EVOLUTION
EVOLUTION ONE
MONAURAL POWER AMPLIFIER
OWNER’S REFERENCE
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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 Performance, and Definition of Terms
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
SECTION SIX: Amplifier Troubleshooting, page 26
WARRANTY, page 28
RETURN AUTHORIZATION PROCEDURE, page 30
SPECIFICATIONS, page 31
iii
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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
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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 trans-
parency 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 dupli-
cate 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 perform-
ance factors: distortion, bandwidth, output impedance and current capability. The
Evolution One excels in each of these areas, delivering absolute accuracy from
extremely low levels of output, virtually at preamplifier levels, to astounding, awe-
inspiring amounts of power.
As the foundation of my new Evolution Series, the Evolution One Monaural Power
Amplifier is designed to complement the Evolution Two Monaural Power
Preamplifier perfectly. Combine the Evolution One and Two with my new LAT-1000
loudspeakers, and experience the extraordinary capabilities of the Evolution
System.
continued
1
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(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.
Sincerely,
Daniel D’Agostino
Chief Executive Officer
2
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SECTION
ONE
About Krell
This section describes the Krell Legacy, innovative Krell amplifier design and technol-
ogy, 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.”
Dan D’Agostino
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 engi-
neering 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.
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 accu-
racy 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 contrib-
utor to high-end audio.
continued
3
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(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 unprecedent-
ed 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 per-
formance 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
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Revolutionary Krell CAST Technology
Current Audio Signal Transmission, termed CAST, is a revolutionary method of con-
necting 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,
Krell Current Mode circuitry again takes over until the signal reaches the loud-
speaker. By maintaining the musical signal in the current domain from beginning
to end, an entire CAST system behaves as if it is one component. With CAST,
circuit board properties and signal transmission aberrations between compo-
nents are eliminated. Cable impedances and their effects on the transmitted sig-
nal are non-existent.
How CAST and Krell Current Mode Interact
While CAST is a new method of transferring the musical signal between compo-
nents, 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
continued
5
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(SECTION ONE: About Krell continued)
(How CAST and Krell Current Mode Interact continued)
CAST preserves the transmitted signal between components. Together, CAST and
Krell Current Mode technologies unify separate Krell components into a single
global circuit. Krell Current Mode technology enjoys bandwidth increases up to an
order of magnitude greater than their voltage based counterparts. This dramatic
increase in circuit bandwidth delivers near perfection in the audible band that typi-
cally suffers from phase distortions in voltage circuits.
CAST Cable Construction
A CAST system uses cables manufactured by Krell and other manufacturers spe-
cially 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 devel-
oped 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, harmonic distortion, and more. The goal for
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 expres-
sion of technology to date.
6
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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 technolo-
gy, 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 propri-
etary 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-
tortion. The signal path is fully complementary and fully balanced from input to
output. The driver and output stages use 28 pairs of 150 Volt, 14 Amp, 50
megahertz power transistors mounted on Krell-designed high efficiency heat
sinks.
All transistors operate in Class A mode. Independent complementary pre-
driver and driver stages for the positive and negative output transistors make
the output stages extremely fast and linear. The output stage develops 450
Watts into an 8 Ohm load, 900 Watts into 4 Ohms, and 1800 Watts into 2
Ohms. This unique circuit is impervious to low-impedance or reactive loads;
the Evolution One amplifier simply drives any loudspeaker with absolute confi-
dence, achieving the very best possible sonic results.
continued
7
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(SECTION ONE: About Krell continued)
Impedance Advantage
The output impedance of the final gain stages is one hundredth that of the final gain
stage in most power amplifiers. This provides extremely wide bandwidth and very
high current capability. The amplifier does not employ global negative feedback—the
final gain stages use only 8 dB of local, nested negative feedback. This is one five-
hundredth the amount used in most solid-state power amplifiers. The result is an
extraordinarily open, liquid, effortless sound.
Robust Power Supply Regulation
For Absolute Voltage Stability
The rails powering the amplifier’s low level and gain stages are regulated twice
for total immunity from fluctuations in the AC mains and virtually noise-free out-
put. All the regulators use current-mode circuitry for wide bandwidth, low output
impedance, and complete immunity to varying load conditions. The high-current
regulators powering the amplifier output stages use fully complementary gain
stages and output drivers. The resulting wide bandwidth and low output imped-
ance of the Evolution One surpasses even the stringent demands of the amplifier
output stages.
