Operation Manual
5. Operation and performance 
C SERIES Operation Manual rev 2.0.0
21 
5.4.7. Constant voltage 70 V and 100 V systems setup and operation 
When using C Series ampliers to drive constant voltage (high-impedance) speaker systems at 70 Vrms or 100 V 
peak, you can in most cases simply connect the speakers to the amplier output terminals, select the correct VPL 
setting, and place the amplier in service.
5.4.8. Output Current Peak Limiter (CPL) 
The Current Peak Limiter (CPL) ensures that the amplier will not be damaged by trying to deliver current to the 
outputs exceeding the physical limitations the transistors. The CPL keeps the amplier within the Safe Operating 
Area. The CPL is non-adjustable and has different limit values depending on model type. The maximum output 
current values for the four C...X models are:
•  C 20:8X, 8 Arms per channel
•  C 10:8X, 5.6 Arms per channel
•  C 10:4X, 8 Arms per channel
•  C 5:4X, 5.6 Arms per channel
CPL activity is indicated by illumination of an orange LED for each channel on the front-panel. Warnings also are 
shown in the DeviceControl software’s GUI. 
A steadily illuminated orange CPL LED indicates a short circuit situation (or very low impedance). The output will 
mute for 6 seconds before measuring the output impedance again. This will continue until the short circuit is xed, 
at which time the output will automatically un-mute. An input signal must be present to allow detection of short 
circuit or low impedance conditions.
TIP: If the CPL LED is steadily illuminated orange while the output is muted and the -4 dB signal LED is 
NOT on, then the amplier output is detecting a short circuit or low impedance condition. The problem 
can be solved by checking input and output cables and examining the state of the loudspeaker load. If 
there is no short circuit present, then the condition may be rectied by lowering the VPL or input levels.
If the CPL indicator is lit continuously, then the amplier is delivering excessive current and is being forced into a 
current limiting state (output muted). 










