Crown 133472-1A Page 26 Application Manual Download

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Chapter 2: Troubleshooting

Amplifi er Application Guide

Figure 2.4

Bad Sound

Figure 2.5

Amp Overheating

Amp

Ov e rhe ating

Is the amp

operating within

its rated

impedance?

Are the filters

(if equipped)

clogged?

Clean or replace

filters.

Yes

Refer amp to

service center.

Is the amp

getting enough

cool air?

See "Rack Cooling" in

Section 1.1, and info

on amp cooling in

Operation Manual

Lower impedances cause

amps to dissipate more

heat. See "Amplifier Load

Impedance" in Section 1.3.2.

Ye s

2.3 Bad Sound

2.4 Amp
Overheating

Bad Sound

Are the IOC or

Clip indicators (if

equipped)

flashing or on?

Is source signal

clean and

undistorted?

Check levels and/or
indicators at source

level for clipping.

Check amp

for clipping.

Yes

Refer amp to

service center.

Yes

Possible Causes

System Gain

Structure. See

"Setting System

Gain Structure in

Section 1.6.

Amp not adequately

cooled. See "Amp

Overheating"

flowchart.

Are input and

output

connections o.k.?

Secure input and

output connections.

Is there a

Hum or Buzz

sound?

See "Hum and

Buzz" in

Section 1.2.2.

Yes

Are ODEP

indicators (if

equipped) dim or

off?

Amp overheating.

See "Amp

Overheating"

flowchart.

Yes

Summary of Contents for 133472-1A

Page 1: ...17 9439 U S A Telephone 574 294 8000 Fax 574 294 8329 www crownaudio com Trademark Notice Amcron BCA and Crown Crown Audio IOC IQ System ODEP and VZ are registered trademarks and Grounded Bridge PIP and PIP2 are trademarks of Crown Audio Inc Other trademarks are the property of their respective owners 133472 1A 1 06 ...

Page 2: ...hese instructions 2 Keep these instructions 3 Heed all warnings 4 Follow all instructions 5 Do not use this apparatus near water 6 Clean only with a dry cloth 7 Do not block any ventilation openings Install in accor dance with the manufacturer s instructions 8 Do not install near any heat sources such as radiators heat registers stoves or other apparatus that produce heat 9 Do not defeat the safet...

Page 3: ...lems 9 1 3 Output Wiring 10 1 3 1 Output Connector Wiring 10 5 Way Binding Post 10 Barrier Block 11 Neutrik Speakon 11 1 3 2 Amplifier Load Impedance 13 1 3 3 Determining Appropriate Speaker Wire Gauge 14 1 3 4 Loudspeaker Protection 15 1 3 5 Solving Output Problems 16 High Frequency Oscillations 16 Sub Sonic Currents 16 1 3 6 Distributed Speaker Systems 17 What is Constant Voltage 17 Transformer ...

Page 4: ...in structure for example should be helpful to you whether you are a beginner or a seasoned professional You can choose to read this guide from cover to cover or if you are already familiar with Crown amps you can jump to specific sections as needed A glossary of terms and list of suggested publications for further reading are also provided for your convenience Please be sure to read all instructio...

Page 5: ...ications listed in the Appendix 1 1 Rack Cooling When installing your Crown amp in a rack you should take steps to make sure that the temperature of the rack stays in a safe range Crown amps with fan assisted cooling and convection only cooling may require different tech niques for best performance When designing your rack cooling system you should consider the requirements for all mounted compone...

Page 6: ... to the amplifier s air intakes you must provide adequate air flow by installing a grille in the door or by pressurizing the air behind the door Wire grilles are recommended over perforated panels because they tend to cause less air restriction A good choice for pressurizing the air behind a rack cabinet door is to mount a squirrel cage blower inside the rack Option 1 in Figure 1 2 At the bottom o...

Page 7: ...t cable wiring for commonly used con nector types Note These diagrams follow the AES wiring convention of Pin 2 hot for XLR connectors Note If two or more channels with the same input ground reference are driven from the same floating source connect only one shield to the source chassis Balanced Grounded Source For use with components equipped with three wire grounded AC line cord or other ground ...

Page 8: ...ating Source Twin Lead Shielded Cable For use with components equipped with two wire AC line cord or battery power Unbalanced Grounded Source Single Conductor Coax or Twisted Pair Cable For use with components equipped with three wire grounded AC line cord or other ground connection Unbalanced Floating Source Single Conductor Coax or Twisted Pair Cable For use with components equipped with two wir...

