QSC Audio CX168 user manual Operation Gain Controls

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OPERATION: GAIN CONTROLS

Gain Controls

The gain controls are located on the right side of the front panel. They are operated by rotating the control clockwise to increase gain or counterclockwise to decrease gain. When turned fully counterclockwise, gain is fully reduced and no output signal will be present. When turned fully clockwise, the voltage gain of the amplifier is +26dB and the output signal will potentially be full strength (provided the input is fully driven).

The gain controls are detented in 21 steps for repeatable

adjustment. Surrounding the Gain control, the power

Location of gain controls on the front panel of the CX168

attenuation level is shown in dB. Each detent is approxi-

 

mately 1dB change in amplifier gain.

 

To operate the gain control, rotate the control’s knob so that

 

the desired level is achieved. A small, flat-tipped screw-

 

driver (#1 blade size) is typically used. Be sure not to use

 

large screwdrivers as it is possible to damage the gain

 

control by applying excessive torque. Gain controls are

 

sensitive, electronic components and should be treated with

 

care.

 

Each channel pair’s gain controls and indicator LED’s are grouped together as shown, right. The channels are paired in the following manner:

Channel Pair #1-

Ch. 1 and Ch. 2

Channel Pair #2-

Ch. 3 and Ch. 4

Channel Pair #3-

Ch. 5 and Ch. 6

Channel Pair #4-

Ch. 7 and Ch. 8

As detailed in the ‘Setup’ section of this manual, channels can only be paralleled and bridged within their channel pair. Example- Channel 3 can be bridged with channel 4 only; it can not be bridged with any other channel.

The dB markings around the gain controls are attenuation. They show attenuation from full gain. At 0db attenuation, the voltage gain of the amplifier is 26dB. If the gain control is set at the 7dB attenuation position, then the voltage gain of the amplifier is 19dB (26dB - 7 dB).

Typical channel-pair control and indicator group on the CX168

Typical gain control showing attenuation level markings and LED’s for the channel. Note that there is only one BRDG (bridge) and one PAR (parallel) indicator per channel pair.

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Contents CX168 Important Safety Precautions Explanation of Symbols FCC Interference StatementTable of Contents Introduction Front Panel Front Panel with Security PlateRear Panel Dimensions Mounting Points Rack Mounting Installation Unpacking & Rack MountingWhat is Included Supporting the Rear of the AmplifierInstallation Cooling & AC Mains Requirements Fan CoolingAC Mains Connection Setup Setting the Mode Configuration DIP Switches SetupSetup Setting the Mode STEREO, PARALLEL, or Bridge ModesSetup Mode Switches Clip Limiter and LOW Frequency Filters Clip LimiterLow Frequency Filter Low Frequency Filtering Tips Frequency Response CurvesConnections INPUTS- Using the Terminal Block Inputs Connections INPUTS- Using the DataPorts Connections Outputs Stereo and Parallel ModeBridge Mode OutputsConnections OUTPUTS- Using the Terminal Block Connectors Terminal Block ConnectionsOperation Power Switch and Gain Controls Power SwitchOperation LED Indicators LED IndicatorsOperation Gain Controls Gain ControlsOperation Gain Control Security Plate Gain Control Security PlateOperation Using the QSC Dataport Connections DataPort ConnectorsUsing the DataPort General Guidelines to using the DataPorts on the CX168 What Can I Connect to the DataPort?Applications Typical Application Examples Four Room Stereo FeedOFF Stereo Mode Parallel ModeAppendix Description of Stereo & Parallel Operating Modes Appendix Description of Bridge Operating Mode Normal Operating LevelsAppendix Multiple Speaker Loads in Series Multiple Lo-Z Loads in SeriesAppendix Multiple Speaker Loads in Parallel Multiple Lo-Z Loads in ParallelTroubleshooting no Sound Problem no SoundProblem Hiss SPECIFICATIONSCX168 Output Power in wattsSpecifications CX168Warranty Information & HOW to Contact QSC Product WarrantyDisclaimer Page Page
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