DA-770-2 - Manual - Online
Contents
1. between 20dB and OdB When the signal exceeds OdB the LED will glow red to indi cate that the amplifier is being driven into clipping See section 4 for ways to prevent this 3 2 2 Controls The DA 770 2 s front panel has only one control a push button to con trol the power of the unit When the push button is depressed the power is on When the button is push button is out the power is off The rear panel contains two input sensitivity knobs as well as two high pass filter switches one knob and switch for each of the two chan nels To adjust the input sensitivity knob you will need a small flat head screwdriver While a typical program source level is present spin the rotary knob as far clockwise as you can without hearing distortion or without the Signal indicator glowing red If the signal is distorting and the knob is all the way counter clockwise adjust the gain down at the source level The high pass filter switch allows you to select the lower cutoff fre quency for each channel The high pass filters on the DA 770 2 have 3 cutoff points which can be selected 35Hz 85Hz 500Hz For more de tails see section 3 3 1 3 3 Special Features 3 3 1 High Pass Filter Your DA 770 2 amplifier has 2 high pass filters one for each channel The high pass filter is used to attenuate reduce the volume of fre quencies below a desired cutoff point The high pass filters on the DA 770 2 have 3 cutoff points which can2. customers with a unique combination of performance and reliability This commitment to excellence has gained the respect of industry professionals around the world We are confident that your new state of the art 70 7V Digital Power Amplifier will provide you with many years of reliable service If after reading this manual you should have any questions concerning amplifier installation and operation please contact your Authorized Stewart Dealer or you may contact us directly using the contact infor mation provided on the back of this manual 1 1 Features The DA 770 2 Series Professional Power Amplifier utilizes a new high speed switching power supply and Class T output topology The am plifier will deliver over 80 Watts at 70 7V of power per channel and is offered in a 2 channel configuration This remarkable performance comes in a very compact package weighing a mere 3 4 pounds and occupying just one half standard rack space The DA 770 2 Series Am plifiers are convection cooled and require no noisy fans for cooling 1 2 Using this Manual In order to obtain maximum performance from your DA 770 2 Series Amplifier please take time to read this brief owner s manual and care fully follow the guidelines for connection and operation This manual provides you with the information necessary to safely in stall and operate your new DA 770 2 Series amplifier in the most com mon scenarios If you find yourself requiring additional assi
3. pour any liquid on the amplifier 9 When left unused for a long period of time the power cord should be unplugged form the outlet 10 Damaged Amplifiers requiring service should be repaired 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 aooo 11 The user should not attempt to service the amplifier beyond that de scribed in the operating instructions All other servicing should be referred to qualified service personnel Table of Contents Important Safety INStrUCTIONS 101i ttt ere 2 Table Of CONTENTS ceeeterr ttt eerste eer eee reese teers er eeee rae 4 1 Welcome oie ere 5 1 1 F Atures verses etree teeters reer ee rere ee er reee err tees 5 1 2 Using this Manuals trier ere erties 5 2 SOTUP rr eer eee 6 2 1 Setup Precautions ee cece eres 6 2 2 Rackmount Installation ccee eee eee eee eee eeeees 6 2 2 1 Single RACKMOUN t teeter eee 6 2 2 2 Dual RACKMOUNt rset e rere 6 2 3 Proper Cooling Considerations ie erie 7 2 4 Product DIMENSIONS 1eeeeese eee ete e eee e ee eee teeters aeeees 7 2 5 Input CONNECTIONS verre te te rie 8 2 5 1 Balanced COnNectionse secs 8 2 5 2 Un
4. safety and operating instructions should be read before the am plifier is installed or operated Retain these instructions for future refer ence All instructions should be followed all warnings on the amplifier and in the operating instructions should be adhered to 3 The amplifier should be situated such that its 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 ventilation openings should be unobstructed 4 This amplifier should not be used near water for example near a bathtub in a wet basement near a swimming pool etc This amplifier is intended to be operated in a controlled indoor environment 5 Do not place the amplifier near heat sources such as radiators heat regis ters stoves or other appliances that produce heat 6 The amplifier should only be connected to 120 VAC 60 Hz power supply Do not defeat the ground or polarization of the power plug 7 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 at the point where they exit the ampli fier To prevent risk of fire or injury damaged cords and cables should be replaced immediately 8 Clean the amplifier with a clean damp cloth Do not use solvents or abra sive cleaners Never
