CVA 7400-7800 - Manual
Contents
1. unbalanced input signals Pinouts are standard see diagrams below Pin 2 of the XLR connector are Hot of Positive Input connections should always be made with the amplifier s power turned off Balanced XLR Connections are made with the following pin assignments 1 Ground 2 Positive 3 Negative Balanced XLR Connections are made with the following pin assignments 1 Ground 2 Positive 3 Ground 12 Special Features The CVA 7400 and CVA 7800 is the result of many years of experience in the research development and manufacturing of amplifiers and other sound equipment It is a combination of old and new cutting edge electronics and timeless purity of sound As such it represents Stewart Audio s commitment to developing the latest available technology to achieve the absolute audio quality and reliability Please take a few minutes to read through this section of the manual which provides an overview of the features that make these amplifiers unique Low Impedance High Current Design The design of the CVA 7400 CVA 7800 is exceedingly conservative with regard to current capabilities This ensures that the amplifier s output devices remain within their Safe Operating Area even under extreme conditions As a result the CVA 7400 CVA 7800 runs low impedance loads safely while retaining the high impact dynamics for which they were designed Auto Impedance Optimization The High F2. Hz at 12dB per octave has been incorporated for distributed systems High Frequency Switch Mode Power Supply The CVA 7400 and CVA 7800 features a radical departure from conventional power supply design Stewart s High Frequency Switch Mode Power Supply Because of this pioneering use of advanced technology some explanation is in order Conventional supplies operating at 60Hz standard line frequency recharge only 120 times per second requiring their storage capacitors and transformer to be quite large to supply the energy needed during the intervals between cycles when power is not available from the wall The power supply must act as a local reservoir of power from which the amplifier circuits draw This storage function is responsible for much of the bulk weight and cost of traditional power amplifiers The Stewart High Frequency Switch Mode Power Supply fully recharges 120 000 times per second 1000 times faster than conventional supplies 6 And out the top In any case be sure that the sides of the rack next to the amplifier are clear of cables power strips etc so that airflow is maintained around the heatsink fins The amount of airflow is necessary will be determined by a number of factors including ambient temperature the amount of heat generated by other equipment in the rack the properties of the rack enclosure being used and how hard the amplifier is working Depending on the installation it may be necessary t
3. ING TO QUALIFIED PERSONNEL ONLY CAUTION AN CAUTION TO REDUCE THE RISK OF ELECTRIC SHOCK DO NOT REMOVE COVER OR BACK NO USER SERVICEABLE PARTS INSIDE REFER SERVICING TO QUALIFIED SERVICE PERSONNEL The lighting bolt within arrowhead symbol within an equilateral triangle is intended to alert the user to the presence of uninsulated J dangerous voltage within the product s enclosure that may be of sufficient magnitude to constitute a risk of electrical shock to person JAN The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance servicing instruction in the literature accompanying the appliance Important Safety Instruction Please Read Prior to Product Installation 1 All of the safety and operating instructions should be read before the amplifier is operated Retain these instructions for future reference All instructions should be followed all warnings on the amplifier and in the operating instructions should be adhered to 2 This amplifier should not be used near water for example near a bathtub in a wet basement near a swimming pool etc 3 The amplifier should be situated so that it s location and position does not interfere with its proper ventilation For example the amplifier must not be placed on a rug bed sofa or similar surface that impedes airflow across the chassis Airflow through the ventilat
