Description
The
Ouad
405-2 is
a two channel
power
amplifier
primarily
intendedfor use
inhigh
quality
soundreproducingsystems.The
amplifierisusuallyusedwith a Ouad
controlunitthough
other
signalsourcescanreadilybeaccommodaled
Theamplifierusesa currentdumping
outputcircuit,a Ouad
invention
whicheliminatesmanv
of theoroblemsassociatedwith
transistoramplifiers.andcoveredby patents
inseveralcountries.
In
a currentdumpingamplifierthereisin effectbotha low
powered
veryhigh
quality
amplifieranda high
powered
heavyduty
amplifier.Thelow power
amplifiercontrolsthe loudspeakers
at
all
times,
callinguponthehigh
power
sectionto provide
most
of
themuscle.The
smallamplifierisso arranged
- it carries
anerror
signal
- that
provided
thelarger
power
transistors
(the
dumpers)
get
within
thetargetareaof therequired
outputcurrent
itwillfill
in
theremainder
accuratelyandcompletely.Thereproduced
quality
is
solely
dependent
on thesmallamplifierwhich
becauseof its
low
power
canbe madevery
goodindeed.
Problems
of crossover.crossoverdistortion,
quiescent
current
adjustment.thermal
tracking,transistormatching,alldisappear.
Thereareno internal
adjustmentsor a'lignmentsandthechoiceof
power
transistortypesislessrestrictive.
Smplifed Schematc of 405-2 Amplifiershowing
ClassA, Dumpers
and BridgeComponents
