Krell Industries Evolution One User Manual

EVOLUTION

EVOLUTION ONE

MONAURAL POWER AMPLIFIER

OWNER’S REFERENCE

Evolution One Monaural Power Amplifier Owner’s Reference, v05.0

Kr

ell 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 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 of the amplifier and the space underneath the amplifier must be
unobstr

ucted at all times during operation. Do not place flammable

material above or beneath the

amplifier.

Before making connections to the amplifier, ensure that the back panel power switch is down.
Make sur

e all cable ter

minations ar

e of the highest quality

, free from frayed ends, short circuits,

or cold solder joints.

The differential circuitry employed with an Evolution One Monaural Power Amplifier requires special
attention when connecting speakers. Do not connect the negative speaker terminals together. Do
not connect the negative speaker terminals to ground.

Do not connect an Evolution One Monaural Power Amplifier to a loudspeaker selector device that
employs a common gr

ound scheme, as it may short-circuit the amplifier output.

THERE ARE NO USER SERVICEABLE PARTS INSIDE AN EVOLUTION ONE MONAURAL POWER
AMPLIFIER.

Please contact Krell if you have questions not addressed in this guide.

®

oduct is manufactur

This pr
by Krell Industries, Inc., its subsidiaries, and authorized agents. Evolution Bias
based on U.S. Patent No. 5,331,291. CAST
trademarks ar

© 2005 by Krell Industries, Inc. All rights reserved P/N 307772

e r

ed in the United States of America. Kr

egister

ed to their r

espective companies.

™, Evolution CAST™, and Kr

ell

is a r

ed trademark of Kr

egister

™ is a trademark of Krell Industries, Inc. and is a Krell technology

ell Current Mode

ell Industries, Inc., and is r

e trademarks of Krell Industries, Inc. All other

™ ar

estricted for use

Contents

List of Illustrations, page iv

A Letter from Dan D’Agostino, page 1

SECTION ONE: About Krell, page 3

The Krell Legacy, Revolutionary Krell CAST Technology,
Ensuring Maximum Per

SECTION TWO: Unpacking and Placement, page 12

Opening the Evolution One Shipping Cartons

SECTION THREE: Anatomy of an Amplifier, page 15

Features and Benefits of the Evolution One Design

SECTION FOUR: Connecting an Evolution One Amplifier to Your System, page 19

CAST and Voltage Connections, Connection Steps,
DC Protection Circuitry, and Remote Control Options

SECTION FIVE: Amplifier Operation, page 22

Powering Up, Adjusting Power Meter Modes,
Switching between CAST and Voltage Connections,
Amplifier Care

formance, and Definition of Terms

SECTION SIX: Amplifier Troubleshooting, page 26

WARRANTY, page 28

RETURN AUTHORIZATION PROCEDURE, page 30

SPECIFICATIONS, page 31

iii

1

List of Illustrations

Figure 1, page 15

Evolution One Amplifier and
Power Supply Chassis Front Panels

Inset Evolution One Amplifier Channel: Front Panel View

Figure 2, page 16

Evolution One Amplifier and
Power Supply Chassis Back Panels

Figure 3, page 17

Evolution One Amplifier Chassis Top

Figure 4, page 18

Evolution One Power Supply Chassis Top

iv

A Letter from Dan D’Agostino

Dear Audio Enthusiast,

Thank you for your purchase of the Evolution One.

The Evolution One Monaural Power Amplifier represents a watershed in my design
philosophy and in my quest for amplifiers that deliver absolute truth in music
reproduction. This new amplifier operates solely in the current domain, with only
one voltage gain stage at its output. I have always been fascinated by the artistry
inherent in great musical performances, and I believe that no component in an
audio system equates more closely to the full range of musical expression than
the power amplifier. The Evolution One reproduces real-life dynamics and trans­parency in a manner that I have not experienced prior to this design. It is my
pleasure to make it available to you.

