transistors from over current stress. The channel’s

PROTECT LED will light. If the short circuit remains, the channel will eventually thermally protect itself by disconnecting the load.

7.3 DC voltage protection

If an amplifier channel detects DC voltage at its output, the circuit will immediately open speaker’s line to prevent loudspeakers damage. The channels PROTECT LED will light.

7.4 Subsonic frequencies

The power amplifier has a built-in subsonic frequency protection circuit, cornered at 10 Hz, for each channel. Also a special high frequency protection automatically disconnects speakers when excessive high frequency energy appears at the output.

7.5 Turn-on / turn-off protection

At power up speakers are disconnected, the power supplies charge for about few seconds and stabilize, the speakers are then connected. When power is removed, speaker loop is synchronized with the turn off signal, therefore no thumps or pops are heard.

The power amplifier automatically protects speakers from DC voltages, subsonic signals and excessive high frequency signals; however, the user must be aware that the amplifier power does not exceed the speaker’s power capabilities.

MT-1500 / MT-3500 Version 1.0

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