FRONT PANEL
Use the POWER switch, located on the front panel’s, right side to switch the appliance’s power on. The soft-start function limits against current inrush peaks on the mains, which in addition prevents the mains line protection switch from activating during power-on. The loudspeaker outputs are activated via relay switching with a delay of approximately 2 seconds to efficiently attenuate eventual power-on noise. The PROTECT LED lights during the delay time and the fans run at maximum speed. This is normal, confirm- ing the immaculate operation of the protection circuitry.
This indicator lights when the power amplifier has been switched on. Causes for the POWER-indicator not lighting are: the appliance is not connected to the mains
or the primary fuse is defective.
The PROTECT LED indicating that one of the internal protection circuits against thermal overload, short-circuit, Back-EMF, HF-occurrence at the output, etc., has been activated. The output relays interrupt the connected loads from
the power amps while input signals are interrupted as well, preventing the connected loudspeaker systems and the power amplifiers themselves from being damaged. Whatever caused the fault – e.g. a short-circuited speaker cable – needs to be reme- died. In case of thermal overload you have to wait until the power amplifier automati- cally regains normal operation.
The SIGNAL LED lights as soon as an audio signal of approximately 30dB below full modulation is present at the output. The LED is dimmed when speaker cables are short-circuited or a protection circuit has been activated.
The 0dB LED lights whenever the power amplifier is driven at its maximum. Higher input voltage does not result in higher peak output voltage. In addition, the 0dB indicator comes in handy when adjusting external limiters.
This indicator lights as soon as the integrated dynamic audio signal limiter is activated and the power amplifier is driven at the clipping limit or generally at its maximum capacity. Short-term blinking is not a problem, because the internal limiter controlls input levels of up to +21dBu down to a THD of approximately 1%. If, on the other hand, this LED lights constantly, reducing the volume is recommended to prevent the loudspeaker systems connected from being damaged by probable overload.
Detent potentiometers scaled in dB (steps of 1dB) for adjusting the power amp’s overall volume. To prevent distortion in mixing consoles connected to your CP-Series amp, setting these controls to a value between 0dB and -6dB is generally recommended. The dB-scale provides direct indication of the control attenuation applied to the fixed internal amplification.
