Krell Industries KSA-100S Quick start guide

~NALOG AND DIGITAL PRODUCTS
S-SERIES
IBIAS LEVEL I
04 040
O~ ~0
01 10
KSA-100S / 200S/300S OWNER’S REFERENCE

INTRODUCTION
Thank you for your purchase of the KRELLKSA-100S/200S/300S power
amplifier. These amplifiers represent the latest evolution in amplifier
technology, matching unprecedented performance with convenience not
obtainable from most high performance audio designs.
Throughout this Reference wewill refer to all three of the amplifiers as KSA.
All three amplifiers operate identically, while their sonic characteristics,
specifications, and dimensions vary. Specific differences will be described
in detail.
To obtain the best performance from your KSA, careful attention should be
paid to placement, installation and operation. A thorough understanding of
these details will help insure satisfactory operation and long life for the KSA
and related system components.
This Owner’s Reference is divided into several sections, each designed to
perform a different function. As you read through it you will become better
acquainted with the features and functions that make the KSAseries
amplifiers a superb value. A Question and Answer section is also included
where answers to common questions are provided. Should you have any
questions or suggestions please feel free to contact your authorized dealer
or the KRELLstaff for assistance.
In the unlikely event that your KSAshould require service, you will be
pleased to know that it is backed by a comprehensive Customer Satisfaction
policy and one of the most advanced service facilities in the industry. For
detailed information on the terms and conditions of service, please refer to
the Warranty and Service section of this Reference, Warranty Registration
Card, and your authorized KRELLDealer or Distributor.
PAGE 2

TABLE OF CONTENTS
4 UNPACKING
5 LOCATION AND REMOTE TURN-ON
6 CABINETRY AND AC POWER CONSIDERATIONS
7 AMPLIFIER FEET AND REMOTE MASTER/SLAVE CONNECTIONS
9 INPUT AND OUTPUT CONNECTIONS
12 AMPLIFIER OPERATION
13 TURN-ONDESCRIPTION
14 SYSTEMNOISE
15 BIAS LEVEL METER
16 FRONTPANEL METERBUTTON
17 REMOTECONTROLFUNCTIONS
18 PROTECTION CIRCUITRY AND TROUBLESHOOTINGSTEPS
20 QUESTIONSANDANSWERS
22 SPECIFICATIONS
23 WARRANTYAND SERVICE INFORMATION
PAGE3

UNPACKING
NOTE:Due to the extreme weight of the KSAamplifiers, it is strongly advised
that unpacking and placement is completed by at least two individuals.
1. Open the box.
2. Fold back the flaps on all four sides of the box and carefully roll it over on
to the exposed end.
3. Pull the box straight up and off exposing the foam packing material.
4. Pull the foam piece from the exposed end of the amplifier.
5. Roll the amplifier carefully onto its handles and remove the second piece
of foam.
The following items will now be visible:
i
i
i
i
4or5
KSAstereo amplifier
Remote control
Warranty card
AC power cord
Rubber feet bottoms (KSA-300S has 5 feet)
NOTE:If any’ of these items are not included, please contact your authorized
dealer immediately for assistance.
6. Removethe plastic bag from the amplifier.
NOTE:Save all packing materials. If you must ship your KSAin the future,
repack the unit in its original packaging to prevent transit damage. Should
the unit require service, send the remote control and ACpower cord with the
amplifier.
CAUTION:Do not connect the power cord to the ACmains before completing
the Installation section.
PAGE 4

BASIC INSTALLATION
LOCATION
Place the KSAon a firm level surface away from excessive dirt or moisture.
When using custom racks or cabinetry, keep in mind the weight and
ventilation requirements for these amplifiers. Ideally the amplifier should be
placed as close to the speakers as possible. It is preferable to run long
balanced interconnect cables to the amplifier and keep speaker cable length
to a minimum. Speaker cable adds impedance to the load the amplifier must
drive, regardless of the cable’s gauge. All KRELLamplifiers will drive the
lowest impedances with ease, but when impedance is added due to long
cable lengths, amplifier power is literally wasted in driving the cable. Long
speaker cables reduce the maximum power that can be delivered to the
speakers.
REMOTE TURN-ON INSTALLATION
Someinstallations do not have adequate space or arrangement flexibility for
the amplifier to be placed near the speakers. To allow for this, the KSA
¯ amplifiers can be turned On or Offfrom a room other than the listening room.
This type of amplifier placement is referred to as Remote Installation. The
KSAcan be placed in a room or space close to the speakers, but out of sight,
and turned On and Off from the listening room. There is a provision
internally to allow the amplifier to be controlled from a wall ACreceptacle
and not from the front panel power switch or remote control. Wesuggest a
standard wall switch be mounted in the listening room to control an AC
power outlet dedicated to the power amplifier. This can be accomplished by
an electrician. Please contact your dealer for assistance.
NOTE:Whenset-up for remote turn-on, the front panel power switch will not
operate, nor will the power switch on the remote control. The meter switches
on the front panel and remote are not affected and will operate normally.
NOTE: Remember to keep speaker cable lengths to a minimum.
PAGE5