4. Still some sensible precautions are in order Always use four screws to affix the amplifier to the rack preferably using flat washers as well to avoid cosmetic damage to the front panel When rack mounting your amplifier it may be necessary to remove the four rubber feet from the bottom of the unit in freestanding installations the rubber feet must be installed In mobile rack mounted installations it is recommended that the rear of the amplifier be stabilized for additional support Thermal Considerations Cooling of the CVA 7400 CVA 7800 is achieved convection through heatsinks mounted on each side of the amplifier In the event that the chassis temperature reaches 87 degrees C an internal thermostat will open turning off the power supply until the amplifier cools down Although the CVA 7400 CVA 7800 sophisticated thermal management system makes it less susceptible to overheating than other amplifiers it remains necessary to provide airspace around the chassis This may mean leaving a rack space open above the amplifier Multiple amplifiers can be racked on top of one another by leaving a full space between them so sufficient airflow is main tained to allow heat to escape If mounted in a sealed rack leave top and bottom spaces open as well to create a chimney effect within the rack which will provide cooling as air is drawn in the bottom 10 Requiring far less capacitance for filtering and storage This high speed recharging re
5. The Undisputed Leader In High Speed Switching Power Supply Technol 222 5 ee STEWARTAUDIO STEWARTAUDIO as CONTRACTOR SERIES Sales and Factory Service CVA 7400 CVA 7800 Stewart Audio Inc 14397 Cuesta Court Suite D1 Sonora CA 95370 Professional Power Amplifier 209 588 8111 Fax 209 588 8113 Owner s Manual e e Specifications FTC Power Rating lt 1 THD 35Hz 20kHz both channels driven Frequency Response 0dB 0 5dB Bandwidth 0dB 3 0dB Signal to Noise A Weighted 400W 12 5 Input Impedance Input Sensitivity 400Wx2 12 5 Slew Rate Damping Factor Input Connectors Output Connectors Voltage Gain Power Requirements 1 8 Power Power Supply Design Dimensions Height Width Depth behind front panel Weight 17 CVA 7800 40Wx2 70 7 volts per channel 35Hz 20kHz 35Hz 20kHz gt 100dB 20K 1V O0dBV lt 30V microsecond lt 200 3 pin XLRBarrier Strip 6 Gauge 5 Way Binding Post 40x 32dB 120C AC 3A High Speed Switching 1 75 in 4 5cm 19 in 48 3 cm 15 3 in 38 9 cm 14 8 in 37 6 cm 11 Ibs 5kg e e Specifications FTC Power Rating lt 1 THD 35Hz 20kHz both channels driven Frequency Response 0dB 0 5dB Bandwidth 0dB 3 0dB Signal to Noise A Weighted 400W 12 5 Input Impedance Input Sensitivity 400Wx2 12 5 Slew Rate Damping Factor Input Connectors Output Connectors Voltage Gain Power Requirements 1 8 Power Power Supply Design Dime
6. Wiring Inputs in Parallel Wiring XLR and Barrier Strip in parallel as throughputs to other equipment requires special consideration when combining balanced and unbalanced lines Connecting an unbalanced lines described above to any input will render all inputs on that channel unbalanced If it is necessary to combine balanced and unbalanced connections on the same channel the unbalanced connector must not ground the Negative input In the case of the Barrier Strip this means using the and leaving the ground terminal unconnected When using the XLR connector s pin 3 must be left unconnected not tied to ground as described above Output Wiring Outputs are available via both 5 Way Binding Posts The Binding Posts will accept bare wire of up to 6 AWG spade lugs hook lugs and a single or dual banana plugs When wiring speakers in stereo red binding post is connected to the speaker s positive terminal black is ground Selectable High Pass Filter The selectable high pass filter for each channel is located on the bottom of the amplifier One of the three different frequencies 32Hz 68Hz 150Hz at 12dB per octave may be selected via the white recessed slide switch Amplifier Bottom Panel White selectable High Pass Filter Switch 150Hz 68Hz 32Hz 32Hz 68Hz 150Hz E 13 Input Wiring The CVA 7400 CVA 7800 s input sections allow the use of the XLR or Barrier Strip connectors and will accept either balanced or
7. d AC outlet
8. duces power supply sagging common with other designs In a Stewart Amplifier it is almost as though power is fed directly from the wall to the speaker with the amplifier acting only as a valve in between to control its flow The power supply s remarkable efficiency at converting energy from the Ac line to a usable form for loudspeaker applications allows many of the major components to be downsized saving space weight and cost Absolute Protection Stewart Audio power amplifiers employ circuits which fully protect the amplifier while avoiding sonic compromise For example a unique circuit monitors the current drawn from the power supply The amplifier s output is not affected