The driver and output stages in the high current regulators use 14 pairs of the
same robust, high performance power transistors used in the amplifier output
stages. All the regulators are located in the amplifier chassis to provide ultra low
impedance supply rails for the audio circuitry.
Evolution Bias Control Systems
The new Evolution Bias system features 12 individual bias levels for optimum
performance and efficiency. Evolution Bias constantly compares the audio signal
at the input stage with impedance at the output stage, and adjusts the bias cur-
rent accordingly. In addition, a proprietary bias monitor continuously measures
and adjusts the output stage bias, eliminating the need for future adjustment or
calibration.
8
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Separate Power Supplies Are Quiet and Powerful
Housed in a separate chassis, the power supply makes use of extensive electri-
cal and magnetic shielding to keep radiated interference out of critical amplifier
circuits. Internal high current line conditioning circuitry filters RF noise on the
AC mains, as well as compensating for asymmetric power waveforms and DC
on the mains. A dedicated 165 VA toroidal transformer with six independent
secondary windings powers the amplifier’s low level stages, gain stages, and
control circuitry. Power for the high current regulators and amplifier output stages
comes from two massive 2500 VA toroidal transformers. These in turn drive eight
35-amp bridge rectifiers and 120,000 microfarads of filter capacitance. High relia-
bility connectors with 56 machined, gold plated, 20-amp contacts transmit these
tremendous power reserves to the regulators.
Advanced Microprocessor Control Monitors
Critical Operational Parameters
If the DC level at the amplifier inputs exceeds a safe level, the microprocessor
control automatically switches in DC blocking capacitors to prevent damage to
the input stages or the loudspeakers. The microprocessor control measures the
load impedance in real time to optimize the performance of the amplifier and
power supply or, in the case of a short circuit, to shut the amplifier off. It monitors
the regulator output voltages, the symmetry between the two halves of the bal-
anced output stages, and it monitors the operating temperatures of the three
main heat sinks. If any of the heat sinks become too hot, the microprocessor
control adjusts the operating parameters of the amplifier and power supply to
help the circuitry run cooler. If the temperature of any of the heat sinks becomes
unsafe, the microprocessor control shuts the amplifier off until it cools down.
In the event of a major protection fault the microprocessor flashes a diagnostic
code on the power/stand-by LED (4). The RMS output voltage and current sig-
nals used by the microprocessor are also used by the power meter (6) (7), on the
amplifier front panel, to display accurate power measurements. For more infor-
mation on diagnostic codes, see Amplifier Troubleshooting, on page 26.
continued
9
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(SECTION ONE: About Krell continued)
Definition of Terms
Following are the definitions of key terms used in your owner’s reference manual.
Inputs and Outputs
Balanced
A symmetrical input or output circuit that has equal impedance from both input ter-
minals 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 completely immune to induced noise from the system or the envi-
ronment.
CAST and Evolution CAST
Krell Current Audio Signal Transmission, or CAST, is a proprietary Krell circuit tech-
nology for connecting analog components, transmitting the audio waveform between
components in the current domain rather than in the voltage domain. The speed and
bandwidth provided by Krell CAST and its circuitry update, Evolution CAST, yield
accurate, realistic music reproduction, enabling connected components to perform
as if they are all part of a single circuit.
Operation
Off
When the power breaker switch on the back panel of the power supply is in the
down position, and the power/stand-by LEDs (4), the backlight (5), and the power
meter scale (6) are not illuminated, the amplifier is off.
Stand-by
A low power consumption status that keeps the audio and regulator circuits at idle.
The power/stand-by LEDs (4) are illuminated in red, when the amplifier is in the
stand-by mode. Krell recommends leaving the amplifier in the stand-by mode when
it is not playing music.
10
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(Operation continued)
Operational Mode
When the power/stand-by LEDs (4), the backlight (5), and the power meter scale (6)
are illuminated in blue, the amplifier 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 voltage domain. This unique technology provides
the component with exceptional speed, and a wide bandwidth.
Evolution Bias
A patented microprocessor control system that maintains Class A bias operation
regardless of musical demand. Class A bias is the most accurate method used to
amplify musical signals. Evolution Bias maximizes an amplifier’s efficiency both in
power consumption and heat generation.
