VAC Phi 110/110 Setup guide

F 220
F 110/110
TheVAC
PhiTwoTwenty
MonophonicBeam
PowerAmplifier
&
Phi110/110 Stereo
Beam PowerAmplifier
Operation&MaintenanceInformation
ValveAmplificationCompany
Manualissued01/24/2004
Revised07/02/2004

PLEASEREADCAREFULLY
YourPhiBeamPower amplifier isfittedwith auniqueoutput tubemonitoringcircuit.Rather than
directly contactingtheaudiopath,andthuscontaminatingthepure sound, thetemperature ofa
small cathoderesistanceissensed.Thefourbi-colorLED’s onthefront panel indicatethetubes’
conditions.
Iftheidle current ofaKT88 output tubedrops belownominallimits,theLEDcorrespondingtothat
tubewill light green. Thisindicatesthateither thebias settingforthattubeshouldbeadjusted, or
thetubeshouldbereplacedatyourconvenience,but itissafetocontinueoperatingtheamplifier.
Theexactidle current ofeachtubemaybetestedbymeansofthemeter andthetestswitches
locatedonthefront panel.Theassociatedbias controlshouldbeadjustedsothattheneedle
pointsdirectly atthedotinthecenter ofthemeter.Whennotestswitchisselected,themeter
indicatestheincoming ac voltage(wall voltage).
Note:TheseLED’s will alsobegreenwhentheamplifier isfirstswitchedon,andwill extinguishwhen
thebias resistorshavereachedfull operatingtemperature after approximately 30 minutes.The
thresholdbetweengreenandnoilluminationisnotprecise;donotbeoverly concernedifsome
positionstakelonger toextinguish.Theconditionofindividualtubesmaybecheckedwith thebuilt
inmeter.
Note:astrong air current couldcausethelightstoremaingreeneveninnormaloperation.
Intheevent thatanyoutput tubedrawexcessiveidle current (a“run away” tubeoratubenot
biasedcorrectly),thehighvoltagesupply intheamplifier will shut downautomatically andtheLED
correspondingtotheproblematicKT88 tubewill indicatered.Theredlight will stayonuntil the
power switchisturnedoff. Thistubemustbereplaced.(Note:TheLED’s fortheother tubeswill
showgreenafter afewminutes...thisshouldbedisregarded.)
Tominimize difficulties, alwayssourcegenuineVAC TestedaudiotubesforyourPhi.

1
CAUTION
THEAMPLIFIERANDPOWERSUPPLY CONTAINNOUSERSERVICEABLEPARTS.DONOT REMOVETHE
BOTTOM PLATESORCHASSISCOVERS.LETHALVOLTAGESAREPRESENTWITHINTHECHASSIS.DO
NOT OPERATETHEUNITSIFTHEYAREWET.
VACUUMTUBESBECOME HOT ENOUGHTO CAUSESERIOUSBURNS.NEVERTOUCH ATUBEWHEN
THEUNITISON.ITMAYTAKESEVERALMINUTESFORTHETUBESTO COOLDOWN AFTERTHEUNIT
ISSWITCHEDOFF.ITISSTRONGLY RECOMMENDEDTHATTHETUBECOVERSBELEFTINPLACEATALL
TIMES.
THETUBECOVERSWILL BECOMEHOT INNORMALOPERATION.DONOT SETORSPRAYANYTHING
ONTHEM.
THEAMPLIFIERANDPOWERSUPPLY ARE HEAVY.ITISADVISABLETO HAVEASSISTANCEIN
UNPACKING,MOVING,ANDSETTINGUP.BESURETO USEPROPERLIFTINGTECHNIQUESTO AVOID
BACKSTRAINANDINJURY.BECERTAINTO INSTALL ITINASECURELOCATIONFROM WHICH ITCAN
NOT FALL OR TIPOVER.
INDEX
Introduction
Unpacking &Assembly
Installation
Input connectors
Operation
Feedback
Triode&Ultra-LinearModes
IlluminatedLogo
Installing NewOutput Tubes
Biasing &Checking Output TubeCondition
Replacement ofLowLevel Tubes
Care OfChassis
Tips andAdvice
AWordAbout TubesinGeneral
Output Tubes
LowLevel Tubes
ImpedanceMatching
Grounding
Tuning YourSystem
Specifications
Footnotes
Warranty&RegistrationForm

