AustralianMonitor-AM1200-pwr-sm维修电路原理图.pdf

Australian Monitor 1 Clyde Street, Silverwater NSW 2128 Australia +61 2 9647 1411 .au SERVICE INFORMATION AM1200 POWER AMPLIFIER CONTENTS: OPERATION MANUAL SPECIFICATIONS COMPONENT & SUB ASSEMBLEY DISCRIPTIONS TEST PROCEDURE SCHEMATIC DIAGRAMS BOARD OVERLAYS PARTS LIST RadioFans.CN 收音机爱 好者资料库OperationManualAM1200RadioFans.CN 收音机爱 好者资料库REFER SERVICING TOQUALIFIED PERSONNEL.NO USER SERVICEABLEPARTS INSIDE.!WARNING!DO NOT EXPOSE TO EITHERRAIN OR MOISTURE!CAUTION!RISK OF ELECTRICAL SHOCKDO NOT OPENThe user should not attempt to service the unit. Onlyqualified and knowledgeable personnel familiar withthe internal workings of the unit should attempt anyrepair, servicing or authorized modification to theunit. The unit does not contain any parts which theuser can service or re-use in this or any other product.IMPORTANT!Please read carefully.This operation manual contains important information regardingsafety precautions, installation, performance, operation andmaintenance of your AM1200 power amplifier. You shouldfamiliarize yourself with the contents of thisSafety Precautionsand Labellingmanual before operating your amplifier.The rear panel of the unit has a number of markings andinternationally recognized symbols related to thehazards and precautions that should be taken whenoperating MAINS connected equipment.The presence of a LIGHTNING FLASH with an arrowheadcontained within the boundaries of an equilateral triangleis intended to alert the user that dangerous uninsulatedvoltages may exist within the units enclosure. Thesevoltages may be of a sufficient magnitude as toconstitute the risk of an electrical shock.This symbol is reinforced with the text:The presence of an EXCLAMATION MARK containedwithin the boundaries of an equilateral triangle isintended to alert the user that there is importantoperating and maintenance literature that accompaniesthe unit.The unit should not be operated in a situation where itmay encounter the entry of water, rain, or any fluids. Toexpose the unit to the above conditions may make theoperation of the unit hazardous and increase the riskof electrical shock.If you are in need of special assistance and theinformation you require is outside the scope of thismanual, please contact your nearest service agent orAustralian Monitor direct:THE TECHNICAL OFFICERAUSTRALIAN MONITORC/- AUDIO TELEX COMMUNICATIONS PTY LTDPRIVATE BAG 149,SILVERWATER. N.S.W. 1811AUSTRALIA.PhoneFaxLocal(02) 9647-1411(02) 9748-2537International61-2-9647-141161-2-9748-2537E.auI.auFeatures:- 4, 3 or 2 channel operation.- Custom designed, 3RU heavy duty alloy chassis.- Modular construction.- Symmetrical layout - even weight distribution.- Linear, well-regulating, high current power supply.- Dual isolated high current secondaries.- High efficiency toroidal mains transformer.- Continuous high power capability.- Lateral Mosfet Class AB output stage.- Binding post and Neutrik Speakon outputconnection.Protection Features- Suppression of inrush current at mains turn-on.- Input muting at turn-on.- Input overvoltage protection.- Radio-frequency interference suppression.- Thermal protection and indication.- Short-circuit protection and indication.- Input signal strapping (loop through) connectors.- Active balanced inputs.- 21 Position detented attenuators.- Massive heat-sink / heat-exchangers.- Efficient front to back cooling.- Dual, twin speed axial fans.- Front and rear carry handles.- Front and rear mounting points.- High-quality, close-tolerance components used throughout.- Mains Circuit Breaker.- Independent DC supply rail fuses per channel.- Layout, grounding, decoupling and componentryhave been optimized to provide the user withstability, reliability and longevity.ContentsPage1.Introduction52.Controls, Connectors and Indicators62.1 Front Panel72.2 Rear Panel93.Installation114.Operation135.Bridge Mode156.Two Ohm or Not Two Ohm167.Maintenance178.Warranty189.Specification19List of IllustrationsPageFigure 1. Block Diagram5Figure 2. Front Panel Layout6Figure 3. Rear Panel Layout8Figure 4. Case Dimensions10Figure 5. Speakon Connector Wiring12Figure 6. Bridge Mode Speaker Wiring151. IntroductionCongratulations on choosing Australian Monitor foryour professional amplification requirements.The design of your AM1200 Audio Power Amplifierembraces all the aspects of a well designed unit. Thevisual design, mechanical, electrical and sonicparameters, along with our dedicated manufacturingprocess, have all been optimized to provide aprofessional tool that exhibits quality, reliability andlongevity.The AM1200 amplifiers are 3 unit (5.25) tall, 19 wideFigure 1 Amplifier Block DiagramIntroduction 5rack mountable units.Each channel of the amplifier comprises a balancedactive input with an attenuator driving a differentialclass A drive stage which in turn drives a fan-cooled,class AB MOSFET output stage configured as asource follower. The unit operates from a high currentcapable linear power supply.These units