Krell S-275 Owners Reference

THE LEADER IN AUDIO ENGINEERIN

G

S–275

Stereo Power Amplifier

Instructions for Use

Owner’s Reference

Krell S-275 1

Introduction

Thank you for your purchase of the Krell S-275 Stereo Power
Amplifier. This configurable power amplifier has a discrete signal
path from input to output and employs a wide bandwidth design
with low negative feedback for sonic accuracy throughout the fre­quency spectrum. All circuits up to the driver stage are balanced
and pure Class A.

Krell’s new surface mount technology (SMT) means that the S-275
is a power amplifier with big power 275 Watts per channel that
does not require big space. SMT allows individual circuit elements
to be placed very closely together. This shortens signal paths and
allows circuit elements to operate at the same temperature, result­ing in more accurate signal transfer and enhanced reliablilty.

The S-275 is a slim line design allowing two amplifiers to fit into a
space normally occupied by one. For systems requiring higher
power, the S-275 can be configured for monaural operation by set­ting a switch on the rear panel. Power output increases to 550
Watts into 8 Ohms. A 6 dB gain switch provides a channel balanc­ing tool for systems using a combination of balanced and RCA
style connections.This owner’s reference contains important infor­mation on the placement, installation, and operation of the S-275.
Please read this information carefully. A thorough understanding of
these details will help ensure satisfactory operation and long life
for your S-275 and related system components.

Definition of Terms

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

Monaural Operation

Monaural operation combines the output of the left and right chan­nels to create a more powerful single channel. In the case of the
S-275, the output increases to 550 Watts.

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 single­ended connections and allow the use of long interconnect cables.
Balanced connections are completely immune to induced noise
from the system or the environment.

Single-ended

A two-wire input or output circuit. Use care when using single­ended connections as the ground connection is made last and
broken first. Turn the system off prior to making or breaking single­ended connections. Single-ended connections are not recom­mended for connections requiring long cable runs.

CONFIGURATIONS

INPUT AND OUTPUT
CONNECTIONS

2 Krell S-275

Definition of Terms, continued

Off

The component is off when the rear panel button is in the down
position.

Stand-by Mode

A low power consumption status that keeps the audio circuits at
idle. Move the rear panel breaker switch to the on position and the
power status indicator illuminates in red. The component is now
ready to be switched to the operational mode. Krell recommends
leaving the component in the stand-by mode when it is not playing
music.

Operational Mode

When the component is in stand-by mode, press the power button
on the front panel and the power status indicator will change to
blue. The component is in the operational mode and is ready to
play music.

12VDC Trigger

The S-275 may be turned on remotely via a 12 volt trigger.
Connect the 12V trigger output from a compatible device to the
12VDC trigger input. The S-275 will go from stand-by to opera­tional mode when a 12 volts signal is applied. The S-275 will
return to Stand-by when the 12 volt signal is removed. The S-275
can turn on other devices via 12 volt connection by connecting
them to the 12VDC trigger output. When the S-275 enters opera­tional mode, it will output 12VDC and remove it when returned to
stand-by.

Input Selection

Put the input select switch in the posistion that matches the con­nection being used. Krell recommends the use of balanced/XLR
whenever possible. In Mono mode,use the left channel connection.

TECHNOLOGY

Krell S-275 3

OPERATION

4 Krell S-275

Unpacking

Follow these steps to safely unpack the S-275:

1. Open the shipping box and remove the top layer of foam. The

S-275 and the S-275 accessory kit containing the following
items are visible:

1 AC power cord
1 packet containing the Quick Setup Guide

and the warranty registration card

2. Grasp the underside of the amplifier and lift it straight out of

the packing box.

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

plastic wrapping.

I

f any of these items are not included please contact your authorized

Krell dealer.

Save all packing materials. If you must ship your S-275 in the future,
repack the unit in its original packaging to prevent shipping damage.

Notes