5. 3S T EWART The Difference is Hear STEWARTAUDIO CH1 CH2 He Compact Series DA 770 2 Power r Signal Clip J DA 7 70 2 Owner s Manual February 2010 Important Safety Instructions Before using your Stewart Audio Inc Power Amplifier please read this Owner s Manual carefully to ensure optimum trouble free perform ance WARNING TO REDUCE THE RISK OF ELECTRICAL SHOCK DO NOT EX POSE THIS AMPLIFIER TO RAIN OR MOISTURE DANGEROUS HIGH VOLTAGES ARE PRESENT INSIDE THE ENCLOSURE DO NOT OPEN THE CABINET REFER SERVICING TO QUALIFIED PERSONNEL ONLY CAUTION A A 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 un insulated dangerous voltage within the product s enclosure that may be of sufficient mag nitude to constitute a risk of electrical shock to person 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 Installation should be performed by a trained and licensed professional to insure safe and lasting operation 2 All of the
6. balanced Connections verre iis 9 2 6 Output CONNECTIONS verre ennnen 10 2 6 1 Wiring Diagram sesseeeseeeserseressrrrrrseeessrinnrnntennrinrennneeenen 10 3 Operation i rere 12 3 1 Operation Precautions ree ees 12 3 2 Controls Indicators ANd CONNECTOLS eee tetas 12 3 2 1 INGICATOLS eee 13 3 2 2 COMPOS ssseeeeeee teers tect eee eee e eee eee e errr ere eaeeeees 13 3 3 Special Features vere ee es 14 3 3 1 High Pass Filter eeceeeert tees 14 3 3 2 Remote On Off eeeeeereee eee e este teeter reer eees 14 4 Troubleshooting eee 15 5 Technical Specifications 0 17 6 Warranty Information 0 ee 18 6 1 Warranty SUMMAary verre ere 18 6 1 1 Eligibility for Factory R pair scceeeeeeteeeerieees 18 6 2 Return ProC dure s ssssesesececeeeeeeeeeesesesesseneeeaeseeesesesuseseeseeegesneees 18 6 2 1 Return Authorization cceceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 19 6 2 2 Packaging INStrUCtIONS 111 eeerere ett eet eet e eet teees 19 6 2 3 Shipping INStrUctionS e eee 19 6 2 4 Estimate Approval verre ttee eters tires 19 6 2 5 Payment of Non Warranty Repair reece 19 This amplifier proudly designed and manufactured in the USA 1 Welcome ee STEWARTAUDIO The Difference is Hear Congratulations on the purchase of your new state of the art Stewart Audio DA Power Amplifier Stewart Audio s commitment to innovation in design and quality workmanship has provided its
7. be selected 35Hz 85Hz 500Hz To make a selection slide the switch to the desired cutoff point The purpose of this high pass filter is to both prevent unwanted noise that can come in with the signal sources as well as to prevent damage to speakers which are unable to handle frequencies which are more suited for a subwoofer 3 3 2 Remote On Off The DA 770 2 includes a Remote On Off function which allows the am plifier to be remotely activated by applying a current to the Remote On Off connector on the rear of the amplifier To use this feature the amplifier s power switch must be in the Off position Then once between 5VDC and 24VDC is applied to the rear connector observing polarity the amplifier will automatically turn on and stay on until the current is removed WARNING Do not apply more than 24VDC to the Remote On Off connector Also ensure that polarity is observed when connecting the remote power source 14 4 Troubleshooting Problem Power indicator does not turn on Procedure If this is the amplifiers first power up allow for up to 30 seconds for the indicator to turn on If you are still experiencing a prob lem check that the amplifier is plugged into a live outlet and that the power switch is in the down position After you have ensured that it is not a power issue disconnect any speakers If the amplifier turns on after a few seconds delay then the problem is in the output connec tion Check wiri
