8-Channel Installed Sound Professional Audio
Contents
1. ti I cee D a in BF BF A orus Serial number label To AC mains RS The correct AC line voltage is shown on the serial number label Connecting to the wrong line voltage is dangerous and may damage the amplifier or constitute the risk of electric shock Verify the correct AC line voltage by checking the specification printed on the serial number label on the rear panel SETUP SETTING THE MODE CONFIGURATION DIP SWITCHES Setup By using the mode switches and connecting to the amplifier properly the CX168 amplifier can be configured as a 1 to 8 channel amplifier This flexibility enables the CX168 to be used for most any multichannel application The CX168 can be thought of as four separate 2 channel amplifiers on one chassis Each of the four amplifier sections may be operated in Stereo Parallel or Bridge mode independently of the others For example channels 1 amp 2 could be set for stereo operation while channels 3 amp 4 are set for parallel operation all while channels 5 amp 6 and channels 7 amp 8 are set for bridge mode The channels are grouped as follows Channels 1 and 2 Channels 3 and 4 Channels 5 and 6 Channels 7 and 8 You can set the operating mode for each group by setting that group s configuration DIP switches in the desired positions It is NOT POSSIBLE to group the channels differently For i2. What is Included Your CX168 shipping container as shipped from the factory includes CX168 eight channel audio power amplifier this user s manual security cover plate for gain controls self adhesive rubber feet use for non rack mount applications eight 3 pin terminal block input connectors two 8 pin terminal block output connectors 14AWG IEC type detachable power cord Rack Mounting Use four screws and washers to secure the amplifier to the equipment rack rails Support the weight of the amplifier while securing it to the rails to avoid bending or distorting the mounting ears The amplifier may be used in an equipment rack or as a stand alone unit Rack mounting is optional Self adhesive rubber feet are provided for non rack mount applications Supporting the Rear of the Amplifier Unless the amplifier is being installed in its final fixed location we strongly recommend supporting the rear of the amplifier Supporting the rear of the amplifier is required for mobile and portable use If the amplifier is to be transported in any way install the optional rear rack mounting ear kit to support the rear of the amplifier During transport the shock loads encountered on the chassis and rack can easily damage an unsupported amplifier and the rack rails With proper support reliability is enhanced Rear rack mounting ear kits are an accessory item and are available from QSC s Technical Services Departme
3. 3 In order for the Ch 1 amp Ch 2 DataPort to control the power status of the amplifier the front panel power switch MUST be in the ON position If the power switch is in the off position the amplifier will not respond to any com mands sent to its Ch 1 amp Ch 2 DataPort 4 The DataPort connection can be used for amplifier status monitoring only using the terminal block inputs for supplying input signals to the amplifier Ensure that the DataPort connection supplies NO INPUT SIGNAL when operating in this fashion If signal is applied to both the DataPort and the terminal block input connector at the same time the signals will be summed and amplified The result may be undesirable 5 If using the DataPort for supplying the audio input signals to the amplifier we don t recommend using the terminal block input connectors even if they are connected to non operating audio sources The DataPort and terminal block inputs are connected in parallel and isolated by about 20k ohms of resistance Even with this isolation it is possible that connection to other signal sources may significantly alter the input impedance at the DataPort This could affect output levels as connections are altered 6 If using the DataPort for supplying the audio input signals to the amplifier do not use the unused terminal block inputs for daisy chaining the DataPort signals to other channel pairs or other amplifiers The DataPort device supplying the audio signal
4. Product Warranty QSC Audio Products Inc QSC guarantees its products to be free from defective material and or workmanship for a period of three 3 years from date of sale and will replace defective parts and repair malfunctioning products under this warranty when the defect occurs under normal installation and use provided the unit is returned to our factory or one of our authorized service stations via pre paid transportation with a copy of proof of purchase i sales receipt This warranty provides that the examination of the return product must indicate in our judgment a manufacturing defect This warranty does not extend to any product which has been subjected to misuse neglect accident improper installa tion or where the date code has been removed or defaced OSC shall not be liable for incidental and or consequential damages This warranty gives you specific legal rights and you may also have other rights which vary from state to state This limited warranty is freely transferable during the term of the warranty period HOW TO CONTACT OSC AUDIO PRODUCTS Mailing address Adresse postale Postanschrift Direccion postal QSC Audio Products Inc 1675 MacArthur Boulevard Costa Mesa CA 92626 1468 USA A Telephone Numbers Num ros de t l phone Telefonnummern N meros de tel fono Main Number Num ro principal Hauptnummer N mero principal 714 754 6175 NS Sales Direct Line Ligne directe ventes
5. 8 3 pin terminal block euro or Phoenix Output 2 8 pin detachable terminal block connectors Control amp Monitoring 4 OSC DataPort connectors Turn on turnoff muting AC coupling DC fault blocking Clip limiting AB B SEE SERIAL NUMBER LABEL ON REAR PANEL FOR THE SPECIFIED OPERATING VOLTAGE Configured at factory for either 100 120 or 230 VAC 50 60 Hz 0 6 6 2 9 2 9 2 14 2 NOTE 1 8 power is representative of current draw with typical music program material with occasional clipping Pink noise 1 3 power is representative of program material with severe clipping CONTROLS DIMENSIONS WEIGHT Front AC POWER switch 8 gain controls Back 4 DIP switch blocks with 10 poles 1 per channel pair Clip Limiters Stereo Parallel Bridge mode selection low frequency filter on off and frequency selection 19 0 48 3 cm wide 3 5 8 9 cm tall 2 rack spaces 14 35 6 cm deep from front mounting rails including rear support ears 21 pounds 9 5 kg net 27 pounds 12 3 kg shipping SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE 31 32 WARRANTY INFORMATION amp HOW TO CONTACT OSC WARRANTY USA only other countries see your dealer or distributor lt THREE YEAR Disclaimer WARRANTY QSC Audio Products Inc is not liable for any damage to speakers or any other equipment that is caused by negligence or improper installation and or use of this amplifier product
6. Verkauf Direkt L nea directo ventas 714 957 7100 Sales amp Marketing Ventes amp marketing Verkauf u Marketing Ventas y marketing 800 854 4079 toll free in U S A only sans frais aux E U seulement zollfrei nur beim USA sin costo en EE UU solamente Technical Service Service a la client le Kundendienst Servicio a la clientela 714 957 7150 800 772 2834 toll free in U S A only sans frais aux E U seulement zollfrei nur beim USA sin costo en EE UU solamente Facsimile Numbers Num ros de t l copieur Telefaxnummern N mero de FAX Sales amp Marketing FAX T l copie ventes amp marketing Telefax der Verkauf u Marketing FAX ventas y marketing 714 754 6174 Technical Service FAX T l copie service a la client le Kundendienst Telefax FAX servicio a la clientela 714 754 6173 Cl World Wide Web www gscaudio com E mail info qscaudio com tech_support qscaudio com NOTES 34 NOTES This page intentionally left blank QSC Audio Products Inc 1675 MacArthur Boulevard Costa Mesa California 92626 USA QSC and the QSC logo are registered with the U S Patent and Trademark Office 2002 QSC Audio Products Inc