have been specifically designed to delivertheir high power output with minimal distortion, andprovide the critical degree of control required by yourspeakers, at high duty cycles for extended periods.6 Controls & ConnectorsFigure 2 Front Panel Layout2. Controls,Connectors& IndicatorsFront PanelFigure 1 shows the panel layout of the AM1200. Thefunctions of the controls and indicators are as follows:1. AttenuatorLevel control for your amplifier is provided by a 21position detented potentiometer and indicates gainreduction in decibels from the 0 dB position(maximum gain, no attenuation).2. Status IndicatorThis is a dual colour LED which displays the statusof the output stage and displays three levels ofoperation.These levels are:Below -20dB(unlit)-20dB and above(green)1dB below actual clipping(red)The LED will turn green once the output voltageexceeds the -20dB point (3.5 volts).The LED will change to red once the output ex-ceeds the -1dB point before actual clipping of theamplifiers output stage. The threshold of the -1dBpoint is referred to the amplifier supply rails andalters with changes in the mains supply, changesin the load and duty cycle fluctuations.The attack and decay time (ballistics), of the statuscircuit are those of a Peak Programme Meter(P.P.M.)NOTE: The amplifier is not damaged by running intoclipping, but speakers may be. To maximise the lifeof your speakers, try to keep clipping infrequent.3. Fault IndicatorThis amber LED will illuminate when a fault conditionexists.The fault detection circuit monitors the differencebetween drive and output in your amplifier.If you have a short on the speaker output (or a blownnegative rail fuse) the LED will flash brightly in syncwith the programme. This LED will also flash withprogramme peaks for gross overloads or if the loadis 2 ohms or less.The circuit has two stages of operation:1. It will provide indication (e.g. gross overload) butdoes not affect the input signal (a faint flash).2. It will indicate and mute the input signal (e.g.shorted output) (brightly flashing or permanentlyon).4. Power SwitchPress the switch DOWN for power ON and UP forpower OFF. At start-up (turn-on) the input to theamplifier is muted by 30dB for approximately twoseconds.5. On / Thermal IndicatorWhen switching the amplifier on, this red LED willmomentarily flash Red, indicating correct operationof the Mains In-Rush Current Suppression circuit.After establishment of the Inrush CurrentSuppression circuit the LED will change to Greenindicating the unit is on and receiving mains power.In the advent of a thermal overload this LED willilluminate red indicating that the internal operatingtemperature of one or all amplifier channels hasexceeded a safe level of operation and the amplifierwill be shut down. The fans will continue to run andonce the amplifier has cooled down sufficiently, theamplifier will start up automatically providing InrushCurrent Suppression and input signal muting untilestablishment of the amplifier after which it willreturn to normal operating mode.NOTE: You should always ensure that the fan grilleis kept clean and free from the build up of dust andlint. This will ensure longer operation of your amplifierand reduce the possibility of it prematurely goinginto thermal shutdown mode.6. Bridge Mode IndicatorThis LED will illuminate yellow when the relativepairs of channels of the amplifier have been selectedto operate in a BRIDGE mode of operation.Selection of the bridge mode is accomplished byengaging the rear panel PUSH TO BRIDGE Switch.See section 5 (page 15) for more information onBridge mode operation.Controls & Connectors 78 Controls & ConnectorsFigure 3 Rear Panel LayoutRear Panel7. Balanced InputA female 3-pin XL type connector is provided oneach input:Pin 1 = Signal Ground;Pin 2 = Hot (non-inverting or in phase);Pin 3 = Cold (inverting or reverse phase).7a.Signal StrappingA male 3-pin XL type connector is provided onchannels A and D and is wired in parallel with thefemale input XLR for strapping / looping signalbetween amplifiers.8. Bridge SwitchPushing this switch in engages the BRIDGED/MONO mode of operation for the relative pair ofchannels. In this mode, your amplifier will onlyaccept signal applied to the Channel-A input XLR(for channels A and B) or signal applied to theChannel-D input XLR (for channels D and C).Channel-A will now control the level of the A/Bbridged pair and Channel-D will now control thelevel of the D/C bridged pair.Speaker termination should be sourced from thered binding-post outputs.9. SPEAKON Output ConnectorThe NEUTRIK (NL4MP) 4 way SPEAKON connectoris provided as the main speaker output termination.This emerging standard of loudspeaker to amplifierconnection allows access to both channels of theamplifier via the one connector for bi-ampapplications. Channel-A (or D) is considered thedominant channel and has both channels wired tothe Speakon connector. See the installation sectionof this manual for detailed information on Speakonwiring.9a.Binding