Krell Theatre Amplifier Standard, TAS Owners manual

Instructions for Use

Owner’s Reference

THE LEADER IN AUDIO ENGINEERING

Theater Amplifier

Standard

Multichannel Amplifier

Theater Amplifier
Standard

Multichannel Amplifier
Instructions for Use

v 02.0

Krell Industries, Inc.
45 Connair Road
Orange, CT 06477-3650 USA

TEL [phone]
FAX [phone]
E-MAIL [e-mail]
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
Industries, Inc., its subsidiaries, and authorized agents. Multi Amp Throughput™ and Krell Current Mode™ are trademarks of Krell Industries, Inc. All other
trademarks and tradenames are registered to their respective companies.

This product complies with the EMC directive (89/336/EEC) and the low-voltage directive (73/23/EEC).

WARNINGS

The amplifier must be placed on a firm, level surface where it is not exposed to dripping or splashing.
The ventilation grids on the top, bottom, and sides of the amplifier must be unobstructed at all times during

operation. Do not place flammable material above or beneath the amplifier.
Contact your authorized Krell dealer, distributor , or Krell before using any devices designed to alter or stabi-

lize the AC power for the Theater Amplifier Standard.
Before connecting the Theater Amplifier Standard, make sure the amplifier is turned off and any output

device (such as a 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.

Use only one set of inputs to the amplifier at a time.
Make sure that only one switch on an input switch bank is in the up (on) position at one time.
Do not connect the multichannel (DB-25) input and the single-ended or balanced inputs at the same time.

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.

© 2001 by Krell Industries, Inc. All rights reserved P/N 305221

Krell Theater Amplifier Standard iii

Contents Page

INTRODUCTION 1
DEFINITION OF TERMS 2
UNPACKING 4
PLACEMENT 5
AC Power Guidelines 5
FRONT PANEL DESCRIPTION: THEATER AMPLIFIER STANDARD 7
BACK PANEL DESCRIPTION: THEATER AMPLIFIER STANDARD 9
CONNECTING THE THEATER AMPLIFIER STANDARD TO YOUR SYSTEM 11
Input and Output Connections 11
AMPLIFIER OPERATION 13
On/Off and Operation 13
Using a Dedicated Wall Switch 13
TROUBLESHOOTING SYSTEM NOISE 14
RECONFIGURATION OPTIONS FOR THE THEATER AMPLIFIER STANDARD 15
To Safely Access the Input Switch Banks 15

Amplifier Factory Default Settings 18
Reconfiguring the Theater Amplifier Standard for MAT Operation 18
Reconfiguring the Theater Amplifier Standard for Bridged Operation 22
Reconfiguring the Theater Amplifier Standard
for Combined MAT and Bridged Operation 24
Example of a Connection Scenario: Multi-power Mode 25

QUESTIONS AND ANSWERS 27
WARRANTY 28
RETURN AUTHORIZATION PROCEDURE 29
SPECIFICATIONS 30

iv

Krell Theater Amplifier Standard

Illustrations Page

FIGURE 1 The Theater Amplifier Standard Front Panel 6
FIGURE 2 The Theater Amplifier Standard Back Panel 8
FIGURE 3 The Theater Amplifier Standard Input Circuit Board

Factory Default Settings 16
FIGURE 4 Reconfiguring the Theater Amplifier Standard for MAT Operation 17

FIGURE 5 Reconfiguring the Theater Amplifier Standard for Bridged Operation 21
FIGURE 6 Reconfiguring the Theater Amplifier Standard for Combined MAT

and Bridged Operation 23

Krell Theater Amplifier Standard 1

Introduction

Thank you for your purchase of the Krell Theater Amplifier Standard Multichannel
Amplifier.

The Theater Amplifier Standard provides substantial five-channel output power that
delivers realistic music reproduction at an exceptional value. The amplifier channels
can be customized quickly through a series of switches. Optional system configurations
include bridged operation and a multi-power mode using the Multi Amp Throughput
(MAT) feature. The Theater Amplifier Standard has balanced and single-ended inputs
for compatibility with other components. The multichannel (DB-25) input also allows you
to integrate the amplifier easily and seamlessly into home theater systems. The
amplifier can be operated using the 12 VDC power on/off (12 V trigger) signals from
other components. The Theater Amplifier Standard is versatile, fitting a variety of
installations including rack-mounted and inside cabinetry.

This reference manual contains important information on placement, installation, and
operation of the Theater Amplifier Standard. Please read this information carefully. A
thorough understanding of these details helps ensure satisfactory operation and long
life for your Theater Amplifier Standard and related system components.

2

Krell Theater Amplifier Standard

Definition of Terms

Following are the definitions of key terms used in your owner’s reference manual.

CONFIGURATIONS

Bridging

A method of linking two amplifier channels by distributing the speaker load between the
positive binding posts. Bridging the channels quadruples the power rating at 8 Ohms.
Bridged configurations should not be used with loads under 4 Ohms.

