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Signal-LED
This green LED lights, when its channel produces an output signal of about 4 Volt RMS or more (0,1V or
more at the input, with 0dB attenuation and standard 40X voltage gain). It is useful to determine whether
the amplifier is amplifying a signal.
Protect LED
When the red LED lights, indicating that the channel has overheated, the channel’s output relay is open,
and the speaker(s) has been disconnected for any of the following reasons:
1. The unit was just powered up and is in the turn – on delay mode
2. The amplifier senses a DC voltage at its output.
Power LED
This indicator LED lights, when the amplifier has been turned on, AC power is available and the low-
voltage power supply and fan are operational.
Protection Features
Every amplifier incorporates several circuits to protect themselves and the speakers under virtually any
situation. Dap Audio has attempted to make the amplifier as “foolproof” as possible by making it
impervious to short and open circuits, DC Voltage and overheating.
When a problem occurs, that causes a channel to go into a protection mode, the PROTECT for that
channel will glow. DC voltage on the output, excessive subsonic frequencies, or thermal overloads will
cause the channel’s output relay to disconnect the speaker load, until the problem is corrected or the
amplifier cools down.
The internal fan(s) will keep the amplifier operating well within its intended temperature range under all
normal conditions.
When a channel’s heat sink temperature reaches 90 ºC, which may indicate an obstructed air supply,
clogged air filter, etc, the channel will disconnect its load. Normal operation will resume automatically
once it cools to 80 ºC. During this time, the channel’s PROTECT LED will light.
Short Circuit
If an output is shorted, the protection circuit will be more sensitive, than in the normal protection situation
and will protect the channel’s output transistors from the current stress. The channel’s PROTECT LED will
light. If the short circuit remains, the channel will eventually thermally protect itself by disconnecting the
load.
DC Voltage Protection
If an amplifier channel detects DC voltage at its output, its output will immediately open to prevent
speaker damage. The channel’s PROTECT LED will light.
Subsonic Frequencies
All amplifiers have a built-in subsonic frequency protection circuit, cornered at 10Hz, for each channel.
An additional feature is a special high frequency protection technology, which enables you to
automatically disconnect speakers, when excessive high frequency energy appears at the output.
Turn-On/Turn-Off-Protection
At power up, the speakers are disconnected. The power supplies charge for about 2-3 seconds and
stabilize, and then the speakers are connected. When power is removed, speaker loop is synchronized
with the turn off signal, therefore no thumps or pops are heard.
Speaker-Protection
All amplifiers automatically protect speakers from DC voltage, subsonic signals and excessive high
frequency signal, but users should be aware of the application limits of their speakers. Be aware that the
amplifiers power does not exceed the speaker’s power capabilities.
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