7. illuminated lit on Other channel pairs similar Mode switch settings and LED indication for parallel mode operation PAR indicator should be illuminated and BRDG indicator should not be illuminated when in parallel mode Bridge Bridge mode combines the two channels of Bridge mode cH O _ CLIP a pair such as Ch 3 amp Ch 4 into one higher awitclies AG Gand up acters 2 Oe powered channel Like parallel mode both inputs of 2 Qi Re oA o ToL GNAL a channel pair are connected in parallel when the CH7 MODE SWITCHES CH8 K AO DE dii mode switch is set for parallel therefore connect i 1 a 1 u i NW L oN We uf only one input per channel pair when in bridge SEER EEEEE asap 0 PP 2648 0 mode There are 4 possible channel pairs that can _ be bridged on the CX168 They are Ch 1 2 Bridge MM O not illuminated out off Ch 3 4 Bridge Ch 5 6 Bridge and Ch 7 8 Bridge CH7 CH 8 mode switch shown Any pair or number of pairs can be independently Other channel pairs similar illuminated lit on configured in bridge mode Use the first channel s input and gain control when in bridge mode The second channel s gain control is non operative and should be turned all the way down Mode switch settings and LED indication for bridge mode operation BRDG indicator and PAR indicator should be illuminated when in bridge mode in parallel or bridge
8. A Do not use terminal block connections for inputs when the CC JO las DataPort is used as the input signal source If you do the signals from the DataPort and terminal block inputs will be 7 mixed possibly with unexpected results O See the following section for general operating notes regarding the DataPorts on the CX168 OSC DataPort Cable Connect to the DataPort using a QSC DataPort cable Align the connector with the socket housing and insert fully Finger tighten the retaining screws OPERATION USING THE OSC DATAPORT CONNECTIONS What Can I Connect to the DataPort Consult your QSC representative for up to date accessory compatibility QSC has several DataPort based accessories available like the CM16a Amplifier Controller amp Monitor DSP 3 Digital Signal Processing Module DSP 4 Digital Signal Processor Module XC 3 Crossover SF 3 Subwoofer Filter LF 3 Low Frequency Filter DCM Crossovers amp Monitors General Guidelines to using the DataPorts on the CX168 1 Each channel pair Ch 1 2 Ch 3 4 Ch 5 6 and Ch 7 8 has its own dedicated DataPort connector that applies control and monitoring functions to its specific channel pair 2 The DataPort for channels 1 and 2 has a special function on the CX168 It is the master DataPort for controlling AND reporting power supply status of the amplifier It is only possible to control and report the status of the power supply using the Ch 1 amp Ch 2 DataPort
9. Hz 12 CONNECTIONS INPUTS Using the Terminal Block Inputs Each channel has an active balanced Euro style terminal block P input jack These terminal blocks allow the input wiring to be CN OBEE vu mewe y BBE terminated using simple hand tools and allows for quick i CH1 _ y CH2 reconfiguration when needed The input impedance is 20k ohm DE o Gi balanced or 10k ohm unbalanced CH3 amp CH4 DATAPORT f ot CHS amp CH DATAPORT Balanced connection is recommended for all audio inputs Balanced signals are less prone to AC hum and other electrical noise Unbalanced signals can be suitable for short cable runs The signal source s output impedance should be less than 600 ohms to avoid high frequency loss in long cables If the DataPort is being used for the input signal source the terminal block connections should not be used for inputs However they may be used for daisy chaining the q X DataPort input signal to other channels or amplifiers The signal 2 available from the terminal block input connections will be about 10 dB lower than the signal presented to the DataPort TERMINAL BLOCK CONNECTORS Terminal Block Connectors Balanced inputs Connect the conductors to the connector as shown Unbalanced inputs Connect the conductors to the connector as shown Make sure that the unused side of the balanced input is e connected to ground as shown P i p
10. be made with great care and all wire terminations should be carefully checked to ensure quality workmanship If the red clip indicator flashes when connecting the speaker cable between the and terminals then that speaker cable or speaker may be shorted Check the cable and the speaker e INDICATION CLIP LEDS BRIGHT AND STEADY The amplifier is in protective muting e Three seconds or so of muting is normal when the amp is turned on After power up muting the Clip LED s should go out e Overheating will cause protective muting and the Clip LED to fully illuminate If the amp is overheated the fan will be running at full speed and the chassis will be very warm to the touch sound should resume within a minute as the amplifier cools to a safe operating temperature DO NOT TURN THE AMP OFF This would stop the fan from cooling the inside of the amplifier Instead reduce the input signal or amp gain setting and wait for the amp to resume operation automatically e Check for proper ventilation If the fan isn t running at all the amplifier requires servicing TROUBLESHOOTING DISTORTION NO CHANNEL SEPARATION HUM HISS FEEDBACK PROBLEM DISTORTED SOUND e INDICATION CLIP LED FLASHING e If the red clip indicator flashes before the signal indicator does the load impedance is abnormally low or shorted Unplug each speaker one by one at the amplifier If the clip LED goes out when you disconnect a cable then that cable or speaker is s
11. check for shorted or abnormal load impedances 18 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 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 parallele
12. mode switch Ch 7 Ch 8 mode switch Room 1 R Room 2 R Clip Limiters ON Low Frequency Filter ON Low Frequency Setting 70 Hz Mode stereo same as first mode switch same as first mode switch same as first mode switch Room 3 R Room 4 OUTPUT R A LE Tri Amp d Stereo Cabinets with Subwoofer Driven by Bridged Channel Pair next page Two discrete 3 way tri amp cabinets are to be connected to the CX168 along with an 8 ohm subwoofer cabinet The subwoofer will require the most amount of power and therefore will be driven by two channels bridged into one Its impedance meets the minimum requirement for bridged output All other drivers are 4 ohms or greater and meet the single channel minimum impedance requirement Each of the tri amp cabinets will be driven with three discrete channels totaling 6 channels The total required channel count is 8 the CX168 is the perfect tool for the job APPLICATIONS TYPICAL APPLICATION EXAMPLES Tri Amp d Stereo Cabinets with Subwoofer Driven by Bridged Channel Pair continued Routing is a function of easiest wiring order and is LF Driver Left Mid Driver Left HF Driver Left HF Driver Right Mid Driver Right LF Driver Right Subwoofer MODE switch configuration Ch 1 Ch 2 Mode Ch 1 Clip Limiter Ch 1 LF Filter Ch 2 Clip Limiter Ch 2 LF filter Ch 3 Ch 4 Mod
13. on off LF filter on off LF filter select and operation modes The amplifier s front panel includes corresponding LEDs to indicate Bridged or Parallel modes in addition to Signal and Clip status Your CX168 power amplifier was designed to provide many years of trouble free great sounding operation We hope you enjoy your new CX168 Power On LED Indicator Cooling Air Exhaust Vents GAIN CONTROL SECTION Ch 1 and 2 shown Ch 1 Gain Control m Ch 1 Clip Indicator n H0 a ee LCh 1 Signal Presence Indicator 24N 2 BRDG ATTEN 26aB 0 p Ch 2 Clip Indicator Ch 2 Signal Presence Indicator Ch 1 amp 2 Parallel Mode Indicator Ch 2 Gain Control Ch 1 amp 2 Bridge Mode Indicator FRONT PANEL WITH SECURITY PLATE LO INTRODUCTION Input REAR PANEL ee Output Connection amp Configuration Switch Configuration Switches Diagrams Cooling Air Inlet Vents a M imi l n i n n fain in Ul REAREA OUTPUTS Output Serial Number Label DataPort Connectors IEC Power Connections Connector DIMENSIONS AND MOUNTING POINTS S Sss e A _ a m oa Optional handles shown ey 14 0 355 6 mm 13 8 1 8 mm 13 6 _345 4 mm Optional handles shown INSTALLATION UNPACKING amp RACK MOUNTING
14. should light up when the switch is in eS the on position is When the power is switched off the LED may takes several To turn the amplifier on jash in on the top por seconds to go out this is normal tion of the rocker switch firmly It should move inward and snap into the on position After switching on the power LED should illuminate To turn the amplifier off push in on the bottom portion of the rocker switch firmly It should move inward and snap into the off position After switching off the power LED should extinguish If the POWER LED fails to illuminate when the switch is in the ON position CLIP POWER CH1 c 1 Check the AC cord and insure that both ends are fully eet ee vee 14 inserted into their receptacles If the power LED still fails to A illuminate 26 orl e er e og ony BRDG 2 2 Check the AC outlet for voltage with a circuit tester or ATTEN 26qB 0 oo known good device lamp etc 3 Make sure that the amplifier is not in STANDBY mode If the amplifier is being controlled by one of its DataPort connectors the amplifier may be in standby mode Verify the AC power status from the DataPort device controlling the amplifier The POWER LED is located at the upper left of the gain controls section of the front panel It is a green LED that illuminates when the power is turned on and the amplifier is properly connected to the co