2
INTRODUCTION
ThePhiBeam Power amplifiersare uniquepower amplifiers, andthemostpower anddetailedin
VAC’s history.Excellent linearityisachievedwithout resortingtoloopnegativefeedback,foramore
natural, dimensionalsound.
AtotaloffourKT88 are usedinClass A1.Uniquely,eachisprovidedwith aseparateDCheater
supply toensure thatnoundesirable couplingsoccur;only theintendedidealsignalpath exists.
Theinput circuitry ofthePhiisderivativeoftheuniqueWilliamsoncircuit,whichprovidespure,
directcoupled,inherently balancedinput amplificationandphasesplitting. Type6SN7/5692 octal
twintriodesdothehonors.
TwosuperbVACoutput transformer,interconnectedinawaythatallowshighpower tobe
deliveredwith thesonicpurityoflowpower devices,providesuperbvoltage/current translation,
allowing impedancesfrom eight ohmstoas lowas oneohm tobedriven.
Themainchassisismachinedfromthickaluminum. Theseparatepower supply allowse.m.f.fields,
switchingtransients,andmechanicalvibrationtobeisolatedfromtheaudiocircuits.Thehigh
voltagesupply utilizesdualchokepifiltering forextremely lownoise.
ThePhiBeamPower amplifiersare designednottothelatestfadbut tosubstance,forthehighest
possible soundquality. Timespent familiarizing yourselfwith thismanualwill bewell rewarded.

3
UNPACKING&ASSEMBLY
Thevacuumtubesandglass coversare packedindividually toprevent damage,andmustbefitted
totheamplifier before installationcanproceed.
Removethefourscrewsthatsecure thealuminumtopframetothechassis
pillarsusing thetoolprovided. Turncounterclockwisetoremove.
Wearthesuppliedcottonglovestominimize thechanceoffingerprinting
thenickel platedchassis. Wipeanyoilsoff immediately.
Takecare toprevent thetoolfrom scratching thechassis.
Removethetopframe.
Fromeachofthefourcolumnsremovethetape,whichpreventedthe
nylonsetscrewsfrom coming looseduring shipment.
Slidethesideandrearglass platesintothepillars’ channels.
Notethattherearglass isslightly wider thanthesideglasses.
Theglass willnotgoall thewaytothechassistop,but has agapatthe
bottom forair flow.
Takecare nottoscratchorbreaktheglass.

4
Thefront glass has theetchedVAC logo. Install thisbetweenthefront pillars.
Takegreatcare nottoscratchthisglass.
Thefront glass fitsintoasmall channel inthefront plate.
Tightenthewhitenylonsetscrewsthatsecure therearglass andside
glasses. Turnclockwisetotighten.
There are foursetscrewsforeachglass plate.
Donottightenthesetscrewsforthefront glass yet.
Install thesix aluminum blocksatthetopoftherearglass andsideglasses.
Ifthere isa‘dimple’intheblock,itshouldfacetheoutsideoftheamplifier.
Tightenthemetalsetscrewsthatsecure eachblockusingtheallenkey
supplied. Turnclockwisetotighten.
Replacethealuminum topframe.
Ensure thatthefront glass fitsintothegrooveinthetopframe.
Ensure thatthetopframesitsflushinthepillars.
Replacethefourscrewsthatsecure thetopframe.Turnclockwiseto
tighten.
(Note:photodoesnotshowthetubesorglass,whichshouldbeinstalled
bythistime.)

