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6. ADVANCED FUNCTIONS
6.1. Protection
The V 40 SE features a comprehensive electronic monitoring and protection system. This system
will automatically switch the V 40 SE off if a fault occurs 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 in [No. 6, chapter 4] to show 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 V 40 SE, 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 10).
The following conditions can cause the protection system to trip:
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Overdriving the V 40 SE to excessive levels or with excessive levels of low frequency.
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A speaker cable short circuit while the speakers are being driven at high listening levels.
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A fault in one or more of the output tubes.
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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 V 40 SE 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 11 "Troubleshooting").
If it is not clear what has caused the protection system to trip, we recommend 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.
6.2. Soft-Start
The V 40 SE 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 active in the first 20 - 30 seconds when the unit is switched on. During this
time you cannot listen. The Soft-Start delay is indicated with the Soft-Start-LED. During the Soft-
Start-phase adjusting the BIAS is not possible.