15. system operator in a e m e sports complex might be located hundreds of yards meters 3 CH4 from the actual amplifiers making normal control and Mi Paes monitoring of the system difficult at best By integrating CHS amp CH6 DATAPORT QSC s DataPort equipped amplifiers with QSC s DataPort gt oC Joy t accessories a dependable and robust control and 3 E l monitoring solution can easily be implemented Atl p fig The DataPort is used for connection to optional QSC nade aN pun DataPort accessories DataPort accessory devices can 1 provide remote cinema monitoring DSP filter and crossover functions Asingle DataPort is assigned to each channel pair Each DataPort is marked with the channel numbers served by that DataPort Note The DataPort connections on the CX168 offer full featured above that each DataPort is clearly labeled and is located be implementation of DataPort accessories and supply the tween its respective channel s terminal block connectors required accessory voltage to DataPort devices that require it CX168 amplifiers DO NOT support direct mounting of smaller accessories like the DSP 3 due to the high density of connectors on the rear panel but they may be connected via cables Using the DataPort AN HEF Use a QSC DataPort cable to connect the CX168 DataPorts low to DataPort accessories Consult the accessory s documentation for recommended mounting and interconnect information l
16. to allow full air flow A AC Mains Connection The correct AC line voltage is shown on the serial number label Make sure the AC WARM 4 AR A EXITS FRONT OF AMPLIFIER uz a PLIFIER ex 00 n 00 Al 00 n 00 Air flow in QSC amplifiers Do not obstruct the front or rear air vents Make sure that plenty of cool air can enter the rack especially if there are other units which exhaust hot air into it CooL AIR ENTERS REAR OF MPLIFIER mains is the correct voltage Connecting to the wrong line voltage is dangerous and may damage the amplifier Connect the AC line cord by orienting the IEC plug correctly and pushing the plug firmly into the IEC receptacle It should seat tightly It can only be inserted when it is properly oriented Use the cord supplied with the amplifier or an equivalent Insure that the wire gauge of the cord is 14AWG Use of 16 or 18 AWG can be dangerous and is not recommended Use the best possible connection to the AC power source Avoid extension cords as they will cause some voltage drop between the AC source and your amplifier If the use of an extension cord is required ensure that it is the shortest length possible and is at least 14 AWG Ensure that all grounding connec tions are maintained NOTE Excessive length or inadequate gauge may result in short muting episodes if all channels are driven to full power
17. total impedance is within 4 to 16 ohms per channel dependant upon operating mode PARALLEL LO Z LOADS Zeq is the abbreviation for equivalent impedance Most PA type speaker cabinets are provided with two or more input jacks that are wired in parallel If one cabinet is connected to the amplifier the load impedance is equal to the one cabinet s specified impedance If you attach another similar cabinet to the remaining jack of the first cabinet the two cabinets are now in parallel with each other and the impedance will be half of the one cabinet value Consult your speaker s documentation for connection details as there are many connection methods in use Below are examples of parallel connections of 4 8 and 16 ohm speakers 2 and 4 ohm parallel loads are not usable because the parallel impedance of 4 ohm loads will always be 2 ohms or less this is too low an impedance for the CX168 amplifier and means the impedance at the two connection points lt _ Zeq gt 2 parallel loads all same impedance Zeq lt _ Zeq _ s 3 parallel loads all same impedance lt _ Zeq _ gt 4 parallel loads all same impedance 1 1 Z3 DO NOT PARALLEL 2 OHM LOADS FOR USE WITH CX168 AMPLIFIERS DO NOT Impedance of speakers Zeq e 8 OHM LOADS FOR USE WITH DO NOT PARALLEL 4 OHM LOADS FOR USE WITH CX168 AMPLIFIERS DO NOT P
18. 20 kHz 0 1 THD 8 ohms 20 Hz 20 kHz 0 1 THD DYNAMIC HEADROOM DISTORTION SMPTE IM Typical 20 Hz 20 kHz 10 dB below rated power Typical 1 kHz and below full rated power FREQUENCY RESPONSE DAMPING FACTOR SIGNAL to NOISE unweighted 20 Hz 20 kHz VOLTAGE GAIN gain control set to 0 dB attenuation INPUT SENSITIVITY for rated power into 8 ohms INPUT CLIPPING Vrms INPUT IMPEDANCE o 0 140 watts all channels driven 80 260 2 dB at 4 ohms Less than 0 02 Less than 0 05 Less than 0 02 0 0 3 0 dB 8 Hz to 50 kHz 0 2 dB 20 Hz 20 kHz gt 200 for 8 ohm load 5 kHz and below 107 dB 26 dB 20 X 1 35 Vrms 10 Vrms 22 dBu 10k ohms unbalanced 20k ohms balanced SPECIFICATIONS CX168 AMPLIFIER PROTECTION COOLING INDICATORS CONNECTORS LOAD PROTECTION OUTPUT CIRCUIT TYPE POWER REQUIREMENTS CURRENT CONSUMPTION 120 VAC typical all channels driven in Amperes Idle 1 8 power 8 ohms 1 8 power 4 ohms 1 3 power 8 ohms 1 3 power 4 ohms Full short circuit open circuit thermal ultrasonic and RF protection Stable into reactive or mismatched loads Continuously variable speed fan back to front air flow through tunnel heat sink Front Panel POWER LED green 8 each 1 per channel SIGNAL green and CLIP red LEDs 4 each 1 per channel pair BRDG LED yellow 4 each 1 per channel pair PAR LED orange Input
19. ARALLEL MORE THAN TWO 8 OHM LOADS FOR USE WITH CX168 AMPLIFIERS PARALLEL MORE THAN TWO CX168 AMPLIFIERS 1 5 3 ohms ttm Note Impedance has a phase angle also This is typically neglected in basic speaker calculations Note 4 ohms is the minimum impedance for stereo or parallel modes 8 ohms is the minimum impedance for bridge mode 27 28 TROUBLESHOOTING No souND Problem NO SOUND e INDICATION POWER LED INDICATOR NOT ILLUMINATED e Check both ends of the AC line cord for proper connection Both ends should be fully seated in their connectors e Check that the AC outlet works by plugging in a known good device or by testing with a voltmeter If too many amplifiers are used on one outlet the building s circuit breaker may trip and shut off power If this is the case unplug some of the amplifiers from the outlet reset the building s breaker and try again For the other amps use an outlet that is connected to another circuit breaker to distribute the load current e If using the DataPort connections the channel 1 and 2 DataPort controls the power supply of the amplifier Check whether or not the DataPort accessory connected to the CX168 is forcing the power supply into standby mode An amplifier which keeps tripping the AC circuit breaker may have a serious internal fault Turn it off remove AC power and have the amplifier serviced by a qualified technician INDICATION SIGNAL LED S NOT RESPONDING TO INPUT SIG
20. F and mid range drivers have filtering before the amplifier and need no filtering from the CX168 The subwoofer cabinet can handle the low frequencies without problem so no filtering for them The LF drivers response specification will dictate at what frequency 33 or 70 Hz the low frequency filter is set for 23 24 APPENDIX DESCRIPTION OF STEREO amp PARALLEL OPERATING MODES NOTE In the following diagrams channels 1 and 2 are shown as examples only Any channel pair can be configured as shown here The channels pairs on the CX168 are Channels 1 and 2 Channels 3 and 4 Channels 5 and 6 and Channels 7 and 8 Therefore in any example below replace channel 1 and 2 with the channel pair numbers you are setting up Stereo Mode Each input signal is sent to its respective channel Each channel has independent low frequency subaudio filtering clip limiting gain control and output connection When to use STEREO input configuration Use stereo mode for stereo sources L R inputs and any other situation that requires each channel to be completely separate from the other How to use STEREO mode 1 Set the MODE switches for stereo mode operation 2 Connect the two input signals to CH1 and to CH2 or signals may be provided from DataPort connection 3 Connect the two speakers one to channel 1 s output terminals one to channel 2 s output terminals Parallel Mode The channel 1 and channel 2 inputs are connected