5
Tightenthefourwhitenylonsetscrewsthatsecure thefront glass usingthe
toolprovided. Turnclockwisetotighten.
Donotover tighten.
Install thevacuum tubes.
Eachtubeoritsboxhas a“V”number,whichcorresponds tothelabelsonthetopplateofthe
amplifier;theseindicatewhere eachtubeshouldbeinstalled.
Fiteachtubeintothematchingsocket,first removing anysticker fromtheamplifier and/orthetube.
Wheninserting andremoving tubes, handle them bytheir bases, notbytheir glass bulbs.
Notethatthere isalocatorpinontheoctal(eight contact)tubesthatindicatesproper alignment.
Forthe300Btubes,twoofthepinsare oflargerdiameter,sothatthetubewill only fitintothe
socketoneway.
Setthebeveledglass topintothealuminumtopframe,orientedsothatthe
twoholesare ontheleft andright side.
Toprepare aPhiforshipment, followthesesteps inreverseorder.
Whenlooseningthemetalandnylonsetscrews, becarefulnottobackthem all ofthewayout of
theholes!Ifametalscrewfallsintotheamplifier, contactVAC forservicedirections.
NOTE:Donotremoveandconnectinput cablesorspeaker cableswhile isamplifier isrunning.
Doing sorisksdamagetoyourloudspeakersortheamplifier.
Donotoperatetheamplifier without aloudspeaker orloadresistorattached.

6
INSTALLATION
01)Attachthecordfromthepower supply totheamplifier andscrewtheconnectorcollar
downfully;thistakesmanyturns.
02)Connectthespeaker cables;theblackleadgoesto“-“or“Ground”.Theredleadgoesto
“+” or“Positive”.Thespeaker impedanceselectorswitchshouldbesettomatchyour
loudspeakers.
03)Settheinput typeswitchtoXLR (andRCAisolated)orRCAdirect. Note:theRCA-isolated
setting oftenproducesless noiseandbetter soundthantheRCA-directinput byquelling
hum and/orbuzz duetosystem groundloops.
04)Fortraditionalstandaloneoperation, setthe12 volttrigger switch
to“manual”.Tousea12 volttrigger tocontrolpower on/power
off,settheswitchto“automatic”.Alsoselect“automatic”when
connectingtotheiVACdatabuss ofthePhi2.0Master Control
Preamplifier.
05)Provideadequateventilation-allowatleast3inchesaboveandtoeachside.
06)Donotplaceinacompletely enclosedcabinet.Donotstackother equipment ontopof
theVAC unit.
07)Donotoperateoncarpetoranyother surfacethatmight blockair flow.
08)Thechassisandglass will becomehotinnormaluse.
09)Donotallowthechassistotouchanymetalparts,suchas theframeofanequipment rack.
Thismight createaparallel groundpath thatcoulddegradethesoundofyoursystem.
10)Connectthepower supply tothepower sourceindicatedonthevoltageselectorcard
(visible bythemainfuse),either 100,120,220,or240 voltsAC. Thevoltagemaybeselect
bymeansoftheremovable selectorcardlocatedbehindthefuseinthepower connectors.
Removethecards andreinstall sothatthedesiredvoltagemayberead;becertainto
changethefusetothecorrectvalue.
11)Avoidpower conditionersthatfloatthegroundpin.
12)Power requirementsare approximately 500 wattsper channel.Paycloseattentiontopower
quality, andbeaware thatdifferent power cords canalter thesound.
13) Checkthebias settingsoftheoutput tubeswhentheunitisfirstinstalled andwhenever
atubeischanged.Itisalsoagoodideatoverifythesettingsperiodically, suchas oncea
week.