BASIC INSTALLATION
CABINETRY CONSIDERATIONS
High bias amplifiers dissipate much of the power they consume in heat.
Because the KSA-100S/200S/300S utilize Sustained Plateau Biasing, they
remain cool when not in use. Whenthe KSAis in use, it can become quite
hot. Therefore, the KSAshould be installed in a location that provides
unobstructed ventilation. If you must install the unit on shelves or in a
cabinet, extra ventilation may be necessary. This often can be accomplished
with cabinet shelf spacing or unit location. In more extreme instances the
use of small fans can aid in removing excessive heat from internal spaces.
Consult your dealer for assistance.
Generally, with the front and rear of a cabinet open, 3-4 inches of clearance
on each side and 8 inches of vertical clearance, the amplifier should have
adequate ventilation.
The KSAamplifiers have very large power supplies. As a consequence the
amplifiers are quite heavy. Whenpurchasing a rack or cabinet, keep weight
in mind. Most racks are not capable of withstanding the weight of these
units.
The exact weight and dimensions for the KSA-100S/200S/300S are in the
Specifications section of this manual.
AC POWER CONSIDERATIONS
The KSAshould have a dedicated 20 amp line and should only be operated
with the power cord supplied. Use of other power cords may damage the
amplifier and void its warranty. Please consult KRELLor your dealer
BEFOREusing any devices designed to alter or stabilize the ACpower for the
KSA. AC line filters and/or stabilizers must meet or exceed the power
transformer size in the amplifier. As an example, the line conditioner will
require a supply reservoir greater than 2800 VAto condition a KSA-200S.
If you have any questions about placement or ACpower conditions, please
consult KRELL.
PAGE 6

BASIC INSTALLATION
AMPLIFIER FEET
The feet on the KSAcan be used in several different ways. They are made from
machined Delrin and are supplied with separate threaded rubber bottoms.
The rubber bottoms can be screwed into the feet for protection of fragile
surfaces such as hardwood floors or furniture. For use on rugs, we
recommend using the feet without the rubber bottoms. KSAfeet can also
accept the KRELLAMDs(Acoustic Mass Damper). The AMDis a type
spiked foot that threads into the bottom of the foot. These improve the
amplifier’s sonic performance in most installations and are particularly
effective on carpeted floors. Please contact your dealer or KRELLwith any
questions.
REMOTE, MASTER/SLAVE CONNECTIONS - LINKING MULTIPLE
AMPLIFIERS
There are two Remote connectors on the back of the KSAlabeled Master and
Slave provided for linking multiple amplifiers together. Whenthe Master/
Slave cables are connected to each of the amplifiers involved, their meter
function controls and On/Off capabilities will be linked and controlled from
one amplifier.
Select the amplifier that you want to receive operation commands. That
amplifier will be the Master. Follow the instructions below for connecting the
amplifiers. Consider the Master receptacle the output and the Slave recep-
tacle the input.
1. Turn all of the amplifiers Offand unplug them from the ACwall receptacle.
Plug the amplifiers back in but do not turn them on before starting. This
ensures all amplifiers are synchronized when the cabling is connected.
Connect one end of the linking cable to the Master output on the back panel.
2. Connect the other end of the linking cable to the Slave Input on the second
amplifier.
3. To synchronize three amplifiers, connect a second linking cable to the
Master output on the second amplifier. Connect the remaining end to the
Slave input on the third amplifier.
PAGE 7

BASIC INSTALLATION
4. Connect additional amplifiers as described in step 3.
5. Whenthe cables are all in place, point the remote control at the amplifier
designated as Master and press the Power button. The amplifiers will all turn
on at the same time.
The meter display for each amplifier may vary. Manually change the meter
display via the front panel until all of the meters match. The amplifier will
remember the meter setting when cycled On/Off via the remote control or
front panel switch. If the unit is unplugged the memorywill not remain and
the meters may need to be resynchronized. Whenlinked and synchronized
correctly, ON/OFFand meter functions will happen simultaneously only
when the remote control is used.
NOTE: Each individual amplifier canbe turned ON/OFF and have meter
functions changed via the front panel separately. If you change an individual
amplifier’s function, it needs to be manually changed back to follow the
functions of the other amplifiers so the synchronization remains intact.
NOTE: Contact your dealer or KRELLIndustries to obtain remote cable
links.
PAGE8