21. Mode Bridge mode combines both output channels into one output This mode is for driving a single high power rated load with CH 1 input twice the normal voltage swing This results in about 4 times the peak power and about three times the sustained power of a single channel It is also common to call this bridge mono mode When to use BRIDGE mode Use BRIDGE mode when you need to deliver the power of two channels to a single 8 ohm load such as a subwoofer Do not use less than 8 ohm loads CH 2 input in bridge mode Refer to the CONNECTIONS section of this not used X yes manual for details MODE switches set to BRIDGE How to use BRIDGE mode BRIDGE MODE OPERATION 1 Set the MODE switches for bridge mode Note that speaker connection for bridge mono mode is 2 Connect the one input signal to channel 1 or channel 2 s different than other modes See section on Connections input Outputs for proper bridge mode output connections 3 Connect the one speaker load to the bridge output terminals 4 For a bridged pair use the first channel s gain control clip limiter and filter The second channel s controls will have no effect 5 Turn the second channel s gain to zero gain Filters and limiter settings of second channel do not matter Normal Operating Levels The amplifier s protective muting system guards against excessive internal temperatures With normal ventilation and loads the amplifier will handle any signal l
22. NAL LEVEL NOT LIGHTING If the green power indicator LED is lit but the signal LEDs do not light up at all check the input Make sure the signal source is working and try another input cable Connect the source to another channel or amplifier to check that it is working If you are using the terminal block inputs be sure the connectors are fully inserted at both ends of all interconnecting cables If you are using the DataPort for your input signal ensure the DataPort cable is properly connected at both ends and that the device supplying the audio signal to the DataPort is properly configured Check gain controls INDICATION SIGNAL LEDS RESPONDING TO SIGNAL LEVEL If the green signal LED indicators are lighting normally the fault is somewhere between the amplifier and the speakers Check the speaker wiring for breaks Check for proper connection at each end Try another speaker and cable if necessary If your system has multiple speakers connected in series any one speaker failure will cause all other speakers in the same series circuit to lose their signal INDICATION CLIP LED FLASHING If the red clip indicator flashes when signal is applied the amplifier output may be shorted Check that the speaker cable connec tions are tight and reliable at both ends Check the speaker cables for stray strands or breaks in the insulation Trim off all loose strands of wire and insulate any exposed wire with electrical tape All connections should
23. QSC CX168 8 Channel Installed Sound Professional Audio Amplifier User Manual AIM TD 000095 00 rev C IMPORTANT SAFETY PRECAUTIONS amp EXPLANATION OF SYMBOLS CAUTION A CAUTION TO REDUCE THE RISK OF ELECTRIC SHOCK DO NOT REMOVE THE COVER NO USER SERVICEABLE PARTS RISK OF ELECTRIC SHOCK INSIDE REFER SERVICING TO QUALIFIED PERSONNEL DO NOT OPEN The lightning flash with arrowhead symbol within an equilateral triangle is intended to alert the user to the presence of uninsulated dangerous voltage within the product s enclosure that may be of sufficient magnitude to constitute a risk of electric shock to humans The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance servicing instructions in this manual The lightning flashes printed next to the OUTPUT terminals of the CX168 amplifier are intended to alert the user to the risk of hazardous energy Output connectors that could pose a risk are marked with the lightning flash Do not touch output terminals while amplifier power is on Make all connections with amplifier turned off WARNING TO PREVENT FIRE OR ELECTRIC SHOCK DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE This amplifier has a serial number located on the rear panel Please write this and the model numb
24. Series Series connection is where the same signal current flows through each of the speaker loads The signal goes into one terminal of the first speaker and out its other terminal then the signal goes into one terminal of the next load and so on If any of the speakers in a series connected branch of a system fails the signal is prevented from flowing through any of the loads no sound Total impedance for series connections is the sum of each of the impedances in the chain see illustration below Series connection schemes are usually used with raw speakers not often with speaker cabinets for wiring conve nience The exposed speaker connections make this method easy for small strings of speakers in one area Most PA type SERIES LO Z LOADS Zeq is the abbreviation for equivalent impedance and means the impedance at the two connection points Z q p 2 series loads Impedance of speakers Note Impedance has a phase angle also This is typically neglected in basic speaker calculations 3 series loads 4 series loads Formula Zeq Z1 Z2 Zeq 21 22 23 Zeq 2 2 4 ohms Zeq 2 2 2 6 ohms Zeq 4 4 8ohms Zeq 4 4 4 12 ohms Zeq 8 8 16ohms Zeq 8 8 8 24 ohms speaker cabinets are NOT wired for series connection ability consult your speaker s documentation for connection information It is not recommended to connect speakers of different imped ances in series because power w
25. aPorts are connected to external devices makes no difference to the amplifier However the host controller to which the amplifier is connected will show the channels in the order that cables are connected 14 CONNECTIONS OUTPUTS Outputs Refer to the label on the rear panel of the amplifier for proper wiring connections The output connection for STEREO and PARALLEL modes is on the left side of the label while the output connection for BRIDGE mode is shown to the right side of the label Note Polarity changes from channel to channel and is different for bridge mode Be certain of polarity of connec tions before applying power Reversed polarity may degrade audio frequency response MODE SWITCH SETTINGS CLIP LIMIT PARALLEL MODE FILTER ON _ FILTER OFF FILTER ON _ Fi 70 Hz FILTER 33 Hz FILTER 70 Hz FILTER _ 33 Hz FILTER ON2 34567 8 9O0N iji MTE E OFF H STEREO MODE 1 45672810 12345678910 12345678910 BRIDGE MONO SWITCH SETTINGS 1234567 8 910 li TO BRIDGE CHANNEL PAIRS SET INPUT SWITCHES AS SHOWN USE THE LOWER NUMBERED CHANNEL S INPUT AND GAIN CONTROL CONNECT SPEAKER AS SHOWN BRIDGEABLE CHANNEL PAIRS CH1 AND CH2 CH3 AND CH4 CHS AND CH6 CH7 AND CH8 Stereo and Parallel Mode In stereo or parallel mode each speaker is connected to its own individual channel of the amplifier This connection method is shown on the left s
26. ae a y shield d a X jumper Terminal block unbalanced connections CONNECTIONS INPUTS Using the DataPorts If used the DataPort must be connected to a QSC DataPort product using a OSC DataPort cable Do not use computer cables they look i DATAPORT similar but can cause operational problems with your amplifier and or CONNECTORS DataPort accessories The CX168 amplifier is equipped with four QSC DataPort connections m that may be used for connecting to accessory QSC DataPort devices Each DataPort services a specific channel pair the channels are paired as CH1 amp CH2 DATAPORT Ch 1 and Ch 2 Ch 3 and Ch 4 Ch 5 and Ch 6 Ch 7 and Ch 8 Each DataPort and its associated terminal block input pair can be configured independently there is no requirement to use a DataPort connection for all channels Only the Ch 1 Ch 2 DataPort can control the a power supply standby mode e The DataPort connection will supply the input signals to the amplifier If C using the DataPort connection for audio input signals do not apply inputs to the terminal block input connectors If the DataPort connection is used only for monitoring amplifier operating conditions and NOT for provi