8. ce must be accompanied by a Return Authorization RA number One can be obtained by contacting Stewart Audio at 209 588 8111 or via e mail at support stewartaudio com NOTE Any defective products received without an RA number will be returned to sender at their expense If Stewart Audio is unable to contact the sender in 14 days the mer chandise will be considered scrap and may be disposed of 6 2 2 Shipment Instructions If Stewart Audio requests that you ship the defective product back to their service center please refer to the guide below To ensure prompt warranty service be sure to follow all instructions 1 Return Authorization RA is required for product being sent to the factory for service 2 See packing instructions in section 6 2 3 3 Ship the defective product using a method which provides for or der tracking or order confirmation The service center is located at the following address Stewart Audio 14397 Cuesta Court Suite D1 Sonora CA 95370 4 Use a bold black marker and write the RA number on three sides of the box 5 Record the RMA number for future reference The RA number can be used to check the repair status 6 2 3 Packaging Instructions Should Stewart Audio request that you ship your product to their ser vice center these instructions must be followed in order to ensure safe delivery If they are not followed Stewart Audio assumes no responsi bility for damaged goods and or accessories tha
9. ilizes the entire chassis as a heatsink to cool the heat generating components inside In the event the internal ambient temperature reaches 85 degrees centigrade the protection circuit will shut down the power supply until the ampli fier cools down Although the sophisticated thermal management system in the DA 70 Series makes it less susceptible to overheating than other amplifiers it remains good practice to provide airspace around the chassis CAUTION Inadequate airflow to the amplifier can cause the amplifier to overheat and potentially become damaged in the process Be sure to provide plenty of air space to allow for convection cooling 2 4 Product Dimensions lt 8 26in gt STEWART CH1 CH2 Signal Clip e 4 10 6in gt by 1 75in 4 6cm Side View 2 5 Input Connections Your DA 770 2 Series amplifier is provided with a 3 pin Phoenix con nector for each input This connector will accept both balanced or un balanced connections however some modifications must be made for an unbalanced connection See the next two sections for instructions on connecting your amplifier to its input source 2 5 1 Balanced Connections When using a balanced input source and connector you must ensure that the hot cold and ground pins of the connector are matched up to the and ground pins of the DA 770 2 s Phoenix connector respec tively Diagrams have been provided for standard XLR and TRS con nec
10. leshooting section you are unable to restore proper function return it to your Authorized Dealer for service Refer to section 6 for instructions 16 5 Technical Specifications Maximum Output 70 7v 80W per channel Frequency Response 0 0 3 dB 1 32Hz 20kHz Full Power Bandwidth 32 Hz 20 kHz 0 5dB Signal to Noise Ratio gt 85dB THD N lt 0 1 Input Sensitivity 1V 0 dBV Standard Voltage Gain 71x 37qB Input Impedance Balanced Unbalanced 10 kQ 5kO Class D Input Connectors Phoenix Type 3 Pin Output Connectors Phoenix Type 2 Pin Remote On Off Connector Phoenix Type 2 Pin Power Supply High Speed Switching Cooling Convection Cooling Front Panel Controls Power On Off Rear Panel Controls Channel Gain HP Filter Hi Pass Filter 32 68 or 500Hz LED Indicators Power Signal and Clip Construction Steel amp Aluminum Operating Voltage 120VAC Dimensions Height 1 75in 4 6cm Width 8 26in 21cm Depth 10 6in 27cm Weight 2 9lbs 1 32kg With hi pass filter bypassed Stewart Audio reserves the rate to change features and specifications without notice 17 6 Warranty Information 6 1 Warranty Summary All Stewart Audio amplifiers and accessories unless excluded in this summary are covered by a 3 year limited warranty on parts and labor from the data of purchase In order to be eligible for warranty repairs the amplifiers and accessories must have been purchased through an authorized Stewa
11. ng and speakers for short circuits Problem Power indicator cycles on and off Procedure This indicates a short circuit on the output wiring Discon nect speaker wires and turn amplifier power switch on If the amplifier stays on the problem is in the output wiring or speakers Check all con nections and consult the manual for your speakers Problem No output on one or both channels Power indicator is lit Procedure Check that level controls are not turned down Check that input and output connections are secure Problem Amplifier overheats and or shuts off Procedure Review section 2 3 on proper cooling procedures Check the signal lights on the front of the amplifier to see if the signal is over driving the signal light flashes red frequently Overdriving the amplifier for extended periods of time can cause a thermal shutdown Problem Only mid and high frequencies are being heard through the speakers Procedure Check that the high pass filter is correctly adjusted for your application Consult section 3 3 1 for more information 4 Troubleshooting cont Problem Output sound is distorted or cracking Procedure Check all cables for damage or loose connections and re duce the gain on the input signal at the mixer or preamp level Replace the cables and loudspeakers temporarily to see if this resolves the problem If problem still exists contact your Authorized Dealer for ser vice If after reading this troub
