Crown Audio Xs Series Protection Systems, Output Current Limiting, DC Protection, 120V 220V 240V

Xs Series Power Amplifiers

4 Advanced Features and Options

Figure 4.1

Fault Indicator

NOTE: For detailed information about these Crown amplifier features, please consult the Crown Amplifier Application Guide, available on the Crown website at www.crownaudio.com.

4.1 Protection Systems

Your Crown amplifier provides extensive pro- tection and diagnostic capabilities, including output current limiting, microprocessor-con- trolled DC protection, circuit breaker, and spe- cial thermal protection for the unit’s transformers.

4.1.1 Output Current Limiting

Output Current Limiting circuitry protects the amplifier output stage from damage caused by short-circuit loads.

4.1.2 DC Protection

DC Protection disconnects the loudspeaker load in the event of an output DC offset exceed- ing 2V. In such an event the yellow Fault LED will illuminate (see Figure 4.1) and the ampli- fier channel will be muted. In the majority of cases, DC protection is indicative of a faulty amplifier channel, and will be accompanied by an illuminated Clip LED, even with no input connected and level controls set at minimum. If this is the case, contact your dealer or service center.

4.1.3 Circuit Breaker

The high-voltage power supplies of your Crown amplifier are protected by a circuit breaker. The breaker rating varies depending on model and supply voltage as follows:

Table 2: Circuit-Breaker Amperage Ratings

	120V	220V	240V
Xs1200	20A	15A	15A
Xs900	18A	12A	12A
Xs700	18A	12A	12A
Xs500	18A	12A	12A

4.1.4 Thermal Protection

The Thermal Protection circuit will activate if the internal heatsink temperature exceeds proper operating temperatures (194 °F, 90 °C). When the heatsink temperature has fallen to a safe level, this protection circuit will automati- cally be reset. Principle causes of thermal pro- tection are:

1)Inadequate ventilation of the equipment rack

2)Incorrect load impedance

3)Output cable short circuit

4)Blocked air vent

5)Heatsinks in need of cleaning

6)Cooling fan failure.

The cause of your amplifier’s thermal protection state should be determined and corrected as soon as possible. Without correction, the Ther- mal Protection circuit will typically reactivate.

page 14 Operation Manual