Important.information.about.tubes.and.tube.products - Blackheart BH1H Killer Ant User Manual

Important Information about Tubes and Tube Products:
The Nature Of Tubes — Why (And When) To Replace Them:
Tubes.are.made.up.of.a.number.of.fragile.mechanical.components.that.are.vacuum-sealed.in.a.
glass.envelope.or.bubble..The.tube's.longevity.is.based.on.a.number.of.factors.which.include.
how.hard.and.often.the.amplifier.is.played,.vibration.from.the.speakers,.road.travel,.repeated.
set.up.and.tear.down,.etc.
Any.time.you.notice.a.change.in.your.amplifier's.performance,.check.the.tubes.first.
If.it's.been.a.while.since.the.tubes.were.replaced.and.the.sound.from.your.amplifier.lacks.
punch,.fades.in.and.out,.loses.highs.or.lows.or.produces.unusual.sounds,.the.power.tubes.
probably.need.to.be.replaced..If.your.amplifier.squeals,.makes.noise,.loses.gain,.starts.to.
hum,.lacks."sensitivity",.or.feels.as.if.it.is.working.against.you,.the.preamplifier.tubes.may.
need.to.be.replaced.
The.power.tubes.are.subjected.to.considerably.more.stress.than.the.preamplifier.tubes..
Consequently,.they.almost.always.fail/degrade.first..If.deteriorating.power.tubes.aren't.
replaced.they.will.ultimately.fail..Depending.on.the.failure.mode,.they.may.even.cause.severe.
damage.to.the.audio.output.transformer.and/or.other.components.in.the.amplifier..Replacing.
the.tubes.before.they.fail.completely.has.the.potential.to.save.you.time,.money.and.unwanted.
trouble..Since.power.tubes.work.together.in.an.amplifier,.it.is.crucial.that.they.(if.there.is.more.
than.one).be.replaced.by.a.matched.set..If.you're.on.the.road.a.lot,.we.recommend.that.you.
carry.a.spare.matched.set.of.replacement.power.tubes.and.their.associated.driver.tubes.
After.turning.off.the.power.and.disconnecting.the.amplifier.from.the.power.source,.carefully.
check.the.tubes.(in.bright.light).for.cracks.or.white.spots.inside.the.glass.or.any.other.appar-
ent.damage..Then,.with.the.power.on,.view.the.tubes.in.a.dark.room..Look.for.preamplifier.
tubes.that.do.not.glow.at.all.or.power.tubes.that.glow.excessively.red.
Whenever.you.replace.the.power.tube(s):
•. Always.have.the.amplifier's.bias.voltage.checked.by.a.qualified.service.center..Improper.
bias.voltage.will.cause.degradation.in.performance.and.possibly.damage.the.tubes.and/or.
the.amplifier..(See."The.Importance.of.Proper.Biasing",.below.for.more.information).
•. We.highly.recommend.that.you.replace.the.driver.tube(s).as.well..The.driver.tube.deter-
mines.the.shape.and.amplitude.of.the.signal.applied.to.the.power.tube(s).and.has.to.work.
almost.as.hard.as.the.power.tube(s)..
You.can.check.your.preamplifier.tubes.for.microphonics.by.turning.the.amplifier.on,.turning.up.
the.gain.and.tapping.lightly.on.each.tube.with.the.end.of.a.pencil.or.a.chop.stick.(my.favorite)..
You.will.be.able.to.hear.the.tapping.through.your.speakers,.which.is.normal..It.is.not.normal.
for.a.tube.to.ring.like.a.bell.after.it's.tapped..If.it.does.ring.then.it's.microphonic.and.should.be.
replaced..Remember.to.use.only.high.quality,.low.microphonic.tubes.in.the.preamplifier.section.
Even.though.power.tubes.are.rarely.microphonic,.you.should.check.them.anyway..The.power.
tubes.can.be.checked.for.microphonics.just.like.pre-amp.tubes.
In.the.case.of.very.high.gain.amps,.you.may.be.able.to.reduce.the.amount.of.noise.generated.
by.simply.swapping.the.preamp.tubes.around.