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1、编号：毕业设计(英文)资料翻译院（系）：计算机系专业：自动化学生姓名：学号：指导教师单位：计算机系姓名：职称：实验师StandalonePhonoPre-ampAHIGH-PRECISIONPHONOPREAMPLIFIERbyFredNachbaur,Dogstar1997,1:INTRODUCTIONTherehasbeenmuchpresslatelyaboutthemerits(anddrawbacks)ofthevenerablevacuumtube.Howmuchofthisretromovementisbasedindemonstrableprincip
2、les,andhowmuchisrootedinnostalgiaorsubjectivityisadebatethatcouldfillvolumes.Whatisclearisthatthereisconsiderablerenewedinterestinvacuumtubes,atechnologythateventwodecadesagowasconsideredasobsoleteasspatsandtophats.Nowthetrendisreversing,andanumberofmanufacturersareagainsupplyingtubegea
3、rforaudiophiles,musiciansandhobbyists.Inmanycases,thesearesimplyvintagecircuitsinnewpackaging.Otherproductsoffernewapproachestovacuumtubetechnology,addingwhatwe'velearnedinthemeantimetocomeupwithsometrulynoteworthydesigns.Theprojectdescribedherefitsintothelattercategory.Whyusetubesanywa
4、y?Thecentralargumentforthepro-tubemovementisthatspecscanbealmostmeaningless,andthatwhatcountsishowitsoundstotheindividuallistener.Highlysubjectivedescriptionsarethereforeused,insteadofthetechno-babblewe'vemore-or-lessgottenusedtoinrecenttimes.Theoppositecampclaimsthatnumbersdon'tlie,and
5、thatyoucan'timprovesomethingbyaddingdistortionofanykind.Bothcampshavevalidpoints.Mostofushaveheardexpensivegearwithspectacularspecifications,butwereleftcoldbythe"toogoodtobetrue,"almostclinicalsoundofsuchequipment.Similarly,mostpeoplewillagreethatjustbecausesomethinghastubesinitdoesn'tm
6、akeitworthlisteningto.Turnononeofthoseold"All-AmericanFive"table-topAMradiosifyouwantastrikingdemonstrationofjusthowbadvacuumtubeequipmentcansound.Perhapsawayofreconcilingthetwoviewpointsistoconsiderthedistinctionbetweenmusicalequipment,andreproductionequipment.Formusicalgear,theindivid
7、ualfrequency,waveformandphasedistortionsarepartofwhatdefinesthesoundof,say,aFendertubeamp.Justasno-onewouldtrytodefineafineStradivariusviolinwithspecsanddistortionfigures,soalsoitwouldbespecioustoarguethatacertaintubeguitaramphasover12%THD(totalharmonicdistortion)at35watts.Repr
