JBL 5234A Manual

JBL
5234A
INSTALLATION
AND SERVICE
MANUAL

TABLE OF CONTENTS
ARCHITECTURAL SPECIFICATIONS
ARCHITECTURAL SPECIFICATIONS 2
PRODUCT SPECIFICATIONS 3
Electrical 3
Physical 3
INSTALLATION 4
InstallationofStandardCrossoverFrequencyModules4
ProgrammingtheinternalHigh-PassFilters5
Mounting 6
Input Connections6
Output Connections6
Use FloatingorBalancedCablesforLongerRuns6
AC PowerConnectionandLineVoltageConversion7
ProtectionofCompressionDrivers8
SETUP AND OPERATION 9
General Applications9
TypicalSystemsEmployingthe5234A9
A SafetyProcedureforI nitial PoweringUpofTheSystem14
Level Control Adjustment 14
System PhasingandSignalPolarity14
SelectingtheLowFrequencyHigh-PassFilterOptions16
BlankCrossoverCardAssembly16
PARTS LIST 18
SCHEMATIC DIAGRAM19
LIST OF ILLUSTRATIONS
FigureDescription
1 TotalHarmonic Distortion 3
2 5234ALowFrequency Cutoff Characteristics3
3 ScrewRemovaltoLiftOffthe Bottom Cover4
4 Identification of Major ComponentsInside5234A4
5 CrossoverCard Mounting Alignment 4
6 OneoftheTwoProgrammingDIPSwitches5
7DIPSwitchProgrammingandResultantLow5
Frequency Cutoff Characteristics
8 Model 5234A Rear Panel6
9 UsingIsolationTransformerstoFloattheCable6
Betweena 5234A Output andanUnbalanced
Load
10UsinganIsolationTransformertoFloat(or7
Balance) theCableBetweena 5234A Output
anda Floating(orBalanced)Load
11UsinganIsolationTransformertoFloatthe7
I nput Cabletothe5234A
12ConventionalTwo-WaySystem (Passive Network)9
13 ConventionalThree-WaySystem (Passive Network)9
14DualChannelTwo-WaySystem(Biamplified)9
15 SingleChannelThree-WaySystem(Triamplified)10
16DualChannelTwo-WaySystem with Monaural10
Subwoofer(s)
17CombiningElectronicand Passive Frequency10
Dividing Networks
18 Wiring DiagramforBiamplifiedSystem11
19 Wiring DiagramforTriamplifiedSystem12
20 Wiring DiagramforTwo-WaySystem with 13
MonauralSubwoofer(s)
2112dB/OctaveBlankCrossoverCard(JBL16
Model 52-5120) with ComponentDesignations
2218dB/OctaveBlankCrossoverCard(JBL16
Model 51-5130) with ComponentDesignations
Table
1 MaximumValuesforLowFrequency8
Attenuating ProtectionCapacitors
2 JBLProtectionCapacitorsforCompressionDrivers8
3 12dB/OctaveCrossoverCardComponentValues17
418dB/OctaveCrossoverCardComponentValues17
WARNING:Toprevent fire orshockhazard,donotexpose
this unit torainormoisture.
The electronicfrequency dividing network shall
containtwochannels,each with low-levelactive
filters that separatethe program into lowand high
frequencybandsatdesignatedcrossoverfrequency
points. Each channelshallhavea transformerless,
differential amplifier input andseparate buffer
amplifiersforitslowand high frequency outputs.
Input and output connectionsshallbemadevia
either 1 /4inch(6.3mm) phone jacksorscrew
terminals provided ontheunit'srearpanel.
Crossover frequencyselectionshallbeaccom-
plishedby internally mounted plug-in circuit
modules,oneperchannel. Each module shallbe
designated with thecrossoverfrequency, printed
insucha position astobeeasilyread through a
window intheunit's front panel.Thedesignated
crossoverfrequencyshallbethe point atwhich
theslopesofthepassbandcurvescross,andwhere
each is3 dB down from theaveragepassband
output level;this point shallbe within ± 10%of
thedesignatedfrequency.A varietyofmodules
shallbeavailable,not only with different crossover
frequencypoints,butalso with 12dBor18dB
peroctave filter slopes.Blank plug-in modulesshall
beavailable, allowing forthe installation ofsuitable
capacitorsandresistorstoachievecustomcrossover
frequencypoints.
In addition, internally switchselectablelow
frequencyequalizationandsubsonic filtering shall
be provided foreachchannel,enablinglowfre-
quencyresponsetobe optimized while blocking
subsonicenergy below thelowestusablespeaker
frequency.Thesedualinlineswitchesshallallow
the following programmable options, all with
12dBperoctavesloperates(exceptthe flat
responsesetting):
a. Flatfrequencyresponse(e.g.,noL.F.cut-
offfilter).
b.20Hz high pass filter, Q = 0.707(Butter-
worth).
c. 20Hz high pass filter, Q = 2 (6dB boost
at20Hz).
d.30Hz high pass filter, Q = 0.54.
e. 30Hz high pass filter, Q = 0.84.
f.30Hz high pass filter, Q = 2 (6dB boost
at30Hz).
g.40Hz high pass filter, Q = 0.707(Butter-
worth).
h.40Hz high pass filter, Q = 2 (6dB boost
at40Hz).
The internalswitchingshallalsoallow both
channels' lowfrequency outputs tobe combined
into a monauralsignalwhich, with an appropriate
crossoverfrequency,issuitablefor driving a sub-
woofer channelwhilethe high frequency outputs
drivea full-range stereospeakersystem.
The unit shallfitina 44mm(1-3/4inch) high
space ina standard483mm(19inch) equipment
rack. Recessed front-panel adjustmentsshallbe
provided forthe high frequency output levelof
each channel.A recessedrearpanelslideswitch
shallallow operation with nominal 100to120V
2

AC or200to240V ACpowermains.
The unmodified frequencyresponseofthe
dividing networkshallbe20Hzto20kHz,
±0.5dB. Distortion shallbe less than0.01%THD
at+18dBv* into 100kohmsorgreater,or0.03%
THD at+18dBv into a 600ohmload.Signal-to-
noise ratio shallbegreaterthan90dB,measured
overa 20Hzto20kHzequivalentbandwidth.
Isolationbetweenchannelsshallbegreaterthan
70dB.
The electronicfrequency dividing networkshall
bea JBL Model 5234A.
PRODUCT SPECIFICATIONS
ELECTRICAL
Gain
0dBinthepassband
Rated Output Level
6.2V rms(+18dBv*)measured with 20Hzto20kHz
equivalent bandwidth filter
Distortion
0.01% THD,20Hzto20kHz @ +18dBv into a load
greaterthan10kn
Frequency Response
±0.5dB,20Hzto20kHz(high-passfunctions
disengaged)
Input Impedance
Greater than50kn,transformerless differential
amplifiersforbalancedorunbalancedlinelevelsources
Output SourceImpedance
50ohms,unbalanced
Output LoadImpedance
600ohmsorgreater
Channel Isolation
Greater than70dB,20Hzto20kHz
Signal/NoiseRatio
Greater than90dB,20kHzequivalent bandwidth
Controls
CH1 & CH2 High FrequencyLevel(front)
Power On/Off(front)
CH1 & CH2SubsonicFilterCharacteristic(internal)
Line VoltageSelector(rear)
Crossover Frequency& FilterSlope
Selectable by plug-in modules,12dBor18dB/octave,
atfactorydeterminedfrequencies(±10%),special
modulesforcertainJBL monitor speakers,orat
customerdeterminedfrequencies(viablank plug-in
modules)
NOTE: One module isrequiredforeachchannel,the
unit comes from thefactory with "jumper"modules
that passthesignal unfiltered sothe unit functionsa
1:2lineamplifier.
12dB/octave 18dB/octave
Model 52-
Freq.
Model 51- Freq.
5120 Blank
5130Blank
5121 250Hz 5132500Hz
5122 500Hz
5133 800Hz
5123 800Hz
5145 (Specialfor
5124 1200Hz
JBL 4345& 4355)
5125 5000Hz
5127 7000Hz
5130(SpecialforJBL4430& 4435)
5140(SpecialforJB L 4343& 4350)
*The 0 dBvreferenceis0.775V rms.Acrossa 600ohmload,this
voltagerepresentsa powerlevelof1 mW(0dBm).
High Pass Filter(SubsonicCutoff)
12dBperoctave rolloff, the cutoff frequencyand
Qswitchselectable
NOTE: Thesecharacteristicsareswitchselectablevia
theinternalDIPswitches,oneperchannel.
Filter
Level atFilter
Frequency Frequency FilterQ
20Hz
-3dB
0.707
20Hz +6dB 2.0
30Hz
-5.5 dB 0.54
30Hz
-1.5dB
0.84
30Hz +6dB 2.0
40Hz
-3dB
0.707
40Hz +6dB 2.0
Power Requirements
6 watts,100-120or200- 240V AC,50or60Hz
OperatingTemperature
5°C (41°F)to55°C (132°F)
PHYSICAL
Mounting Dimensions
44mmx 483mmx 194mmdeep
(1-3/4inx 19inx 7-5/8indeep)
NetWeight
1.8kg(4lb)
ShippingWeight
3.0kg(6-1/2lb)
Figure1 — TotalHarmonicDistortion
(Distortion componentsindBbelow+18dBv output)
Figure2 — 5234ALowFrequencyCutoffCharacteristics
(Selectable eachchannelbymeansofinternalswitches)
JBL continually engages in research related to product
improvement. New material, production methods and
design refinements are introduced into existing products
without notice as a routine expression of that philosophy.
For this reason, any current JBL product may differ in
some respect from its published description, but will
always equal or exceed the original design specifications
unless otherwise stated.
3