Krell amplifiers are best known for their ability to drive any loudspeaker to sound
its best, without regard to impedance or efficiency. The Evolution One amplifier
joins this awesome current capability with a new, ultra-linear circuit topology. It is a
strong belief of mine that linearity, an amplifier’s ability to output an exact dupli­cate of the input signal, is the ultimate measure of that amplifiers worth. I drive
Krell amplifier designs toward the common goal of linearity; through the rigorous
application of Krell design principles that focus our efforts on four major perform­ance factors: distortion, bandwidth, output impedance and current capability. The
Evolution One excels in each of these areas, delivering absolute accuracy from

emely low levels of output, vir

extr
inspiring amounts of power.

tually at pr

eamplifier levels, to astounding, awe-

As the foundation of my new Evolution Series, the Evolution One Monaural Power
Amplifier is designed to complement the Evolution T

eamplifier per

Pr

fectly. Combine the Evolution One and Two with my new LAT-1000

wo Monaural Power

loudspeakers, and experience the extraordinary capabilities of the Evolution
System.

1

continue

d

(A Letter from Dan D’Agostino continued)

I have some exciting news for you. Work on a new source component for the
Evolution Series is ongoing as of this writing. Possessed of the unique Evolution
technologies that power the amplifier and preamplifier, this Evolution source will
expose the real advantages of the latest recording formats while taking compact
disc playback to the next level. I encourage you to audition it as soon as it is
released.

ely,

Sincer

Daniel D’Agostino
Chief Executive Officer

2

SECTION ONE

About Krell

This section describes the Krell Legacy, innovative Krell amplifier design and technol­ogy, and defines key terms used in this reference.

The Krell Legacy

“I design every Krell component to set the standard

for workmanship, style, and performance.”

High-end audio is a demanding pursuit—an ongoing quest for excellence in
music reproduction that drives equipment manufacturers to strive for the absolute
in design and performance. With a keen understanding of this passionate drive,
Krell Industries, Inc., was founded in 1980.

Over the past 2-1/2 decades, Krell has earned a distinguished reputation for engi­neering innovation and product excellence. The company’s history is replete with
product introductions that have deeply impacted the high-end audio industry.
The most discriminating audiophiles and product reviewers have consistently
recognized Krell components for standard-setting performance.

Dan D’Agostino

The Evolution One amplifier brings Krell design to a new level, setting a standard for
performance that will not soon be matched. The shear breadth of this amplifier’s
dynamic range capabilities conveys a startling realism that transcends previous
designs. Seemingly unlimited frequency response, combined with unerring accu­racy and fortitude, extend a tradition that began with the first Krell amplifier — the
KSA-100.

The KSA–100 was the first high-power, high-current, true Class A biased stereo
power amplifier available to audiophiles. It was the first Krell product, and its
resounding success established Krell as an important new technological contrib­utor to high-end audio.

3

continue

d

(SECTION ONE: About Krell continued)

From the KSA–100 to the present, Krell C.E.O. Dan D’Agostino has continually
“pushed the envelope” of performance in his search for greater amplifier power.
His exploration of new technologies, driven by his never-ending quest to elevate
the standard of excellence, has resulted in breakthrough audio designs. Over the
years, the Krell line of power amplifiers, including benchmark products such as the
KRS–100, KRS–200, and the Audio Standard models, has established a legacy of
unparalleled sonic performance.

The Krell product line has diversified, but Dan’s fundamental research into amplifier
design and performance remains at the core of the company’s achievements. Every
Krell component upholds the legacy, incorporating unique technologies that are the
direct result of Dan’s discoveries in audio amplification.

The Evolution One amplifiers build on the Krell legacy. They provide unprecedent­ed linearity with the control and accuracy that only comes from superior current
capability. The sound is lively and unconstrained, in a manner that evokes live per­formance and the true sound of instruments.

Dan D’Agostino remains committed to the development of new designs and
technologies. And the Krell legacy will continue to evolve with products that deliver
innovative engineering, perfection in build quality, and outstanding audio performance.

4

Revolutionary Krell CAST Technology

Current Audio Signal Transmission, termed CAST, is a revolutionary method of con­necting analog audio components for unparalleled sonic performance. Innovative
engineering combines the new Krell CAST circuitry with existing Krell Current Mode
technology to create entire CAST systems that reproduce music with incredible range,
tonality, and precision.

The Voltage Signal Transmission
and the Traditional Audio System

Traditionally, signal is transmitted in the voltage domain between two components.
In an audio system, each component is a discrete entity with unique characteristics
that act upon the musical signal independently. Each component is unaware of the
other components in the system. The cables that connect the components also
have their own electrical characteristics, which affect the sonic presentation of the
entire system. CAST transmission unifies individual components and interconnects
into an electrically linked whole. The original signal remains unaltered from source to
speaker.