11
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SECTION
TWO
Unpacking and Placement
This section describes the procedures for safely unpacking and placing your
Evolution One Monaural Power Amplifier. Each Evolution One amplifier channel
is shipped in 2 cartons: a power supply chassis in 1 carton and an amplifier
chassis in the other carton.
Opening the Amplifier Shipping Carton
Each Evolution One shipping carton measures 27.5 in. (69.9 cm) wide by 12 in.
(30.5 cm) high by 20.8 in. (52.8 cm) deep and contains 1 amplifier power supply
chassis or 1 amplifier chassis.
Power Supply Chassis. The combined weight of the shipping carton and the
power supply chassis is 110 lbs. (49.8 kg). Each power supply chassis measures
15.8 in. (40 cm) wide by 6.4 in. (16.1 cm) high by 20.5 in. (52.2 cm) deep and
weighs 95 lbs. (43 kg).
Amplifier Chassis. The combined weight of the shipping carton and the
amplifier chassis is 70 lbs. (31.7 kg). Each amplifier chassis measures 15.8 in.
(40 cm) wide by 6.2 in. (15.8 cm) high by 21.5 in. (54.7 cm) deep and weighs
55 lbs. (24.9 kg).
To Remove the Chassis from the Shipping Carton
1. Open a shipping carton and remove the top layer of foam. You see these
items:
1 Evolution One power supply chassis or amplifier chassis
1 packet containing the owner’s reference and warranty card
2. Orient the shipping box so that one person stands at the front of the carton
and the other person stands at the back of the carton.
2 people needed
12
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3. Simultaneously grasp the pair of cardboard handle cutouts at the front and
back of the carton and lift the chassis straight up out of the carton.
2 people needed
4. Place the chassis in a safe location and remove the protective plastic
wrapping.
2 people needed
5. Open the remaining 3 cartons of the Evolution One, using steps 1-4 above
as a guide.
2 people needed
6. Place the power supply chassis where you intend to use the assembled ampli-
fier channel. Krell recommends that you do not move the amplifier after it is
assembled.
2 people needed
7. Locate the 4 locating pins (23) and the power connector (24) in the top plate of
the power supply chassis. See Figure 4, on page 18.
8. Make certain the amplifier chassis feet (13) and the amplifier power connector
(not shown) align with the 4 power supply locating pins and power supply
power connector as you lower the amplifier chassis onto the power supply
chassis. Use the outer edges of the amplifier and power supply chassis as a
guide. The dimensions of the chassis are identical. When viewed from the top,
the power supply chassis will disappear beneath the amplifier chassis, indicat-
ing proper alignment of the feet, pins, and power connectors.
2 people needed
9. Visually inspect the union between the amplifier and power supply chassis.
Verify that the each of the amplifier chassis feet has descended upon the
power supply chassis locating pins, and that both halves of the power connec-
tors have mated squarely with one another.
10. Press firmly on the amplifier chassis to ensure that the connector is properly
engaged.
continued
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(SECTION TWO: Unpacking and Placement continued)
Placement
Before you install an Evolution One amplifier into your system, please follow the
guidelines in this section to choose its proper location. This will facilitate a clean,
trouble-free installation.
Each Evolution One amplifier requires at least two inches (5 cm) of clearance
on each side and at least eight inches (20 cm) of clearance above the compo-
nent to provide adequate ventilation. An Evolution One amplifier channel meas-
ures 15.8 in. (40 cm) wide by 12.5 in. (31.6 cm) high by 21.5 in.(54.7 cm) deep
and weighs 150 lbs. (67.9 kg).
Although Evolution Bias circuitry reduces the high heat dissipation and heat out-
put of traditional Class A circuitry, Evolution One amplifiers still can become hot
under normal operation. When the front and rear of a cabinet are open, the air
space between the chassis and shelf must be unobstructed. If you place the
amplifier in a closed cabinet, you may need to modify shelf spacing or use small
fans to increase ventilation.
Place the amplifier as close to the loudspeakers as possible. Although Krell CAST
technology permits you to use interconnect cables of any length, try to keep the
cable length to a minimum. All Evolution One amplifiers drive the lowest imped-
ances with ease. When impedance is added due to long loudspeakers cable
lengths, amplifier power is wasted in the cable. Long loudspeakers cables reduce
the maximum power that is delivered in the loudspeakers.
AC Power Guidelines
Each Evolution One amplifier channel needs to be operated from a dedicated AC
circuit rated at a minimum of 20 amps. A 30 amp AC circuit is preferable, but not
required.
