Audio Research LS27 Preamplifier

by Dennis Davis, March 30, 2011 © www.theaudiobeat.com

othingshouldbesimplerthancomparinganew versionofanexistingproducttoitspredecessor, asitmakesthe“allotherthingsbeingequal”rulechild’splaytofollow.AudioResearch’sLS27linestageisjustonedigitremovedfromtheextremelysuccessfulLS26,whichIusedinmysystemfortwoyears--untiltheReference5tookitsplace.I’mnotadversetoeasyassignmentswhenthemenuincludessomethingastastyasanAudioResearchlinestage.Acomponentthat’spureplug-in-and-play,withnotoe-inorlevelingorbreak-in,leavesonlytheexerciseoftypingthereviewasachore.WiththeLS27,everythingprecedingthosekeystrokeswaspurepleasure.

TheLS27isAudioResearch’smiddle-rangelinestage,sittingbetweenthe$3995LS17andthe$11,995Reference5.(The$24,995ReferenceAnniversaryisaspecialeditionforasmallnumberofmogulsandlotterywinners.It’ssoontogooutofproduction,solet’snotcountthataspartoftheline.)At$6995,the

LS27isaseriouscomponentthataregularaudiophilecanaspiretoowningwithoutrobbingabank.ItupdatesthecosmeticlookoftheLS26’sfrontpanel,switchingoutblackforsilverhandles(thoughtheblackarestillavailable)ThereisalsoaDarthVaderversion:blackinallbutthebuttons.TheLS27alsoreplacestheoldersquare-buttonarraywithanewsetofroundbuttons,acosmetictouchfirstseenontheReferenceAnniversary.

Underthehood,thingslookverysimilartotheLS26,untilyoureyesstraytothebackofthecircuitboardandyounoticethattheunithasbecomealmostaninchandahalfdeeper.Thisisnotsurprising,astheLS26wasalreadypackedfullofcomponents,andtheLS27’supgradedparts

requiredadditionalbreathingspace.Bulkpower-supplystoragehasbeenincreased.Anewpowertransformeralongwithnewoutputandbypasscouplingcapacitorsaccountfortheaddedrealestate.Despitethesechanges,theLS27weighsinafew

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ounceslighterthanitspredecessor.ThestatedspecificationsoftheLS27,exceptforweightanddimensions,areidenticaltothoseoftheLS26.

LiketheLS26,itsreplacementremainsapureclass-Adesignwithzerofeedback.Ithasafullyregulatedsolid-statepowersupplyandahybridJFET/tubeaudiocircuitusingtwo6H30dual-triodesintheanalogstage.AswiththeLS26,ithasthreeselectablelevelsettingsforeachinput,witharecommendationthatthehighestsettingbeusedforbestperformance.IfoundthistobetoohighforanyofthecartridgesIuse,butthelowersettingsadjustforanyphonostage/cartridgecombination.

TheLS27alsosportsachoiceofbalancedorsingleendedinputsandoutputs,withatotalofeightinputchoices.Unlikewithmostlinestages,aright-leftbalancecontrol,aphaseinversionswitch,amono/stereoswitch,andatube-hourcounterarealsoincluded.Forme,abalancecontrolisessential,andIsuspectmostaudiophilesdonothavecustom-builtlisteningroomsthatneednotweakingofright-leftbalance.

AllofthesefunctionsmaybecontrolledwiththeubiquitousAudioResearchremote.TheLS27alsoincludesaprocessorpass-throughforhome-theateruse.AudioResearchstatesthatallofthesefunctionsarecontrolledbyanewmicroprocessor,althoughIcouldnotdetectanydifferenceinapplication.Indeed,withtheexceptionofthetube-hourcounter,IcouldcontrolallotherfunctionswhetherIwasusingtheLS26,LS27orReference5remote.Thatistosaythattheyallworkedflawlesslyandintuitively.

AudioResearchlongagodispensedwithattachedpowercords,andtheLS27hasa15-ampIECinlet.Ahigh-qualitypowercordshipswiththeunitforthosenotinclinedtobuyanadd-onpowercord.

