LC Audio Technology Zappulse 2.2-SE Service manual

ZAPpulse2.2SpecialEdition

AndZAPpulse2.2Standard

COOKBOOK

Pulse Field

Technology

AssembledandtestedPWMAmplifiermoduleforDIYAudio!

CreditCardsizedfootprint!

[upto580WattsRMSin4Ohms]

ZAPpulseamplifiersrepresentthebestin
PWM(PulseWidthModulation)
amplifiers.Basedonasingleintegrating
modulatorstage,theZAPpulsehasthe
shortestfeedbackdelayofanyPWM
amplifieravailableonthemarket,
allowingforbestpossiblesoundquality.
Thesemodulesareultraefficientatsome
96%oftheappliedpowerisusableaudio
power!Thismeansalmostnoheatsinking

LCAudioTechnologyInc.

isnecessary.Despitethesmallsize
thesemodulesareincrediblyruggedand
willdrive2Ohmsandevenlower
impedanceswithnohazzle!Power
exceeding1kWpermoduleisfully
supported!Theinputstageisfully
balanced,withoutconversioncircuits,so
bothbalancedandunbalancedsignals
areequallyusable.Soundqualityison
levelwithmarketleadingClassAamps!

Content.

ActiveCrossoverwithZAPpulse2.2
BridgeTiedLoad,anddisablingofprotection
CompensatedMode
CompleteAmplifierSchematic

Connectionofinput/output
Connectionofpower

CoolingRequirements
Effectsofswitchingfrequency
Mechanicalproperties
MoreZAPpulsetechtalk
MinimalistSystem
PassiveVolumeControl
PrincipleofOperation
Professionaluse(PA)

supply

19
8
11
14
7
5
17
9
20
4
17
7
3

19
ShoppingList
SurroundSystem
SyncronousMode
TableofOutputpowervs.PowerSupplyVoltage
TechnicalData

1.0

2.2SE

2.1SE

2.0

1.0
ZAPpulseSoundQualityvs.Version ZAPpulseEmissionsvs.Version

1.1

1.1

2.0

2.1SE

MoreInformations:www.lcaudio.com

2.2SE

18
19
16
6
12

IDE

Harddisk

LCAudioTechnologyApS

ZAPpulse2.2SE

ThisbookletisintendedfornoncommercialusebyDIYaudioconstructors.Contentsmaybecopiedanddistributedfreelyforprivateornon
commercialuse.Nocopyingforcommercialpurposesisallowed.Copyright2004-2005LCAudioTechnologyInc.

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PrincipleofOperation.

Inaconventionalamplifiertheinput
signalisamplifiedthroughvarious
analogstagestoaprogressivelyhigher
amplitude.Inthefinalstagesofthe
amplifier,theoutputstage,highcurrent
capabilityisaddedtoenablethe
amplifiertodriveloudspeakerloads.
Whencurrentisdrawnoutoftheoutput
stagetotheload,heatisdissipatedin
theoutputstages,sincetheload
currentmultipliedwiththevoltagedrop
overtheoutputdevicegivesapower
value(ofaverage60%ofthemax.
outputpower)thatneedstodissipatein
heatsinks.60%isnotthepowerloss

Filter

atmaximumoutputpower,butthe
averageheatdissipatedatvarious
outputpowerlevels(exceptverysmall
levelsbelow1W).Soa100Watt
amplifierwillasaverageneedto
dissipate60Wattspowerintoheat
sinks.TheZAPpulseoperatesina
differentway,theoutputdevicesare
eitherofforonwithnosignificant
voltagedrop.Soevenwhentheload
drawlargeamountsofcurrent,thereis
onlyminimalpowertobedissipated.To
controlthesignalamplitude,thepulse
widthoftheoutputsquarewaveis
controlledveryaccurately.

+60V

Gnd

Integrator

Differential
Comparator

+

Aftertheoutputdevicesthesquare
waveneedtobefilteredwithachoke
andcapacitor.Thisfilterregeneratesan
analogsignalthatcanbefedtothe
loudspeakers.Thechokeand
capacitor'squalityisparamountinorder
togetagoodsoundquality,soweuse
anoversized(1.5kW)ultrahighspeed
ferritecorewithsilverconductorand
TEFLONinsulator.Thischokehasa
verylowimpedance(only5milliOhms),
andallowsforagooddampingfactorin
anyspeakerload.Togetanoutput
signalofsay30V,theoutputdevices
aremadetoswitchhigh75%oftime,
and25%oftimelow.Inthiscase

PulseField

Technology

GateDriver

OutputFilter

PowerStage

thePulseWidthis75%.SinceV+toV­voltageis120V,theoutputvoltageseen
fromV-is75%of120V=90Vasseen
fromtheminusrail.Translatingto30V,
aboveGND.(Aswantedinour
example.Operatingfrom+60Vto-60V
allowsforanyoutputvoltageinthis
range,including0V.ThusatotalDC
coupledsystemforhighestpossible
soundperformance.PulseWidth
ModulationisoftenshortenedtoPWM.
AveryimportantstageinaPWM
amplifieristhemodulator.Itcanbe
madeivariousways,withdifferent
properties.Wehaveselectedand
optimizedthebalancedintegratingtype.

