4 OPERATION

P.19

4.3.4 Speaker Protect Limiter

Whenever the SOA protection of the power amp switches back the current rail there could be a small clipping at the output; but the microprocessor is also triggered by this protection and will reduce the signal level immediately to minimise the effect.

The user can decide either to use Speaker Protect or not. If you use this amp for low frequencies (bass / Sub bass) and you want to squeeze the absolute maximum out of it, Speaker Protect can be switched off. For all other applications (e.g. Full Range) it’s recommended to keep Speaker Protect switched on.

4.3.5 DC Protection

Each output of the power amp is constantly monitored for persistent DC voltage levels. If the 3 V threshold voltage is exceeded at any of the outputs, the main SMPS will shut down and the channel will be automatically switched off. The microprocessor performs a sophisticated strategy to locate the cause of the malfunction. DC can be located in the output stage, driver stage or at the input of the amplifier.

Output Stage

When a DC voltage is located at an output stage, the main SMPS remains switched off. The On LEDs will show a flash sequence corresponding to this malfunction. (See 6 Troubleshooting)

Driver Stage

When a DC voltage is located at the driver stage only the defective channel’s output stage and the DCA are muted. The other channel continues to work. The On LED of the defective channel will indicate the malfunction by starting the relevant flash sequence. (See 6 Troubleshooting)

Amplifier Input

When DC is located at the input stage only the DCA of the affected channel is muted. The other channel continues to operate normally. If the DC signal at the input vanishes, the microprocessor will de-mute the affected channel and the amplifier will work as usual again.

USER MANUAL

VORTEX 6, 4, 2.6 and 200V

4.3.6 DC Servo

To prevent DC Offset at the speaker output the VORTEX is fitted with two DC Servos. (Hence there are no capacitors in the signal path!)

4.3.7 Over Current Protection

The output stage is permanently monitored for possible current surges. There are two limiting levels of over current depending on output voltage.These limits will be set automatically. This improves reliability without degrading sound quality when driving complex loads.

4.3.8 Thermal Protection

The microprocessor uses several sensors in the amp in order to ascertain temperature data. If the microprocessor detects a temperature of more than 85 °C at the heat sinks, the input signal on that channel is reduced. If the temperature exceeds 100 °C, the main SMPS is switched off.

The On LED of the overheated channel will start a blinking-sequence. (See 6 Troubleshooting)

4.4 Mains Protections

4.4.1 Inrush Current Limitation

Within 2 seconds of the VORTEX being switched on, the inrush current limiter will increase mains current from nearly zero to nominal value. This value depends on program material, output level and speaker loads.

4.4.2 Mains Over Voltage Detection

Mains Over Voltage Detection is always operative. When the mains voltage exceeds approx. 267 V (230 V operation), 134 V (120 V operation) or 117 V (100 V operation),the amplifier will switch off.When the mains voltage returns to nominal value, a soft start occurs.