Krell Industries KSA-i400 Quick start guide

KSA-i400 Power Amplifier
Owner’s Reference

KSA-i400 Owner’s Reference
© 2022 by Krell Industries LLC. All rights reserved.Page 2 of 15
Table of Contents
Page
Getting Started 3
Unpacking / Placement / AC Power Guidelines 4
Front Panel 5
Rear Panel 6
Operation 8
Protection Modes 11
Specifications 12
Warranty 14
Service 15
Krell Contact Information 15

KSA-i400 Owner’s Reference
© 2022 by Krell Industries LLC. All rights reserved.Page 3 of 15
Getting Started
Thank you for your purchase of a Krell KSA-i400
component. The KSA-i400 is a high performance
amplifier incorporating all of Krell’s best
technologies - iBias™ for true Class A operation up
to 400 watts per channel but without the constant
heat of traditional Class A designs, XD for low
output impedance that maintains firm control over
the speakers for hard hitting tight bass and brilliant
highs, and Sym-Max which virtually eliminates 2
nd
order harmonic distortion for a more realistic 3D
musical experience.
WA R N I N G ! Do not place the component where it
could be exposed to dirt or excessive moisture. The
ventilation grids on the top, bottom, and sides of
the KSA-i400 must be unobstructed at all times.
Do not place flammable material on top of or
beneath the unit. When making connections to this
or any other model, make sure all components are
off. Turn off all system power before connecting the
KSA-i400 to any other component. Make sure all
cables are of the highest quality, free from frayed
ends, short circuits or cold solder joints.
CAUTION! The top, sides, and bottom of the
KSA-i400 may get hot during use.
This product complies with the EMC
directive (89/336/EEC) and the low-
voltage directive (73/23/EEC). This
CLASS 1 apparatus must be
connected to an AC MAINS socket
outlet with a protective earthing
connection.
WARNINGS
CAUTION
NO USER SERVICEABLE PARTS INSIDE.
RISK OF ELECTRIC SHOCK
DO NOT OPEN

KSA-i400 Owner’s Reference
© 2022 by Krell Industries LLC. All rights reserved.Page 4 of 15
Unpacking / Placement / AC Power Guidelines
Unpacking
The KSA-i400 is very heavy and requires two strong people to lift it and position it.
Place the shipping box on a firm level surface. Lift off the top of the shipping box and remove the small
cardboard box located in the center of the protective foam. This box contains a power cord and a
12V trigger cable. Remove the top protective foam. The unit can now be lifted out of the bottom part
of the shipping box and placed in the desired location.
Placement
The KSA-i400 may generate substantial heat while in operation and is intended for use indoors in a
typical residential environment. Place it on a firm level surface where it will not be exposed to
excessive heat, humidity, dust, or moisture of any kind. Krell recommends that it be placed in open
air and not in an enclosed cabinet or rack. The bottom, sides, and top must remain unobstructed in
order to maintain adequate air flow. Do not place it directly on a deep pile carpet. It should not be
placed on top of other equipment nor should other equipment be placed on top of it. Please contact
Krell if it must be placed in a rack as forced air circulation will be required.
AC Power Guidelines
The KSA-i400 requires a dedicated AC circuit rated at a minimum of 20 amps for 100-120VAC
operation or 13 amps for 220-240VAC operation. Do not use extension cords, adapters, or power
strips. Krell does not recommend the use of power conditioners with the KSA-i400.

KSA-i400 Owner’s Reference
© 2022 by Krell Industries LLC. All rights reserved.Page 5 of 15
Front Panel
1) Power Button
2) Indicator Lights
Front Panel Features Description
1) Power Button
The primary function of the power button is to switch the unit from stand-by to operate or
operate to stand-by. It may also be used to start a software update or a factory restore.
See the Operation section for more information about these functions.
2) Indicator Lights
The indicator lights provide information about the status of the unit. Solid green indicates
stand-by and solid blue indicates on . See the Operation section for more information about
status.
2 2 1

KSA-i400 Owner’s Reference
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6
Rear Panel
1) AC Mains Inlet
2) Power Switch
3) 12VDC Trigger Input
4) RJ45 Ethernet Jack
5) Speaker Binding Post, Positive
6) Speaker Binding Post, Negative
7) RCA (single-ended) Input Jack
8) XLR (balanced) Input Jack
1 2 3 4 5 5 6
7 8 7 8