Page 9: ...you have noticeable hum or buzz in your system you may want to check your cable connections to see if the unwanted noise is being introduced via a ground loop To determine the proper wiring first check whether the output from your source is unbalanced or bal anced if you don t know refer to the unit s back panel or Operation Manual Next determine if the source s power cable is floating ungrounded ...

Page 10: ...tion Never short or parallel the output channels of an amplifier to itself or to any other amplifier Figure 1 5 Balanced RFI Filters A balanced audio circuit will have both positive and negative legs of the circuit that are isolated from the ground circuit These balanced legs exhibit identical impedance character istics with respect to ground and may also carry the audio signal at the same level b...

Page 11: ...that might accidentally tie conductors together when making or breaking the connec tion for example a standard 1 4 inch stereo phone plug 3 Never use connectors that could be plugged into AC power sockets Accidental AC input will be an electri fying experience for your equipment But you will find out real quick if your speakers are any good at 60 Hz 4 Avoid using connectors with low cur rent carry...

Page 12: ...ge notch on the outer edge of the insert lines up with the large groove on the inside of the con nector housing The insert should slide easily through the housing and out the other side until it extends approximately 3 4 inch 19 mm from the end of the housing as shown in Figure 1 16 5 Slide the chuck D along the cable and insert into the housing making sure that the large notch on the outer edge o...

Page 13: ...an electrical circuit consider the following analogy a wire is much like a water pipe Elec trical current is like the water flowing through the pipe Imped ance s role is that of the valve The valve resists or impedes hence the terms the flow of water through the pipe If the valve is opened less imped ance water flows freely As the valve is turned toward the closed position more imped ance the flow...

Page 14: ...the following formula You can use the table in Figure 1 22 to find the net impedance for many common speaker combinations Note for best results do not wire speakers of differ ing impedances one 4 ohm and one 8 ohm for example together If two 8 ohm speakers are wired in series they form one 16 ohm load for the amplifier since impedances add when speak ers are wired in series If on the other hand th...

Page 15: ...d Cable D line mark the required length of the cable run 5 Draw a pencil line from the mark on the Source Resistance line through the mark on the 2 Cond Cable line and on to intersect the Copper Wire E line 6 The required wire gauge for the selected wire length and damping factor is the value on the Copper Wire line Note Wire size increases as the AWG gets smaller 7 If the size of the cable exceed...

Page 16: ...his allows you to apply the most appropriate protection for the type of driver being used In general low frequency drivers woofers are most susceptible to thermal damage and high frequency drivers tweeters are usually damaged by large transient voltages This means that your loudspeakers will tend to have better protection when the woofers are protected by slow blow fuses and high fre quency driver...

Page 17: ...lication an even higher 3 dB frequency may be desirable Another way to prevent the amplifier from prematurely activating its protection systems and to protect inductive loads from large low frequency currents is to connect a 590 to 708 µF nono larized capacitor and 4 ohm 20 watt resistor in series with the amplifier s output and the positive lead of the transformer The circuit shown in Figure 1 25...

Page 18: ...way Systems with Expansion Modules This section shows how multi way systems can be effectively designed using optional expansion modules that feature active crossover networks Example systems are shown for single and multiple amp two way systems and three way systems The range of frequencies present in full range music is wider than most any single speaker component can accu rately reproduce Becau...

Page 19: ...Chapter 1 Crown Amplifiers In Depth 19 Amplifier Application Guide Figure 1 27 Typical Single Amp Stereo Two Way Hookup Figure 1 28 Typical Two Amp Bridge Mono Two Way Hookup ...

Page 20: ...cause the insertion loss of passive crossover networks is eliminated 2 Consistent power bandwidth power bandwidth is changed in multi way pas sive systems if transducers change impedance or vaporize blow up 3 Levels can be matched more accurately to the components 4 Improved dynamic range Active crossovers for Crown amps are available in both PIP and SST mod ules see your Operation Manual for deta...

Page 21: ...k pin assignments Note the mating connector for the RJ 11 jack contains 4 contact pins in a six slot case as shown in Figure 1 31 The maximum signal that can be exposed to the fault jack is 35 VDC and 10 mA Best results are obtained with 10 mA LEDs 1 6 Setting System Gain Structure To get the best performance from your sound system you should carefully set up your system s gain structure Gain stru...

Page 22: ...le Power amplifiers are designed to produce a set amount of gain The function of the level control knob typically is to adjust the signal level coming into the amplifier s input stage Where to set the level controls on the amp depends on the system and how much gain you have available prior to the amplifier With the level controls turned down the ampli fier can still reach full rated output power ...