7
INPUTCONNECTORS
XLRconnection,balancedorsingle-ended,are madetotheXLRjackonthe
rearpanel.
TheINPUTSELECTtoggle switchissettotheBALANCEDposition.
TheXLR connectionfollowstheEIA“pin2hot”polarityconvention.
RCA(single ended)connectionnormally ismadetotheRCAjackontherear
panel. Thisisthe“directin”mode.
TheINPUTSELECTswitchissetto“RCA”
Inmanysystemsalower noisefloorandbetter soundisachievedwith RCA
single-endedsourcesbyusingtheXLRinput viathelower RCAjackandthe
switchsettoBALANCEDposition.
Note:thephotoshowsanearlier versionthatrequiredanRCAtoXLR
adapter. Later unitshaveboth anXLR connectorandalower RCAjack.
Thebalancedinput alsohas aswitchthatallowspin1tofloatorbeconnectedtothechassis.Set
thisswitchforbestsound/lowestnoiseinyoursystem.
NOTE:Donotremoveandconnectinput cablesorspeaker cableswhile isamplifier isrunning.
Doing sorisksdamagetoyourloudspeakersortheamplifier.
Donotoperatetheamplifier without aloudspeaker orloadresistorattached.

8
OPERATION
Bytimedelay, soundwill beginapproximately 60 seconds after turnon.
Aswith all highfidelityproducts,thesoundcharacteristicoftheVACchangessomewhatas itwarms
up. Bestsoundwill beachievedafter about onehourofoperation.Weadviseagainstleavingthe
equipment onatall timesforsafetyreasons(see SafetyNoticeatthefront ofthismanual),and
becauseoftheattendant accelerationofoutput tubewearandpower consumption. Lifeofthe
output tubesaverages5,000 to10,000 hours.
AnytimethattheVACPower Amplifier has notbeenusedforafewweeksthesoundmaybe
different.Thisisalsonormalforhighresolutionaudioequipment.Optimumsoundshouldreturn
after afewhoursofoperation, preferably with anaudiosignal. Refer tothediscussionofbreakin
containedintheINTRODUCTIONsectionofthismanualforfurther information.
PleasenotethatalthoughyourVAC System has beenrun for48 hoursatthefactory, thebreak-in
timeofhighresolutionaudioequipment isinfuriatingly long. ThePhisoundwill continuetoseason
forapproximately 200 hours.Theearly soundoftheamplifier will beless extended,dynamic,and
coherent.Thenthesoundwill improvenoticeably,followedbyaperiodofdarker sound,finally
giving waytothedesiredmusicality. Patienceisavirtue.
Alsobeaware thatmanycomponentsdisplaytheneedforanewbreakinperiodafter being
transportedinunheatedcargoaircraft.
ILLUMINATEDLOGO
Theilluminationlevel ofthefront VAClogowill changewith ambient light levels,dimmingas room
light dims, andbrightening as room light brightens.
WhenthePhiamplifier isconnectedtoaVACpreamplifier equippedwith theiVACdatabuss,light
level iscontrolledbythepreamplifier.Thisfeature causesall oftheVACcomponentstotracklight
together.InthecaseofPhiamplifiers, thisensuresthatall lookidenticalregardless ofbrighter and
dimmer spotsintheroom.
Whenusedalone, eachPhiamplifier setsitsownlogointensityindependently.