Use the power cord shipped with the amplifier channel to make the AC connection.
Operation with a power cord other than the one supplied by Krell may induce
noise, limit current, or otherwise impair the amplifier’s ability to perform optimally.
14
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SECTION
THREE
Anatomy of an Amplifier
This section describes Evolution One features and benefits.
Figure 1 Evolution One Amplifier and Power Supply Chassis Front Panels
1
5
6
7
8
CAST
50W
POWER
5000W
4
3
9 10
11
12
2
4
1 Amplifier Chassis
2 Power Supply Chassis
3 Power/Stand-by Button
4 Power/Stand-by LED
5 Backlight
Inset
Evolution One
Amplifier Channel
Front Panel View
6 Power Meter Scale
7 Power Meter Wand
8 CAST LED
13
9 50 W Scale LED
10 5000 W Scale LED
11 Cast/Balanced Button
12 Meter Range Button
13 Amplifier Feet
14
14 Power Supply Feet
continued
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(SECTION THREE: Anatomy of an Amplifier continued)
Figure 2 Evolution One Amplifier and Power Supply Chassis Back Panels
1
BALANCED
INPUT
CAST
INPUT
IN
IN
OUT
EVOLUTION ONE
KRELL INDUSTRIES, INC.
45 CONNAIR ROAD
ORANGE, CT 06477-3650
USA
NO USER SERVICEABLE PARTS INSIDE
MADE IN USA
15
16
18
19
17
2
50/60 Hz
EVOLUTTION ONE
KRELL INDUSTRIES, INC.
45 CONNAIR ROAD
ORANGE, CT 06477-3650
USA
NO USER SERVICEABLE PARTS INSIDE
MADE IN USA
21
20
15 Balanced Input
16 CAST Input
17 Amplifier Binding Posts
18 RC-5 Input
19 12 V Trigger In/Out
20 IEC Power Cord
Receptacle
21 Power Breaker Switch
16
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Figure 3 Evolution One Amplifier Chassis Top
17
17 Amplifier Binding Posts
22 Amplifier Front
22
continued
17
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(SECTION THREE: Anatomy of an Amplifier continued)
Figure 4 Evolution One Power Supply Chassis Top
23
24
23
23 Locating Pin
24 Power Connector
25 Power Supply Front
25
18
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SECTION
FOUR
Connecting the Evolution One
to Your System
This section describes Evolution One amplifier connections and outlines remote
control options. Each Evolution One has a CAST 4-pin connector, a balanced input
via an XLR connector, a 12 Volt trigger In/Out connection, and an RC-5 input on
the back panel.
CAST Connections
Krell recommends using its proprietary Krell CAST system for unparalleled sonic
performance for connections between an Evolution One amplifier and other
CAST-equipped components. Krell CAST uses flexible interconnecting cables that
can be drawn through tight spaces and concealed.
Balanced Connections
Evolution One amplifiers also offer balanced connections. Balanced connections
not only can minimize sonic loss but also are immune to induced noise, especially
for installations using long cables.
Cable Connection Steps
The following steps describe how to connect cables to an Evolution One
amplifier:
1. Turn off all power sources and components before connecting inputs and out-
puts.
2. Neatly organize wiring between to and from the amplifier and all components.
Separate AC wires from audio cables to prevent hum or other unwanted noise
from being introduced into the system.
continued
19
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(SECTION FOUR: Connections, continued)
3. Connect the Krell CAST cables from your CAST-enabled preamplifier or
source component to the left and right Krell CAST 4-pin bayonet inputs (16)
on the amplifier (1) back panel. For balanced operation, connect the intercon-
nect cable from your preamplifier to the balanced XLR input (15) on the ampli-
fier back panel.
4. Connect the loudspeaker cables to the amplifier binding posts (17), located on
the amplifier back panel. Amplifier binding posts accept spade lugs only.
5. Insert the AC mains power cord plug into the IEC power cord
receptacle (20), on the back panel of the power supply chassis.
6. Turn to Amplifier Operation, on page 22.
Note
If a CAST and balanced source are connected to the amplifier during the initial installa-
tion, the Evolution One amplifier defaults to CAST, when it is powered on. If only one
source is connected, the amplifier will automatically select that source. For more informa-
tion, see Switching Between CAST and Balanced Inputs, on page 23.