INSTALLATION
WARNING:Inmany cases, installationofthe JBL 5234A
Electronic FrequencyDividingNetworkinvolvesopening
thecovertogain access tointeralcircuitmodulesand
programming switches. Inaddition,conversionoftheline
voltagemayinvolveinstallationofa newpower cord. Since
dangerous ACvoltagesexistinsidetheunit,cautionmust
be exercised. These instructionsareintendedforuseby
qualified service personnelonly.
InstallationofStandard
Crossover FrequencyModules
The dividingnetworkisshippedwitha pairof
52-5120 crossovermodules (cards), eachwithtwo
100 ohmresistorsthatconverteachchannel into
a one-input, two-output unitygaindistribution
amplifier.Thetwocardsthereforeequipthe
5234A tofunctionasa pairofindependentone-
input, two-output amplifiers;thenetworkinputs
can beparalleledtoprovidefouroutputsfroma
single source.The HIGH outputswillbeatunity
gainwhenthe HIGH FREQUENCY LEVEL con-
trolsaresetatmaximum(thecontrolscanbe
turneddownif loss isdesired).
Prior toitsuseasa frequencydividingnetwork,
these jumpered"blank"cardsmustberemoved
fromthe5234Aandtheappropriatefrequency
selection cardsmustbeinstalledintheirplace.
To installthe cards:
1. Place the5234Aupsidedownona soft
surface, removethetwoPhillips-head screws from
eithersideofthe case, and lift the bottom cover
fromthe chassis (Figure3).
2. Removetheoldcrossovercardsby lifting
both sides ofa cardsimultaneouslyandgently
(Figure 4).Frictionfromthethreemountingpins
and theelectricalconnectormustbeovercome.
3. Alignthethreeholesineachnewcrossover
card withthecorrespondingmountingpinsonthe
mainprintedcircuitboard(Figure5).Thecom-
ponentsonthecardshouldfacetowardthe chassis,
withthefrequencydesignationlabeltowardthe
front panel.
4. Aseachcardisgentlypressedagainstthe
mountingpinstops(roughly6 mm,1/4in),
electrical connectionwillbemadebetweenthe
card connectorandsixpinsontheprintedcircuit
board.
5. Unless LFprogrammingistobereset(referto
next topicinthismanual),replacethe bottom
cover, observingtheproperorientation.Thecover
willnot seat properlyinthe chassis ifrotated180°
Secure thecoverwiththefour screws. Theunitis
nowreadyformountingandconnectionofthe
various inputsandoutputs.
NOTE: Operation of the 5234A without a crossover card
will not damage the unit, although neither will it pass any
audio signals.
Figure 3 — Remove These Screws toLiftOfftheBottomCover
Figure 5 — CarefullyAlign Crossover CardwithThreeMounting Pins
&Male Chassis Connector
NOTE: Information regarding the capacitor and resistor
values necessary to "make up" 12 dB/octave and 18 dB/
octave cards, as well as the components used on standard
JBL cards, is given near the end of this manual.
4
CH1 CrossoverCard
CH2 CrossoverCard
Power Supply
Figure 4 — IdentificationofMajorComponentsInside5234A
CH2 ProgrammingSwitches
CH1 ProgrammingSwitches

ProgrammingtheInternalHigh-PassFilters
Insidethe5234A,eachchannelisequipped with
a miniaturebankoffiveOn-Offslideswitches. Each
bankofslidersishousedinsmallrectangularpack-
ageresemblingan integrated circuit,andsincethe
multi-switchhousinghastworowsofpinswhich
secure ittothecircuitboard,itisknownasa dual
in-linepinswitch(hence "DIP"). Each ofthetwo
DIP switchesperformstheidenticalfunctions,one
forChannel1 andthe other forChannel2
(Figure4).
OfthefiveslidersoneachDIPswitch,#1
through #4determinethehigh-pass filter character-
istics ofthechannel,while#5isreservedforcreat-
inga monaurallowfrequency output forthetwo
channels (Figure6).
The 5234Aisshipped with theswitchessetfor
flat lowfrequencyresponseanddiscretelow
frequency outputs. IntheSetupandOperation
sectionofthismanual,considerationsinselecting
thevariouslowfrequency cutoff characteristics
are discussed.Ifa characteristic other thanthe
factorypresetisdesired,itcanbeestablished
as follows:
1. Placethe5234Aupside down ona soft
surface, removethetwoPhillips-headscrews from
eithersideofthe case, and lift the bottom cover
from the chassis (Figure3).
CAUTION: The5234AACpowercordshouldnotbe
connectedtothepowerreceptacle.Also,anypower
amplifierstowhichtheFrequencyDividing Network
maybeconnectedshouldbeturnedOffduringthis
procedure.
2. LocatetheDIP.switch(es)forthechannel(s)
tobeprogrammed.
NOTE: In a triamplified system, use high-pass filtering
only on the channel used for the low-mid/high transition;
the mid/high channel should be set for flat response. In a
biamplified system with a mono subwoofer, both chan-
nels' DIP switch "mono"sliders must be engaged.
3. SettheDIPswitch(es)accordingtothe
information inFigure7.
4. Replace,the bottom cover,observingthe
properorientation.Thecover will notseat
properly inthe chassis if rotated 180°.Secure
thecover with the four screws.The unit isnow
readyfor mounting andconnectionofthe
variousinputsand outputs.
Black square indicates
switch position.
20Hz,Q=0.707
(-3dB@20Hz)
1100
20Hz,Q = 2
(+6dB@20Hz)
1001
30Hz,Q = 0.54
(-5.5dB@30Hz)
0101
30Hz,Q = 0.84
(-1.5dB@30Hz)
00101
FLAT, MONO
1000or0100
30Hz,Q = 2
(+6dB @ 30Hz)
0001
40Hz,Q=0.707
(-3dB@40Hz)
0000
40Hz,Q = 2
(+6dB@40Hz)
MONO(Bothchannels
mustbesetto Mono.)
00100
FLAT (Discretechan-
nels, theFactoryPreset)
Figure7 — DIPSwitchProgrammingfortheVariousHigh-Pass
FilterCharacteristics,& Mono Mode
NOTES:
1. Curvesarelabeledbya binarycode.A "1" = ON(switch
closed), anda "0"= OFF(switchopen).
2. Bitpositions#1and#2selectthe cutoff frequency.
3. Bit position #3,whenclosed,gives flat response.
4. Bit position #4,whenclosed,lowerstheQ.
5. Bit position #5,whenclosedon both channels,combines
theLF outputs toa mono summedsignal.
6. Shadedareasarenotrelevantto function beingdescribed.
5
1101
Figure6 — OneoftheTwoDIPSwitches that AllowProgramming
ofthe Model 5234ALowFrequencyCharacteristics