CONNECTIONS
INPUT AND OUTPUT CONNECTIONS
CAUTION:When making connections to this component or any other, make
sure the power amplifier is OFF and the preamplifier is in the MUTEor
STAND-BY mode.
The wiring to and from the amplifier, and all components in, general, should
be arranged in a neat, organized manner. Specifically, ACwires should be
separated from audio wires. This practice avoids hum or other unwanted
noise from being induced into the system.
1. Connect the speaker cables to the amplifier’s output terminals.
The KSAutilizes two custom sets of parallel binding posts for the left and
right channels respectively. This configuration makes cable connections
and bi-wiring simple. The binding post will only accept a spade lug or ring
terminal of proper inner radius. Bare wire, banana lugs or pins will not work.
Each binding post is labeled either (+) or (-) between the sets of posts on
rear panel. The (+) sign between the binding posts indicates the positive
output terminal. This is commonly referred to as red or hot. The (-) sign
between the binding posts indicates the negative output terminal. This is
commonly referred to as black or ground.
CAUTION:Makesure all cable terminations are of the highest quality, free
from frayed ends, shorts or cold solder joints.
2. Connect the interconnect cables from your preamplifier to the input of the
KSA.
The KSAhas balanced and single-ended inputs ’. The balanced inputs use 3-
pin XLRconnectors and the single-ended inputs use standard RCAconnec-
tors. Werecommenduse of balanced interconnects sonically, and electrically
because of their ability to reduce noise and not incur significant sonic loss
due to extreme cable lengths.
CAUTION:Use only one input to the amplifier at a time. The KSAis shipped
with shorting pins in the XLRinputs. These pins should remain in the XLR
inputs if you are operating the KSAin the single-ended mode. When the
shorting pin is inserted, pin 1 and pin 3 are shorted together. The shorting
pins must be removed to connect the KSAfor balanced operation.
PAGE 9

CONNECTIONS
The pin assignment for the XLRis:
pin 1 = shield (ground)
pin 2 = non-inverting input (hot)
pin 3 = inverting input
NOTE:The RCAcenter conductor for each channel is wired in parallel with
pin 2, the non-inverted input. Only one of these inputs should be connected
to a preamplifier. Do not attempt to use the single-ended and balanced
inputs simultaneously.
3. Insert the ACpower cord into the receptacle located on the back of the
KSA.Insert the other end into the wall ACreceptacle. (Refer to the Basic
Installation section, for ACpower requirements)
4. The amplifier is now ready for operation. Should you have any questions
regarding system set-up, contact your dealer or KRELLIndustries.
PAGE 10

CONNECTIONS
LOUDSPEAKERS
KSA AMPLIFIER
R L
PAGE 11

OPERATION
AMPLIFIER OPERATION
Understanding the ’operation of the amplifier is very easy. Equally important
is an understanding of the care that should be exercised when operating the
system as a whole, in relation to the enormous power output of the KSA.
Simple mistakes, such as switching between active sources without muting
the preamplifier output, or bumping/miscuing a cartridge, can generate
large transients at low frequencies. With this type of transient the KSAcan
generate enough power to damage most loudspeakers. All switching of
sources should be done with the preamplifier level either muted or fully
attenuated. Inputs to the amplifier should not be changed while the
amplifier is on.
NOTE:Care must be taken when setting high playback levels. Because of
their tremendous reserve of clean power, KRELLamplifiers safely drive
speakers to higher sound pressure levels than other amplifiers. This also
means driving the speakers to their limit. Always turn the level downat the
first sign of distortion.
Whenturning the system off, turn the volume on the preamplifier all the way
down or put it into the MUTEor STAND-BYposition. Turn the amplifier off.
This avoids the possibility of a turn-off transient from another component
getting to the speakers. Because of the tremendous output power in the KSA
amplifiers, the amplifier should not be turned on or off with music playing.
This can arc the speaker output relays and potentially damage the amplifier.
PAGE12

OPERATION
DESCRIPTION OF TURN-ON SEQUENCE
Whenturning on the system, the amplifier should always be last.
The KSAOn/Off switch is part of a multi-level turn-on circuit that goes
through several steps of protection. Upon turn-on, the amplifier’s outputs
are not connected to the speakers. After the protection circuits have
determined that the unit has completely stabilized, the speaker relays will
engage. Youwill hear a click at this point. The LED’sin the bias meter will
start at the highest bias level upon turn-on and slowly work their way down
to no-bias. This process takes approximately 1 minute. The amplifier is
ready to use once the bias meters have settled to the no-bias level.
1. Push the black Power button on the amplifier front panel to turn it on.
The Power button is the larger of the two buttons at the top of the face plate.
The blue LEDlabeled POWERin the center of the bias meter will illuminate
when the Power button is depressed. The amplifier will progress through the
turn-on sequence described above.
2. With the preamplifier in the Mute position, or volume control fully
attenuated, select a source. Turn the volume control up to your desired
listening level.
3. Enjoy.
PAGE13

OPERATION
SYSTEM NOISE CONSIDERATIONS
AC grounding often becomes critical when connecting high performance
audio gear. When mixing and matching audio components, each with their
own ground potentials, a low frequency hum can become present in one or
both speakers. This can often occur when introducing a new component into
the system.
If there is a low frequency hum coming from the speakers when the KSAis
connected into the system, follow these simple trouble-shooting steps:
1. Check all of the input and output connections, making sure they are of
sound construction. With the amplifier off, remove the interconnect wiring
and tum the amplifier back on. If the hum disappears, shut the amplifier
off and reinsert one of the interconnect cables and turn the amplifier back
on. If the humis present with one or both interconnects inserted, there may
be a defective cable. Have the interconnect cabling checked before proceed-
ing.
2. If the interconnect proves to be fine, more than likely you are experiencing
a ground loop. This can often easily be eliminated. Contact your dealer or
KRELLfor assistance.
PAGE 14

OPERATION
BIAS LEVEL METER
The KSAamplifiers utilize Sustained Plateau Biasing, a proprietary KRELL
design. The Bias display meter on the front panel of the amplifier displays
which level of bias the amplifier is utilizing. Unlike sliding bias designs,
Sustained Plateau Bias only changes level when the demand situation
relative to input and source material changes. The signal passes through a
section called an Anticipator circuit. Once the level of bias is determined by
the Anticipator circuit, it automatically biases the output ~f the amplifier
before the signal is passed through the output stage. The Anticipator circuit
is several times faster than the output stage itself. This technique insures
all signal is passed through the amplifier in pure Class A operation. If the
amplifier only requires a low level of Class Abias, the amplifier will bias itself
to use only the amount of Class A power necessary to the demand
parameters. Should the demand parameters exceed the bias level the
amplifier is presently working under, the amplifier will increase its bias to
the next level to allow all signal to comethrough in Class A operation. If the
demand parameters are less then the bias level indicates for more than 15-
20 seconds, the amplifier will drop to the next lowest bias level.
The bias levels are indicated by appropriate LEDsin the faceplate meter
display as they are activated.
Should the demand parameters reach a point at which the temperature of
the external heatsink reaches approximately 80 degrees Celsius, the last two
levels of bias 3 and 4 will be disabled until the heatsink temperature drops
to a safe operating level. The overall output power of the amplifier is not
changed when this occurs, only the amount of class A power. You will notice
the LEDscorresponding to the top two levels of bias will not illuminate. The
LEDsfor levels 3 and 4.will come back on when the heatsink temperature
is at safe operating levels. This temperature fluctuation will not harm the
amplifier. It is provided for consumer safety in a home listening environ-
ment.
PAGE 15

OPERATION
FRONT PANEL METER BUTTON
A small button beneath the Power button on the front panel controls Bias
Meter display illumination. Whenengaged, the meter display will no longer
indicate bias levels; only the Blue pilot LEDwill be visible. The Bias Level
meter can also be turned on or off via the remote control.
PAGE 16

OPERATION
REMOTE CONTROL FUNCTIONS
The KSA-100S/200S/300S are the first high performance amplifiers to
utilize remote control functions. The amplifiers can be switched on or offand
the meter function can be changed from your listening position via the hand-
held remote control.
The KSAremote control duplicates the front panel switches on the amplifi-
ers. The Power button will turn the amplifier on and off, while the Meter
button will choose between a full bias meter display or no bias LED
illumination.
When the amplifier is switched On, the Blue POWERLED and Bias Level
Meter display will illuminate. Whenthe amplifier is switched Off, no LEDs
will be illuminated.
Whenthe Bias Level Meter is turned off, no LEDswill be visible except for
the blue pilot LED.Whenthe Bias Meter display is on, the bias level will be
displayed with the appropriate LEDs.
BATTERY INSTALLATION
NOTE:Batteries should be replaced when the KSAfunctions from the remote
control become intermittent.
1. Removethe four hex head screws from the back of the remote control.
2. Remove the back plate to expose the battery storage compartment.
3. Replace batteries (Refer to the polarity drawing while inserting the
batteries)
4. Replace the back plate and insert the four hex head screws.
PAGE 17

OPERATION
PROTECTION CIRCUITRY
There are no fuses in the KSA.The amplifier is protected by a series of non-
intrusive, opto-coupled circuits that constantly evaluate the amplifier’s
operation. Appropriate protective action exists for DCconditions, short
circuit, oscillation, ACpower anomalies, high ground resistance and out-of-
phase ground. Collectively, the protection circuitry is designed to avoid
damage to the amplifier or speakers caused by other defective components,
faulty wiring, mishandling of the system or amplifier failure. Whenthe
protection circuit is engaged, the amplifier will shut off and short its output.
The amplifier can be turned on after resolving either the input or output
problem.
SIMPLE TROUBLE-SHOOTING STEPS
Follow these steps when trying to resolve the cause of potential amplifier
related failure. If the amplifier will not turn on, or stay on:
1. Disconnect all input and output connections. Once this is completed, try
turning the amplifier on.
If the amplifier does not come on, check the circuit breaker on the back
panel. If the circuit breaker has popped out or appears to be more extended
than usual, reset the breaker switch by pressing it back in. If the amplifier
still does not come back on, call KRELL.
If the amplifier does not come on and the circuit breaker on the back of the
unit seems normal, check the house circuit breaker or fuse for the power
outlet associated with the amplifier.
NOTE:Whenturning the amplifier on and off between cable checks, let the
amplifier settle for at least 45 seconds before turning it back on.
2. If the amplifier turns on and appears to work properly again, turn the
amplifier off and reconnect the output speaker cables for one channel only.
If the amplifier turns on normally, reconnect the other channel output
speaker cables.
PAGE 18

OPERATION
Should the amplifier turn off when either output cable is connected, the
problem is cable or speaker related. Check to make sure there are good
mechanical connections on the speaker cabling and there are no frayed ends
or wires shorting the output terminals together. Have your speaker cables
checked and repaired if necessary by your dealer before proceeding.
3. If the amplifier turns on normally with only the speaker cables connected
to the output, turn the amplifier off and reconnect the interconnect cable
for one channel only. If the amplifier turns on normally reconnect the other
channel’s interconnect cable and turn on the amplifier.
Should the amplifier turn off when either interconnect cable is connected,
the problem is cable, preamp or source component related.
Check to make sure there are good mechanical connections on the intercon-
nect cabling and there are no broken terminations. Have your interconnect
cables checked and repaired if necessary by your dealer before proceeding.
Should the cabling from the preamplifier to the amplifier input be functional,
check source component interconnects. Should the interconnects prove to
be sound throughout the system, have the preamplifier and any suspect
source components checked. The source components should be checked
individually through the preamp, should the preamp prove to work properly.
4. Should all of the system components, cabling and ACpower requirements
be sound and the amplifier continues to not work, call your dealer,
distributor or KRELLto arrange for service. Service can be handled directly
through KRELL. Should you need a KRELLcomponent serviced please call
the factory to discuss the problem and obtain a Return Authorization
number (RA#) and shipping information.
PAGE19

QUESTIONS AND ANSWER
Q. Should I leave the KSAon at all times?
A. Because of Sustained Plateau Bias, the KSAcan be left on at all times
without fear of damage, excessive heat or excessive power consumption. The
KSAamplifier however, is designed to be turned On/Off, and can do so
without degradation. The amplifier will work at full performance within
minutes of turn-on.
Q. When I push the power button on the front of the KSA, the amplifier
doesn’t turn on. What should I do?
A. Check the input and output connections, then retry the amplifier. Check
the circuit breaker on the back of the unit and reset it if necessary. Consult
the protection circuitry section of this manual for more detailed trouble-
shooting procedures.
Q. WhenI turn the amplifier on there is a loud humthrough the speakers.
There wasnever a hum before the KSAwas in the system. What should I do?
A. Often when a new component is introduced into an audio system a hum
may become present. This is often caused by a ground loop in the system or
by defective cabling. Check your cables to and from the amplifier. If the hum
persists, contact your dealer or the KRELLstaff for assistance.
Q. Can I use special audio power cords on the KSA?
A. You can experiment with special power cords as long as they are grounded
on both ends, meet the amplifier’s 20 amp power requirement, and are safety
approved by organizations like CSAor UL. The use of them, however, is not
recommended without first consulting your dealer or the KRELLfactory.
Q. Myspeakers only have one set of binding posts. Whichset of binding posts
should I use on the amplifier?
A. The two binding posts for each channel on the KSAare the same point
electrically. You can use either the top set of posts or the bottom set. They
sound and work the same.
PAGE20