in any way until the power rating is exceeded indicating the presence of a short or overload Under these conditions the power supply will simply shut down until the short is removed at which point the supply will slowly ramp up to full power protecting the load from a surge of energy In the event of an amplifier malfunction this circuitry will also protect the speakers since the power is immediately disconnected from the amplifier Most other amplifier designs require the presence of relatively high levels of signal in order to detect a shorted output At low signal levels such amplifiers will continue to drive a short causing rapid heat buildup thermal runaway and finally amplifier failure The current sensing circuitry in all Stewart Contractor S
9. eanly with no stray wire strands to short terminals Keep in mind that other components in the system can cause problems which may appear to be caused by the amplifier systematic troubleshooting will allow you to isolate the source difficulty If you fail to correct the problem by following the steps outlined below do not attempt to open or repair the unit yourself Please contact Stewart Audio at 209 588 8111 to obtain a Return Authorization RA Number and shipping instructions Once RA Number is obtained return the unit to Stewart Audio 14407 Cuesta Court Sonora CA 95370 Do not return any amplifier to Stewart without first obtaining an RA Number Refer to the enclosed Warranty Information for Terms and Conditions of Warranty NOTE Upon installation of the CVA 7400 CVA 7800 there will be a turn on delay of up to one minute after AC power is applied to the amplifier This is a result of the initialization sequence preformed by the amplifier s High Frequency Switch Mode Power Supply Subsequent delays will be minimal as long as the CVA 7400 CVA 78001 remains connected to AC power 14 Safety Before using your Stewart Audio Inc Power Amplifier please read this Owner s Manual carefully to ensure optimum trouble free performance WARNING TO REDUCE THE RISK OF ELECTRICAL SHOCK DO NOT EXPOSE THIS AMPLIFIER TO RAIN OR MOISTURE DANGEROUS HIGH VOLTAGES ARE PRESENT INSIDE THE ENCLOSURE DO NOT OPEN THE CABINET REFER SERVIC
10. eries amplifiers is capable of detecting a shorted output even at low program levels increasing reliability under conditions which could cause other amplifiers to fail Front Panel Sophisticated simplicity is a design objective in the development of all Stewart Audio amplifiers These amplifiers remain simple and intuitive to operate even while incorporating some of the most advanced technology available today Power On Off and Power Level Indicators The front panel provides visual feed back of the amplifier s status via several LED indicators The power switch is accompanied by a red LED which illuminates upon turn Note Upon installation of the CVA 7400 CVA 7800 there will be a turn on delay of up to one minute after AC power is applied to the amplifier This is a result of the initialization sequence performed by the amplifier s High Frequency Switch Mode Power Supply Subsequent delays will be minimal as long as the CVA 7400 CVA 7800 remains connected to AC power Each channel features two additional LEDs which indicate the level of the power being produced Green indicates a signal of 20dB while Red indicates that the amplifier is being pushed into clipping These level indi cators are accurate at any load impedance Level Controls A calibrated detented multiple position input level control has been pro vided for each channel These controls are located behind security covers and are easily accessible on the front pane
11. ion openings should be unobstructed 3 Do not place the amplifier near heat sources such as radiators heat registers stoves or other appliances that product heat The amplifier should be only be connected to 120 VAC 60 Hz power supply Do not defeat the ground or polarization of the power plug Route power cord and other cables so that they are not likely to be walked on tripped over or stressed Pay particular attention to condition of cords and cables at plugs and the point where they exit the amplifier To prevent risk of fire or injury damaged cords and cables should be replaced immediately Clean the amplifier with a clean damp cloth Do not use solvents or abrasive cleaners Never pour any liquid on the amplifier When left unused for a long period of time the power cord should be unplugged form the outlet Damaged Amplifiers requiring service The amplifier should be serviced by a qualified service technician when The power cord or AC plug has been damaged Objects have fallen or liquid has spilled into the unit The amplifier has been exposed to rain or other moisture The amplifier does not appear to operate normally or exhibits a marked change in performance e The amplifier has been dropped or the enclosure damaged ae FP 10 The user should not attempt to service the amplifier beyond that described in the operating instructions All other servicing should be referred to qualified service personnel