Out

Gnd

-60V

ZAPpulse2.2SE

ThisbookletisintendedfornoncommercialusebyDIYaudioconstructors.Contentsmaybecopiedanddistributedfreelyforprivateornon
commercialuse.Nocopyingforcommercialpurposesisallowed.Copyright2004-2005LCAudioTechnologyInc.

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MoreZAPpulseTechtalk!

TheheartoftheZAPpulseamplifierisa
balancedintegratingPWMmodulator.It
basiclyintegratestheDClevelofone
switchingcycleoftheoutputstage,
includinganyswitchingnoises,slope
differencesetc.Thenthisvalueis
compared,andcorrectedinthenext
switchingcycletocreateanoutput
signalofexactly0Volt.Thiscorrection
isperformedeveryswitchingcycle,
whichisabout500.000timesper
second.

Theinputsignalisinjecteddirectlyinto
theintegratortokeepsignalpathsultra
short.Nosignalconditioning,suchas
DCblocking,HFblockingorother
limitingfactors arepresentonthe
ZAPpulsemodule.Soifthisisrequired
byyourapplication,youhavetoadd
thesefunctionsoutsidethemodule.
Whensignalisappliedtotheinput,the
integratornolongercorrectstheoutput
signallevelto0Volts,buttotheaudio
signal.
Thefeedbackgroupdelayiskeptvery
low,onlyaround1uS,toallowforTIM
freeoperation.Theanalogintegrating
feedbackloophasalowergroupdelay
ofanycompletelydigital(DSPbased)
feedbackloop.Andsinceoutput
switchingnoiseproductsarethesame
nomatterthemodulatortype,the
analogfeedbackloopgivesamuch
betterrejectionofnoiseproductsthana
truedigitalapproach.It'sallabout
speed,andhowfastthenoisecanbe
cancelled.

switchinglosseslowatheavyspeaker
loads.Howeveratlowsignalamplitudes
themainpowerlosscomesfrom
capacitiesintheMOSFET's,so
transitionsareslowedtoreduceEMI,
noiseandidleloss.Thisiscontrolledby
thePulseFieldcircuitintheGatedriver.

Asimplerulesaysthatatnosignal,a
ZAPpulselosessome9.5Wattspower
tocapacitiesintheMOSFET's,andat
fullpoweritlosesanother9.5Wattsto
serialresistance.Soat500Woutyou
onlyhavetodissipatearound19Watts
totheheatsinks.

OnegreatadvantagePWMamplifiers
haveoverconventionalanalog
amplifiersis,thatPWMamplifiershave
exceptionalabilitytoexpandthesound
stagewithaddedsoundlevel.An
analogamplifierwouldtypicallycollapse
thesoundstageathigherlevels,
dependingonthesizeofthepower
supply(whywehavehugepower
supplybanksinallouranalog
amplifiers).ThePWMwillplaywithwide
anddeepsoundstageatanylistening
level,evenwithavery(almosttoo)
smallpowersupply.Wehavemade
testswitha2x250WRMSZAPpulse
amp,runningwithonlytwo2200uF
100Vmaincaps.Anditstillhasplenty
ofbasscontrol,definition,widthand
depth.Opportunitiesforinteresting
experimentsinthisfieldareobvious.

Theoutputsquarewavehasabase
frequencyoftyp.460kHz,andrise
timesofsome10.000V/uS.Theslopes
areminimisedtoaround80nStokeep

ZAPpulse2.2SE

ThisbookletisintendedfornoncommercialusebyDIYaudioconstructors.Contentsmaybecopiedanddistributedfreelyforprivateornon
commercialuse.Nocopyingforcommercialpurposesisallowed.Copyright2004-2005LCAudioTechnologyInc.

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ConnectionofaPowerSupply

TomakeZAPpulse2.2SEwork,simply
connectatypicalAudioPowerSupply
of+/-35Vto+/-72V.(max.60Vforthe
standardversion).Theoutputpower
dependsonthevoltageofthepower
supply.The2.2standardversionuses
63Vcapacitors,ontheboard,whilethe

2.2SEuses100Vcaps.Thisiswhythe
SEcanbemadetodelivermuchhigher
powersthanthestandardmodules.In
thestandardversion,thesoundquality
ofthemaincapsmustbeconsidered.

+60V

Power
GND

Power
GND

OUT

-60V

Themidrangeandtreblesonic
propertiesofthesecaps,willinteract
withtheoverallsoundperformanceof
theamplifier,sowerecommendusing
veryhighqualitycapswithstandard
modules.WiththeSEmodulesthemid
andhighfrequencyperformanceisfixed
atthehighestlevelbytheBCVishay
seriesRLI136(100uF100V).SoPSU
capsonlyneedtohavegoodbass
props. Alwaysuseshortandheavy

wirebetweenPSUcapsandmodules
(lessthan4-5inches).

SHORT!

SHORT!

SHORT!