DC Protection Circuitry / Using a Tube Preamplifier
The Evolution amplifier has a built-in DC monitor that continuously monitors the
audio signal at the input. If too high a level of DC is detected, the amplifier auto-
matically mutes the output and engages DC coupling capacitors at the input
stage.
For more information about DC protection circuitry features, see Amplifier
Troubleshooting, on page 26.
20
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Remote Control Options
The Evolution One amplifier is compatible with the remote controls included with
the Krell Evolution Two preamplifier, other Krell preamplifiers or preamplifier/
processors, and it is compatible with the Universal Krell Touch Screen Remote.
Please contact your authorized Krell dealer, distributor, or Krell, if you wish to pur-
chase a separate remote control for the Evolution One amplifier.
The following remote control options are available, for amplifiers installed outside
of the listening area:
RC-5 Remote Control
Each Evolution One amplifier has an RC-5 remote input (18) on the back panel.
The RC-5 remote input accepts a remote command enabling it to switch
between stand-by and operational modes and to switch between CAST and bal-
anced inputs. The RC-5 remote control is used with a third party remote control
system that provides RC5 (IR) data with the carrier intact, via a wired connection.
A stereo tip, ring, sleeve 1/8” mini connector is used in the following configura-
tion: Tip = RC-5 data, Ring = +5 V, Sleeve = GND.
12 Volt Trigger
The Evolution One amplifier has a 12 Volt trigger input/output connection (19) that
sends and receives 12 VDC power on/off (12 V trigger) signals to/from other Krell
components and other devices that incorporate a 12 Volt trigger. Mono 1/8” mini
connectors are utilized with the following configuration: Tip = +12 V, Sleeve = GND.
Notes
When the Evolution One is in the operational mode, the 12 VDC Out provides
12 Volts of DC output. When the component is in the stand-by mode or off, the DC output
is 0 Volts.
A minimum of 30 mA is required to operate the 12 Volt trigger.
21
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SECTION
FIVE
Amplifier Operation
Evolution One amplifiers are easy to operate. However, it is important to exer-
cise care during operation due to the enormous power output of each amplifier.
Switching between active sources (such as a CD player or a recording device)
without muting the preamplifier output, or bumping or miscuing a source can
generate large transients at low frequencies. Evolution One amplifiers may gen-
erate enough power with these transients to damage loudspeakers.
IMPORTANT
Always mute or fully attenuate the preamplifier level when switching sources.
Do not change input connections to the amplifier when the amplifier is on.
Use care when setting high playback levels. Because of their tremendous
reserves of clean power, Evolution One amplifiers can safely drive speakers to
higher sound pressure levels than other amplifiers. Always lower the volume
level at the first sign of loudspeaker distress.
Powering On, Powering Down, and Powering Off
When powering on any system, turn on amplifiers last. When powering down, turn
off amplifiers first. Krell recommends leaving the Evolution One amplifier pow-
ered down (in the stand-by mode) between listening sessions. Turn the amplifier
off using the power breaker switch (21) on the back panel of the power supply
chassis (2), when the system is not being used for an extended period of time.
The procedure for amplifier operation follows:
1. Insert the AC power cord plug into the dedicated wall outlet.
2. Move the power breaker switch to the up position, to place the amplifier in
stand-by mode. The power/stand-by LEDs (4) on the amplifier and power sup-
ply chassis illuminate in red.
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3. Press the power button (3), located underneath the far left edge of the amplifier
chassis front panel. The power/stand-by LEDs (4) on the amplifier and power
supply chassis illuminate in blue. The backlight (5) and the meter scale (6) on the
amplifier chassis illuminate in blue.
You may now switch between CAST and balanced operation. For more infor-
mation, see Switching between Cast and Balanced Inputs, below.
4. With the preamplifier muted, or the volume control completely lowered, select
a source. Increase the volume control to the desired listening level.
5. To place the amplifier in stand-by mode, press the power button (3) on the
front panel. It is now safe to turn off the rest of the system.
Switching Between CAST and Balanced Inputs
If a CAST and balanced source are connected during the initial installation, see
Cable Connection Steps, pages 19-20, the Evolution One defaults to CAST and
the CAST LED illuminates in blue when the amplifier is powered on.
If only one source is connected, the amplifier automatically selects that source. If
the amplifier detects a balanced source, there is no illuminated LED.
To switch between CAST and balanced inputs, press the CAST/Balanced button
(11), located underneath the far right edge of the amplifier chassis front panel.