12. l of the amplifier They operate in conventional fashion I e full clockwise maximum level Rear Panel XLR Inputs Each channel has a female XLR balanced input connector which may also be used with unbalanced lines See Input Wiring in the section on Installation page 12 for more details Note the XLR input is wired in parallel with the Barrier Strip input so that either may be used as a through connection to feed additional amplifiers or other equipment 5 Way Binding Post Output Connectors Each channel incorporates a pair of heavy duty 5 Way Binding Post output connectors They will accept bare wire spade lugs hook lugs and single or dual banana plugs Additionally the binding posts are situated so that when the amplifier is configured for bridged operation one dual banana plug may be inserted across the terminals See Output Wiring in the section on Installation page 13 for more details Remote Turn on Feature When using the CVA 7400 CVA 7800 with a Controller or other preamplifier with a remote trigger outlet the amplifier can be turned on remotely This unique circuit will allow several amplifiers to be connected directly to the AC Power Strip The Remote Turn On input may be Activated by any five volt signal source Removable AC Line Cord For convenience during the installation Stewart has included a removable AC power cord Please make sure that this cord is connected to a grounded 20 amp un switche
13. nsions Height Width Depth behind front panel Weight 16 CVA 7400 200Wx2 70 7 volts per channel 35Hz 20kHz 35Hz 20kHz gt 100dB 20K 1V O0dBV lt 30V microsecond lt 200 3 pin XLRBarrier Strip 6 Gauge 5 Way Binding Post 40x 32dB 120C AC 3A High Speed Switching 1 75 in 4 5cm 19 in 48 3 cm 15 3 in 38 9 cm 14 8 in 37 6 cm 10 Ibs 5kg Congratulations You have purchased a powerful product which will provide you with many years of reliable service Stewart Audio s committed to innovation in design and quality workmanship has provided its customers with a unique combination of performance and reliability This philosophy has attracted the attention a gained the respect of industry professionals around the world The CVA7400 Contractor Series Power Amplifier delivers more than 200 watts per channel in stereo mode while the CVA 7800 delivers more than 400 watts per channel in stereo mode Stewart Audio s unique power shift correction feature allows the amplifier to produce crystal clear uncolored sound This remarkable performance comes in a package weighing only 10 pounds and 11 pounds while occupying just one standard rack space Thermal concerns are minimized in the CVA 7400 and CVA 7800 by innovative circuitry and extraordinary efficiency making installation simpler than ever before We at Stewart Audio strive to bring you the finest in professional electronics and we thank you for your choice
14. o guarantee airflow around the heatsinks by rearranging system components or installing a cooling fan in the rack Note To minimize thermal concern an accessory cooling fan panel may be installed Fans may be installed in the front or rear of the rack in the upper most slots Fans should be blowing out of the rack For further information please contact Stewart Audio s customer service In a free standing installation in which the unit is sitting on a shelf or hard floors the rubber feet must be mounted to the bottom of the amplifier Under no circumstances should the amplifier be placed directly on carpeting of a similar surface AC Power Considerations Your Stewart amplifier is designed to operate on 120 volt 60Hz alternating current Power consumption will depend on load impedance signal level and dynamic properties of the program material At 12 5 per channel power draw averages approximately 110 watts The CVA 7400 CVA 7800 is equipped with unique inrush current limiting circuitry which minimizes power drawn from the wall to 8 Amps of less on power up Multiple amplifiers may all be switched on at once without the need for staggered turn on configurations 11 Installation Mechanical Consideration The Stewart Audio CVA 7400 CVA 7800 occupies one standard rack space and is only 15 deep and weighs just 10 and 11 pounds respectively making it easier to install and transport than almost any other comparable amplifier