9
FEEDBACK
Your Phiisequipped withvariablenegativefeedback,controlled byatoggleswitchonthe rearpanel.
The switchhastwo positions:zero feedback,and12 dBofoverall negativefeedback.
Withmanyloudspeakers,the bestoverall soundwill beattainedwithzero feedback.
Somespeakers havesignificantvariations ofimpedancewithfrequency;suchspeakers maysoundbetter
when feedbackisselected.
Thinkoffeedbackasbeinglikeaspice,and“seasontotaste.” Auditionyour systembothways,andselect
the settingthat provides the bestoverall soundquality.
When feedbackisused,the amplifier will evidenceless gain,less noise,lower measured distortion,anda
lower sourceimpedance.
Keep inmindthat the humanear/brainauditorysystemworksverydifferently thantestgear,eachtendingto
measure differentthings.Asaresult, there isnotauniformcorrelationbetween measurementsandsound
quality.
TRIODE&ULTRA-LINEAR MODES
Triodeamplificationistheoldestformofamplificationknown,while partialtriode("ultra-linear")
operationofpentodesandbeampower tubesdatesbackto1937.Both modesofoperationare
available with yourVAC Phiamplifier viaasingle switchonthetopplate.
Althoughthemodemaybechangedwith theamplifier inoperation,westrongly suggestthatyou
turnonly operatetheswitchwhentheamplifier isoff andthetubeshavecooleddown [VACUUM
TUBESBECOME HOT ENOUGHTO CAUSESERIOUSBURNS.NEVERTOUCH ATUBEWHENTHEUNIT
ISON.ITMAYTAKESEVERALMINUTESFORTHETUBESTO COOLDOWN AFTERTHEUNITIS
SWITCHEDOFF.] Turntheswitchtothepositionindicated, thenpower theunitupandlisten.
Less power isavailable inthefull triodemode,but distortionbefore clippingmaybereduced,as
isoutput sourceimpedance. Experiencerevealsthatthetriodemodewill soundsomewhatlean
onsomesystemsandbetter definedonothers. Inmanywaysthisisanissueofsystem matching,
anduniversalrecommendationsdonotexist.Listentoboth,andselectthemodemostpleasingin
yoursystem.
Notethatthebias current will typically readslightly lower inthetriodemodethanintheultra-linear
mode.Simply followtheBIAS procedure ifnecessary torestore thecorrectreadingforeachtube.

10
INSTALLINGNEWOUTPUTTUBES
Output tubesare typeKT88.Replacement output tubesshouldbepurchasedfromVAC. Itis
important thatthetubesbecheckedforanytendencytomechanicalorelectricalshorts(see Safety
Noticeatthefront ofthismanual).Itisdesirable thattubesbeinmatchedquartetsforeachchannel,
andbeclosetothe"bogey"valuesforthemajorparameters.Makecertainthateachtubefitsfirmly
initssocket.
ALL POWERMUSTBEOFF.Removethetopglass andtheoldtubesafter they havecooleddown
(THECOVERBECOMESQUITEHOT INNORMALUSE;TUBESBECOMEHOT ENOUGHTO CAUSE
SERIOUSBURNSWHENINOPERATIONANDMAYTAKESEVERALMINUTESTO COOLDOWN).Install
thenewtubesfirmly andfully inthesockets,observingthatthetubewill only fitintothesocketin
oneorientation,determinedbytheplastic“keyway” inthecenter ofthebase.Donotuseexcessive
force. Replacethetopglass cover before operating theamplifier.
Whenever atubeischanged, thebias settingsmustbecheckedandadjusted.
Aslight violetglowinthetubeisnotcauseforconcern.Ifatanytimetheplate(theoutermostmetal
structure) oftheoutput tubesbeginstoglowbright orangeorredSWITCH OFF IMMEDIATELY.The
redglowindicatesthatthetubeis"runningaway",beingdestroyedbyconductingexcessive
current. Tubesmayrun awayforseveralreasons:
1)Thetubeisnotfully insertedinthesocket.
2)Thetubefitsloosely inthesocketandthuscannotmakecorrectcontact.Suchatubeis
unusable.
3)Thetubeisdefective.
Intheevent thattrouble isencounteredcheckconnectionsand/ortry another tube.Stopifthe
problem persistsandconsultwith yourdealer orVAC.
Forfurther information,refer toTips &Advice:TubesinGeneralandTips &Advice:Output Tubes.