Figure 8 - Model 5234ARearPanel
Mounting
The 5234Aissuitablefor mounting inoneEIA
standardrackspace without additionalbracingor
ventilation.A full setof mounting hardwareis
included.Alternatively,the unit maybeplacedon
a shelforcountertop.As with anylowlevelsignal
processing electronics,itisadvisablenottomount
the unit neara strongsourceofstrayelectro-
magneticfields,suchasimmediatelynexttothe
powertransformerora largeamplifier.Inany
installation,bearinmindthatallexternalconnec-
tionsaremadeontherearpanel,andthemaximum
allowableambienttemperatureforthe unit is55°C
(132°F).
InputConnections
Inputconnectionstothe5234Amaybeeither
unbalancedorsymmetrical(i.e.floatingorbalanced)
Clearly labeledscrewterminalsandparallel-wired
phone jacks ontherearpanelacceptthelinelevel
input toeachchannel(Figure8).Thephone jacks
are 6.3mm(1/4in)diameter3-circuittype,wired
so thetipisforaudiohigh,theringisforaudiolow,
andthesleeveisforshieldground.Witha balanced
or floating source,usea 3-circuit("stereo"type)
phoneplug.Withanunbalancedsource,thering
andsleeveofthe3-circuitplugmustbeshorted;
thisisautomaticallyaccomplishedbyinsteadusing
a standard2-circuitphoneplug.
NOTES:
1. Exchange of the HIGH (+) and LOW (-) connections
will result in a reversal of signal polarity.
2. Figures 9, 10 & 11 illustrate balanced or floating
input and output connections. Figures 18 through 20
illustrate wiring for typical installations.
OutputConnections
The 5234Aoutputsareunbalanced,deliveringup
to6.2V rms into a 600ohmorhigherimpedance
load(+18dBv). Each channelhasa HIGHfrequency
andLOWfrequency output, andeachofthese out-
putsisavailableattwopointsontherearpanels:
a setofscrewterminalsora parallel-wiredphone
jack (Figure8).Thephone jacks are6.3mm
(1/4 in)diameter2-circuittype,wiredsothetip
is fortheaudiosignalandthesleeveisforthe
common(shieldground).
Use FloatingorBalancedCablesforLonger Runs
Shielded cablesarerequiredforall input and
output signals.Ifthe output cablelengthsare
greaterthan4.5m to6 m (15 to20ft),werecom-
mendinstallingisolationtransformers(600£2:
60012) ateachendofthecable. This allowsdual-
conductorshieldedcabletobeusedina floating
mode,greatlyreducingthepossibilityofradio
frequencyinterference(RFI)orhum.Ifthe
amplifiertowhichthe5234A output isconnected
has a balancedor floating input, onlyonetrans-
formerneedbeinstalled— attheendofthecable
connectedtothe5234A output.
Similarly, longer input cablesshouldbe
balanced or floating toreducesusceptibilityto
RFI andhum.Ifthe output ofthedevicefeeding
the5234Aisbalancedorfloating,notransformer
is requiredatall;simplyusea dual-conductor
shieldedcable.Ifthe input sourceisunbalanced,
an isolationtransformershouldbeusedatthe
source device's output.
Withshortercables,particularlywhereintercon-
nectedequipmentismountedina singlerackor
is poweredbythesameACreceptacle,thereis
less needforbalancedor floating input and output
cables.
Figure 9 — UsingIsolationTransformerstoFloattheCable
Betweena 5234AOutput& AnUnbalancedLoad
TIP-SLEEVE
PHONE PLUG
'TOISOLATION
. TRANSFORMERS, ETC.
UNBALANCED
AMPLIFIER
INPUT
6
AS BELOW
AS BELOW
AS BELOW
INTERCONNECTING
CABLE
ISOLATION
TRANSFORMER
(MOUNT CLOSE
TO 5234A)
CASE AND/OR
ELECTROSTATIC
SHIELD GROUND
ISOLATION
TRANSFORMER
(MOUNT CLOSE
TO AMPLIFIER)
CASE AND/OR
ELECTROSTATIC
SHIELD GROUND,
PLUS CABLE SHIELDS
600 SI: 600 SI
OR

TIP-SLEEVE
PHONEPLUG
INTERCONNECTING
CABLE
TOISOLATION
TRANSFORMER &
INTERCONNECTING CABLE
Figure10— UsingAnIsolationTransformertoFloat(orBalance)theCableBetweena 5234A Output
&a Floating(orBalanced)Load
UNBALANCED
OUTPUTOF
MIXER,GRAPHICEQ,
OR OTHERSIGNAL
SOURCE
ISOLATIONTRANSFORMER
(MOUNT CLOSE TOSIGNAL
SOURCE OUTPUT)
FROMINTERCONNECTING
CABLE & ISOLATION
TRANSFORMER
TIP-RING-SLEEVE
PHONEPLUG
Figure11— UsingAnIsolationTransformertoFloatthe Input Cabletothe 5234A
AC PowerConnection& LineVoltageConversion
The 5234Acanbepowered from either100to
120V ACor200to240V AC50or60Hzmains.
The SUPPLY VOLTAGE SELECT switchonthe
rearpanelconvertsthe unitfrom one operating
rangetothe other (Figure8).Asshipped,the unit
is setfor100to120V ACoperation,andtheline
cord provided issuitableforuseintheU.S.,
Canada or Japan. Toconvertthe unit for operation
with other mainsvoltagesor outlet types,usethe
following procedure.
1. Besurethe5234Aisnotconnectedtoany
powersource.
2. Slidethe SUPPLY VOLTAGE SELECT
switchtothe appropriate range.
3. Executeoneofthesetwoalternatives:
a) Removethe bottom coverby removing the
twosmallPhillipsheadscrewsoneachsideof
the case, (Figure3)andchangetheline cord
toonewhoseattachment plug matchesthe
powerreceptacle.Securethenew cord tothe
chassis with a feed through cableclamp.Also,
besuretosolderthehigh,neutraland ground
conductorstothesameterminals from which
thecorrespondingconductorsofthe original
cord wereremoved.*
—or—
b)Installa suitableadaptertomatethe plug
ontheexistingline cord with thepower
receptacle.
NOTE: Any line cord or adapter used for 200-240 V
operation in the U.S., Canada or Japan must be both
U.L. listed and C.S.A. certified. For 240 VAC,
50/60 Hz operation in other countries, select a line
cord based on governing local regulations.
CAUTION:This unit maybedamagedifoperated
with thesupplyvoltageselectswitchsetincorrectly
forthelinevoltageapplied.Also,verifythemains
areAC since, insomecountriesaswellascertain
areas within theU.S.,DCmainsexist.
*ln U.S.A.versions,theblackwireis "hot", the white wireis
"neutral,"andthegreenwireis ground. InEuropeanversions,
blue is "hot", brown is"neutral,"andgreen/yellowis ground.
7
AS BELOW
AS BELOW
AS BELOW
OR
BALANCED ORFLOATING
AMPLIFIER INPUT
600SI: 600n
ISOLATION
TRANSFORMER
(MOUNT CLOSE
TO 5234A)
JCASE AND/OR
ELECTROSTATIC
SHIELD GROUND
AS BELOW
INTERCONNECTING
CABLE
600SI: 600 SI
OR
10Kn:10KSI

Protection of Compression Drivers
Whenever a midrangeorhighfrequencycom-
pression driverisconnecteddirectlytoa power
amplifier,itisrecommendedthata capacitorbe
wiredin series with thedriverinordertoattenu-
atedunwantedlowfrequencyandswitching
transient signals, andtoblockDCcomponents,
any ofwhichcandamagethedriver. This applies
tomostbiamplifiedandtriamplified systems
employingcompressiondrivers.(Inconventional
systems with passive, high-leveldividingnetworks,
thenetworkcomesbetweenthepoweramplifier
and thedriver(s)sotheprotectionisalready
built-in.)
NOTES:
1. In all JBL monitors which are designed for biamplifi-
cation, the dividing networks already incorporate the
required attenuation capacitors between the inputfs) and
the compression driver(s).
2. Series capacitors are not required for low frequency
and midrange cone or dome type transducers.
CAUTION: Itis imperativethat each output ofthe 5234A
electronic frequencydividingnetwork be properly con-
nected. Inadvertentexchange oflow andhighfrequency
outputconnections (atthe 5234A, the poweramplifiers,
or the transducers) may result in severe damage to midrange
or highfrequencyloudspeaker system components. Ifin
doubt,alwaystest thelow frequencyloudspeaker(s)first,
since the presence of highfrequenciestherewill be less
apt to cause damagethan the converse.
The lowfrequency series protectioncapacitors
shouldbenon-polarizedelectrolytics,eithermylar,
metallizedpolyesterorpolyestertype with working
voltages ofatleast50V.DONOTUSE POLAR-
IZEDELECTROLYTICCAPACITORS. Maximum
capacitance dependsnotonlyonthecrossover
frequencyusedforthedriver,butalsoonthe
driver's impedance,aslistedinTable1.Suitable
10% tolerancecapacitorsareavailabledirectly from
a JBLprofessionalproductsdealerorJBLdirectly;
therecommended values forspecific cutoff fre-
quencies, andtheirJBLpartnumbers,arelisted
intheTable2.
Crossover Frequency
CapacitorValues
(Driver Impedance)
Crossover Frequency
sn
4a
250 Hzto500Hz
40M F
80M F
150MF
500 Hzto 5000 Hz
20M F
40M F
80M F
Above 5000 Hz
2M F
5u F
8uF
Table 1:Maximum Values forLow Frequency Attenuating
Protection Capacitors
Capacitor
Value
JBL
Part Number
For Optimum Results at
These CrossoverFrequencies
(Based on Driver Impedance)
Capacitor
Value
JBL
Part Number
8n
4a
72 MF 52938 275 Hz
550 H/ 1100 Hz
52 MF 52939 400 Hz 750 Hz
1500
Hz
20 MF
53881 1000
Hz
2000 Hz
4000 Hz
16.5MF
1 0358 1200
Hz
2500 Hz
5000 Hz
13.5MF
1035Q' 1500
Hz 3000 Hz
6000 Hz
12 MF
10434 1700
Hz
3500 Hz
7000 Hz
8 MF 10391 2500 Hz
5000 Hz
10000 Hz
7 MF
57529 3000
Hz 6000 Hz
11000 Hz
6 MF 10296 3500 Hz 7000 Hz
13000 Hz
4 MF
41040 5000 Hz
10000 Hz
3 MF
11937 7000
Hz 13000 Hz
Table 2:JBL Protection Capacitors for CompressionDrivers
NOTES:
1. The optimum value cited in Table 2 assumes that the
capacitor is active at approximately one octave below the
listed crossover frequency, assuring minimum acoustical
interference with crossover region performance while
maintaining a good degree of protection.
2. Somewhat smaller capacitor values may be required
for additional protection in high-power sound reinforcement
systems.
3. To shunt the reactive component of the compression
driver's impedance below horn cutoff, a 50 W resistor having
a value of two to three times the rated impedance of the
compression driver should be connected across the driver's
terminals.
CAUTION: Below the cutofffrequency ofthe capacitor,
thepoweramplifierwill be unterminated. Ifthe power
amplifierhas an outputtransformer(typical of vacuum
tubeamps and somesolidstateampsdesigned to drive
constant voltage lines), a 20W resistor equal toten times
the compression driverimpedanceshould be installed
across the amplifieroutputterminals.
8

SETUP & OPERATION
General Applications
When used for two-channelbiamplification, each
channel INPUT ofthe 5234A receives the full-range
programsignal from a linelevelsource such asa
preamplifier,mixingconsole or graphicequalizer.
Identical frequencyselectionmodules are installed
in both channels, andthe dividingnetwork separates
each ofthetwo channel'ssignals into high andlow
frequency bands. Each channel'sLOW and HIGH
outputsthenfeedindividualpoweramplifiers (or
discrete amplifier channels), which in turn drive
theirrespectiveloudspeakercomponents.
The 5234A also maybe used asa dividingnet-
work fora singlechannel of triamplification. In this
application, Channel 1 ofthe 5234A receives the
full-rangeprogram signal, and separates it into two
bands, one consisting oflowandmid frequencies,
theother of highfrequenciesonly. The Channel 1
HIGH output thenfeeds the amplifierwhichdrives
thehighfrequencydriver,while the Channel 1
LOW output (carrying lowandmid frequencies) is
connected tothe 5234A's Channel 2 INPUT. The
Channel 2 crossover point is chosen to fall inthe
regionwhere thelow frequencyloudspeaker's
operatingrangeends andthe midrangedriver's
operatingrangebegins.Therefore,Channel 2's
LOW output is suitable for feeding the amplifier
which drives thelow frequencyloudspeaker,while
its HIGH output is suitable for feeding the
amplifierwhichdrives the midrangedriver. In this
way, the CHANNEL 2 HIGH FREQUENCY
LEVEL controlbecomes a midrangedriverlevel
control andis independent ofthe CHANNEL 1
HIGH FREQUENCY LEVEL control,which
affects only the highfrequencydriver.*
As a convenience, the 5234A is supplied with
"blank" frequencydividingmodulesthathave
jumperresistorsinstalled in such a way that the
input signal is split andfedtothe channel's HIGH
and LOWoutputs. As such, the 5234Aoperates
as a fullybuffereddual distribution amplifier
(described inthe Installationsection of this
manual). Whilethis isnotthe primarypurpose of
the unit, the capability canbe usefulwhen itis
necessary to split a signal and driveseparatelines
and prevent any short or noisesource onone line
from causingproblems onthe other.
Typical Systems Employing the 5234A
Figures 12and13 illustrateconventionalloud-
speaker/amplifier systems for reference. Figures 14
through 17 depictvariousbiamplified andtri-
amplif Fed systems; theseshowtypicalexamples of
5234A applications,although byno means are they
all-inclusive. Figures 18 through 20 providewiring
details for typical systems.
*The frequencydivisioncould be donedifferently, with one chan-
nel handling the low-to-mid/high transition, and thatchannel's
HIGH output feeding the secondchannel,whichhandles the
mid-to-high transition. In that case, however, theHF LEVEL con-
trol ofthe firstchannelwouldaffect both the midrange and high
frequency drivers,while theHF LEVEL control ofthe second
channel wouldaffectonly the highfrequencydriver. The scheme
presented hereavoidsthisoverlapping of function,preserving
discrete control forthe midrange and highfrequencydrivers.
PROGRAM
SOURCE
LOUDSPEAKER SYSTEM
Figure 12— ConventionalTwo-Way System (Passive Network)
LOUDSPEAKER SYSTEM
Figure 13— ConventionalThree-Way System (Passive Network)
PROGRAM
SOURCE
PROGRAM
SOURCE
5234A
ACTIVE
FREQUENCY
DIVIDING
NETWORK
LOUDSPEAKER SYSTEM
Figure 14— DualChannelTwo-Way System (Biamplified)
9
ONE
AMPLIFIER
PASSIVE
FREQUENCY
DIVIDING
NETWORK
HIGH
LOW
PROGRAM
SOURCE
ONE
AMPLIFIER
PASSIVE
FREQUENCY
DIVIDING
NETWORKS
HIGH
MID
LOW
LOUDSPEAKER SYSTEM
FOUR
AMPLIFIERS
HF
LF
HF
LF
HIGH
LOW
HIGH
LOW
CHANNEL
CHANNEL
iissiiisiisi

PROGRAM
SOURCE
5234A
ACTIVE
FREQUENCY
DIVIDING
NETWORK
Figure15- Single ChannelThree-WaySystem (Triamplif ied)
(Duplicatethissetup fora stereothree-waysystem.)
FOUR
AMPLIFIERS
LOUDSPEAKER SYSTEM
ACTIVE
FREQUENCY
DIVIDING
NETWORK
FOUR
AMPLIFIERS
PROGRAM
SOURCE
PROGRAM
SOURCE
CHANNEL
2
5234A
ULTRA-HIGH
PASSIVE FREQUENCY
DIVIDING NETWORK
LOUDSPEAKER SYSTEM
PASSIVE
FREQUENCY
DIVIDING
NETWORK
SUBWOOFER
Figure 16— DualChannelTwo-WaySystem with Monaural
Subwoofer(s)
ACTIVE
FREQUENCY
DIVIDING
NETWORK
PASSIVE FREQUENCY
DIVIDING NETWORK
10
THREE
AMPLIFIERS
LOUDSPEAKER SYSTEM
LOUDSPEAKER SYSTEM
FULL
RANGE
HIGH
LOW
PASSIVE
FREQUENCY
DIVIDING
NETWORK
PROGRAM
SOURCE
Mono position
(#5) ONon both
DIPSwitches
SUBWOOFER
HIGH
MID
LOW
FULL
RANGE
5234A
PROGRAM
SOURCE
HIGH
LOW
Figure 17— CombiningElectronic & PassiveFrequency
DividingNetworks
LOUDSPEAKER SYSTEM
OPTIONAL SECOND SUBWOOFER
HIGH
MID
LOW
CHANNEL
llllllllll
ULTRA-HIGH
HIGH
MID
LOW

BLANCED
ORFLOATING
PGMSOURCE
UNBALANCED
PROGRAM
SOURCE
SIGNAL
AMPLIFIER
AMPLIFIER
AMPLIFIER
Figure18A— Wiring Diagram for Biamplified SystemUsingScrewTerminals
forConnections.(Dashlinesindicatebalancedconnections,solidlines
unbalancedconnections.)
Input and output wiring maybeusedinany combination, phone jacks
orscrewterminals.
LOUDSPEAKER SYSTEM
CHANNEL1
LOUDSPEAKER SYSTEM
CHANNEL2
PROGRAMSOURCE
(BALANCED)
TIP-RING-SLEEVE PHONEPLUG
AMPLIFIER
AMPLIFIER
LOUDSPEAKER SYSTEM
CHANNEL2 AMPLIFIER
Figure18B— Wiring Diagram for Biamplified SystemUsingPhoneJacks
forConnections.
11
CHANNEL2
AMPLIFIER
HIGH
LOW
CHANNEL1
SIGNAL
HIGH
LOW
EITHER
SIGNAL
(UNBALANCED)
SIGNAL
HIGH
LOW
LOUDSPEAKER SYSTEM
CHANNEL1

Figure19A— Wiring Diagram for Triamplified SystemUsing
Screw Terminal Connections
Input and output wiring maybeusedinany combination,
phone jacksorscrewterminals.
PROGRAMSOURCE
(BALANCED)
TIP-RING-SLEEVE PHONEPLUG
Figure19B— Wiring Diagram for Triamplified SystemUsing
PhoneJacksforConnections
AMPLIFIER
AMPLIFIER
TIP-SLEEVE
PHONEPLUGS
12
PROGRAMSOURCE
(BALANCED)
(UNBALANCED)
SIGNAL
AMPLIFIER
AMPLIFIER
AMPLIFIER
LOUDSPEAKER SYSTEM
HIGH
MID
LOW
EITHER
(UNBALANCED)
SIGNAL
SIGNAL
AMPLIFIER
LOUDSPEAKER SYSTEM
HIGH
MID
LOW

CHANNEL2
PROGRAMSOURCE
CHANNEL1
PROGRAMSOURCE
(LOW FREQUENCY"
LOUDSPEAKERS)
LOUDSPEAKER SYSTEM
OPTIONAL
Figure20— Wiring Diagram for Two-Way System with Monaural Subwoofer(s)
UsingScrewTerminals.Usecorresponding phone jacksifdesired.
NOTE: Usecrossover frequency cardsfor approximately 80Hzto150Hz
crossover point. Set both DIPswitchesfor mono. Second subwoofer and
amplifier are optional, and will be driven bythesamesignalasthe other
subwoofer.
13
(UNBALANCED)
SIGNAL
(BALANCED)
SIGNAL
AMPLIFIER
AMPLIFIER
LOUDSPEAKER SYSTEM
PASSIVE
FREQUENCY
DIVIDING
NETWORK
HIGH
LOW
SUBWOOFER
HIGH
LOW
PASSIVE
FREQUENCY
DIVIDING
NETWORK
AMPLIFIER
SUBWOOFER
(LOW FREQUENCY
LOUDSPEAKERS)

A SafetyProcedurefor Initial Powering
UpofTheSystem
Priorto full operationofthe dividing network/
amplifier/loudspeakersystem,itis important to
verify that thevariousfrequencybandsarecon-
nectedtothecorrectamplifiersandloudspeakers.
The following procedureshouldbe followed for
each programchannel prior tooperation.
1. With all POWER off(amplifiersincluded),set
the5234AHIGH FREQUENCY LEVEL control at
#2, andadjusttheprogramsource output to
minimumlevel.(Thesourcemaybewidebandpink
noiseormusic.)
2. Ifthepoweramplifiersareequipped with level
controls,adjustthemtoapproximatelyonequarter
ofthemaximum.
3. Turnontheprogramsource,the5234A,and
thepoweramplifier(s)forthechannelundertest.
4. Graduallyincreasetheprogramsourcelevel
until itjustbecomesaudible.
CAUTION: Ifthesoundcomesmainly from themidrange
orhighfrequencydriver(s),shutoffallpowerimmediately
andcheckallwiring.SincetheHIGH FREQUENCY LEVEL
controlisturneddown,thelowfrequencytransducer
should becomeaudiblefirst;ifthisisnotthe case, andlow
frequencysoundsareemerging from higherfrequency
drivers, theoutputwiringisreversedsomewherebetween
the5234Aandtheloudspeakersystem.Continuedopera-
tion couldeasilydamagecompressiondrivers.
5. With thelowfrequencytransducersproducing
bass, graduallyincreasethe5234AHIGH FRE-
QUENCY LEVEL control.(Ina triamplified system,
dothisfirstonthechannelwhichfeedsthe high
frequencydriver,Channel1.),Correctsystemwiring
will beverifiedifthetreblecomponentofthepro-
grammaterialincreasesinlevelandisemerging from
the high frequencydriver.(Ina triamplified system,
repeatthisprocedureforthechannelfeedingthe
midrangedriver,andverifytheHF LEVEL control
increases midrange output.)
Level ControlAdjustment
There areseveralpointsinthesoundsystem
wherelevelscanbeset.Naturally,itis important
that thegainstructurebeestablishedcorrectly
so that no input isoverdriven,andso that thebest
signal-to-noise ratio possibleismaintained.Beyond
that, however,itbecomesnecessaryto obtain the
correctlevelbalancebetweenthevariousfrequency
bandsso that overallfrequencyresponseconforms
tothedesiredcharacteristic.
Inmanyinstances,manufacturersofmulti-
amplifiedloudspeakersystemsprovideinstructions
forbalancinglevelsoftheindividualdriversinthe
system. Intheabsenceofformalinstructions,orin
the case ofcustomloudspeakersystems,balance
can beestablishedbyadjustinglevelstoachievethe
flattestresponseasmeasured with a real-time
analyzer anda pinknoisesource(muchlikethe
techniquedescribedintheSystemPhasingand
Signal PolaritySectionofthismanual).Alternately,
subjectiveevaluationoffamiliarprogrammaterial
can providea good meanstobalancelevels.In
fact,perfectly flat electro-acousticresponseis
seldomdesirableforthelistener,sosubjective
evaluationmaybethepreferabletechnique.
NO TE: Each program channel should be adjusted indi-
vidually. Subjective evaluation should be made while
seated in the normal listening location. If subjective analysis
is to be used and the power amplifiers are equipped with
level controls, initially adjust those controls to one half
their rotation and then regulate as necessary.
Subjective AdjustmentofBiamplifiedSystems
NOTE: The following procedure applies to each channel
of a 5234A used in a dual channel biamplified system.
1. With theHIGH FREQUENCY LEVEL control
at#0,adjusttheprogramsource output fora
comfortablelisteninglevel.
2. RotatetheHIGH FREQUENCY LEVEL con-
trol clockwise until a satisfactory high frequency
balance hasbeenobtainedintheprogrammaterial.
Ifnecessary, trim thesourceand/oramplifierlevels.
3. Turnoffthefirstchannel'ssignalsourceand/or
amplifiers,andadjusttheotherchannelpersteps1
and2 above.
NOTE: Once the HIGH FREQUENCY LEVEL and
amplifier level controls have been adjusted in this manner,
readjustment is not generally needed. Some method of
locking the power amplifier level controls (or at least
marking the desired settings) is recommended.
Subjective AdjustmentofTriamplifiedSystems
NOTE: When both channels of the 5234A are used for a
triamplified loudspeaker system, the recommended
installation is such that the CHANNEL 1 HIGH FRE-
QUENCY LEVEL CONTROL regulates the output of
the midrange driver, and the CHANNEL 2 HIGH FRE-
QUENCY LEVEL CONTROL governs the high frequency
driver (Refer to the General Applications Section and
Figure 19).
1. With both HIGH FREQUENCY LEVEL
controlsat#0,adjusttheprogramsource output
fora comfortablelisteninglevel.
2. RotatetheCHANNEL1 HIGH FREQUENCY
LEVEL control clockwise until a satisfactorymid-
rangelevelhasbeenobtained.
3. RotatetheCHANNEL2 HIGH FREQUENCY
LEVEL control clockwise until a satisfactory high
frequencybalancehasbeenobtained.Ifnecessary,
trim thesourceand/oramplifierlevels.
4. Itmaybenecessarytoreadjustthemidrange,
source andamplifierlevelstoachievethemost
desirableoverallbalanceoftheloudspeakersystem.
5. Ina two-channelsystem, turn offthefirst
channel's signalsourceand/oramplifiers,andadjust
theotherchannelpersteps1 through 4 above.
NOTE: After the HIGH FREQUENCY LEVEL controls and
amplifier level controls have been adjusted in this manner,
readjustment is not generally needed. Some method of
locking the power amplifier level controls (or at least
marking the desired settings) is recommended.
System Phasing& SignalPolarity
A majorfactorinthenaturalsoundcharacterof
a multi-wayloudspeakersystemistherelative
polarity andphaserelationshipbetweenthevarious
14

transducers. Physical driverpositioningandrelative
electrical polaritywillaffectfrequencyresponsein
thecrossoverregion,andimproperphaseor
polarityrelationshipsbetweenchannelscan cause
a lossof bass responseand/ordegradationofthe
stereo image.
NOTE: Where this discussion involves the exchange of
signal-carrying conductors, POLARITY is the topic, not
phase. Polarity reversal is nota 180° PHASE SHIFT,
although some people loosely describe it as such.
Physical driverpositioningaffectstherelative
phase ofsignals,but,forthepurposesofthisdis-
cussion, itisassumedthattheloudspeakersystem
is alreadyconstructedandtherefore nothing canbe
donetoalterthephaserelationshipbetweentrans-
ducers. Itistruethatina multi-waysystem with
separately packagedmidandhighfrequencyhorns
and bass bins,itisadvisabletoexperiment with
relativephasingbymovingdriverstoalignthe
acoustic planeofallthetransducerdiaphragms.
These techniquesarebeyondthescopeofthis
manual, however.Wehave limited thisdiscussion
tothemethodofestablishingthecorrectsignal
polarityforthecomponentsinanyonechannel
multi-waysystem,aswellasthecorrectpolarity
relationshipbetweenchannels.
Two suitablemethodsforestablishingpolarity
ofcomponentsina two-waysystemaredescribed
inthe following paragraphs.Eitheronemaybe used,
dependingontheavailabilityoftestequipment.A
three-wayorfour-waysystemwouldbetreatedina
similarmannerbyfirstestablishingtheproper
polarityforthetransducersofthelowfrequency
transducers, andthenprogressingtothemidrange
andhighorultra-highfrequencytransducers,as
applicable.
Objective Method ofPolarityDetermination
The following testequipmentis necessary:
a. A real-time1/3octaveorcontinuous spec-
trum frequencyresponseanalyzer.
b.A microphoneofknown,calibratedfrequency
response.
c. A pinknoisesource.
NOTE: To optimize the results obtained with this procedure,
the loudspeaker systems should be placed in their normal
operating locations.
NOTE: If different loudspeaker systems are used, or in a
stereo system, first establish common polarity among the
low frequency drivers as follows:
1. Connectthepinknoisesourcetotwochannels,
set thetwochannelsforthesamecomfortablelevel,
andobservelowfrequencyresponseonthe real-
timeanalyzer (RTA).
2. Nowintentionallyreversethepolarityofone
lowfrequencytransducerandseewhetherthelow
frequencyresponsediminishesor increases. Ifit
diminishes, thesystemhadbeencorrectlywired
initially;returnthetransducerwiringtotheoriginal
polarity.Iflowfrequencyresponse increases, the
twochannels'lowfrequencytransducerswere
reversed inpolarityrelativetooneanother;leave
thewiringinthe"improved"configuration.
NOTE: In stereo or multi-channel systems, folio w steps 3
and 4 below for one channel at a time.
3. Usingpinknoiseasprogrammaterial,adjust
thesystemvolumetoa comfortablelisteninglevel.
Then setthelevelofindividualtransducerstodis-
playtheflattestoverallfrequencyresponseonthe
real-timeanalyzer.
4. Reverse thepolarityofthehighfrequency
driverandobservetheeffectonthefrequency
response through thecrossoverregion.Proper
transducerpolarityisindicatedbytheflattest
frequencyresponse through thecrossoverregion
(as shownbytheRTA).
5. Onceproperpolarityamongthetransducers
ofa loudspeakersystemhasbeendetermined,
otherloudspeakerssystemsintheinstallation
(assuming theyarethesamemodel)maybecon-
nectedaccordinglyanddouble-checked with the
RTA.
Subjective Method ofPolarityDetermination
The following methodisrecommendedto
establish properpolarityoftheloudspeakersystem
whennotestequipmentisavailable.Tooptimize
theresultsobtained with thisprocedure,theloud-
speaker systemsshouldbeplacedintheirnormal
operatinglocations.
NOTE: If different loudspeaker systems are used, or in a
stereo system, first establish common polarity among the
low frequency drivers as follows:
1. Connecta programsourceknowntocontain
substantial bass totwochannels,setthetwochan-
nels forthesamecomfortablelevel,andlistento
theintensityofthelowfrequencies.
2. Nowintentionallyreversethepolarityofone
lowfrequencytransducerandseewhetherthelow
frequencyresponsediminishesor increases. Ifit
diminishes, thesystemhadbeencorrectlywired
initially;returnthetransducerwiringtotheoriginal
polarity.Iflowfrequencyresponseimproves,the
twolowchannels'lowfrequencytransducerswere
reversed inpolarityrelativetooneanother;leave
thewiringinthe"improved"configuration.
NOTE: In stereo or multi-channel systems, follow steps 3
through 5 for one channel at a time.
3. Adjustthevolumefora comfortablelistening
level andsettheapproximatesystembalanceusing
thenoiseheardbetweenstationsofanun-muted
FM tuner.
4. Listentoa recordingofa malevoicelong
enoughtobeaccustomedtotheperformanceof
theloudspeakersystem.
5. Reverse thepolarityofthehighfrequency
loudspeaker,whichwillproducea changeinvoice
character. Whenthetransducersareincorrect
polarity,a recordedmalevoiceshouldsound
naturalandexhibitpresence(an"up front"
quality),incontrasttotheundesirable"hollow"
soundheardwhenthetransducersareoutofphase.
NOTE: If the crossover point lies above 2 kHz, reversing
the polarity of the high frequency driver will create little
(if any) perceptible difference in system performance. The
15

"correct"polarity in such a case will be that which yields
the most natural quality with a variety of program material.
6. Onceproper polarity amongthetransducers
ofa loudspeakersystemhasbeendetermined,other
loudspeakersystemsintheinstallation(assuming
theyarethesamemodel)maybeconnected
accordingly.
Selecting theLowFrequency
High-Pass FilterOptions
As describedintheInstallationSectionofthis
manual, the5234Aprovidesforlowfrequency
high-pass contouring byuseofbinaryDIPswitches.
Whilethe method ofsettingtheseswitcheswas
discussed, itremainstotreatthereasonsfor
choosingvarioussettings.
Inthemostbasicterms,onecanselect flat
response (norolloff),ora 12dBperoctaveroll-
offbelow20Hz,30Hzor40Hz.Whilethespecific
filter characteristicscanbefurthermodified,in
generalthemajorpurposeofhigh-pass filtering is
toremovesubsonicsignalenergybelowthelowest
useable loudspeakerfrequency. Without high-pass
filtering,subsonicsignalcontentcanwasteamplifier
power(loweringtheavailableheadroom),andin-
duce distortion inaudibleregionsby modulating
thehigher bass andmidrangefrequencies.
Oneofthespecialfeaturesofthe5234Aisthe
6 dBboostat20Hz,30Hzor40Hzselectable
with theDIPswitches(theQ=2setting).This
moderateboostequalization,coupled with the
high-passfiltering,can often improvetheacoustical
response ofa soundsystem.
The useofthe6 dBboost/high-pass filter option
maximizes theusefullowfrequencyacoustic output
whileminimizingconeexcursions both inandout
ofthesystemoperatingrange.Theuseofthis
option requirescertainprecautions,andcareshould
betakennottoexceedthepowerratingsofthe
system. Bear in mind that the6 dBofboostresults
ina four-timesincreaseinpower from theamplifier
totheloudspeakersystem.However,thisboostis
restrictedtotheoctavejustabovethesystem's
lower cutoff.
Theboost/high-pass filter functionshould
normallybeappliedtoventedbox systems, setto
theboxtuningfrequency.Theboost/high-pass
filter canbeused with closed-box(sealed)loud-
speaker systems,butbecauseofthe high cone
excursions ofthesesystemsnear cutoff, caution
mustbetakenso that theconesdonot "bottom
out" during high level passages. Ingeneral,
forsealedboxsystemsitisbettertouseoneof
thehigh-pass filter settings that producea rolloff
without a peak (e.g., with a Q 0.707).Ifitisdesir-
able that theloudspeakersystemhavea slightpeak
near anacoustic cutoff of30Hz,the5234A's
slightlyunderdamped rolloff (Q=0.84)maybe
selected.
Suggestions forJBLProfessionalSeriesProducts
1. Generally,JBLstudiomonitorsshouldhave
high-pass filtering at30Hz.
2. Soundreinforcementsystemstunedto40Hz
shoulduse40Hzhigh-passfiltering.Thisincludes
most4500seriesenclosuresand4600systems.
3. Forverylowcrossoverfrequencypointsin
subwooferapplications,monaural,summingofthe
lowfrequency outputswill tendtocancelextrane-
ouslygenerated,oppositelypolarizedlowfrequency
signals suchasturntablerumble,discwarpand
acoustic feedback.Therefore,settingtheDIP
switches fora monauralLOW output canincrease
themaximumusableacoustic output level.
4. The6 dBboost/high-pass filter option may
beused with anyJBLProfessional Series system
whenrequiredto flatten andextendthelow-
frequencyresponse,provided that the filter
frequencyisappropriatelychosen.
Blank CrossoverCardAssembly
In addition tothestandardcrossovercards,
circuitsforothercrossoverfrequenciesmaybe
assembled onblankcrossovercardsusingstandard
components.Filterslopes(12dBor18dBper
octave) areidenticaltothoseofthestandard
crossover cards.Thecrossoverfrequencycanbe
written onthecardbracketand will appear through
the front panelwindowofthenetwork.
Figure 21- 12dB/OctaveCrossoverCard(JBL Model 52-5120)
Figure 22- 18dB/OctaveCrossoverCard(JBL Model 51-5130)
16

Table3:12dB/OctaveCrossoverCardComponentValues
Resistors areall1/4W,± 5%tolerance.Capacitorsareall± 5%
tolerance, metallized polyesterunlessotherwise noted.
Crossover Frequency Capacitors
(Cl'-C5')
Resistors
(Rl'-R5')
50Hz .22MF 10kn
70Hz .22uF 7.5kil
100Hz .22IdF 4.7kil
200Hz .12jdF 4.7kil
250Hz(JBLPartNo.52-5121) .018iiF 24kil
300Hz .082JUF 4.7kil
400Hz .056juF 5.1kit.
500Hz(JBLPartNo.52-5122) .015IdF
15 kil
600Hz .039fdF 4.7kil
700Hz .032jdF 5.1k£l
800Hz(JBLPartNo.52-5123) .027JUF 4,7kil
900Hz .027IdF 4.7kil
1.1kHz .022JUF 4.7kil
1.2kHz(JBLPartNo.52-5124) .082jUF 11kil
1.5kHz .012JUF 6.2kil
2 kHz .012IdF 4.7kil
2.5kHz .0082fdF 5.6kil
3 kHz .0068IdF 5.6kH
3.5kHz .0068MF 4.7kil
4kHz .0056IdF 5.1kn
4.5kHz .0039IdF 6.2kil
5 kHz(JBLPartNo.52-5125) .0015jUF 15 kn
5.5kHz .0033IdF 6.2k!2
6 kHz .0033jUF 5.6kil
7kHz(JBLPartNo.52-5127) .018UF 11kI2
7.5kHz .0027jUF 5.6k£2
8kHz .0027IdF 5.1kil
8.5kHz .0012fdF 11k£2
9 kHz .0022UF 5.6kil
9.5kHz .0012IdF 10kn
10kHz .0022IdF 5.1k!2
JBL PartNo.52-5140 .018/iF
Rl 27kil
Designedforthe4343
R2 27k£2
and4350 Studio Monitors
R3 22kn
R4 22kn
R5 22kT2
JBL PartNo.52-5130
Cl'0.039 IdF
Rl'll k£2
Designedforthe4435
C2'0.082 IdF
R2'll k£2
R3'll kSl
and4430 Studio Monitors
C3'0.0013 idF
R2'll k£2
R3'll kSl
C4|0.01 jdF
R4'l3 kn
C 5'jumper
R5'N/A
R6'N/A
C6'jumper
R5'N/A
R6'N/A
NOTE: Thevaluesforthecrossoverfrequenciescanbecalculated
byusingthe formula RC=Q.l125.WhereR istheresistanceinkn,
F
C isthecapacitanceinIdF, andF isthefrequencyinHz.The
recommended valueforR is4.7kn.
Table4:18dB/OctaveCrossoverCardComponentValues
Resistors areall1/4W,± 5%tolerance.Capacitorsareall± 5%
tolerance, metallized ployesterunlessotherwise noted.
Crossover Frequency Capacitors
Resistors
80Hz
CI N/A
Rl N/A
(High Pass Only) C2'
N/A
R2'
N/A
C3'
N/A
R3 N/A
C4'
.33 juF R4
11kfi
C5'
.33 IdF
R5'
4.3 kn
C6'
.33 IdF
K6'
75 ki"2
100Hz
Cl' .39jUF
Rl' 6.8kil
C2'
1.0IdF
R2'
6.8kn
C3'
.056juF
R3' 6.8kI2
C4' .15 fdF
R4'
9.1kO
C5'
.15 IdF
R5'
3.6k£l
C6'
.15 IdF
R6'
62kil
160Hz
Cl'
.33 IdF
Rl'
4.3 k!2
C2*
.82IdF
R2'
4.3 kn
C3'
.047fdF
R3'
4.3 kil
C4*
.056juF R4f
13' kO
C5' .056jUF
R5" 5.1kn
C6'
.056IdF
R6'
5.1k£2
(Table 4 continued nextcolumn)
Crossover Frequency Capacitors
Resistors
200Hz
Cl'
.22IdF
Rl'
5.1kil
C2'
.56IdF
R2'
5.1kil
C3' .033 juF
R3 5.1kil
C4'
.039IdF
R4' 15 kH
C5' .039IdF R5'
5.6kil
C6.' .039uF R6'
100kil
290Hz
Cl'
.12IdF Rl'
6.2kft
(JBL PartNo.
51-5145
C2'
.33 IdF
R2'
6.2kn
Designedforthe4345
C3'
.018juF R3'
6.2kf2
and4355 Studio
C4'
.033 IdF R4'
12kn
Monitors)
C5'
.033 IdF
R5'
4.7kn
C6'
.033 IdF
R6'
82kil
300Hz
Cl' .12IdF
Rl'
5.1kil
C2'
.22IdF
R2'
5.1kn
C3'
.012IdF
R3'
5.1kil
C4'
.033 juF
R4'
6.8kn
C5'
.033 IdF
R5'
2.7kn
C6'
.033 IdF
R6'
47kn
500Hz
Cl'
.082IdF
Rl' 5.1kO
(JBL PartNo.
51-5132)
C2'
.22[dF
R2'
5.1kn
C3' .012jUF R3'
5.1kn
C4'
.033 IdF
R4'
6.8kn
C5'
.033 IdF
R5'
2.7k£2
C6'
.033 /dF
R6' 47k^2
800Hz
Cl' .056IdF
Rl'
4.7kO
(JBL PartNo.51-5133)
C2'
.15 IdF
R2' 4.7kI2
C3' .0082jUF R3'
4.7kil
C4'
.012}dF
R4'
12kil
C5'
.012IdF
R5'
4.7 kJT2
C6'
.012fdF R6'
82kil
1 kHz
Cl' .039IdF Rl' 5.6k$
C2'
.1 jUF
R2'
5.6kn
C3'
.0056IdF
R3'
5.6kn
C4'
.015IdF R4'
7.5kn
C5'
.015IdF
R5'
3 kn
C6'
.015/dF
R6'
51 kn
1.2kHz
Cl' .039IdF
Rl'
4.7kn
C2'
.1 IdF
R2'
4.7kil
C3'
.0056 MF
R3'
4.7kn
C4'
.0082(dF
R4'
12kn
C5'
.0082IdF
R5'
4kn
C6'
.0082fdF
R6'
82 kn
1.6kHz
Cl'
.033 juF Rl'
4.3 kil
C2'
.082fdF
R2'
4.3 kn
C3'
.0047fdF
R3'
4.3 kn
C4'
.0056IdF
R4'
13 kn
C5'
.0056juF R5'
5.1kn
C6' .0056IdF
R6'
91kn
2 kHz
Cl'
0.22MF Rl'
5.1kn
C2'
0.56/iF
R2'
5.1kn
C3'
.0033jtiF
R3' 5.1kn
C4' .0039fdF R4'
15 kn
C5' .0039IdF
R5'
5.6kn
C6'
.0039 MF R6'
100kn
5 kHz
Cl' .0082uF
Rl'
5.1kn
C2'
.022MF
R2' 5.1kn
C3' .0012IdF
R3'
5.1kn
C4'
.0015IdF R4'
15 kn
C5'
.0015juF R5' 5.6kn
C6'
.0015jUF
R6'
100kn
5.5kHz
Cl .0068IdF
Rl''
5.6kn
C2
.018MF
R2'
5.6kn
C3'
.001MF R3'
5.6kn
C4'
.0018MF R4'
12 kn
C5'
.0018MF
R5'
4.7kn
C6'
.0018MF
R6'
82kn
3 kHz
Cl'
.0056 MF
Rl'
4.7kn
C2'
.015MF
R2'
4.7kn
C3'
.0082 MF (use
R3'
4.7kn
Silver Micaonly)
C4
.0012MF R4'
12 kn
C5' .0012MF
R5'
4.7kn
C6' .0012MF
R6'
82kn
10kHz
Cl'
.0039IdF
Rl'
5.6kn
C2'
.01MF
R2'
5.6kn
C3'
.00056 MF(use
R3'
5.6kn
Silver Micaonly)
C4'
.0015MF R4'
7.5kn
C5'
.0015MF R5'
3 kn
C6'
.0015MF R6'
51kn
17

JBL 5234A PARTS LIST
Parts list continued on flap.
18
Circuit JBL
DescriptionPartNo.
Description/Notes
BARRI ER INSULATOR
61656
CAPACITOR — All capacitors arein (JLF unless otherwise noted.
C201 13189 0.011400
V
JACKS
PHI
82716
PH2
82716
PH3 82716
PH4
82716
PH5
61441
PH6
61441
KNOBS
54969
Power Switch
52192 Level Control Qty.2
LINE CORD (120V)
W301 59613
Black
POWER TRANSFORMER
Tl
61646 3
SWITCHES
S201
54953
DPDT
Power Switch
S30I 55355
Line Voltage Select
TERM!
NAL STRIPS
TBI
86422
TB2 86422
TB3 86422
CONNECTORS
Jl 52599
6 pin
J101 52599
6 pin
CAPACITORS — All capacitors areinjuF unless otherwise noted.
Cl
48141 4.7
63 V
C2 48141 4.7
63 V
C3
48141 4.7
63 V
C4
48141 4.7
63 V
C5
11397
25 25
V
C6 48505 100
25 V
C7
54998
0.1 100
V
metal poly.
C8
54998
0.1 100
V
metal
poly.
C9
48433 20
pF
500 V
mica
CIO 48433 20
pF
500 V
mica
Cll
54998 0.1 100
V
metal poly.
C12
54998 0.1 100
V
metal poiy.
C13
59127
0.27 100
V
metal
poly.
C14 59127
0.27 100
V
metal
poly.
C15
59127
0.27 100
V
metal
poly.
C16
59127 0.27 100
V
metal poly.
C17 58725-2206 220 pF
50 V
C18 58725-2206
220 pF
50 V
C19
58730-2206
220 pF
25 V
C101
48141 4.7
63 V
C102
48141 4.7
63 V
C103
48141 4.7
63 V
C104 48504
100
25 V
C105
11397
25 25 V
C106
48504
100
25 V
C107 54998
0.1 100
V
C108
54998
0.1 100 V
C109
48433 20
pF
500 V
mica
C110
48433 20
pF
500 V
mica
C113
59127
0.27 100
V
C114
59127 0.27 100
V
C115
59127
0.27 100
V
C116
59127
0.27 100
V
Circuit
JBL
Description Part No.
Description/Notes
RESISTORS — Resistors are fixed. carbon-film, 1/4W,±5%
unless otherwise indicated
carbon-film, 1/4W,±5%
Rl 58683-4702
47 k
±2%
R2
58683-4702
47 k
±2%
R3 58683-4702 47 k
±2%
R4 58683-4702
47 k
±2%
R5
35549 100
R6 35621 /
100 k
R7
36538 2.7 m
R8
36538
2.7 m
R10
36425 47
Rll
36481 10 k
R12 36481
10 k
R13
36410
10
R14
36410
10
R15 36410
10
R16 36410
10
R17
36425 47
R18
35621
100 k
R19 35621
100 k
R20 58683-330 3.3 k
R21
58683-3600 360
R22
58683-1200
1.2 k
R23
58683-3001 3 k
R24
58683-3001
3 k
R25
58683-3002 30 k ±2%
R26 58683-3002
30 k +2%
R27
36481
10 k
R28
36481 10 k
R29
35549
100
R30 35621
100 k
R31
36482 11 k
R32 36483 12
k
R33
36410
10
R34
36410
10
R35
36465 2.2 k
R36
36465 2.2 k
R101
58683-4702 47 k
±2%
R102
58683-4702
47 k
±2%
R103
58683-4702
47 k
±2%
R104
58683-4702
47 k
±2%
R105
35549
100
R106
35621
100 k
R107
36538
2.7 m
R108
36538
2.7 m
R110
36425 47
Rill
36481
10 k
Rll2
36481
10 k
R113
36410
10
R114
36410
10
R115
36410
10
R116
36410
10
R117
36425 47
R118
35621
100 k
R119
35621
100 k
R120
58683-3301 3.3 k
R121
58683-3600
360
R122
58683-1201
1.2 k
R123
58683-3001
3 k
R124
58683-3001
3 k
R125
58683-3002 30 k
R126
58683-3002
30 k
R127
36481
10 k
R128
36481
10 k
R129
35549
100
R130
35621
100 k

Circuit
JBL
Description
Part No.
Description/Notes
POTENTIOMETERS
R9
51367
10k
R109 51367 10k
RELAYS
SI
61322
S101
61322
SEMICONDUCTORS
CR1
52544 1N914B
CR2
52544
1N914B
CR3
52544
1N914B
CR4 52544
1N914B
CR5
39869
1N4003
CR6 61324
16V 1 W ± 5%
CR7
39869
1N4003
CR8
39869
1N4003
CR9
39869
1N4003
CR10
39869
1N4003
CR101 52544 1N914B
CR102 52544
1N914B
CR103 52544
1N914B
CR104
52544 1N914B
Ql
55201
Q2
48340
Q3
55201
Q4
48340
Q5 55411
Q6
55201
Q7
55201
Q8
55412
Q9 55411
Q101
55201
Q102
48340
Q103
55201
Q104
48340
Ul
59028
TL074CN Dual OP AMP
U2 61325
TL082CP Dual OP AMP
U101
59028
TL074CN Dual OP AMP
SWITCHES
SI
61322
S101 61322
SEMICONDUCTOR
CR2
59894
Green LED
JUMPERS
Rl
51430
Jumper
CR1
51430
Jumper
LENS CAP
59893
Green
RESISTORS — All resistors are fixed, carbon-film
unless otherwise indicated.
,1/2W,+5%
R7
10940
1 k
R8
10940
1 k
CONNECTOR
51634

JBL
ProfessionalDivision
James B. LansingSound, Inc., 8500BalboaBlvd., P.O. Box 2200, Northridge, California91329U.S.A.
UBL/harman international
Printed in U.S.A.5234A l/SM11/81
PN61308