Thereisnoneedtousehugecapacitorbanks,like
withClassAorA/Bamplifiers.Almosallthepower
ofthePSUwillbetranslatedtoaudiopower,so
smallercapswillworkjustaswell.10.000uFis
adequatefordriving2channelsatfullpower.

10.000uF
63V

10.000uF

63V

+60V

Power
GND

-60V

ExternalGateDrive.

-60V

SHORT!

SHORT!

SHORT!

+

+

10.000uF
63V

10.000uF

63V

Remove
bubble

+60V

Power
GND

Power
GND

OUT

TheZAPpulse2.2SEmodulehasanon-boardGateDriveregulator.Itderivesit's
voltagefromthenegative-60Vrail(whythenegativerailhasahigherconsumption
thanthepositiverail).Byfeedingaseparategatedrivevoltagefromthepowersupply
(15-20VDC200mA)youcanreducetheidlelossofaZAPpulsemodulefrom9.5W
to5W.Thiswillmakeyouramplifierevencooler!IMPORTANT!TheGatedrivevoltage
(minus)mustbetiedtothe-60VrailNOTtoGND!

ZAPpulse2.2SE

ThisbookletisintendedfornoncommercialusebyDIYaudioconstructors.Contentsmaybecopiedanddistributedfreelyforprivateornon
commercialuse.Nocopyingforcommercialpurposesisallowed.Copyright2004-2005LCAudioTechnologyInc.

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+60V

Power
GND

GateDrive

-60V

OutputPowervs.PowerSupplyVoltage.

TheOutputpowercanbecalculatedas
afunctionofthemax.signalamplitude,
whichdependsonthesupplyvoltage.
At+/-60VSupplyVoltagetheampcan
ideallydeliver120Vpp.Tocalculatethe
outputpowerweneedtheRMSvalue,
whichissimply120/2pi=120/2,82=
42,6Vrms(inthisexample).
Outputpoweristhencalculatedusing
OhmsLaw:

2

U

P=

R

P=OutputPowerRMS
U=RMSVoltage(42,6)
R=SpeakerImpedance(8)

TransformerACV
2x24VAC
2x27VAC
2x33VAC
2x36VAC
2x40VAC
2x42VAC
2x45VAC
2x50VAC

DCVoltage
+/-32VDC
+/-36VDC
+/-45VDC
+/-49VDC
+/-55VDC
+/-58VDC
+/-62VDC
+/-69VDC

Inthisexample223wattsRMS.
Thiswasidealvalues,inZAPpulsethe

practicalvaluesarecorrectedwitha
seriallossof1-3VDCdependingon
loadimpedance(1V@8Ohms).

At+/-60VDCyouwillgetapractical
outputpowerof:some210WattsRMS.

Seebelowforoutputpowersatother
transformervoltages,andload
impedances.

Bottomtableshowsbridgemode
ZAPpulsemodulesoperatingatvery
highpower!

8OhmsPower
60W
78W
119W
144W
180W
200W
230W
286W

4OhmsPower
106W
137W
222W
266W
340W
380W
438W
548W

YoucanalsoBridge-tieyourspeaker
loadstogethigheroutputpower.For
thisyouneed2ZAPpulsemodulesper
audiochannel.

TransformerACV
2x24VAC
2x27VAC
2x33VAC
2x36VAC
2x40VAC
2x42VAC
2x45VAC
2x50VAC

:Notrecommendedforsafeoperationofmodules.note

ZAPpulse2.2SE

ThisbookletisintendedfornoncommercialusebyDIYaudioconstructors.Contentsmaybecopiedanddistributedfreelyforprivateornon
commercialuse.Nocopyingforcommercialpurposesisallowed.Copyright2004-2005LCAudioTechnologyInc.

DCVoltage
+/-32VDC
+/-36VDC
+/-45VDC
+/-49VDC
+/-55VDC
+/-58VDC
+/-62VDC
+/-69VDC

8OhmsPower
219W
286W
448W
542W
682W
758W
879W
1100W

6

4OhmsPower
397W
526W
837W
1019W
1291W
1439W

note
note

LCAudioTechnologyInc

ConnectionofIn-andOutputs.

HereyoucanseehowinputsandoutputsareconnectedtotheZAPpulsemodule.

UnbalancedInput.

+60V

STRIPLINE

Power
GND

-Out

OUT

-60V

+Out

BalancedInput

+60V

STRIP
LINE

1 2

3

OUT

XLRFEMALE
Chassisplugas
seenfromrearside.

IfyouwanttoensuresafeoperationofyourZAPpulsemodule,dontlettheinputwiresclosetoloudspeaker
cable,powerlinecable,powertransformersortheFerritecoil.Dontleavelonginputwiresunconnected.

Power
GND

-60V

-Out

+Out

PassiveVolumecontrol

Potentiometer22klog.

Seenfrom
FRONT

OUT

ZAPpulse2.2SE

ThisbookletisintendedfornoncommercialusebyDIYaudioconstructors.Contentsmaybecopiedanddistributedfreelyforprivateornon
commercialuse.Nocopyingforcommercialpurposesisallowed.Copyright2004-2005LCAudioTechnologyInc.

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+60V
Power

GND

-60V

-Out

+Out