15. requency Switch Mode Power Supply and amplifier design used in the CVA 7400 CVA 7800 adapts to the demands placed upon the amplifier enabling them to run with maximum efficiency regardless of the load impedance Thermal management problems normally associated with amplifiers of this capacity are therefore greatly reduced Resources otherwise applied toward dealing with thermal problems can be put to better use in higher quality active components for increased reliability and improved performance Balanced Unbalanced Inputs The CVA 7400 CVA 7800 incorporates XLR and Barrier Strip input connectors wired in parallel This allows throughput of the signal to additional amplifiers or other equipment such as DAT recorders etc 6 Gauge 5 Way Binding Post and 1 4 Outputs The CVA 7400 CVA 7800 Binding Posts output connectors will accept banana plugs spade lugs or bare wire up to 6AWG In addition the Binding Posts are positioned to allow one standard banana plug to be used when operating the amplifier in bridged mode In Rush Current Limiting A breakthrough from Stewart the CVA 7400 and CVA 7800 unique inrush Current limiting circuitry minimizes power drawn from the wall to 8 AMPS or less on plug in Staggered turn on configurations for multiple amplifier setups are now a thing of the past as multiple amplifiers may be switch on simultaneously Selectable High Pass Filter A selectable high pass filter for each channel 32Hz 68Hz 150
16. short circuit Condition on the output Disconnect speaker wires and turn amplifier power switch on If amp stays on the problem is in the output wiring or speakers Power indicator on no output from one or both channels Check input level controls input and Output cables input signal and speakers If operating in bridged mode be sure connections are made to Channel 1 s inputs Low volume in one or both channels Check input level controls input signal levels and input wiring Be sure both speakers are the same impedance Amplifier overheats and or shuts off Review section on Thermal Considerations Note that overdriving amplifier for a long period can cause thermal shutdown Note that overdriving amplifier hard enough can cause momentary shutdown Distorted output Check signal level and signal source Check speaker s Noise on output Check signal source for noise If you are running input cables of more than 30 feet balanced lines can reduce noise levels considerably See sections on Input and Output wiring for more information on wiring balanced lines 15 Troubleshooting If you experience difficulty in operating your CVA 7400 CVA 7800 chances are good that you will be able to remedy the problem yourself using standard troubleshooting techniques and suggestions offered in the table on the following page If you wire your own cable it is imperative that all connections be made cl
17. which we See as appreciation for our efforts Stewart Audio Inc Sonora CA 95370 209 588 8111 Fax 209 588 8113 Contents Introduction Wire ce hierar tt BO rears 00 81s Ae 1 Contents For the Record cceeceeeeee ees 2 DI CLY 2s cacsone TA A 3 amp 4 Spectal Feat r s niecne aa ances 5 7 Front Panel Features sinc acs drcueey sees chun aeh eed 8 Rear Panel Features 2h csndeacsses ei acne ene eaa es 9 Installation 2046 20 vaasosasanradenseaosaannmnadis 10 13 Trouble Shooting h houcsenresrssecwanrsrenennead s 14 15 Technical Information 00ee ees 16 17 For The Record Please fill out and return the enclosed warranty card at your convenience This information will provide proof of ownership for warranty purposes and will allow us to notify you if necessary In the spaces provided below record the model and serial number located at the rear of your amplifier Model No Serial No Purchase Date Retain this information for future reference Troubleshooting Reference Chart Symptom No output Power indicator LED is off Note there is a normal delay of up To 1 minute when amp is first plugged in or circuit breaker is reset Recommended Action Be sure power outlet is live Be sure power switches are on Check circuit breaker Wait 1 minute after plugging in cord or resetting breaker No output Power indicator LED Cycles on and off This indicates a
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