CAST cables must be engaged for this function to be operational.
continued
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(SECTION FIVE: AMPLIFIER OPERATION continued)
Adjusting Power Meter Modes
The Evolution One amplifier uses microprocessors to monitor RMS output voltage
and current signals. This information is output to a custom front panel power
meter (6) (7), which displays an accurate power measurement for the selected
meter range on the power meter scale (6). The power meter has 4 modes of opera-
tion accessed by the meter range button (12): 50 WATT range, 500 WATT range, 5000
WATT range, and OFF.
There are two ways to cycles between the operational modes:
Press the meter range button, located underneath the bottom right edge of the
amplifier chassis front panel or,
Press the select key (SEL) on the Evolution Two preamplifier, on another Krell pream-
plifier, or on the Universal Krell Touch Screen Remote.
Scale
Blue Front Panel LED
50W LED illuminates
None
Blue Backlight & Meter Scale Light
Illuminated
50 Watt
500 Watt*
5000 Watt
Illuminated
5000W LED illuminates
Meter is inactive
Illuminated
Off
Not illuminated
*Factory default
Power Meter Range and Power Meter Wand Action
The power meter (6) (7) enables you to monitor the power output of the Evolution
One amplifier. The 500 Watt scale is the factory default. The 50 Watt scale range is
the most sensitive, and displays the smallest changes in power output, with the
greatest physical movement of the power meter wand (7). Conversely, the 5000
Watt scale is the least sensitive, and displays the largest changes in power output,
with the smallest physical movement of the power meter wand.
Turning Off the Lights on the Amplifier
Channel Front Panel
When the meter range button (12) cycled to OFF, the lights on the front panels are
not illuminated.
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Amplifier Care
An Evolution One amplifier is capable of enormous power output, and it is impor-
tant to exercise care during system operation. Avoid any action that can generate
large transient signals. Always mute the preamplifier output before switching
between active sources or cuing an LP. Do not change inputs to the amplifiers
while the amplifiers are on.
Use care when listening at high volume levels. Because of their tremendous reserve
of clean power, Evolution One amplifiers can drive loudspeakers to much higher
sound pressure levels than other amplifiers without clipping. Always lower the
volume level at the first sign of loudspeaker distress.
Exercise great care when handling an amplifier — especially at the back panel.
Rings, necklaces, bracelets, and other pieces of metal jewelry can conduct elec-
tricity. Consider removing them before touching any part of the back panel.
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SECTION
SIX
Amplifier Troubleshooting
System Protection
Each Evolution One amplifier has a built-in DC monitor that continuously moni-
tors the audio signal at the input, as well as other sophisticated protection cir-
cuits that monitor other areas of the topology, in order to safeguard the amplifier.
This circuitry constantly evaluates the operation of the amplifiers and provides
protection against potentially damaging DC input or output and short circuits.
Regulator operation is also continuously monitored to ensure constant voltage to
the output stage. These protective systems are designed to prevent damage to
Evolution One amplifiers or loudspeakers caused by other defective components,
faulty wiring, system mishandling, or amplifier failure.
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Evolution One amplifiers report operational issues by flashing the power/stand-by
LEDs (4) in red, in a specific sequence, or by tripping the rear panel breaker (21),
as follows:
Diagnostic Codes
Possible Condition
Course of Action
1 flash, pause, 2 flashes,
repeat; then the amplifier
reverts to stand-by mode
Amplifier is over
temperature
Allow the amplifier
to cool. When the LEDs
stop flashing, the ampli-
fier has cooled down.
flash, pause, 5 flashes,
repeat; then the amplifier
reverts to stand-by mode
Short circuit
on output
Check all connections
at the amplifier and loud-
speaker binding posts.
Cycle the power breaker
switch (21) on the power
supply and attempt to
power on the amplifier.
Call the factory if the
problem persists.
1 flash, pause, 7 flashes,
repeat; then the amplifier
reverts to stand-by mode
Line frequency error:
The amplifier is set for
60 Hz, but is attempt-
ing to operate via a
50Hz system.
Contact your local
authorized Krell
dealer or distributor.
Output mutes while music
is playing, and then sound
resumes.
DC detected at input
during playback.
Check source and
preamplifier for
Input capacitors are
automatically engaged.
excessive DC output.
