Audio Research LS27 Preamplifier by Dennis Davis, March 30, 2011 © www.theaudiobeat.com othing should be simpler than comparing a new version of an existing product to its predecessor, as it makes the “all other things being equal” rule child’s play to follow.Audio Research’s LS27 line stage is just one digit removed from the extremely successfulLS26, which I used in my system for two years -- until the Reference 5 took its place. I’m not adverse to easy assignments when the menu includes something as tasty as an Audio Research line stage. A component that’s pure plug-in-and-play, with no toe-in or leveling or break-in, leaves only the exercise of typing the review as a chore. With the LS27, everything preceding those keystrokes was pure pleasure. The LS27 is Audio Research’s middle-range line stage, sitting between the $3995 LS17 and the $11,995 Reference 5. (The $24,995 Reference Anniversary is a special edition for a small number of moguls and lottery winners. It’s soon to go out of production, so let’s not count that as part of the line.) At $6995, the LS27 is a serious component that a regular audiophile can aspire to owning without robbing a bank. It updates the cosmetic look of the LS26’s front panel, switching out black for silver handles (though the black are still available) There is also a DarthVader version: black in all but the buttons. The LS27 also replaces the older square- button array with a new set of round buttons, a cosmetic touch first seen on the Reference Anniversary. Under the hood, things look very similar to the LS26, until your eyes stray to the back of the circuit board and you notice that the unit has become almost an inch and a half deeper. This is not surprising, as the LS26 was already packed full of components, and the LS27’s upgraded parts required additional breathing space. Bulk power-supply storage has been increased. A new power transformer along with new output and bypass coupling capacitors account for the added real estate. Despite these changes, the LS27 weighs in a few 1 N
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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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