27. controls If noise continues to build up with zero mic gain there is a serious fault in the signal processors or cables Working in succession from the signal source towards the amplifier check each device in the signal path by reducing its gain or unplugging It PROBLEM HUM e Use a common AC ground connection for all audio equipment e Check the input cables for broken ground shield connection e Use balanced connections for the entire signal chain e The design of the amplifier eliminates internal hum fields but external transformers or other magnetic devices may cause hum Move cabling and signal sources to identify hot spots in the Magnetic field from power supplies in equipment can system then avoid those spots Cables with faulty shielding are a common entry point for hum Use top quality cabling Another common source of magnetic fields are wall warts or pluggable transformers keep input wiring away from them from power supplies transformers and other magnetic field producing devices induce hum into cabling that is located in the field If hum is a problem try relocating cabling so that is away 29 30 SPECIFICATIONS CX168 OUTPUT POWER in watts FTC 8 ohms per channel 20 Hz 20 kHz 0 05 THD 90 4 ohms per channel 20 Hz 20 kHz 0 1 THD 30 EIA 8 ohms 1 kHz 0 1 THD 1 channel driven 20 100 watts all channels driven 4 ohms 1 kHz 0 1 THD 1 channel driven Bridged Mono 16 ohms 20 Hz
28. d 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 Odb 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 POWER CH 5 4 180 sy 26 SS ATTEN 26dp o 5 o9 m Stes 5 1 ej 180 ey 26 Ay l Kerl eo ATTEN zed PRIS o9 o Jom N SIGNAL eee QD s N 2 move er co zedB o PAR IP ezl 2 v Du O l M s Ox NAS SA eBo PRIS o9 zea o PAR Location of gain controls on the front panel of the CX168 CLIP Berea No sional fo 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 OPERATION GAIN CONTROL SECURITY PLATE Gain Control Security Plate After final gain adjustments have been made the gain controls can be covered with a security plate This easy to use security plate makes it difficult for others to adjust the gain This may be desirable in instances where the gain controls should not be tampered with To install the security
29. ding audio inputs to the amplifier then the terminal block inputs OSC DataPort Cable may be used to supply the audio inputs to the amplifier How to Connect to the DataPort Direct mounting of DataPort accessories is NOT supported by the CX168 amplifier Devices that are normally mounted directly to the amplifier must be mounted remotely and connected to the DataPort using a DataPort cable This is due to the high density of connectors on an eight channel amplifier there is not enough space to allow for accessories to be mounted directly to the back of the amplifier If the accessory attaches with a QSC DataPort cable orient the HD 15 male plug correctly with the DataPort socket on the amplifier it is D shaped and will fit only one way Push the plug onto the socket firmly and ensure it is seated properly Finger tighten the 2 retaining screws Do not over tighten Basic DataPort Notes 1 The amplifier Gain controls will need to be set at their anticipated high level setting Use reduced level setting during setup amp test 2 If using the DataPort for audio input signals control of the audio level will be accomplished with the DataPort accessory device to which the amp Is connected 3 Control of the amplifiers AC power standby mode will only be possible via the Ch 1 2 DataPort The amplifier s POWER switch must be physically set to the ON position to use the standby control feature 4 The order in which the four Dat
30. e Ch 3 Clip Limiter Ch 3 LF Filter Ch 4 Clip Limiter Ch 4 LF filter Ch 4 LF frequency Ch 5 Ch 6 Mode Ch 5 Clip Limiter Ch 5 LF Filter Ch 6 Clip Limiter Ch 6 LF filter Ch 6 LF frequency Ch 7 Ch 8 Mode Ch 7 Clip Limiter Ch 7 LF Filter Ch 8 Clip Limiter Ch 8 LF Filter Ch 4 Ch 3 Ch 2 Ch 1 Ch 5 Ch 6 Bridge Ch 7 amp 8 Stereo ON OFF ON OFF Stereo ON OFF OFF ON 70 Hertz Stereo ON OFF OFF ON 70 Hertz Bridged OFF OFF no effect in bridge no effect in bridge High Frequency Driver High Frequency Driver Mid Range Driver Mid Range Driver Low Frequency Driver Low Frequency Driver Subwoofer Cabinet OQ Channels 1 through 6 are configured for stereo mode because all channels are completely separate from one another Channels 7 and 8 are bridged to combine their power to drive the subwoofer sub s are the most inefficient driver and therefore require the largest portion of the system power Clip limiters are used on the mid range drivers and the HF drivers because they are the most fragile and are damaged easily by clipping events The LF drivers and the sub s are rugged enough to handle even prolonged clipping events without damage and thus no clip limiting is used Low frequency filtering is used only on the LF drivers The H
31. e for Gain Controls ceea aA 19 DataPort COnncton cennsa ER 20 DataPort Guidelines for the CX168 0 ccc eeeeen 21 APPLICATIONS Four Room stereo Felisenea a a ainsi ean aes 22 Tri Amplified Stereo Cabinets with Subwoofel ccccccecceseteteeseseseees 22 APPENDIX Detailed Explanation of Stereo Parallel and Bridge Operating Modes 24 Multiple Speaker Loads in S ri S ccc cc cccecccecscesteeecseetseesseeersees 26 Multiple Speaker Loads in Parallel cc cccccccccecseeseeteeteeseeteenes 27 TROUBLESHOOTING ooo ccc a A 28 SPECIFICATIONS 3 0 5 0 200 etek ha ates She Sat ae oa ates 30 WARRANTY INFORMATION o oo cece ceseeseeseeseeseeseeseeseeseeseeseeseeseeseeseenes 32 HOW TO CONTACT OSC AUDIO PRODUCTS on neesseessssenenenseeesseneneeees 32 INTRODUCTION Congratulations on your purchase of the CX168 power amplifier To help you obtain the best results from your purchase we encourage you to carefully review this manual With information including connections configuration and operation it offers many useful guidelines The CX168 provides a high level of channel density in a small lightweight form factor ideal for multi zone audio systems Representing the culmination of OSC s extensive experience in power amplifier development the CX168 is a highly versatile reliable and user friendly tool that will likely remain a central component of your system for years to come Like the entire CX Series the CX168 is
32. e insulation back excessively Loose strands and exposed wire beyond the terminals may cause a short circuit and cause protective muting of the amplifier Once all the required connections have been made to the terminal block connectors they may be inserted into the OUTPUTS jack on the rear panel Orient the connector properly it only fits one way and push it in until it is fully seated in the receptacle Note each connector is oriented so its wires face outwards How to make connections to the terminal block 1 Strip the wires approximately 0 28 7mm 2 Twist any loose strands of wire together 3 Loosen the appropriate retaining screw fully 4 Insert the stripped wire into the receptacle 5 Tighten the appropriate retaining screw to secure 1 0 4 0 mm Wire Size 18 10 AWG ee Strip Wire oa 7mm Insert Wire 0 Q GE Q d a g 4 Tighten m0 Screw im o 1 6 ArT Pe 9 Ea g i eg N i Q eD Pee 2 DODO e a E M I l OUTPUTS Gavan DYED 15 16 OPERATION POWER SWITCH and GAIN CONTROLS Power Switch O n The power switch is a rocker type switch Itis located on the left side of the front panel To turn the amplifier on push in on the top of the switch To turn the amplifier off push in on the bottom of the switch The green power LED
33. ency response below 33 Hz or if low frequency filtering is provided by other devices Know the specification of the speaker cabinet you are driving Match the low frequency roll off setting to the specified low frequency capability of the speaker cabinet Do not drive the speaker with frequencies below its rating Unless you have low frequency filtering before the amplifier use the low frequency filter to protect your loudspeakers from cone over excursion caused by frequencies below the speaker s limits The 33 Hz rolloff is a good all purpose setting Turn the filter on by setting the appropriate DIP switch to ON position and select 33 Hz using its 33 70 Hz DIP switch This setting is a good starting point for most large full range cabinets The 70 Hz rolloff is a good setting to use with smaller compact speaker cabinets having limited bass capability Turn the filter ON and select the 70 Hz setting when using smaller cabinets The frequency selection 33 or 70 Hertz has no effect unless the filter is set to the ON position Frequency Response Curves r oTU er cCO a 1 0 5 1 Oo 0 5 1 2 5 1 w 3 5 4 5 1 oa 5 5 Filet 70Hz Filter Filter ON 33 Hz 10 20 50 100 200 500 1k 2k 5k 10k 20k 50k 100k Frequency