Krell Multi Amp Throughput (MAT)

An internal configuration option that sends the same music signal to all amplifier
channels using one balanced or single-ended connection. MAT reduces installation
complexity and cabling requirements in systems containing multiple amplifiers. MAT
also allows a variety of connection scenarios, including powering loudspeakers that
have two sets of binding posts and independently powering multiple pairs of stereo
loudspeakers to extend the listening environment throughout your home.

INPUT AND OUTPUT CONNECTIONS

Balanced

A symmetrical input or output circuit that has equal impedance from both input
terminals to a common ground reference point. The industry standard for professional
and sound recording installations, balanced connections have 6 dB more gain than
single-ended connections and allow the use of long interconnect cables. Balanced
connections are less susceptible than single-ended connections to induced noise from
the system or the environment.

Multichannel (DB-25)

A balanced input or output circuit that allows for the simultaneous connection of all
audio outputs plus one 5 VDC (5 Volt trigger) via a single cable. DB-25 inputs and
outputs are becoming popular for connecting an audio/video surround sound processor
and power amplifiers, simplifying the integration of the two components into your
system.

Single-ended

A two-wire input or output circuit

. Use care when using single-ended connections as the

ground connection is made last and broken first. Turn the system off prior to making or
breaking single-ended connections. Single-ended connections are not recommended
for connections requiring long cable runs.

Krell Theater Amplifier Standard 3

Definition of Terms, continued

OPERATION

Off

When the back panel power switch is in the down (off) position and the red stand-by
LED turns off, the component is off.

Stand-by Mode

When the AC power cord is plugged into the wall and the back panel power switch is in
the up (on) position, the red stand-by LED illuminates, indicating that the component is
in the stand-by mode. This low power consumption status keeps the audio and
regulator circuits at idle. Krell recommends leaving the component in the stand-by
mode when it is not playing music.

Operational Mode

From the stand-by mode, when the power button on the front panel is pressed and the
blue power indicator illuminates, the component is in the operational mode and ready to
play music.

TECHNOLOGY

Krell Current Mode

A proprietary Krell circuit topology in which the audio gain stages of a component
operate in the current rather than the voltage domain. This unique technology provides
the component with exceptional speed and a wide bandwidth.

4

Krell Theater Amplifier Standard

Unpacking

Open the shipping box, which contains:

1 amplifier unit (packed in foam end-caps)
1 AC power cord
5 AGC-12 (12-amp) speaker fuses

1 12 VDC output (12 V trigger) cable
1 T-15 Torx wrench
1 packet containing the owner’s reference manual

and the warranty registration card.

IMPORTANT

Two people are needed to remove the amplifier from the shipping box.

1. One person grasps the underside of the foam end-caps at one end of the amplifier;
at the same time, the second person grasps the underside of the foam end-caps at
the other end of the amplifier.

2. Slowly lift the amplifier straight out of the shipping box.

3. Place the amplifier in a safe location and remove the protective plastic wrapping.

Notes

If any of these items are not included in the shipping box, please contact your
authorized Krell dealer, distributor, or Krell for assistance.

Save all packing materials. If you ship your amplifier in the future, repack the unit in its
original packaging to prevent transit damage. See Return Authorization Procedure,
on page 29, for more information.

Krell Theater Amplifier Standard 5

Placement

Before you integrate the Theater Amplifier Standard into your system, review the
following guidelines to choose the location for the component. This will facilitate a
clean, trouble-free installation.

The Theater Amplifier Standard requires at least two inches (5 cm) of clearance on
each side and at least two inches (5 cm) of clearance above and below the component
to provide adequate ventilation.

The Theater Amplifier Standard does not require any type of special rack or cabinet for
installation. For the dimensions of your amplifier see

Specifications

, on page 30.

Place the amplifier as close to the loudspeakers as possible and keep the speaker
cable length to a minimum. Speaker cable adds impedance to the load the amplifier
must drive, regardless of the cable’s gauge. Krell amplifiers drive the lowest
impedances with ease, but long speaker cables reduce the maximum power that is
delivered to the loudspeakers.

AC POWER GUIDELINES

Krell recommends operating the Theater Amplifier Standard from a dedicated 20-amp
AC power line. The Theater Amplifier Standard should be used only with the AC power
cord supplied. Please contact your Krell dealer, distributor, or Krell before using any
devices designed to alter or stabilize the AC power for the Theater Amplifier Standard.

1 Power Button

2 Stand-by LED

3 Power Indicator

13 2

Theater Amplifier Standard

Figure 1 The Theater Amplifier Standard Front Panel

Krell Theater Amplifier Standard 7

Front Panel Description: Theater Amplifier Standard

See Figure 1 on page 6

The Theater Amplifier Standard front panel provides power on and indicates operating
status.

1 Power Button

Use this button to switch the Theater Amplifier Standard power between the stand-by
and the operational modes and also to switch the 12 VDC output (12 V trigger) on and
off.

2 Stand-by LED
The red stand-by LED illuminates when the AC power cord is plugged into the wall and

the back panel power switch is in the up (on) position.

3 Power Indicator

The blue power indicator illuminates when the amplifier is in the operational mode.