12. ng hookup Improper wiring can re sult in damage to equipment or potentially harm to the operator Consult section 2 for setup instructions 2 Tampering with the circuitry or making unauthorized changes is not only dangerous but may also violate local regulations 3 Use care when making connections between the amplifier and the input or output equipment Using equipment that is not capable of handling the output wattage may lead to permanent damage NOTE Stewart Audio will not be held responsible for dam age to your DA 770 2 or connected equipment if the in structions in this manual are not followed 3 2 Controls Indicators and Connectors Front View Compact Series DA 770 2 STEWART CH1 CH2 Power as r Signal Clip 3 e e 1 on off C1 Signal clip indicator lights 2 Power on off switch 3 Power indicator light Rear View 4 Hay DEI 35 sio 35 soo HIGH PASS 2 INPUT 1 4 Power cable socket IEC C13 Q Input sensitivity knobs O Speaker inputs 3 High pass filter selectors 6 Remote on off connector 9 Speaker inputs 12 3 2 1 Indicators The DA 770 2 has 3 front panel LED indicators The first is the power indicator which will illuminate when power is supplied to the amplifier This indicator may take up to 30 seconds to light up when the amplifier is first turned on The other 2 LED indicators are the Signal indicators one for each channel These LEDs will glow green if the signal is
13. refer to the following chart to choose the appropriate wire gauge for your installation Distance Wire Gauge Up to 500ft 22 AWG 500 1000 ft 20 AWG Over 1000ft 18 AWG Speaker leads connect by means of Phoenix type block connectors supplied with the unit Strip speaker leads 1 4 and insert into connec tor observing proper polarity With a small flat blade screwdriver tighten the screw until the leads are held securely in place Inspect for possible shorts or broken wires 2 6 1 Wiring Procedure Once the wire leaders have been prepared as described above con nect the speakers as shown in the diagram while the unit is powered off A single DA 770 2 is capable of supplying 80W of power per channel As a buffer a typical installation will only utilize 75 of the total SOW once all of the speakers have been connected If each speaker is using a 5W power transformer up to 12 speakers can be connected per channel 80W 75 60W Phoenix Style Connector Rear of DA 770 2 Channel 2 Channel 1 i ii CAUTION Stewart Audio will not be held responsible for damage to speakers that happen as a result of being un able to handle constant 70 7 volts All loudspeakers MUST be fitted with a 70 volt transformer in order to prevent se rious damage to the equipment 3 Operation 3 1 Operating Precautions 1 Before use your amplifier must be configure for proper operation including input and output wiri
14. rt Audio dealer and submitted by the original pur chaser This warranty is only valid in the country in which the amplifier was purchased 6 1 1 Eligibility Requirements Stewart Audio warrants against all malfunctions which come as a result of component or manufacturer defect The amplifier is also covered from all failures which arise during the warranty period 3 years from date of purchase that are not a result of misuse The following actions will void your warranty e The power cord or AC plug has been damaged through misuse e The amplifier has been exposed to moisture or extreme tempera tures e The amplifier has been dropped items have been dropped on the amplifier or the enclosure has been damaged e The amplifier has been opened by the operator e The amplifier was improperly packaged when sending to the fac tory for repair resulting in damage e Any of the precautions or instructions found in this manual were not followed Damages resulting to the amplifier which are not covered under this warranty can be factory repaired at cost to the customer Use the con tact information below to initiate the repair process 6 2 Return Procedure This section includes the return procedures which must be followed in order to prevent processing delay or cost to the customer Please read the entire section before contacting Stewart Audio for returns 18 6 2 1 Return Authorization Number All returns to the factory for servi