KSA-i400 Owner’s Reference
© 2022 by Krell Industries LLC. All rights reserved.Page 7 of 15
Rear Panel Features Description
1) AC Mains Inlet
IEC 320 inlet for connection to an AC mains outlet. See the serial number label on the rear
panel of the unit for the specific voltage requirements. Use only the supplied power cord or
one with an equivalent current rating.
2) Power Switch
Move the power switch to the up position to apply power to the unit or the down position to
remove power. The power switch is also a circuit breaker. In the event of an internal fault it
may automatically move to the down position to remove power from the unit.
3) 12VDC Trigger Input
For connection to a home control system or other component with a 12VDC trigger output
to switch the unit on (+12V) or off (0V). This input accepts a 3.5mm mono plug where the
tip is hot and the sleeve is ground.
4) RJ45 Ethernet Jack
For connection to a LAN (local area network) at speeds of 10/100 Mbps. This must be
connected to the LAN router in order to access the embedded web page. The router must
have access to the Internet in order to get software updates.
5) Speaker Binding Post, Negative
Connect the negative wire from the speaker to this post. The binding post accepts 5/16”
(8.0mm) spade connectors, bare wire, or banana plugs. This is internally connected to
ground.
6) Speaker Binding Post, Positive
Connect the positive wire from the speaker to this post. The binding post accepts 5/16”
(8.0mm) spade connectors, bare wire, or banana plugs.
Caution! – Hazardous voltages may be present on this post when the unit is
in operation. Do not touch.
7) RCA (single-ended) Input jack
RCA jack for connection to single-ended analog audio sources (2.7Vrms maximum input
voltage). Insert the shorting jumper between pins 1 and 3 of the XLR jack when using this
input.
8) XLR (balanced) Input Jack
XLR jack for connection to balanced analog audio sources (2.7Vrms maximum input
voltage). Pin 1 is ground, pin 2 is non-inverting (+), and pin 3 is inverting (-).
Krell recommends balanced input connections for the best performance.

KSA-i400 Owner’s Reference
© 2022 by Krell Industries LLC. All rights reserved.Page 8 of 15
Operation
Power
Connect the KSA-i400 to an AC mains outlet and turn on the rear panel power switch. After about 4
seconds the front panel indicator lights will illuminate green. The unit is now in stand-by. Wait
another 8 seconds then press and release the power button. An audible click will be heard from the
unit and the indicator lights will fade from green to blue. The blue illumination will fade out and in for
about 8 seconds and then remain constant. The KSA-i400 is now ready to play. To return to stand-by
press the power button again.
Web Interface
The KSA-i400 has a Web interface that provides status information and the ability to remotely control
the unit. It is easily accessed with most commonly available Web browsers. First, with the unit off,
connect an Ethernet cable from the rear panel jack on the KSA-i400 to the LAN router. Turn on the
rear panel power switch. Open a Web browser on a device connected to the same LAN and type
http://krell-ksai400-xxxx.local into the URL window ( xxxx is the last four digits of the serial
number).
When the KSA-i400 is in stand-by the Web page will be grayed-out and only the Power button will be
active. Click on the Power button to turn on the unit. The KSA-i400 will turn on and a few seconds
later the Web page will come up to full brightness and various status information will be displayed.
About 15 seconds later the temperature display will appear. Channel 1 is the right channel and
Channel 2 is the left channel. During use it is normal for there to be a difference of a few degrees
between the channels.
The No Signal Timeout feature will put the KSA-i400 in stand-by if an input signal is not detected
during the selected time period. The default setting is Disabled.

KSA-i400 Owner’s Reference
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Web page KSA-i400 in stand-by
Web page KSA-i400 on

KSA-i400 Owner’s Reference
© 2022 by Krell Industries LLC. All rights reserved.Page 10 of 15
Factory Restore
This will restore any internal settings back to their factory default values. Turn on the KSA-i400 from
the rear panel. Wait 2 seconds after the green stand-by lights come on then press and hold the
power button until the green lights begin to fade out and in; release the power button. After about 13
seconds the lights will go off and then come back on steady. The factory restore is done.
If the Web interface is inaccessible and the LAN connection is good, a factory restore may solve the
problem.
Software Update
Note: Upon reaching a certain point in the update process power must not be removed from the
KSA-i400. If this happens, the unit may be rendered inoperable. Read through the entire
software update process before attempting to perform a software update.
From time to time Krell may release new versions of software to add features or fix a problem. The
KSA-i400 must be connected to the LAN router with access to the Internet in order to perform the
software update. With the KSA-i400 in stand-by press and hold the power button until the green
stand-by lights begin to flash; release the power button.
While the green lights are flashing the unit is checking for newer software. If they stop flashing and
stay steady that means the unit already has the latest software. If the lights change to red that
means it was unable to connect to the server to check for software updates. This can be caused by
a lack of connection to the LAN or the router not allowing the KSA-i400 to connect to the Internet.
If there is new software available, the lights will start to flash blue. The KSA-i400 is downloading the
software update. If the lights change to red that means the download failed. Sometimes this can be
caused by slow response over the Internet. Try the software update again later.
When the unit is done downloading the software the lights will flash blue with two flashes per period.
The unit is copying and verifying the software download. If the lights change to red there was a
problem with the downloaded file. Try the software update again later.
Do not turn the unit off or otherwise remove power beyond this point in the software
update process!
The lights will go off at this point and then come back on blue, fading in and out rapidly. The program
memory is being overwritten. The lights will then go off briefly and then come back on steady green.
The KSA-i400 is in stand-by and is ready to use.