34. equipped with QSC s exclusive PowerWave switching power supply technology to virtually eliminate noise and hum while reducing the unit s overall weight Comprehensive protection circuitry includes DC infrasonic thermal overload and short circuit protection The CX168 includes 4 HD15 DataPorts one per channel pair for remote management or DSP These ports allow each channel pair to be governed by OSControl OSC s audio networking system enabling the system operator to control amplifier gain levels check the unit s clipping and thermal status plus monitor numerous additional system parameters Power Switch FRONT PANEL Alternatively these DataPorts facilitate connection of signal processing equipment such as OSC s DSP 3 which offers two channels of independent digital signal processing including crossover filters shelf filters signal delay compression peak limiting and parametric filters As individual channel pairs may be bridged the CX168 is configurable as a 4 5 6 7 or 8 channel unit Further the CX168 features detachable Phoenix style input and output connectors enabling the audio system to be wired with greater ease Other features include 1 dB recessed and detented gain controls and a security cover for tamper proof installations The CX168 is easy to use All operating mode switches are grouped together on the rear panel with one switchblock per channel pair These switches enable clip limiter
35. er down and keep them for your records Model CX168 Serial Number Date of Purchase Purchased From FCC INTERFERENCE STATEMENT NOTE This equipment has been tested and found to comply with the limits for a class B digital device pursuant to part 15 of the FCC rules These limits are designed to provide reasonable protection against harmful interference in a residential installation This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance to the instructions may cause harmful interference to radio communications However there is no guarantee that interference will not occur in a particular installation If this equipment does cause harmful interference to radio or television reception which can be determined by switching the equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures Reorient or relocate the receiving antenna Increase the separation between the equipment and the receiver Connect the equipment into an outlet on a circuit different from that to which the receiver is connected Consult the dealer or an experienced radio or TV technician for help Copyright 2002 QSC Audio Products Inc OSC is a registered trademark of OSC Audio Products Inc QSC and the OSC logo are registered with the U S Patent and Trademark Office The Audio Precision logo is the proper
36. evel including overdrive Lower load impedances and higher signal levels produce more internal heating Loads below 4 ohm loads may trigger thermal shutdown A Note on Sound Pressure Levels Sound is heard as the ear converts vibration from sound waves into impulses in the nerves of the ear Sounds above 90 decibels particu larly if the sound is prolonged may cause such intense vibration that the inner ear is damaged 90 decibels is about the loudness of a large Duration of Exposure Sound Level truck about 5 yards away A jackhammer emits sounds of about 120 C ce a dB from 3 feet away and a jet engine emits sound of about 130 dB from 100 feet away Motorcycles snowmobiles and similar engines e 2 O f range around 85 to 90 dB and a rock concert may approach 100 dB A Oooo o a S B OE general rule of thumb is that if you need to shout to be heard the sound is in the range that can damage hearing music carry high risk for hearing loss In the U S the maximum job noise exposure is regulated by law Both the length of exposure and the extent decibel level of exposure are considered If exposure is at or greater than the maximum exposure protective mea sures must be taken The table at right is referenced from OSHA s Permissible Noise Exposure table G16 Some jobs in the entertainment industry involving loud noise from 25 26 APPENDIX MULTIPLE SPEAKER LOADS IN SERIES Multiple Lo Z Loads in
37. horted Try another cable and speaker to locate and or remove the fault e INDICATION CLIP INDICATOR NOT FLASHING e This could be caused by a faulty speaker or loose connection Check the wiring and try another speaker e The signal source may be clipping Keep the amplifier gain controls at least halfway up 10 dB or less so that the source does not have to be overdriven PROBLEM NO CHANNEL SEPARATION e Check the mode switch settings on the back of the amplifier If the mode switches are set for BRIDGE or PARALLEL mode there will be no channel separation The mode switches must be set for STEREO for each channel to operate independently e Make sure other equipment in the signal path to the amplifier such as mixers preamps etc is set for stereo not mono PROBLEM HISS e Unplug the input cables to the amplifier If the hiss goes away then the problem is with the equipment or cables leading to the amplifier e If the hiss is present with no audio input cables connected check that the AC line cord is properly grounded at its connection to the line If the ground connection is OK and the hiss continues with no input cables connected then the amplifier requires servicing e To keep the normal noise floor low operate the primary signal source at full level without clipping and avoid boosting the signal further between the source and the amplifier PROBLEM SQUEALS AND FEEDBACK e Microphone feedback should be controlled with mixer
38. ide of the connection diagram rear panel or in the diagram right Use 4 ohm minimum impedance in stereo or parallel mode Ensure the mode configuration switches are set for stereo or parallel mode when connecting speakers to each channel s output Bridge Mode In bridge mode each speaker is connected to a bridged pair of outputs The channels must first be bridged by setting the mode configuration switches to the bridge settings Then con nect the speakers as shown on the right side of the connection diagram rear panel or in the diagram right Use 8 ohm minimum impedance in bridged mode Ensure the mode configuration switches are set for bridge mode when connecting speakers to bridged output pairs BRIDGE MODE PRECAUTIONS Do not use 2 ohm or 4 ohm loads in bridge mode 8 A ohms is the minimum impedance for bridge mode operation This mode puts a high demand on the amplifier and speaker Excessive clipping may cause protective muting or speaker damage Ensure the speaker has a sufficient power rating OUTPUTS Stereo or parallel connection single speaker shown con nected to amplifier channel 6 output Ensure that all speaker connections maintain proper polarity to to a K OUTPUTS Bridge connection single speaker shown connected to am plifie
39. ifier clip occasionally With robust low frequency drivers the occasional clipping should cause no problems SETUP MODE SWITCHES CLIP LIMITER AND LOW FREQUENCY FILTERS Clip Limiter mode switches 1 amp 10 up ON switches 1 amp 10 down OFF Chl MODESWITCHES CH2 12 723 E SE UGG CW CH 1 CH 2 mode switch shown Other channel pairs similar Switch 1 operates the first channel s limiter switch 10 operates the second channel s limiter CAUTION Clip limiting reduces extreme overdrive peaks allowing a higher average signal level without distortion Increasing the gain with the clip limiter engaged until clipping is again audible can double the average output power Be careful not to exceed the power rating of the speakers Low Frequency Filter Low Frequency Filter mode switch 3 up first channel s filter OFF switch 3 down first channel s filter ON switch 8 up second channel s filter OFF switch 8 down second channel s filter ON switch 2 up first channel s filter frequency is 33 Hz switch 2 down first channel s filter frequency is 70 Hz switch 9 up second channel s filter frequency is 33 Hz switch 9 down second channel s filter frequency is 70 Hz When driving speakers with limited low frequency response it is important to limit the low frequency response of the amplifier Doing so can result in more usable ba