15. scrap and may discard it 6 2 6 Payment of Non Warranty Repairs Payment for non warranty repairs must be submitted to Stewart Audio before the product will be returned to the customer 20 Stewart Audio Product Line Sub Compact Products AV 25 2 35W x 2 4 Ohms 25W x 2 8 Ohms Half Rack Compact Series DA70 2 70W x 2 4 Ohms 35W x 2 8 Ohms DA70 4 70W x 4 4 Ohms 35W x 4 8 Ohms DA770 2 80W x 2 Constant Voltage 70 7V rms out CVA 25 1 25W x1 25V 70V CVA 50 1 50W x1 25V 70V Products PA Series PASOB 50W x 2 4 Ohms 25W x 2 8 Ohms 100W x 1 8 Ohms bridged PA100B 90W x 2 4 Ohms 50W x 2 8 Ohms 180W x 1 8 Ohm bridged AV Series AV50 50W 4 Ohms 25W 8 Ohms 100W 8 Ohms bridged 1U 2U Products World Series World 600 190W x 2 4 Ohms 110W x 2 8 Ohms Contractor Series CVA7400 200W x 2 Constant Voltage 70 7V rms out World 1 2 350W x 2 4 Ohms 200W x 2 8 Ohms World 1 6 550W x 2 4 Ohms 300W x 2 8 Ohms CVA7800 400W x 2 Constant Voltage 70 7V rms out World 600R Recessed controls World 2 1 650W x 2 4 Ohms 400W x 2 8 Ohms World 1 2R Recessed controls Custom Amps Contact factory For more information contact sales stewartaudio com
16. stance please feel free to contact your Authorized Dealer or you may contact us directly using the contact information provided on the back of this manual 2 Setup 2 1 Setup Precautions CAUTION Before installing your amplifier make sure that A you have read the Important Safety Precautions at the be ginning of this manual 2 2 Rackmount Installation The DA 770 2 amplifier takes up only 1 2 of a standard 19 rack unit While it is not necessary to rackmount your DA 770 2 amplifier there are two options available if you would like to do so a single rackmount or a double rackmount NOTE Regardless of which rackmount option is used the A 4 adhesive rubber feet must be removed from the bottom of the unit 2 2 1 Single Rackmount A single DA 770 2 amplifier can be mounted on one rack unit with the RMK 70 S rackmount kit The kit includes 2 brackets which will center the DA 770 2 ona single rack unit 2 2 2 Dual Rackmount Two DA 770 2 amplifiers can be mounted on one rack unit with the RMK 70 D rackmount kit The kit will connect the two amplifiers and center them on a single rack unit Single Rackmount with RMK 70 S Compact Series DA 770 2 STEWART cH Power Dual Rackmount with RMK 70 D Compact Series DA 770 2 Compact Series DA 770 2 Power ci Power 2 3 Proper Cooling Considerations Cooling of the DA 770 2 Series amplifiers is achieved by Stewart s unique whole chassis heatsink design which ut
17. t are sent with your unit 6 2 3 Packaging Instructions cont 1 Please write the RA number on three sides of the box Include the Stewart Audio RA number inside the box and a brief description of the problem 2 Do not ship any accessories manuals cords hardware etc with your unit These items are not needed to service your product Stewart Audio will not be held responsible for these items if they are returned with the amplifiers 3 When shipping your amplifier it is important that it has adequate protection We recommend you use the original packing material when returning the product for repair If you do not have the origi nal box see number 4 4 If you provide your own shipping pack the minimum recom mended requirements for materials are as follows a 275 P S I burst test Double Wall carton that allows for 2 inch solid Styrofoam on all six sides of unit or 3 inches of plastic bubble wrap on all six sides of unit b Securely seal the package with an adequate carton sealing tape c Do not use light boxes or peanuts NOTE Damage caused by poor packaging will not be covered under warranty 6 2 4 Estimate Approval An estimate for all non warranty repairs will be provided to the cus tomer once the unit has been shipped to the factory The customer is responsible to approve this estimate within 7 days If the repairs are not approved within 14 days Stewart Audio reserves the right to con sider the unit
18. tors Please refer to the manual of your input source in case it does not follow the standard pin out Input Connector tof Female XLR Input Connector Male TRS ne as Mieg Shield Connector enlarged to show detail 2 5 2 Unbalanced Connections When using an unbalanced input source and connector a jumper must be added between the negative terminals and the ground terminals Once this has been done the unbalanced source can be connected to the positive and ground terminals Diagrams have been provided for standard RCA and TS connectors Please refer to the manual of your input source in case it does not follow the standard pin out Input Connector Male RCA t it Ground yo C A jumper has been added between the Ground negative terminals and ground Shield Input Connector Ground R Male TS a A eal 4 amp A A jumper has been added between the negative terminals and ground Ground Shield 2 6 Output Connections Because of the differences in the way that constant voltage amplifiers work as opposed to a typical 8 ohm setup the wiring procedure as well as the gauge of wire used is very different The low current running through the wires to the speakers because of the high constant voltage allow you to use much thinner wire gauges than in an 8 ohm setup Please
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