Post OutputsBinding posts (banana jacks) are provided forspeaker output termination with banana plugs orbare wire. The red post is used as positive and theblack post is used as negative.10.Mains LeadYour amplifier is supplied with a heavy duty mainsControls & Connectors 9lead (power cord) appropriately rated for the mainssupply voltage marked on the rear panel of youramplifier.The wires in the mains lead are coloured inaccordance with the following code:BROWN=ACTIVE;BLUE=NEUTRAL;GREEN AND YELLOW=EARTH.! CAUTION !Your amplifier must always be earthed!11.Mains Circuit BreakerA “push to reset” thermal acting circuit breaker issupplied on your amplifier providing overall protectionof your amplifiers power supply and theinterconnecting mains. The breaker will isolate theactive mains conductor in the event of a highcurrent internal fault or in continued overloadconditions.The breaker will not be able to be reset immediatelyafter tripping. A cool down period of around 30seconds is required before the breaker will resetback into circuit. If the breaker trips immediatelyafter a reset, then a fault may have developed withinthe amplifier.12.D.C. Rail FusesYour AM1200 amplifier is fitted with 8 Amp fuses perrail - per channel, as overload protection for theoutput stage of your amplifier.These fuses are in series with the high currentsupply rails to the amplifiers output stage and willblow when:1) An internal fault exists;2) There is a sustained overload;3) There is a sustained short circuit;4) Sustained load fault.Note: The front panel Fault Indicator will illuminateand pulse in sync. with the program source if thenegative supply Rail fuse blows.Distortion will result and the front panel Status LEDwill illuminate RED if the Positive Rail fuse blows.Replace only with 8 Amp, 3AG fast acting typefuses.Figure 4 Dimensions10 Installation3. InstallationMains Lead WiringWARNINGYour amplifier must be earthed at all times!When you first receive your amplifier it may not havea mains plug attached. You must ensure that anappropriate plug is used and corresponds with theamplifiers current (ampere) requirements and meetsthe approval of your local energy authority.Please refer termination of this lead to qualifiedpersonnel. Australian Monitor takes noresponsibility for any damage or harm resultingfrom improper termination of this lead!The wires in the mains lead are coloured in accordancewith the following code:GREEN AND YELLOW = EARTHConnect to the terminal marked with the letter E, withthe EARTH SYMBOL or coloured GREEN.BLUE = NEUTRALConnect to the terminal marked with the letter N (orcoloured WHITE in USA and Canada, or colouredBLACK in the United Kingdom).BROWN = ACTIVE (LIVE)Connect to the terminal marked with the letter A or L(or coloured BLACK in USA and Canada or colouredRED in the United Kingdom).Power RequirementsMains VoltageCircuit Breaker Rating100 to 120 volts20 Amps220 to 240 volts10 AmpsPower Consumption at idle= 250 WattsConsumption at rated 4 ohm power= 2300 WattsEnsure that your mains voltage is the same as the rearpanel mains voltage marker (+/- 10%).MountingYour amplifier is designed for standard 19 rackmounting and occupies 3 EIA rack units (5.25). Themounting centres are:Vertical:2.25(57.15mm)Horizontal: 18.15 (461.1mm) to 18.62 (473.0mm).The slots in the mounting flange will accept boltdiameters up to 1/4 (6.35mm).We recommend that you provide additional support forthe amplifier, especially if road use is planned, as theweight can bend some racks otherwise. This supportcan be provided by secure shelving, support rails or arear rack mounting strip to match up with the rear rackmount points provided on your amplifier.CoolingEach pair of channels in your AM1200 amplifier iscooled by an axial fan which draws cool air from thefront of the unit and expels the heated air via the rearof the unit. These units offer two speed fans which runat half speed, switching to full speed when the internalheatsink temperature exceeds 600 C (1280 F).An unrestricted airflow into and out from the unit mustbe provided. Any restriction of the air flow will causeheat to build up within the unit and possibly force theunit into its thermal shutdown mode.If the units are to be operated in an environmentwhere the airflow is restricted such as sealed racks oreven when running 2 ohm loads, the cooling shouldbe supplemented by extra cooling fans to evacuatethe heated air and aid the flow of cool air through theunit.Input WiringIMPORTANT! Do not directly connect pin 1 on theamplifiers input or strapping XLR, to the amplifierschassis, speaker ground or power ground!NOTE: Input signal ground is not to be used asa safety ground (earth).The input to your amplifier is a balanced 3-pin systemand requires all three pins to be connected. Only highquality twin-core shielded cable should be used.When wiring for a balanced source the connectorgoing to the input of your amplifier should be wired asfollows:Pin 2 =HOT (In Phase - non inverting).Pin 3 =COLD (Reverse Phase -