40. ill be divided unequally between them If you are experienced with mixing and matching speaker loads of varying impedances no damage to the amplifier will result as long as the total impedance is within 4 to 16 ohms per stereo parallel channel or 8 to 16 ohms bridged Below are examples of series connections for 2 4 8 and 16 ohm speaker loads Series connections resulting in an impedance of 250 ohms or greater are not recommended Zeq Z1 Z2 Z3 Z4 Zeq 2 2 2 2 8 ohms Zeq 4 4 4 44 16 ohms Zeq 8 8 8 8 32 ohms APPENDIX MULTIPLE SPEAKER LOADS IN PARALLEL Multiple Lo Z Loads in Parallel If each speaker load is connected across the same signal source the output of the amplifier then the loads are in parallel with one another If one of the speakers fails in a parallel connected system branch the remaining speakers will continue to operate If all speaker loads are the same impedance the total imped ance of a parallel connected system branch is the impedance of one speaker load divided by the number of loads in the branch example three 8 ohm loads in parallel 8 3 2 667 or roughly 2 7 ohms too low to use on the CX168 It is not recommended to connect speakers of different imped ances in parallel because power will be divided unequally between them If you are experienced with mixing and matching speaker loads of varying impedances no damage to the amplifier will result as long as the
41. mode the unused input terminals may be used for daisy chaining the input signal to other channels of the CX168 or to other amplifiers For pictorial description of operating modes see Appendix 9 Note Do not connect more than one input per channel pair when operating in parallel or bridge mode However Clip Limiter The CX168 amplifier has separate clip limiters for each of the 8 channels These clip limiters respond only to actual amplifier clipping Amplifier clipping generates internal error signals which cause the clip limiter to quickly reduce gain and minimize the overdrive To preserve as much of the program dynamics as possible limiting occurs only during actual clipping Each channel s clip limiter can be switched on or off individually The clip limiter is internally set to respond as fast as possible after clipping is detected For program material that is primarily full range the effect on the overall audio quality should be imperceptible We recommend using the clip limiters for almost all applications especially full range audio applications Clipping can cause high frequency artifacts to be output to the speakers potentially damaging fragile high frequency drivers For program material that is primarily low frequency in nature low frequency or subwoofer drive this may be perceived as a rubbery effect on the audio If this is the case it may be preferable to turn the clip limiters off and let the ampl
42. nation normal for weak input signal strength Fully illuminated on normal CLIP Each channel has a red clip LED that illumi nates when the channel clips It is located to the upper right of each channel s gain control Normal indication illuminates briefly at extreme output power peaks Occasional clipping at high power levels may be normal At power on the clip LEDs may briefly flash during turn on muting Continuous operation at high power may trigger thermal protection circuitry shutting down the channel pair concerned The CLIP LEDs for the channel pair will fully illuminate to indicate thermal protection activation The channels are paired as Ch 1 and Ch 2 Ch 3 and Ch 4 Ch 5 and Ch 6 Ch 7 and Ch 8 If no indication normal if the amplifier is operated at nominal output levels If the input signal is weak it may not be capable of driving the amplifier into clipping even at full gain Occasional illumination Occasional clipping once briefly every few seconds when operation at high power levels does not indicate trouble Continuous operation at high power may trigger the thermal protection circuitry shutting down the amplifier and fully illuminating the clip LED Iluminated most of the time Not normal for cleaner sound reduce the output of the amplifier and or input signal to avoid thermal shutdown of the amplifier and possible speaker damage If clipping persists at normal levels
43. nstance you can not bridge channels 3 amp 5 because they are not in the same channel group Before setting the configuration DIP switches you must first decide how the amplifier will connect to the speaker system MODE configuration DIP switches are located on the rear panel and look like the illustration above Switch positions shown are for example only Set switches as required for your application MODE SWITCH SETTINGS CLIP LIMIT ON2 345 67 8 9ON FILTERS coc Bi Le aS S L oz ack 26 B _ l m o Sr456728 Bz ETA e ae pas th N Sin 22 z D o BRIDGE MONO SWITCH SETTINGS 1234567 8 910 TO BRIDGE CHANNEL PAIRS SET BRIDGEABLE CHANNEL PAIRS CH1 AND CH2 CH3 AND CH4 CH5 AND CH6 CH7 AND CH8 MODE switch settings and speaker connection diagrams are printed on a rear panel label as shown above SETUP SETTING THE MODE STEREO PARALLEL OR BRIDGE Modes The following descriptions apply to a channel pair such as Ch 1 amp 2 or Ch 7 amp 8 It is possible to set each channel pair s mode differently and customize the system configuration All pos
44. nt or from your dealer or distributor Refer to the literature included with the rack mounting ear kit for installation instructions Two methods of rear rack mounting ear attachment are possible use the method that best suits you application Save the container and packing material so the amplifier may be shipped without damage if service is ever required If the original container is not available be sure to use a strong shipping container with enough packing material to prevent the amplifier from being damaged in transit Fasten ear to a amplifier with screws S Optional rear rack mounting ear attachment methods refer to the rear rack mounting ear kit s documentation for details S ie N Ear is fastened to rack rails then amplifier is N installed so its support X notch is positioned on the support pin of the rear ear INSTALLATION COOLING amp AC MAINS REQUIREMENTS Fan Cooling The CX168 amplifier draws cool air into the rear of the amplifier and exhausts hot air from the front This is done so the equipment in the rack stays as cool as possible This method of cooling gives the operator direct air tempera ture feedback at the front of the rack where it is the most convenient The front panel s temperature indicates how hard the amplifier is working The fan varies speed automatically to maintain safe internal temperatures and minimize noise Keep the front and rear vents clear
45. plate 3 Line up the tabs with the keyed portion of the ventilation slots insert into the slot and then slide the panel fully right locking it in the slot 1 Use a 9 64 or 3 5mm hex key to loosen the screw Do not remove just loosen sev eral turns oe 2 Orient the panel as shown and slide the right end 4 Make sure the LED s are visible then tighten the of the plate under the screw screw with the hex key Do not over tighten _ When properly installed the security panel will still allow you to monitor all the channel status LED s and power LED The 5 amplifier front panel will look like the illustration right after installing the security plate 19 OPERATION USING THE OSC DATAPORT CONNECTIONS DataPort Connectors 4 OSC s DataPort equipped amplifiers offer operators of larger C CH1 amp CH2 DATAPORT audio systems a high degree of system monitoring and D lot JO Mt a operation from remote locations A
46. r channels 5 and 6 bridged with mode switch settings Ensure that all speaker connections maintain proper polar ity to to CONNECTIONS OUTPUTS USING THE TERMINAL BLOCK CONNECTORS OUTPUT TERMINAL SAFETY WARNING Do not touch output terminals while amplifier power is on Make all connections with amplifier turned off Risk of hazardous energy When selecting speaker cable wire always use the largest wire size and shortest length of wire practical for an installation Larger wire sizes and shorter lengths minimize power loss and degradation of damping factor Do not place speaker cables next to input wiring Terminal Block Connections The output connections are made by attaching speaker wires to the 8 pin terminal block connectors Once these connectors have been populated with the necessary speaker wire connections plug the terminal blocks into their respective output jack The output jacks are configured in two discrete connectors One connector carries the connections for channels 1 through 4 The other channels 5 through 8 Each connector has 8 pins each of which connects to the speaker wire using a screw clamp Refer to the diagram right for the basic connection procedure Be sure that speaker polarity is maintained The locations of the and terminals on the amplifier is not the same for each channel Ensure that all wires are neatly terminated with no loose strands Do not strip th