CAST Basics

Here’s how a CAST audio system works. Internally, each CAST source transfers,
or amplifies, current using Krell Current Mode circuitry. This current signal is
then output using CAST circuitry. When the signal is received by a CAST input,

y again takes over until the signal reaches the loud-

ent Mode cir

ell Cur

Kr
speaker
to end, an entire CAST system behaves as if it is one component. With CAST,
cir
nents ar
nal are non-existent.

r

. By maintaining the musical signal in the cur

oper

cuit boar

d pr

e eliminated. Cable impedances and their ef

cuitr

ties and signal transmission aber

ent domain from beginning

r

rations between compo

fects on the transmitted sig

-

How CAST and Krell Current Mode Interact

While CAST is a new method of transferring the musical signal between compo­nents, its origin stems from Krell Current Mode, the technology developed to
transfer the musical signal within a component. CAST combined with Krell Current
Mode takes circuitry signal transmission to the next evolutionary level. In essence,
Krell Current Mode maintains the integrity of the signal within the component and

-

d

5

continue

(SECTION ONE: About Krell continued)

(How CAST and Kr

ell Current Mode Interact continued)

CAST preserves the transmitted signal between components. Together, CAST and
Krell Current Mode technologies unify separate Krell components into a

global circuit.

Krell Current Mode technology enjoys bandwidth increases up to an

single

order of magnitude greater than their voltage based counterparts. This dramatic
increase in circuit bandwidth delivers near perfection in the audible band that typi­cally suffers from phase distortions in voltage circuits.

CAST Cable Construction

A CAST system uses cables manufactured by Krell and other manufacturers spe­cially licensed by Krell. Thin and flexible CAST cables are constructed with the
same build quality as other Krell components and are aesthetically matched to the
components that Krell manufactures. An all-metal body and locking connectors
with gold contacts are part of the standard no-compromise specification devel­oped for every CAST cable made.

Evolution CAST

By employing radical current mirror circuitry, the Evolution components elevate the
CAST technology to another level. This advanced use of the technology increases
the linearity, transient speed, and bandwidth of the Evolution components while
reducing the distortion by an order of magnitude.

The Best Musical Performance

When you operate a CAST system, you will hear significant improvements in every
performance area: speed, precision, dynamic range, depth and width of the sound
stage, transient impact, tonal balance, har

monic distor

tion, and mor
CAST is the same company goal used for all Krell products. Krell strives for the
delivery of the best performance of a musical event for you, using the full expres­sion of technology to date.

6

e. The goal for

Ensuring Maximum Performance

“My pursuit of excellence in sound reproduction and

my love of great musical performance has led me
to the Evolution One Amplifier, and fuels the ongoing
Evolution design effort at Krell.”

Dan D’Agostino

The Krell Evolution One Monaural Power Amplifier, built upon the foundation of
huge, regulated power supplies and output stages, is designed to drive any
loudspeaker with complete control. The product of breakthrough Krell technolo­gy, this amplifier provides a sound that is supremely dynamic and musical.
Indeed, it is the sound of the music itself.

Core Technologies

Class A, Balanced, Current Mode Gain
Topologies from Input to Output

Audio signal voltages are converted to currents at the amplifier input, and the
audio signal remains in the current domain throughout the entire amplifier until
the output stages. All signal gain is realized in the current domain using propri­etary multiple-output current mirrors with extraordinary open loop linearity. The
current mirrors in the final gain stages use 36 pairs of high voltage, high speed
transistors. Originally developed for demanding, high bandwidth video circuits,
these transistors help yield gain stages with superb accuracy and very low dis-

tion. The signal path is fully complementar

tor
output. The driver and output stages use 28 pairs of 150 Volt, 14 Amp, 50
megaher
sinks.

tz power transistors mounted on Kr

y and fully balanced from input to

ell-designed high ef

ficiency heat

All transistors operate in Class A mode. Independent complementary pre­driver and driver stages for the positive and negative output transistors make
the output stages extr
Watts into an 8 Ohm load, 900 Watts into 4 Ohms, and 1800 Watts into 2
Ohms. This unique cir
the Evolution One amplifier simply drives any loudspeaker with absolute confi
dence, achieving the very best possible sonic results.

emely fast and linear

cuit is imper

vious to low-impedance or r

7

. The output stage develops 450

eactive loads;

continue

-

d