Mesa/Boogie Mini Rectifier Twenty-Five

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IMPEDANCE
Wiringupspeakerstoprovidethemosteffectiveloadandmakingsurethatallofthemareinphasewillhelp
increatingthebestsoundpossible.Thisisnottoodifficult,aslongasyouunderstandafewthingsaboutloadingandhowto
connectyourspeakerstoprovideanoptimalresistiveload.
MESA/Boogieamplifierscanhandle4and8ohmseffectively.Neverrunbelow4ohmsinatubeamplifierunlessyouare
absolutelycertainthatthesystemcanhandleitproperly;thiscancausedamagetotheOutputtransformer.Afewamplifiers
canhandle2ohmseffectivelywithoutdamagingthem(forexampletheMESA’sBass400+).Youcanalwayshaveahigher
resistance(16ohms,forexample)withoutdamagingresults,buttoolowofaresistancewilllikelycauseproblems.
MIS-MATCHING:
Whenrunningahigherresistance(forexample:8ohmoutputinto16ohmcabinet),aslightlydifferent
feelandresponsewillbeeminent.Aslightmismatchcanprovideadarkersmoothertonewithalittlelessoutputandattack.
Thisresponseisaresultoftheamplifierrunningabitcooler.Sometimeswhenusingmorethanonecabinetamismatchwill
betheonlyoption.
WHAT IS MY CABINET’S IMPEDANCE?
Ifyouhaveonlyasinglespeaker,youjustmatchthatsinglespeakersimpedance
totheamplifier,andyouaredone.Inmanycases,youwillhaveanumberofspeakers,andthenyoumustcalculatethe“load”
thattheamplifierwillneedtosupport.Therearegenerallythreewaystowiremultiplespeakerstogether.Theyareasfollows:
SERIES:
Whenyouwire(hook-up)speakersinSeries,thespeakersresistance(asmeasuredinohms)isadditive-i.e.
puttingtwo8ohmspeakersinSeriesresultsina16ohmload.
Speaker A = 8 Ohms
Speaker B = 8 Ohms
SERIES:
Connect the Negative side of Speaker A
to the Positive side of Speaker B
POSITIVE =
NEGATIVE =
B
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SPEAKER IMPEDANCE MATCHING & HOOK-UP GUIDE: