Krell Industries Power Amplifier KST100 Quick start guide

A, INTRODUCTION
Thankyou for your purchase of the KRELLKST-100
poweramplifier.Thisamplifier represents the latest
evolution ~n amplifier technologyand incorporates many
innovativedesign features.
Toobtain the best performancefrom. your KST-100,
careful attention sfiould be paidto placement,installation
andoperation. Athoroughunderstandingof these details
will help insure satisfactory operationandlonglife for
the KST-100and related system components.
This Owner’sReferenceis divided into several sections,
eachdesignedto perforn}_,a different function. Asyou
.read throughthis Owners Referencey~ouwill becgme
19etter acquaintedwiththe features andfunctionstlaat
makethe-KST-100a superb value. AQuestion and An-
swer section is also included whereanswersto common
questions are provided. Shouldyou haveany questions or
suggestionspIease feel free to contact yourauthorized
dealer or the KRELLstaff for assistance.
In the unlikely, event that your.KST-1.00shouldrequire
serviceyouwill be pleased_to k~nowthat it is backedbya
c.omprehensiveCustomerbatistaction policy and one of
tlae mostadvancedservicefacilities in the industry.~t~or
detailed informationon the termsand conditions ot ser-
vice, please consult yourwarranty.registration card, your
authorized KRELLDealer or Distributor.
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TABLE OF CONTENTS
4UNPACKING AND ASSEMBLY
5BASIC INSTALLATION AND OPERATION
6 INPUT AND OUTPUT CONNECTIONS
8AMPLIFIER OPERATION
9PROTECTION CIRCUITRY
10 MONAURAL CONVERSION OPERATION
11 REAR PANEL DESCRIPTIONS
12 QUESTIONS AND ANSWERS
14 SPECIFICATIONS
15 WARRANTYAND SERVICE INFORMATION
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B. UNPACKING AND ASSEMBLY
NOTE:Doto the weightof the KST-100it is s.trongly
advised that unpackingand placementis completedby at
least twoindividuals.
1. Openthe boxon one end.
2. Foldbackthe flaps onall four sides of the boxand
carefully roll it overonto the exposedend.
3. Pull the boxstraight up andoff exposingthe foam
packingmaterial.
4. Laythe foamcontainer downon the floor and pull off
the top section.
Thefollowingitems will nowbe visible:
1
1
1
4
KST-100stereo amplifier
Warrantycard
ACpower cord
Rubber bottoms
NOTE:If any of these items are not included please
contact yourauthorized dealer immediatelyfor assis-
tance.
5. Pull the amplifier out of the remaininglayer of foam.
6. Removethe plastic bag fromthe amplifier.
NOTE:Saveallpacking materials. If you mustship. your
KS.T-100in the future, repack,the unit in its original
packagingto prevent transit damage.
CAUTION:Donot connect the power cord into the AC
mainsbefore completingthe Installation section.
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C. BASIC INSTALLATION
AND OPERATION
1. Place the KST-100on a firm level surface awayfrom
excessivedirt or moisture.Ideally the amplifier shouldbe
placedas close to. the speakersas possible. It is always
preferable to runlong_interconnectcables to the amplifier
andkeep speaker calSle length to.a minimum=Speal~er
cable does addan impedanceat the output ot the ampli-
fier, regardless of the cable’s g.uage. AIIKRELLamplifi-
ers wilI drive the lowestimpeclanc,es withease. When
impedanceis added,the amplifiers poweris literally
wastedin driving cable. Longspeakercables reduce the
maximumpowerthat can be delivered to the speakers.
2. Amplifiers dissipate muchof the powerthey consume
in heat. TheKST-1~00shouldbe installed in a location
that providesunobstructedventilation. If youhavet.o
install the unit onshelvesor in a cabinet, extra ventilation
maybe necessary. This can be accomplishedwith "whis-
per"-type fans. Consultyourdealer f-or assistance.
Generally,withthe front andrear of a cabinetopen,2-3
inches of clearance oneachside and8 inches of clear-
anceabovethe amplifier should provide adequateventi-
lation.
Theexact dimensionsfor the KST-100are in the Specifi-
cations Section below.
3. The KST-100should have a dedicated line and should
only be operated with the powercord supplied. Useof
other powercords maydamagethe ampIifier or void its
warranty. Please consult KRELLor your dealer BEFORE
using a~nydevicesdesignedto alter or stabilize the AC
pgwertor the KST-100.If youhave any questions about
placementor ACpowerconditions please consult
KRELL.
4. Thefeet on the KST-100can be used in several differ-
ent ways. Theyare madefrom machinedDelrin and are
supplied with separate threaded rubber bottoms. The
rubber bottomscan be screwedinto the feet tor protec-
tion of fragile surfaces suchas hardwoodfloors or furni-
ture. For use on rugs, werecommendusing.the feet wi.th-
out the rubber bottoms.KST-100feet can also accept tlae
KRELLAMDs(Acoustic Mass Damper). These improve
the amplifier’s sonic performancein mostinstallations.
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D. INPUT AND OUTPUT
CONNECTIONS
CAUTION:Whenmaking connections to this component
or any other, makesure the poweramplifier is OFFand
the preamplifier is in the MUTEor STANDBYmode.
1. Connectthe speakercables.to. the outputterminalsof
the amplifier. Tile KS~T-100utilizes twosets of parallel
5-w~ybindingposts tor the left andright channels.This
confi~gurationmakescable connectionsand bi-wiring
simple.
NOTE:Thebinding, posts are of the highest quality but
will breakif over.tigla.tened.In.se.rt wireor spadeluginto
the connectoranOtighten until there is no movement
fromthe cable.
CAUTION:Makesure all cable terminations are of the
highest quality, free fromfrayedends, shorts or cold
solderjoints.
2. Connectthe interconnect cables fromyour preampli-
fier to the input of the KST-100.
Thewiring to and fromthe amplifier, andall components
in general, should be arranged ma neat, organizedman-
net. Specifically_, ACwires shouldbe separated from
audio wires. Ttiis practice avoids humor other unwanted
noise frombeing inducedinto the system.
TheKST-100has balancedand Single-endedi,np.uts. The
balancedinputs use 3-pin XLRconnectors anti the
single-ended inputs use standard RCAconnectors.
CAUTION:Useonly one input to the amplifier at a time.
TheKST-100is shipped with shorting pins in the XLR
inputs. Thesepins sliould remainin the XLRinputs if
you are operating the KST-100in the single-ended mode.
.Whent.he shortingpinis inserted, pin 1 andpin 3 are
shorted together. Tile shorting pins mustbe removedto
connectthe KST-100for balancedoperation.
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Thepin assignment for the XLRis:
pin _1-=shield (ground) .
p!n 2 = non-inverting~nput(hot)
p~n3 - inverting input
NOTE:TheRCAcenter conductor for each channel is
wiredjn,parallel withpin 2, the non-inv.ertedinput. Only
oneot tlaese inputs shouldbe connecteclto a preamplifier.
3. Insert the ACpowercordinto the receptacle located on
the backof the KST-100.Insert the other endinto the
wallACr_.eceptacle. (Referto sectionC, BasicInstalla-
tion and Operation, for ACpowerrequirements)
7

Eo AMPLIFIER OPERATION
1. Pushthe blackbreakertypeswitc.h on the front of the
amplifier to turn it on. TheLEDin the switchwill illumi-
nate.
Whenturningonthe system,the a _m,plifier shouldalways
be last. Uponturn-on, the amplifier s outputs are not
connectedtothe speakers. After the protection circuits
havedeterminedthat the unit has completelystabilized,
the.speaker relays will be engaged.YouwilI hear a click
at th~s point. Theamplifier is nowreadyto use. The
amplifier will be at temperatureandsoundits best after
approximately30 minutes.
2. Withthe preamplifie.r in the Muteposition, or volume
control fully attenuated, select a source. Turnthe volume
control upto yourdesired listening level.
3. Understandingthe operationof the amplifier !s very
easy. Equallyimportantis an understandi.ngof the care
that should be exercised whenoperating the systemas a
whole,in relation to the enormouspoweroutput of the
KST-100.Simplemistakes, such as switching between
active sources withoutmutingthe preamplifier output, or
bumping/miscuinga cartridge., can genera~telarge tran.-
sients at lowfrequencies.Withthis type9t transient the
KST-100can generate enoughpowerto damagemost
loudspeakers. All switching of sources shouldbe done
withthe preamplifierlevel either mutedor fully attenu-
ated. Inputs to the amplifier shouldnot be changedwhile
the amp-lifteris on.
NOTE:Care must b.e taken whensetting high playback
levels. Becauseof their tremendousreserve of-clean
power,KRELLamplifiers safely drive speakers to higher
soundpressure levels than other amplifiers. Thisalso .
meansdriving the speakersto their fimit. Alwaysturn the
level downat the first sign of distortion.
Whenturning the systemoff, the amplifier should
ALWAYSbe first. This avoidsthe possibility of a turn-
off transient fromsomeother componentgetting to the
speakers.
8

E PROTECTIONCIRCUITRY
Thereare no fuses in the KST-100.Theamplifier is
protectedbya series of non-intrusive,opto-c_o,upled
circuits that constantlyevaluatethe amplifiers operation.
Appropriateprotective action exists for DCconditions,
short circuit, oscillation, ACpoweranomalies,high
groundresistance and out-of:phase ground. Collectively
the protection circuitry is designedto avoiddamageto
the amplifier or speal~erscausedbyothe.r defective com-
ponents, faulty wiring, mishandlingof tlae systemor
amplifier failure. Whenthe protection circmt is engaged,
the a.mplifierwill shut off andshort its output. After
resolving either the input or output problemthe amplifier
can be turned on.
Theamplifier also has a circuit breakertype powe.r
switchthat protects it fromexcessive ACcurrentdraw.
Shouldthe breaker shut off frequently or becomedifficult
to pushONcontact yourdealer or Krell Industries.

G. MONAURALCONVERSION
AND OPERATION
TheKST-100can be easily cgnverted into a 400watt
monauralamplifier. Toswitcla the amplifier to mono
followthese instructions.
1. Removethe topcover fromthe amplifier via 8 topcover
screws.
2. Findthe toggleswitchlocated at the rear of the ampli-
fier mountedonthe circuitboard.. Mo.vethe toggle switch
overto the Monosetting printecl ontlae circuitboard.
3. Reinstall the topcoverand the 8 topcoverscrews.
OPERATION
1. Theinput of the KST-100in Monooperation is the
Left channelinput only.
Connectthe Left output of yourpreamplifier to the Left
channelinput of the ~lesignated left channelmonoampli-
tier. Connectthe rig~ht outputof yourpreamplifierto the
left channelinput ot the designatedright channelmono
amplifier.
2. Theoutput of the KST-100in Monooperation is the
positive outside bindingposts of eachchannel. Theinside
Blackbindingpost of eachchannelin monois not opera-
tional.
Connectthe left and right channelouter bindingposts on
eachamplifier to the loudspeaker.
NOTE:Paycareful attention to the labeling onthe.
backpanel of the KST-100whenmakinginput anti output
connections. Connectingthis amplifier i~or monaural
operation can becomeconfusing.
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H. REAR PANEL DESCRIPTIONS
INPUTS:
Balanced via 3 pin XLRconnector
Single ended via RCAconnector
XLR PIN CONFIGURATION
p!n 1 Shield (ground)
p!n 2 Non-invertingor 0 degrees (hot)
p~n3 Inverting or 1-80degrees
OUTPUT:
Twopairs of five-waybindingposts in parallel,
per channel
OTHER:
Standard ACreceptacle
20 ampcircuit breaker type powerswitch
OPTIONS:
Black Faceplate
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I. OUESTIONS AND ANSWERS
Q. ShouldI leave the KST-100ONat all times?
A. Althou.ghyou could leave the KST-100ONat all
times withoutfear of damageto the amplifier, werecom-
mend30 minutesof warm-up_before critical listening and
switchingthe amplifier off whennot in use.
~. WhenI pushthe powerswitch onthe front of the
ST-100,the amplifier doesn’t turn ON.Whatshould I
do?
A. Unplugthe amplifier fromthe ACreceptacle and
removettie input fromthe amplifier. Checkthe output
connections,,then plugthe amplifier .backin. Pushthe
power.switch onthe front panel. If the powerswitch
resists being turned ONor shuts OFFonce engaged,
unplugthe unit andcall yourdealer or Krell industries.
t~. WhenI turn the amplifier onthere is a loud hum
roughthe speakers. There wasnever a humbefore the
KST-100wasin the system. Whatshould I do?
A..O. ften whena newcomponentis introduced into an
auclio systema hummay15ecomepresent. This is often
causedby_a groundloopin the system.Tryputting a 3
prongto 2 prongACadaptor (cheate.r plug) on the
powercord, lifting the groundfromthe unit. This should
makethe humdisappear. If not, try another adaptorelse-
wherein the system.
NOTE:Alwayskeep one major audio component
grounded.
NOTE:Eventhough the groundis lifted fromthe power
amplifier,it .is still groundedvia the interconnectcables
throughoutthe rest of the system.
Q. CanI use special audio powercords on the KST-100?
A. Youcan experimentwith special powercords as long
as they ar, e groundedon bothendsandmeetthe
amplifier s I5 amppowerrequirement.
12

Q. After the amplifier is playing for about one hour it
becomesvery hot. Is this normal?
A. Yes. Dueto the design of the KST-100it will become
quite warmwhendriven hard. If the amplifier should
have a severe temperature inbalance between the left and
fight channel, unplugthe unit and call your authorized
dealer or Krell.
Q. I tried a ne.w. preamplifier in myaudio system and
when| turnecl ttle unit ontlae KST-100shut off. Is the
amplifier defective?
A. Morethan likely the amplifier is not defective. When
connecting components you should always keep the
amplifier off. Theamplifer sensed a bad input signal and
slaut off, protecting itself and the speakers.
There also could have been a bad cable connection or
excessive DCoffset comingfrom the output of the. pre-
amplifier. Beforeturning t, he amplifier on, checktlae
input cables. If that doesnt help, bring the preamplifier to
the dealer for testing.
13

¯ I. SPECIFICATIONS
KST-100
GAIN
26dB,
SIGNAL-TO-NOISE
102dB unweighted
THD
1Kat 8 ohms
less than. 1%
20Kat 8 ohms
less than .3%
INPUT IMPEDANCE
47,000 ohms(47K)
INPUT SENSITIVITY
1.5 volts for 100watts out
OUTPUT IMPEDANCE
¯ 1 ohms
OUTPUT VOLTAGE
80 volts peak to peak 8 ohms
OUTPUT POWER
All readings are continuousoutput power,
per channel
ohms 100watts
ohms 200 watts
ohms 400 watts
ohm 800watts
DIMENSIONS
18.0" WIDE
14.8" DEEPwith handles
6.5" HIGHwith feet
SHIPPING WEIGHT
60 pounds
14

K. WARRANTYAND SERVICE
INFORMATION
Thereare nouser-serviceable parts inside the KST-100.
TheKST-100has a limited warrantyof .five years parts
and labor. Returnfreight is includedinthe warranty.. The
warranty,pe~od,beginson~thedate of purchaseandis
activated witla the return ot the enclosedWarrantyCard
anda copyof the Sales receipt. Please return the war-.
ranty card immedia.tely.aftersuccessfulinstallation anti
operationare completecl.
Thewarrantyfor Krell productsis valid ~nILq~in t.he coun-
try to whichthey wereoriginally shippeda.nd at the
fiictory. If youthinkthere are problemswitla yourunit
please contact yourdealer, distributor or the factory
immediately.
Please do not return, anyunit to KRELLfor repair with-
outfirst calling to cliscussthe problemandto ot~taina
ReturnAuthorizationnumber.-Freightto the factory or
distributor is yourresponsibili.ty. R.~tumfreight to you
will be paidbythe factoryor dlstrit)utor.
Anyunauthorized.updates or modifications performedto
the unit will voidtlae warranty.
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