Mercury Epiphone Valve Junior - Using a Variac and Current Meter; Importance of Variac and Current Meter; Safety Warning for Technicians

34 Epiphone Valve Jr.•Mercury Upgrade Kit
ThisprojectanditsdocumentationistheresultoftechnicalinvestigationsmadebytheengineeringstaffofMercury Magnetics.Thedisclosureoftheinformationhereinmaypertaintoproprietaryrightsand
thefurnishingofthesedocumentsdoesnotconstituteanexpresedorimpliedlicensetousesuchmaterials.
Using a Variac & Current Meter
Don’t power-up your amp without ’em!
NOTE:IFYOUARENOTAQUALIFIEDAMPTECH,DONOTATTEMPTTOPOWERUPYOUR
MODIFIEDAMPLIFER,YET.INSTEAD,MercuryRECOMMENDSTHATITBEINSPECTEDBYA
QUALIFIEDTECHNICIAN.ANAMPTECHWILLGOOVERYOURWORKANDVERIFYTHATITIS
SAFETOPOWERITUP.
Aftermodifyingyouramp,thenextstepistopoweritupusingavariacandcurrentmeter.
TheVariacandcurrentmeterallowsyoutoslowlyaddvoltagewhilecheckingtheindicatorstomakesure
thatyourhandiworkiscorrect.Withoutavariacyouruntheextremeriskoffryingyouramporsomeofits
components,gettinghurt,electrocuted,etc.
AVariacisastandardamptechtool.Noamptechshouldbewithoutone.Theyareavailablefrommany
electronicstoresoronline,eBay,etc.Pricesstartatabout$50andgoupfromthere.Thebetterunits(such
astheTenmaisolatedvariableACpowersupplyshowninthesephotos)includeoutputcurrentmetering.
ConsiderthatthecostofaVariacisfree,becauseasingleerrorwithoutonecaneasilycostmorethanthe
Variacitself!
Asthefollowinginstructionsshow,you’llneedtomonitortheoutputcurrentwhileincreasingpowertothe
ampwiththeVariac.IfyourVariacdoesn’thaveaself-containedcurrentmeterthiscanalsobedonewitha
separateamperesmeterconnectedtothefuse-holderoftheamp(withthefuseremoved).
SpecicinstructionsforhowtouseVariacsandcurrentmetersarebeyondthescopeofthismanual.Check
theweborownermanualsofthedevicesforspecicmethods.
BE FOREWARNED!
IF YOU BYPASS THIS STEP
THERE IS A VERY REAL
POSSIBILITY THAT YOU WILL
CAUSE DAMAGE TO THE AMP
AND/OR SERIOUS HARM TO
YOURSELF!