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4.3.2 Signal LEDs
The green signal LED is illuminated when the voltage level at the output reaches
approx. 4 V; this corresponds to a power of approx. 4 W at an impedance of
4 Ohms.
4.3.3 Clip LEDs (multifunctional)
The clip LEDs are bi-coloured: green/red. Each colour indicates a different status.
The intensity of the green light is defined by the current passing through
the output stage of each channel (lowest brightness is proportional to
approximately 1 A, the maximum brightness reflects the maximum output
current). The red colour indicates the amount of signal clipping in each
respective channel. If the green LED (current indicator) and red LED (clipping
indicator) light up simultaneously, the Clip LED is yellow.
If the amplifier is overdriven for prolonged periods, the Clip LED will appear red
to alert the user more effectively (the green component of the LED is switched
off ).
Monitoring the output current and clip via the LEDs can aid the detection of
incorrectly wired components and faults in the loudspeakers at an early stage.
(See 6 Troubleshooting)
4.4 Power Amp Protection Systems
4.4.1 Clip Limiter
If the power amp is overdriven, the clip detection circuit triggers the micro-
processor. The processor reduces input signal level by controlling the DCA.
The strategy is implemented in software. For sinusoidal input signals the
microprocessor limits the input signal in such a way that non-linear distortions
of the signal never exceed 1 %.
The clip limiter can work on each channel independently (except in mono-
operation).To disable the Clip Limiter, see 4.2.3 Limiter Switch.
4.4.2 Under Impedance Limiter
As a result of incorrectly connected or defective loads, under impedance or even
short circuits may be presented to the power amp channels.
In order to detect an under impedance, the microprocessor calculates the result-
ant impedance. If an impedance of less than 2,66 ohms/channel is detected, the
microprocessor limits the signal to the power amp until a subsequent measure-
ment indicates that impedance has risen to a safe level. Whenever the under
P.21
USER MANUAL
VORTEX 3 QUADRO
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