ThelinestagearrivedfromAudioResearchwithabout200hoursloggedon.Beforelisteningtoit,Iranitinanother50hoursorsousinga

burn-inCD.AudioResearchnowpacksallofitstubeelectronicswithanoticethatthedevice

continuesbreakinginuntilsomewherearoundthe600-hourmark.Isuspectthatthisvariesbyunit,withthemoreexpensivemodelsandtheirlargercapacitorsbreakinginmoreslowly.IhavelistenedtootherAudioResearchmodelsstartingfromscratchandknowthatthebiggestchangesoccurinthefirstcouplehundredhours,soIfeltconfidentthatthisunitwasgoodtogoat250hours.Aftertheadditionalbreak-intime,IlistenedtoawiderangeofmusicbeforecomparingtheLS27toitspredecessor.

udioResearchlinestagesallshareaverystrong familysonicresemblance.Theyarealsothe productsofoneoftheindustry’smostconsistenttrickle-downprograms.EachnewReferencelinestageiseventuallyfollowedbyanewversionoftheLSlinestage,withthoseadvancesfromthetopmodelscaledbackandincorporatedintothemid-levelmodel.Sothoseaudiophileswhorefrainedfrommortgagingtheirhome

duringthereal-estatebubbletospringforaReference3waitedforthereleaseoftheLS26.NowtheLS27holdsoutpromisethattheReference5advanceshavetrickleddowntoit,notchingitupneartheperformanceoftheReference3(therewasno4,asitisconsideredanunluckynumberintheFarEast).

Amongtheirconsistentstrongpoints,AudioResearchlinestageshaveanuncannyabilitytoorganizemusicalinformationintoadeep,widesoundstage,especiallywiththebestofbothstereoandmonorecordings.Thesolidityand“youarethere”qualitiesoftheinstrumentswithinthatstageareequallyremarkable,andtheyhavedonenothingbutgetbetterbothwithintheAudioResearchrangeofproductsandviewedovertimeaseachnew

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generationofaparticularmodelappears.TheLS27isnoexceptiontothisrule.Whetherit’sreproducinglarge-scaleorchestralworkssuchasStravinsky’sFirebirdonMercury[MercurySR90226]orsmall-scalejazzensembleasexemplifiedbythestunningmonoreissueofKennyDorham’sAfro-Cuban[BlueNote/MusicMattersMMBLP-1535],thepreampwillthrowaslargeandrealisticasoundstageasyourcartridgeandphonostagecanpassontoit.

It’sthesolidityandfocusofimageswithinthatsoundstage,however,thatreallyseparatetheveryexpensiveunits,withmassivepower-supplypartsandultra-spendycapacitors,frommoreaffordablelinestages.TheLS27doesnotmatchwhattheReference5achievesinthisregard,nordoesanyotherpreamplifierinthispricerange.Theverybestunitscancastextremelyconvincingthree-dimensionalimages,inthesamewaythatadjustingthedepthoffieldofinacameraviewfinderwillcausetheimageto“pop”andtakeonathree-dimensionalquality.Youcan’tmakeasgoodanimagewithacheapTokinalensasyoucanwithtopLeicaglasswork,andthesamelimitationsapplytopreamplification.AudioResearchdoesnotmakeanyTokina-levelproducts,andtheLS27islikeagoodLeicalens,butnotthefastest-apertureversionofaparticularsize.Itcanproduceverystableimageswithinthesoundstage,ifnotachievethedivineresultsthataReference5canpulltogether.However,theLS27givesyouanawfullycloseapproximationofwhatAudioResearch’smuchmoreexpensiveReferencelinestagecandoundermostcircumstances.Onless-complexrecordedmaterial,thedifferencescanbesubtleindeed.

TheLS27performedbeautifullyinthefrequencyrangeofstringinstruments.IspentagooddealoftimelisteningtothenewCoupd’ArchetsetofviolinistJohannaMartzy’srecordings,The EMI Recordings[COUP16-23],andtheLS27performedbrilliantly.ItreproducedMartzy’suniquetone,whichisonthecoolside,withoutever

soundingharsh.ItcapturedthatcoolnesswhileatthesametimeplacedenoughairaroundtheinstrumenttomaketheserefurbishedearlyEMIrecordingssoundalmostmodern.Iplayedsome

ofthismusicforafriendanddidn’ttellhimthathewaslisteningtotheLS27insteadoftheReference5.Hewasagogatthebeautyoftherecordingandgavenothoughttotheequipment.

TheLS27wasalsoaccomplishedatrevealingsmallorlargechangesinotherequipmentinthechain.ItaccuratelycapturedthedifferencesinstringsoundbetweenLyraandKoetsucartridges,andIusedittodiscernandevaluatethedifferencesbetweenVPI’sSuper

Platterandstandard-issuealuminumplatter,andthenthedifferencesbetweenthealuminumplatterbare,witharubbermatandwithapapermat.TheLS27didnotobscureinanywaythedifferencesamongthesevariations.

