Manual

4 OPERATION

USER MANUAL

D - P O W E R S E R I E S

P. 19

D - P O W E R

S E R I E S

4.3 Power Amp Protection Systems

4.3.1 Clip Limiter

If the power amp is overdriven, the clip detection triggers the Attack-Release-

Circuit (ARC). The ARC delivers the control voltage for the gain reduction. Two

different attack modes (fast and slow) can be selected with the Clip Limiter

switch (see 4.1.4 Limiter Switch).

4.3.2 SOA Protection

Whenever the power transistors leave their Safe Operation Area (SOA), the

SOA-protection in stereo mode switches back the current rail of the respective

channel. In mono modes the rails of both channels are switched back.

4.3.3 DC Protection

Each output of the power amp is constantly monitored for persistent DC voltage

levels. If the 3 V thresholds are exceeded at any of the outputs, the corresponding

channel will be muted. If DC was only detected for a short moment, the ampli-

ﬁer will release mute and work as normal. If DC is detected for longer periods or

repeatedly if this happens,the ampliﬁer will switch to standby mode.

Switch off the ampliﬁer, wait until the power LED stops ﬂashing and switch the

ampliﬁer on again.

4.3.4 Over Current Protection

Over current is permanently controlled in the output stage. There are two limit-

ing 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.

4.3.5 Thermal Protection

There are several sensors inside the ampliﬁer in order to ascertain temperature

data. If a temperature of more than 85 °C is detected at the heat sinks, the input

signal on that channel is reduced. If the temperature exceeds 100 °C, the main

SMPS will be switched off.