11
CHECKINGOUTPUTTUBECONDITION
Asdescribedatthebeginningofthismanual,thePhiisequippedwith theKT88 Sentry circuit,
whichcontinuously monitorseachoutput tubetoensure thatitisoperatingwithinnormallimits.
Eachtubehas acorresponding indicatorlight onthefront panel.
Agreenindicatorlight will beseenas theamplifier warmsup,orwhenatube’s idle current isless
thannormal.Itissafetouseyouramplifier under theseconditions,but thetubeshouldbereplaced
atyourconvenience.Thethresholdbetweengreenandnoilluminationisnotprecise;donotbe
overly concernedifsomepositionstakelonger toextinguish.Theconditionofindividualtubesmay
becheckedwith thebuiltinmeter.
Byoperatingthetestswitchesbelowthelight,themeter will displaytheexactidle current inthe
tube-thisisusedinsettingthebias.Becertaintostopthemusicbefore makingthereading.
Typically,themeter will indicatenearthedotatthecenter ofthescale.Alower indicationwill also
beobservedifyourpower voltageislow.
Ifastrongair current isblowingontheamplifier,itispossible thatatubewithinthenormalcurrent
rangewill still displaythegreenindicatorlight.
Ifatubedrawsexcessivecurrent,theindicatorlight will turnredandthehighvoltagesupply will
shut down. Thistubeshouldbereplacedbefore using theamplifier.
Pleasenotethatoperatingtheamplifier without adequateventilationwill causetheredindicator
lightstocomeonandtheamplifier toshut off.Operatingtheamplifier onathickcarpetwill cause
this, andisnotsafe.
Output TubeBias Adjustment:
Bias settingsitshouldbecheckedwhenyouinstall youramplifier andapproximately onceevery
month thereafter. Itmustalsobeadjustedeachtimeatubeisreplaced.
Allowtheamplifier toreachnormaloperatingtemperature (about tenminutesofwarmupshould
besufficient).Mutethepreamplifier andutilize thetwotoggle testswitchesonthefront panel.Push
thefirsttoggle switchupandobservethebias meter.Usingasmall flatbladedscrewdriver,rotate
thecontroldirectly abovetheswitchuntil theneedle iscenteredonthesmall blackdotnearthe
topofthemeter. Thenpushthattoggle switchdown,andadjustthecontrolbelowthetoggle.
Repeatforthesecondtoggle, andthen, becausetheadjustmentscaninteractslightly,recheckall
fourtubes, starting onceagainwith firsttoggle.

12
REPLACEMENTOFLOWLEVELTUBES
All power mustbeswitchedoff.Allowtubestocooldown.Removethetopglass cover.Remove
andreplacewith newtubesoftheappropriatetypes,notingthelocationofholesinthesocketand
pinsofthetubes. Replacetheglass cover before operating theamplifier.
Replacement tubesare available from VAC andother sources.
Forfurther information,refer toTips &Advice:AWordAbout TubesinGeneralandTips &Advice:
AWordAbout LowLevel Tubes.
CAREOFCHASSIS
VAC chassisare machinedaluminum forsuperiorelectromagneticperformance.Themainchassis
isfinishedinnickel plating, whichiskeptwaxedtoprevent oxidation, staining, ordiscolorationof
thenickel. Thepower supply chassisisfinishedindurable texturedgloss paint. Cleaning theunits
with adampcloth WHILETHEAMPISSWITCHEDOFF ANDUNPLUGGEDshouldsuffice.Donotget
cleaningsolutionsontoorintothetubesockets.Alight coatofwaxshouldbeappliedperiodically
tothenickel surfaces, taking care thattheamplifier iscoolandunplugged.