47. rrect AC source The power LED extin guishes when the power is turned off OPERATION LED INDICATORS LED Indicators The LED indicators provide basic operation information to the operator The nor mal indications of the LED s are shown below NOTE The BRDG and PAR mode A 26dB 0 POWER CH1 12 990 indicator LED s are discussed on page 9 POWER The power on indicator LED is located at the upper left of the gain control cluster It is green and illuminates when the power switch is set to the on position and AC power is present at the IEC cord receptacle Normal indication at power on the LED will illumi nate If no indication Check AC power cord AC mains and that the DataPort is not being used to force the amplifier into Standby mode When power is switched off the LED may take several seconds to extinguish go out this is normal PAR SIGNAL Each channel has a green signal LED located to the right of its gain control The signal LED lights up when the input signal is sufficiently strong Normal indication illuminates when the input signal is present and sufficiently strong If no indication check gain settings input cables connections and audio source If audio source is extremely low signal strength signal LED may not illuminate this is normal but indicates that the input signal strength should be increased Occasional illumi
48. sible combinations will not be shown The following describes the behavior of one channel pair in the three modes of operation and the BRDG and PAR LED s Stereo Stereo mode supports two completely Stereo mode cH O separate audio channels usually referred to as left switches 4 5 6 amp 7 down 2 005 7 O meiir 7 and right Stereo configurations have two separate CH7 MODE SWITCHES CHO Sf input signals and two separate output signals l l J J J l NI Wh _ T CH7 CH8 mode switch shown not illuminated out off Other channel pairs similar g j illuminated lit on Mode switch settings and LED indication for stereo mode operation BRDG and PAR indicators should not be illuminated when in stereo mode o BRDG o2 A Parallel Parallel mode applies one input signal to Parallel mode CLIP CLIP both channels Both inputs of a channel pair are switches 4 5 6 up 1 O 2 ccs connected in parallel when the mode switch is set switch 7 down an N O val AT Q sera for parallel therefore connect only one input per CH7 MODE SWITCHES CHG OEA channel pair when in parallel mode The outputs are j j T ii i ALA AN ALAE I connected the same as stereo mode Each speaker JOU HBO EEOE 2648 0 2648 0 will be supplied the same signal which is still MN controlled by that channel s gain control O not illuminated out off CH 7 CH 8 mode switch shown
49. ss response since the speaker is not being overloaded by very low frequencies it can t handle Explanation Low frequency sound waves require much more speaker cone motion to produce the same apparent loudness as higher frequencies Properly designed speaker enclosures help the speaker to move more air with less motion using techniques like porting Such enclosures only benefit from porting down to a certain frequency Below this frequency the speaker is unloaded and is basically free to move around uncontrollably without producing much bass Limiting the frequency range of the low frequency content enables the speaker to behave the way it was designed to If frequencies lower than designed are supplied to the speaker performance will degrade chi B E SWITCHES CH2 I H 23 8 CH 1 CH 2 mode switch shown Other channel pairs similar Switches 2 and 3 operate the first channel s filter switches 8 and 9 operate the second channel s filter All low frequency filters will change the character of low frequency transients For best results the cabinet design speaker capabilities and program material must be taken into account when configuring low frequency filtering SETUP MODE SWITCHES CLIP LIMITER AND LOW FREQUENCY FILTERS Low Frequency Filtering Tips The OFF position should be used only for subwoofer systems with rated frequ
50. together applying a single input signal to both channels of the amplifier A signal into any input jack will drive both channels Each channel s low frequency filtering clip limiting and gain control still function independently Each channel drives its own speaker load You can patch the input signal on to additional amplifiers daisy chain by using any of the remaining input jacks This feature eliminates the need for Y cables When to use PARALLEL input configuration Use parallel mode when you need one signal to drive both channels each channel having its own control gain clip limiter low frequency filter How to use PARALLEL mode 1 Set the MODE switches for PARALLEL mode 2 Connect the one input signal to either channel s input connector The unused input may be used for daisy chaining the signal to another device or channel pair 3 Connect the two speakers one to channel 1 s output terminals one to channel 2 s output terminals CH 1 input MODE switches set to STEREO CH 2 input STEREO MODE OPERATION NOTE Ensure that the MODE SWITCHES are set to STEREO when feeding two separate signals to the two channels CH 1 input MODE switches set for PARALLEL CH 2 input notused input z a aa a EE gt Amplifier 2 CH2 input connectors may be used to daisy chain the input signal to additional amplifiers PARALLEL MODE OPERATION APPENDIX DESCRIPTION OF BRIDGE OPERATING MODE Bridge
51. ty of Audio Precision Beaverton OR All trademarks are the property of their respective owners TABLE OF CONTENTS INTRODUCTION CATEGO DVOTVISW sscschscitedte Senet cor sienielkeens eased nelans cad ed taba isbn valde clea 4 Front Rane ls lUStratl on cern Ree enn eed tld nin eens e E 4 Rear Panel Ilustratii ete tat a AA 5 MoUnitifig D aS O Sa kU Noh a a a a aalan bak lon 5 INSTALLATION Whats Inel dedissseieunenan a A a a A vane gia 6 Hacks MON a aa aea a aa a A A E A bl A ee LAT 6 Supporting the Rear of the Amplifier 6 FAN GOON GY erae aT aA sets ile AE O ARAR 7 AC Mains AC Power Connection c ccesscsessesessesesseseesesessesessesesseseseesessesesseseeeetees 7 SETUP Setting the Configuration MODE Switches eee 8 Setting Operating Mode Stereo Parallel or Bridge 0ccccccce cnc 9 N IMIR SOTHNG NAANA AA AAA ESAE A A 10 Low Frequency Subaudio Filter Settings ccccsscsecsecssessectesseessestesseesesseeneens 10 Low Frequency Filtering Tips and CX168 Frequency Response Curve 06 11 CONNECTIONS Inputs Connecting to the Input Terminal Block Inputs 0 0 12 Connecting to the DataPort INPUtS 0 ccc cesses teteteseeseeneeee 13 Outputs Connecting the Outputs in Stereo or in Bridge Mode 14 How to use the 8 pin Output Connectors eee 15 OPERATION POWEr SWAG teh Ae ah a as 16 BED INCIGAtOTS Moo ete tte aN Os TI EE E A ee 17 Gain CONTOS ooir theese ede nach tad lasted Maia E 18 Security Plat
52. will not accurately report gain and levels will be effected 7 The heat sink temperatures of the CX168 are reported on the first channel of each channel pair s DataPort In other words to monitor all four heat sink temperatures all four DataPorts must be connected to the monitoring device such as OSC s CM 16a Temperatures will be reported on channels 1 3 5 and 7 21 22 APPLICATIONS TYPICAL APPLICATION EXAMPLES Four Room Stereo Feed A simple application of the CX168 would be an installation with 4 rooms of coverage each room to be provided with a stereo audio feed All speakers are 4 ohm or greater impedance and have a frequency response rated down to 45 Hz making them suitable for the 70 Hz low frequency setting Clip limiting will be used with these full range speakers Operating mode of all four channel pairs will be set to stereo because the audio inputs are stereo and a stereo result is desired in each room Input connections can vary too much to provide meaningful examples For this example assume that each input has its own discrete signal provided at the terminal block input connectors Routing would make sense if kept in room number order Room 1 Fed by channel pair 1 Ch 1 amp 2 Room 2 Fed by channel pair 2 Ch 3 amp 4 Room 3 Fed by channel pair 3 Ch 5 amp 6 Room 4 Fed by channel pair 4 Ch 7 amp 8 MODE switch configuration Ch 1 Ch 2 mode switch Ch 3 Ch 4 mode switch Ch 5 Ch 6
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