TXS0108ERGYR-Tkool Electronics

Tkool Electronics

IDescriptionThisblogintroducesthepoweramplifierwithNE5532andLM1875Tasthecorecomponents.Thepoweramplifierwearediscussinghereisahigh-fidelitytwo-channelstereosubwooferpoweramplifier.Here,wewilldiscussitsmethodsandprocedures,schematicdesign,assemblyanddebugging,andspeakerproduction.Hopethisblogcanprovideagoodreferenceforbeginners.Figure1.LM1875CatalogIDescriptionIILM1875TandNE5532Overview2.1PowerAmplifierLM1875T2.2Pre-amplificationComponentNE5532IIICompositionofPowerSupplyIVAssemblyandDebuggingSpeaker4.1ElectricalInspection4.2BoxProductionVIntheEndOrdering&QuantityIILM1875TandNE5532OverviewFirst,weintroducethecorecomponentsthatwewilluse.Andthen,thebasiccharacteristicsofthesecomponents.Audiopoweramplifierisgenerallycomposedofthefollowingthreeparts:powersupply,pre-amplifierandpost-amplifier.Here,wewillusehigh-efficiencyHI-FIpowerintegratedchipLM1875Tasthecoreoriginal.LM1875Tadoptsapositiveandnegative15Vdualpowersupply,theleft,andrightchannelsworkinOCLmode,andthebassworksinBTLmode.AsfarasthecharacteristicsofLM1875Tareconcerned,ithasthecharacteristicsofgoodsoundquality,goodfrequencyresponse,lowcostandrelativelysimplecircuit.Inaddition,thepre-amplifierpartusestheNE5532integratedoperationalamplifier.2.1PowerAmplifierLM1875TLM1875Thasexcellentperformance.Manyluxury-lookingactivespeakers,mid-rangepoweramplifiers,andsubwoofersonthemarketuseLM1875T.ThepoweramplifiercircuitcomposedofLM1875Tchiphasthefollowingcharacteristics:Theoutputpowerislarge,themaximumpowercanreachabout20W;Thestaticcurrentissmall,theloadcapacityisstrong,andthedynamiccurrentislarge,whichcandrive4～8speakers;Thecircuitissimple,easytomanufactureandlowcost;Withaninternalprotectioncircuit,itisahigh-fidelitypoweramplifiercomponentwithstableperformance.Theblogdesignofthisarticleisadual-channelstereosubwooferpoweramplifier,butLM1875Tisamono-channelpoweramplifierintegratedcircuit,sothedual-channelOCLworkingmodeusesoneLM1875Tforeachchannel.SincethebassworksinBTLmode,wehavetousetwopieces.LM1875Thas5pins.Theyarepositivepowersupply,negativepowersupply,positiveinput,reverseinput,andoutput.ThecircuitisshowninFigure2.Figure2.LM1875Circuit2.2Pre-amplificationComponentNE5532Beforethepoweramplifiercircuit,itisgenerallynecessarytoaddapreamplifier.Thepurposeofthisistoamplifythevoltageofvariousinputweakelectricalsignals.Inordertoensurethattheoutputelectricalsignalhashighfidelity,thepre-amplifierisNE5532.NE5532isahigh-performance,low-noise,dualoperationalamplifierintegratedcircuit.Comparedwithmanystandardopamps,NE5532hasbettersoundperformance,excellentoutputdrivecapability,relativelyhighsmallsignalbandwidth,andlargepowersupplyvoltagerange.Therefore,itisverysuitableforhigh-qualityandprofessionalaudioequipment,instruments,controlcircuitsandtelephonechannelamplifiers.Whenusedforaudioamplification,thetoneiswarmandhighfidelity.ThefunctionalblockdiagramofNE5532isshownasinFig.3.Figure3.NE5532FunctionalBlockDiagramIIICompositionofPowerSupplyLM1875Tadoptsapositiveandnegative15Vdualpowersupply.TheoperatingvoltageofNE5532isalso15V.Weneedtostepdownthemainspowerto15Vthroughastep-downtransformer,thenrectifyitthroughtherectifierbridgeKBL406,filteritthroughalargecapacitor,anddirectlysupplyittothepoweramplifier.Inthisway,largeroutputpowerisobtained.After7815and7915,theregulatedoutput15VisusedasthepowersupplyofthepreamplifierNE5532.ThecompositionofthepowersupplyisshowninFigure4.Figure4.PowerCircuitFigure5.PowerAmplifierCircuitBoardIVAssemblyandDebuggingSpeakerWhenstartingthecircuitinstallation,firstcheckthecircuitboardagainstthecircuitdiagram.Forexample,checkwhetherthemaincomponentsareinstalledcorrectly,andwhetherthesolderjointshavemissingsolderingorfalsesoldering.Thenturnonthepowertodebugthecircuit,andmakespeakersafterthedebuggingiscompleted.TheactualproductionisshowninFigure6.Figure6.PhysicalShootingPic4.1ElectricalInspectionUseanACsignalgeneratortoaddatinysinusoidalsignaltothesignalinput.Then,usetheoscilloscopetomeasurethethreeoutputsignalsofthepoweramplifierboard.Atthistime,observewhetherthesinemeetstherequirementsandwhethertheparametersinthetestarerelativelystable.Then,connecttwofull-rangespeakerstotheleftandrightchannels,andconnectawoofertothebassoutputport.Atthistime,addthesongsignaltocarefullycheckwhetherthethreespeakersareworkingproperlyandthesoundisgood.Iftheabovestepsarewellexpressed,thenproceedtothenextstep.4.2BoxProductionThekeytomakingspeakersistheselection,sizeandothersteps.Intheexperiment,weusedthelaminatesinthelaboratoryforsplicingandassembly.First,drawasketch.Thepaintingisdividedonthreedifferentsubstrates,andthenmadeintotwopartsrespectively.Afterdrilling,polishing,splicingandbonding,thecompletedcircuitpartsareinstalledintheirrespectiveparts.Then,wedividetheentirepoweramplifierintothreeparts.Twosatellitespeakers,aswellasawooferandpoweramplifierboard.Thesethreepartstogetherformacomplete2.1subwooferpoweramplifier.Here,thereisaplacethatneedsspecialattention.Whenmakingthebasspartofthecabinet,theimpactofvibrationshouldbefullyconsidered.Therefore,wehavetodesigndampingcomponents.VIntheEndAftertheinstallationisnormal,connectthemusicsignalsourceandlistentothemusiceffect.Thesoundreproducedbythiscircuithasastrongsenseofhierarchy,aclearsenseoforientation,andanobvioussenseofspaceanddistance.Inaddition,thesoundimageorientationisclear,thewidthisoutstanding,andthesounddynamicrangeislarge,givingpeoplearealfeeling.