DAPAudio Stageamp 2.2, User Manual

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12
Reliability protection function
1. Clip/Limit
This feature has two protection functions:
1) Limit on the input signal range, to prevent input signal overload beyond the amplifiers rated range and
cause square wave output to damage the speaker.
2) When the signal waveform is distorted, it can automatically adjust gain and limit distortion signal
output.
Note : If the input signal e22dBu (10V), clip limit will be impossible, so do not increase the input
source signal unlimitedly.
2. Soft clip
This function can be selected by using the ON/OFF switch. When the input signal exceeds the setting
range, it will smoothly limit the input waveform range. Compared to clip limit, soft-clip provides even a
more powerful output.
3. Overheat protection
1) When the amplifier works at full load for a long time , the fans will reach the maximum speed,
thus providing maximum air flow. In case the internal transistor temperature rises to 95 degrees Celsius,
the first step of power demotion (down ½
output power) will be activated to ensure that in overheated
state, the amplifier will maintain program output. Depending on different music characteristics, the
amplifier will return to the original output power within 3-10 minutes.
2) When the amplifier is subjected to overload for a continuous period of time and no temperature
improvement is made, it will advance to the next level of power demotion. Transistor temperature will
reach 105 degrees Celsius and the amplifier will reach full protection mode. The output will be
completely muted and no sound will be reproduced. At this time, the protection LED and temperature
LED are lit at the same time.
Absolute minimum nominal load Impedance for Bridge operation is 4 Ohm per channel
Absolute minimum nominal load Impedance for Parallel / Stereo operation is 2 Ohm per channel
4. VHF protection
If the amplifier output has reached a certain range, and frequency exceeds 10KHz, such as MIC
feedback shout, then amplifier may go into VHF protection after 3 seconds. The protection LED (PRT)
on the front panel will be on, the amplifier output will be muted and no sound will be reproduced. Sound
reproduction will recover automatically after 10 seconds of protection. If the output signal does not
change, VHF protection will remain active.
5. Short-circuit protection
All Stage Amp models are equipped with a short circuit protection. This protects your amplifier against
short-circuitry. When the output is short circuited, the protection LED (PRT) on the front panel will be on
and the amplifier will be muted. The operating mode will be restored 10 seconds after the short circuit
has been removed.
6. AC Power Supply Protection
If the AC power voltage drops below the allowed working voltage (-165V), the power supply will be
turned off automatically until the power voltage is restored to normal.
7. DC protection
1) If the a DC voltage (2.6V or higher) occurs on the output signal, the DC protection circuit will be
startup in order to protect the speakers. The protection LED (PRT) on the front panel will be on and the
amplifier output will be muted.
2) If there is DC output and for any reason the protection relay should not be able to disconnect the
speakers, the output stage is designed to short circuit the amplifiers output. The fuse will blow, thus
protecting the speakers.
Ex-factory setting
1. All the volume adjustment buttons were set to -∞ .
2. Power switch was set to OFF .
3. Grounding selector switch was set to ON .
4. Working mode selector switch was set to STEREO .
5. Sensitivity selector switch was set to 0.775V .
6. 30Hz high pass selector switch was set to ON .