13
TIPS&ADVICESECTION
AWordAbout TubesinGeneral
Itistruethateachbrandoftubesounds different inaparticularhighresolutioncircuit.Thisis
becausenotwomanufacturersmakeatubetypeinquitethesameway,andthecentraltendencies
oftheperformanceparameterswill differ slightly with eachmaker.Toemphasize thepoint,examine
theplatestructure ofanytwo6SN7fromdifferent manufacturerswill probably findthatthey may
noteventhesameshapeandsize.(Becarefulhere, as oftenatubeismadebyafirmother than
indicatedonitslabel.Intheheydayoftubesitwas commontocrossbrandbetweenmajorlabels,
suchas GEandRCA.Todaymanylabelsdonotmanufacture their tubesatall,includingGoldAero
andRAM.)
Thissonicvariabilitymayatfirstseemaliability,but further thought will revealthatitisanadvantage,
justliketheabilitytoadjustVTAonatonearm. Theowner ofatubeamplifier canselectthosetubes
whichsoundliketherealthinginhis/her specificsystem. Ofcourse,ifthemanufacturer youprefer
israre youmaywant topurchaseafewspare tubesforthefuture.
Howlongshouldtubeslast?Ithas longbeenknowninprofessionalcircles(andprobably now
forgotten)thatatubesuchas the12AX7will displaybetter performancecharacteristicsafter two
years ofcontinual operationthanwhenitwas new. Innormaluseitisnotunusualforalowlevel
tubetolast5yearsorlonger.Output tubesare another story,as they are continually providing
significant amountsofcurrent.Here thesoundisyourbestguide.Certainly atubeshouldbe
replacedwhenitsemissionissignificantly downoritstransconductanceissubstantially out of
specification. Innormaluse, output tubeswill lastatleast2yearsandperhaps more than5years.
Itisnormaltosee aslight violetglowinapower tubesuchas a300B orEL34.However,avivid
violetindicatesexcess current flowthroughthetubeandshouldbeinvestigated.
VAC cantesttubesforconcernedcustomers.

14
Tips:Output Tubes
YourVACAmplifier usestheKT88 kinkless tetrode.Itisstrongly recommendedthatreplacement
tubesbepurchasedonly fromVAC. If,however,youwant tocustomize thesoundtoyourtastes,
beaware thatas with interconnectsandspeaker cables, eachtubemanufacturer'sKT88 tends to
haveadistinctsound, as well as itsownreliabilityprofile.
Tips:LowLevel Tubes
TheVoltageAmplifier/PhaseSplitter anddriver tubesinthePhiisthe6SN7mediummuoctaltwin
triode.Youramplifier isfittedwith thecurrent productionVACTested6SN7fromChina,whichwe
findsuperiortotheNOStypeswehavetried. There are dozensofversionsofthistubeavailable
innewoldstock(NOS) fromavarietyofsources.Itwouldbeimpossible tocharacterize themall.
Other equivalent typenumbersare 5692, 13D2, B65, ECC32, QA2408, QB65, andCV1988.
TubesV1andV2shouldbetransconductancematched,andtubesV3andV4shouldbe
transconductancematched;thisminimizesdistortion.
Westrongly recommendobtaining tubesas setsfrom VAC.

15
Tips:ImpedanceMatching
Westrongly suggestthatyouexperiment with thethree available impedanceconnectionsforthe
bestsonicmatchwith yoursystem. Sincenoloudspeaker representsanunchangingimpedanceat
all frequencies,itisimpossible toassertwith certaintywhichoutput tapisappropriatetouse.In
manysystemsanamazing differenceinsoundwill existbetweenthevariousimpedancetaps.
Theavailable connectionsonyourPhiare:
Labeled Usewith speakersof
8ohms4to8ohms
4ohms2to4ohms
2ohms1to2ohms(Phi220 only)
Sincetheimpedanceofmostloudspeakersvary over awiderangeexperimentationisessential.
Mostspeakershavearatedimpedanceof4or8ohms.Werecommendstartingwith the8ohm
connection; after youknowthesoundifthatconnection, try the4ohm connection. Choosethe
connectionthatsounds besttoyourears.
Ifyoubi-wire yoursystem(run separatespeaker leads fromtheamplifier tothehighandlow
frequencytransducers)youmaydiscover thattwodifferent impedancetaps workbest.
Contrary topopularmisconception, nopower islostduetounusedoutput taps.
Formore informationconsultVAC TechnicalMonograph90-9.

