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.