Protective Circuits - Omnitronic E-Series User Manual

8.3 Adjusting the level
1. First, set the volume controls of the pre-amplifiers to zero and turn both gain controls of the amplifier to
mid-position. There should be no loud humming. Should humming persist, check the connection cables
between the pre-amplifier and the amplifier (switch off components before).
2. Adjust the level controls to the desired volume value. In case of overload, the red CLIP indicator lights
up. In this case, reduce the volume correspondingly.
3. In bridge mode the level control for channel 2 is disabled. Volume adjustment is made with the level
control for channel 1.
Additional information on the operation
When operating the amplifying system, please make sure that the loudspeakers always sound well. When
distortions can be heard, either the amplifier or the loudspeaker is overloaded. Overloads can quickly lead to
amplifier or speaker damage. In order to avoid damage, please reduce the volume immediately when distortions
can be heard. When speaker systems are destroyed by overload, the guarantee becomes void. Always check the
sound pressure level with a meter in order to keep to the threshold.
8.4 Switching on the limiter
The integrated limiter reduces the input signal if a limit level at the output is reached. This will prevent
distortions and protect the connected speakers. With the selector switch LIMITER it is possible to switch on
the limiter circuit.
• left position: limiter is switched off
• right position: limiter is switched on
8.5 Ground lift switch
If an interfering hum noise can be heard without a music signal, a ground loop may be the reason for this.
The ground lift selector switch allows for interrupting the ground loop and the humming should be eliminated.
For this purpose the set the selector switch to position LIFT. Thus signal ground and housing ground are
separated.

9. PROTECTIVE CIRCUITS

The integrated protective circuits prevent damage to the speakers and the amplifier. If activated, the
speakers are electrically separated from the amplifier and the PROTECT indicator lights up:
• for a few seconds after switching-on until the speaker outputs are ready for operation
• in case of overheating of the amplifier
• in case of a short-circuit at a speaker output
• in case of a DC voltage at a speaker output
If the red PROTECT indicator lights up during operation or if it does not extinguish after switching on, the
amplifier has to be switched off and the cause of the fault has to be removed.
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