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Full Power Balanced
X Series Power Amplifiers
700cx, 400cx, 300cx Stereo
750Mcx, 450Mcx,
350Mcx Monaural
with Krell CAST II Technology
v 02.0Krell Industries, Inc.
45 Connair Road
Orange, CT 06477-3650 USA
TEL 203-799-9954
FAX 203-891-2028
E-MAIL krell@krellonline.com
WEBSITE http://www.krellonline.com
This product is manufactured in the United States of America. Krell ®is a registered trademark of Krell Industries, Inc., and is restricted for use by Krell Indus-
tries, Inc., its subsidiaries, and authorized agents. Sustained Plateau Bias III-„¢ is a trademark of Krell Industries, Inc. and is a Krell technology based on
U.S. Patent No. 5,331,291. CAST-„¢, CAST II-„¢, Krell Current Mode-„¢, Krell Link-„¢, and Krell Playback System-„¢ are trademarks of Krell Industries, Inc.
All other trademarks are registered to their respective companies.
©2002 by Krell Industries, Inc. All rights reserved P/N 305976
This product complies with the EMC directive (89/336/EEC) and the low-voltage directive (73/23/EEC).
WARNINGS
The Full Power Balanced amplifier must be placed on a firm, level surface where it is not exposed to drip-
ping or splashing.
The ventilation grids on the top of the Full Power Balanced amplifier must be unobstructed at all times during
operation. Do not place flammable material on top of or beneath the component.
Before making connections to the Full Power Balanced amplifier, ensure that it is off and the preamplifier
is in mute or stand-by mode. Make sure all cable terminations are of the highest quality and free from
frayed ends, short circuits, or cold solder joints.
The differential circuitry employed with Full Power Balanced amplifiers requires special attention when connect-
ing speakers. Do not connect the negative speaker terminals together. Do not connect the negative speaker ter-
minals to ground or attempt to bridge the left and right speaker binding posts of Full Power Balanced stereo ampli-
fiers.
Do not connect a Full Power Balanced amplifier to a speaker selector device that employs a common
ground scheme, as it may short-circuit the amplifier output.
THERE ARE NO USER SERVICEABLE PARTS INSIDE ANY KRELL PRODUCT.
Please contact your authorized Krell dealer, distributor, or Krell if you have any questions not addressed in
this reference manual.
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INTRODUCTION 1
DEFINITION OF TERMS 1
REVOLUTIONARY KRELL CAST and CAST II TECHNOLOGY 3
UNPACKING 4
PLACEMENT 4
AC Power Guidelines 5
FRONT PANEL DESCRIPTION 8
700cx, 400cx, and 300cx Stereo Power Amplifiers 8
750Mcx, 450Mcx, and 350Mcx Monaural Power Amplifiers 8
BACK PANEL DESCRIPTION 11
700cx, 400cx, and 300cx Stereo Power Amplifiers 11
750Mcx, 450Mcx, and 350Mcx Monaural Power Amplifiers 12
CONNECTING THE FULL POWER BALANCED AMPLIFIER
TO YOUR SYSTEM 13
Input and Output Connections 13
Krell Link Connections 13
DC Protection Circuitry 14
Using a Tube Preamplifier 14
AMPLIFIER OPERATION 15
On/Off and Stand-by Operation 15
Krell Link Operation 15
REMOTE CONTROL OPERATION 16
How to Turn Off the Amplifier LEDs 16
How to Turn On the Amplifier LEDs 16
How to Switch between Krell CAST and XLR Inputs 16
Using a Dedicated Wall Outlet and Switch 16
AMPLIFIER TROUBLESHOOTING 17
How to Troubleshoot System Noise 17
How to Evaluate Amplifier Operation 17
QUESTIONS AND ANSWERS 19
WARRANTY 20
RETURN AUTHORIZATION PROCEDURE 21
SPECIFICATIONS 22
Krell Full Power Balanced X Series Power Amplifiers iii
Contents
