P.28
4.3.2 DC Protection
Each output of the power amp is constantly monitored for persistent DC
voltage levels. If the 10 V threshold voltage is exceeded at any of the out-
puts, the corresponding channel will be automatically switched off. A DC
issue can be located in the output stage, the driver stage, or at the input
of the amplifier.
Output Stage
When a persistent DC voltage is located at an output stage, the main
SMPS will be permanently switched off. This will be indicated on
the display.
4.3.3 DC Servo
To prevent DC Offset at the speaker output, the
LINUS10
amplifiers are fit -
ted with two DC Servos (hence there are no capacitors in the signal path!).
4.3.4 Overcurrent Protection
The output stage is permanently monitored for possible current surges.
There are two limiting levels of overcurrent depending on output voltage.
These limits will be set automatically. This improves reliability without de-
grading sound quality when driving complex loads.
4.4 Mains Protections
4.4.1 Inrush Current Limitation
Within 2 seconds of the
LINUS10
amplifiers being connected to the mains,
the inrush current limiter will charge the primary capacitances in a con-
trolled way, limiting the maximum mains current during startup.
4.4.2 Mains Overvoltage Detection
The mains overvoltage detection is always operative. When the mains volt -
age exceeds approx. 267 V (230 V operation), or 134 V (120 V operation)
the amplifier will switch off. When the mains voltage returns to nominal
value, a soft start occurs.
4.4.3 Mains Surge Overvoltage Protection
The
LINUS10
is fitted with a varistor unit, protecting the SMPS from spo-
radic surge overvoltages coming from the mains distribution.
If active, this protection is indicated by a orange LED behind the dust cover
(on the right side). If this LED is not lit, this means that the amplifier has
already suffered significant overvoltages surges and that the varistor pro -
tection needs to be exchanged.
4.4.4 Mains Failure Detection
Mains Failure Detection is always operative. When the mains supply is
interrupted for approx. more than 4 mains cycles, the amplifier will detect
and display a mains voltage loss. When the mains voltage returns to a
normal value, a soft start occurs and the amplifier returns to normal / previ -
ous operation.
4 OPERA
TION
USER MANUAL v1.0
CODA AUDIO LINUS10
4.3 Power Amp Protection Systems
4.3.1 SOA Protection
To ensure that the power transistors are only used in the Safe Operation
Area (SOA), the SOA-protection would mute the corresponding channel if
not. If the power transistors are back in their SOA, the channel is automati-
cally unmuted again.
CODA AUDIO
LINUS 10