16
Tips:AudioGrounding
Systemsincorporatingsingle-endedinterconnectcables(“RCAcables”) are pronetoaproblem
knownas “groundlooping”,whichcanresultinextraneoushumsandbuzzesaudible throughthe
loudspeaker.Ifthisoccursinyoursystem, youhavetwooptions:1) toworktominimize theground
loop, or2) usethebalancedinput viathesuppliedadapter tobreakthegroundloop.
Tominimize thebuzz using thenormalRCAinput jack, there are severalsteps youcantake:
1)Usetheshortestinterconnectspossible.
2)Useinterconnectswith goodshielding properties.
3)Keepthetwoamplifiersandtheir cablesas closetogether as possible.
4)UsethesameAC outletforboth channels.
5)KeeptheAC cords awayfrom theaudiocables.
6)Keepthepower supply chassisawayfrom audiochassisandaudiocables.
7)Try different groundsettingsonyourpreamplifier,ifithas them. Forexample,theVAC
Signature,Phi,andRenaissancepreamplifiersmaybesetto“ungrounded”or“XLR”audio
modes.
8)Theuseofcheater plugsisnotrecommendedandposesas safetyhazard.
Thesimplestapproachistorun theRCAcable intothebalancedXLRjackviathesuppliedadapter.
Thebalancedinput isbufferedbyawidebandtransformer,andeffectively breaksgroundloops
inmostsystems.

17
SPECIFICATIONS
TheVACPhihas beendevelopedwith thecriticalearas themajorarbiter ofquality,withboth
conventionalanduniquemeasurementsproviding insight andguidanceas necessary.Thelackof
emphasisonmeasurementsisduetothefactthatengineering'sarsenalofequipment and
techniquesdonotoperateonthepatternrecognitionprincipalsthatcontrolhumanperceptionof
sound.
Intheimmortalwords ofDaniel vonRecklinghausen,ifitmeasuresgoodandsounds bad,itisbad.
Ifitmeasuresbadandsounds good, you'vemeasuredthewrong things.
Forthoseconcernedwith testbenchperformance,thefollowingdescribestypicalmeasured
performanceofthePhi220 whenoperatedat120 VAC, 60 Hz.
Power Output:220 wattscontinuousaveragepower at1kHzwith less than2%THDinto
4ohmsconnectedtothe8ohm tap.
FrequencyResponse:down0.5dB at7Hzand30 kHz, ref0dB =1watt @1kHz.
down3.0dB at3.5Hzand115 kHz, ref0dB =1watt @1kHz.
AbsolutePolarity:Doesnotinvertabsolutephase.

WARRANTY
Your equipmentiswarranted for aperiod ofthirty(30) daysfromthe dateofpurchase.In addition,ifthe
registrationformisreceived byVACalongwithacopyofyour sales receiptfromanauthorized VACdealer
withinthisthirtydays,aservicecontractwill beextended tocover your equipmentfor three (3)years (tubes
excepted). Thiswarrantyapplies only tounitssoldinthe United States ofAmericathroughauthorized VAC
dealers.Itcovers factoryserviceandstandard return shipping. For warrantyinformationoutside ofthe U.S.
contactthe importer ofVACequipmentfor your country.Unitssoldoutside ofthe U.S.shouldstill be
registered withVAC.
Your questions andcommentsare alwayswelcome.Contact:
ValveAmplificationCompany
1911 EastAvenue North
Sarasota, FL34234
Telephone [phone]Fax[phone]
[e-mail]
_____________________________ Detachandmail totheaddress aboveassoonaspossible. ____________________________
Phi110/110 &220 RegistrationForm
Name________________________________________________________________________
Address________________________________________________________________________
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Telephone_______/_______-_____________e-mail __________________________________
Dealer name________________________________City____________________________________
Salesperson___________________ Purchase date____________SerialNumber ________________
How didyoufirstlearn ofVACproducts?____________________________________________________
What other brands/modelsdidyouconsider?_________________________________________________
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What made youdecide onthe VAC?_______________________________________________________
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What else wouldyoulikeus toknow?_______________________________________________________
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Optional:
What magazines do youreadregularly?________________________________________________________
What are your hobbies (besides fillinginwarrantycards)?_______________________________________
What are your favoritetypes ofmusic? ______________________________________________________
_____________________________________________________________________________________
On what format?(CD,LP,DVD,SACD,MP3,etc.) ______________________________________________