Page 23: ...blems with your amplifier In some situations the problem may not be with the amplifier but rather may be caused by a system condition The flowcharts do not cover every possible scenario you may encounter Figure 2 1 provides a key to help you interpret the flowcharts Chapter 2 Troubleshooting Start and Finish Points Question Comment Action Step Figure 2 1 Flowchart Key ...

Page 24: ...s AC source supplying power to outlet Does amp have a fuse or circuit breaker No No Reset circuit breaker Restore AC power to outlet No No Refer amp to service center Yes Yes Did it trip again Yes Amp o k to operate No Circuit Breaker Fuse Yes Is an IQ System controlling amp Verify power to amp is turned on in IQ System No Yes Yes Is fuse internal or external Internal External Internal Fuses NOT u...

Page 25: ...her Fault TLC or ODEP Refer amp to service center Are speakers connected Is there a short circuit on the speaker line Amp overheated or in other standby condition See Amp Overheating flowchart and or refer to Operation Manual No Yes Remove the short circuit Connect Speakers to Amp No No Yes Yes Yes Yes No Are speakers protection systems tripped or speakers damaged Repair or reset speaker Yes No Is...

Page 26: ...ection 1 3 2 Yes 2 3 Bad Sound 2 4 Amp Overheating Bad Sound Are the IOC or Clip indicators if equipped flashing or on Is source signal clean and undistorted Check levels and or indicators at source level for clipping Check amp for clipping Yes No Refer amp to service center Yes Possible Causes System Gain Structure See Setting System Gain Structure in Section 1 6 Amp not adequately cooled See Amp...

Page 27: ...s circuits which attenuate a signal may also be used to lower the level of a signal in an audio system to prevent overload and distortion Balanced Line A cable with two conductors surrounded by a shield in which each conductor is at equal impedance to ground With respect to ground the conductors are at equal potential but opposite polarity the signal flows through both conductors Band Pass Filter ...

Page 28: ...electrical circuit Cur rent is measured in Amperes or Amps abbreviated I Ohms law defines current as voltage V divided by resistance R with the following expression I V R Damping Factor Though technically more complex than this damping factor is usually thought of as an indicator of how tight an amplifier will sound when powering bass speakers A speaker s driving motor is a coil of wire called a v...

Page 29: ...or safety ground is a connection to the power company s earth ground through the power outlet In the power ground of an electronic component with a grounded plug the ground connection on the plug is wired to the component s chassis This wire conducts electricity to power ground if the chassis becomes electrically hot preventing electrical shock In audio ground usually refers to either the electric...

Page 30: ...and vice versa If you use gear of both levels there are various level matching devices on the market to properly interface the items Linear Power Supply A power supply that converts AC mains power for use by the amplifier by means of a conventional transformer operating at the same frequency as that of the AC mains supply usually 50 to 60 Hz Loudspeaker A transducer that converts electrical energy...

Page 31: ...fier In audio an electronic device that amplifies or increases the power level fed into it to a level sufficient to drive a loud speaker Radio Frequency Interference RFI Radio frequency electromagnetic waves induced in audio cables or equipment causing various noises in the audio signal Removable Terminal Block Buchanan Phoenix A series of screw terminal connections arranged in a line on a removab...

Page 32: ...ult to record and reproduce eating up precious headroom and often resulting in overload distortion Careful use of compression can help tame transients and raise average level although over compression will result in a dull squashed flat sound to the signal Trim Found on most mixers trim controls provide the initial level setting for each channel s input gain In most cases trim adjusts gain of the ...

Page 33: ...s by Bob Bushnell Melvin J Wierenga Melvin J Wierenga Paperback 289 pages 1st edition May 15 2000 Howard W Sams Co ISBN 0790611783 Handbook for Sound Engineers The New Audio Cyclope dia by Glen M Ballou Editor Hardcover 1506 pages 2nd edi tion January 1 1991 Focal Press ISBN 0240803310 JBL Audio Enginering for Sound Reinforcement by John Eargle and Chris Foreman Paperback 452 pages 1st edition May...

Page 34: ...n remedying the defect including surface shipping costs in the United States will be borne by us You must bear the expense of shipping the product between any foreign country and the port of entry in the United States and all taxes duties and other customs fees for such foreign shipments HOW TO OBTAIN WARRANTY SERVICE You must notify us of your need for warranty service not later than ninety 90 da...

Page 35: ... finance charges less a reasonable depreciation on the product from the date of original purchase Warranty work can only be performed at our authorized service centers We will remedy the defect and ship the product from the service center within a reasonable time after receipt of the defective product at our authorized service center HOW TO OBTAIN WARRANTY SERVICE You must notify us of your need f...

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