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6. ADVANCED FUNCTIONS
6.2. Electronic Protection System
The RE 290 features a comprehensive electronic monitoring and protection system. This system
will automatically switch off the RE 290 in case of a fault occurring in the power section.
The protection system has been designed to keep the unit safe from the consequences of
overloads of any kind and to protect the output tubes from current surges.
The RED “Protection” LED lights up to indicate that the protection system has tripped.
The amplifier will not play music once the protection system has tripped and you will
not be able to check or adjust the BIAS setting.
The BIAS LEDs will show "yellow" for each of the four output tubes.
If a Black Box or a Super Black Box is connected to the RE 290, the front panel (operate) LED of
the Black Box / Super Black Box will go out. If the Super Black Box is connected, tripping the
protection system will automatically activate the discharge circuit of the Super Black Box (see
chapter 8.2).
The following conditions can cause the protection system to trip:
-
Overdriving the RE 290 to excessive levels or with excessive levels of low frequency.
-
A speaker cable short circuit while the speakers are being driven at high listening levels.
-
A fault in one or more of the output tubes.
-
A fault in one of the preamp tubes which overloads the affected channel.
Once the protection system has cut in, the only way you can turn the RE 290 back on,- is to turn
the on/off switch off and then on again. Allow the unit two minutes to cool down before switching it
back on. If possible, identify and eliminate the cause of the problem (see chapter 9
"Troubleshooting").
If it is not clear what has caused the protection system to trip, we recommend that you check the
BIAS before attempting to use the amplifier again. Tube faults can often result in widely varying
BIAS settings. When these settings exceed a particular value they can cause the protection system
to trip.
6.3. Soft-Start, Inrush current limitation
The RE 290 input and output tube heaters as well as its high-voltage rails are logic controlled to
ensure that the conduction of the output tubes as well as input stage voltages are constantly
monitored and controlled by the
Power Management system
to protect the vital internal parts
(tubes, rectifier, electrolytic caps, switches, etc.) against excessive turn-on current. This increases
the lifetime not only of the tubes, but also the caps, while all power related components derive
benefit through this system.
The Soft-Start is always activated within the first 60 seconds after the unit is switched on. During
this time you cannot listen.
During the Soft-Start-phase, adjusting the BIAS is not possible.