ItalsowasachampatreproducingthebestofRudyVan

Gelder’sBlueNoterecordings.Theearliestoftheseareinmono,andanexceptionallinestagecanpresentanalmoststereo-likeimagewithnoneofthedrawbacksofearlystereo.KennyDorham’sAfro-Cubansoundedalarminglyreal.LiketheDorham45rpmset,AcousticSounds’remakeofNatKingCole’sgreatmonoalbumAfter Midnight[CapitolRecords/AnalogueProductionsAAPP782-45]alsothrewanincrediblemonosoundstagethatlackednothingwiththeLS27.That’snottosaythatitdoesn’tshowuptheimbalancesofpoorstereo.Itcertainlydidn’tglossoverthesedetails,anditlikewisedidn’ttampthemdown,assomeless-stellarlinestagescando.

omparedtotheLS26($5995),theLS27isdefinitely amoveupthespectrum,makingthatthousand- dollarincreaseinprice,alongwiththeimprovedpowersupplyandmoreexpensiveparts,whollyjustifiable.Iexpectedtheimprovementinsoundstagingsolidity,butIwasn’tpreparedforajumpintonalqualityandbass

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definition.However,withinminutesofaside-by-sidecomparisonofthetwounits,mylisteningpanelwaslikeagroupofOlympicjudges,declaringaclearwinfortheLS27becauseoftheseimprovements.ShelbyLynne’s“JustaLittleLovin’,”fromtheCDofthatname[LostHighway1744825],madeitclearthattheLS27hadtighteneduptheLS26’sbassand

refineditshighs.IneverconsideredtheLS26lackingintheseareasuntilthiscomparison.Extendedlisteningtothetwounitsconfirmedthisfinding,butshoweditwasmorepronounced

withsomerecordings,asIcouldnotreproducethesignificantdifferenceswithmostmaterial.OnoneofmyfavoritetestLPsforthequalityoftheupperfrequencies,SalvatoreAccardo’sDiabolus In Musica[DeutscheGrammophonDGG4776492],thedifferencesbetweenthewayinwhichthetwounitsinterpretedtheviolin,cymbalsandtriangleweresubtle,confirmingthattheLS26wasnoslouchinthisdepartment.Butwithafewmoderndigitalrecordings,suchastheShelbyLynne,theimprovementsinthenewunitwereobvious.

SimilarsubtleenhancementsweredetectedinareaswheretheLS26wasalreadyquitestrong.Bothunitshaveaverylownoisefloor,andthisgivesrisetoacuteretrievaloflow-leveldetailandnotableclarity.Likethepriormodel,theLS27soundedunforcedanddeliveredannaturalentréetotheflowofrecordedmusic--anuncommonabilityforallbutafewlinestagesinthispricerange.WhileIhadthebenefitofauditioningtheLS27withamuchmoreexpensivephonostage,IsuspectthattheLS27alongwithAudioResearch’snewPH8willbeamatchmadeinheaven. oifyoucan’taffordtoinvestmoremoneyin yourhi-fisystemthanyouhavetiedupinyour Maserati,theLS27maywellbetheidealheartofasystemyoucanlivewithforthelonghaul.It’sanextremelyversatileandmusicallinestagethatissurelyonetobeatinitspricerange.AudioResearchcontinuestopullonerabbitoutofthehatafteranother.

Price:$6995

Warranty: Threeyearspartsandlabor.

AudioResearchCorporation3900AnnapolisLaneNorth,Plymouth,Minnesota55447(763)577-9700

www.audioresearch.com

Associated Equipment

Analog:VPITNT-6turntablewithrimdriveandSDSspeedcontroller,VPI12.7tonearm,LyraSkalaandTitanMonocartridges,KoetsuCoralcartridge,AudioResearchReferencePhono2phonostage.

Digital:AudioResearchReferenceCD7CDplayer.

Preamplifier: AudioResearchReference5.

Power amplifier: AudioResearchReference110.

Loudspeakers:Kharma3.2withEnigmafilterandwiringupgrade.

Interconnects:NordostValhalla.

Speaker cables:NordostFrey.

Power conditioners:QuantumQBase8andQX4.

Power cords:NordostValhalla.

Equipment rack, platforms and accessories:BillyBagsequipmentrackmodifiedwitha4”mapleplatform,StillpointsUltraisolators,StillpointsComponentStands,FurutecGTXD-RhodiumACoutlet.

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