Once DC has been elimi-
nated, cycle the power
breaker switch (21) to
disengage the input
capacitors.
The power breaker switch
(21) trips; then the amplifier
powers off. The amplifier
repeats this action when
powered on.
Possible component
failure.
Contact your local
authorized Krell
dealer or distributor, or
the Krell Service
Department.
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Warranty
Each Evolution Series amplifier has a limited warranty of five years for parts and
labor on circuitry. Should this product fail to perform at any time during the warran-
ty, Krell will repair it at no cost to the owner, except as set forth in this warranty.
This warranty does not apply to damage caused by acts of God or nature.
The warranty described on this page shall be in lieu of any other warranty, expressed
or implied, including, but not limited to, any implied warranty of merchantability or
fitness for a particular purpose. There are no warranties which exceed beyond
those described in this document. If this product does not perform as warranted
herein, the owner’s sole remedy shall be repair. In no event will Krell be liable for
incidental or consequential damages arising from purchase, use, or inability to use
this product, even if Krell has been advised of the possibility of such damages.
Proof of purchase in the form of a bill of sale or receipted invoice substantiating
that the unit is within the warranty period must be presented to obtain warranty
service. The warranty begins on the date of the original retail purchase, as noted
on the bill of sale or receipted invoice from an authorized Krell dealer or distribu-
tor. Previously owned equipment, when re-purchased from an authorized Krell
dealer or distributor, has the balance of the original warranty, based on the origi-
nal date of manufacture.
The warranty for Krell products is valid only in the country to which they were
originally shipped, through the authorized Krell distributor for that country, and at
the factory. There may be restrictions on or changes to Krell’s warranty because
of regulations within a specific country. Please check with your distributor for a
complete understanding of the warranty in your country.
If a unit is serviced by a distributor who did not import the unit, there may be a
charge for service, even if the product is within the warranty period.
Freight to the factory is your responsibility. Return freight within the United States
(U.S.A.) is included in the warranty. If you have purchased your Krell product outside
the U.S.A. and wish to have it serviced at the factory, all freight and associated
charges to the factory are your responsibility.
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Krell will pay return freight to the U.S.A.-based freight forwarder of your choice.
Freight and other charges to ship the unit from the freight forwarder to you are also
your responsibility.
Krell is not responsible for any damage incurred in transit. Krell will file claims
for damages as necessary for units damaged in transit to the factory. You are
responsible for filing claims for shipping damages during the return shipment.
Krell does not supply replacement parts and/or products to the owner of the unit.
Replacement parts and/or products will be furnished only to the distributor perform-
ing service on this unit on an exchange basis only; any parts and/or products
returned to Krell for exchange become the property of Krell.
No expressed or implied warranty is made for any Krell product damaged by
accident, abuse, misuse, natural or personal disaster, or unauthorized modification.
Any unauthorized voltage conversion, disassembly, component replacement,
perforation of chassis, updates, or modifications performed to the unit will
void the warranty.
In the event that Krell receives a product for warranty service that has been modified
in any way without Krell authorization, all warranties on that product will be void.
The product will be returned to original factory layout specifications at the owner’s
expense before it is repaired. All repairs required after the product has been returned
to original factory specifications will be charged to the customer, at current parts
and labor rates.
All operational features, functions, specifications, and policies are subject to change
without notification.
To register your product for warranty benefits, please complete and
return the Warranty Registration Card enclosed in the shipping box within
15 days of purchase. Thank you.
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Return Authorization Procedure
If you believe there is a problem with your component, please contact your dealer,
distributor, or the Krell factory to discuss the problem before you return the component
for repair. To expedite service, you may wish to complete and e-mail the Service
Request Form in the Service Section of our website at:
To contact the Krell Service Department
TEL
203-799-9954, Monday-Friday
9:00 AM to 5:00 PM EST
203-799-9796
FAX
E-MAIL
Evolution One
PRODUCT
MODEL NUMBER
SERIAL NUMBER
To return a product to Krell, please follow this procedure
so that we may serve you better:
1. Obtain a Return Authorization Number (R/A number) and shipping address from
the Krell Service Department.
2. Insure and accept all liability for loss or damage to the product during shipment
to the Krell factory and ensure all freight (shipping) charges are prepaid.
The product may also be hand delivered if arrangements with the Service Department
have been made in advance. Proof of purchase will be required for warranty validation
at the time of hand delivery.
IMPORTANT
Use the original packaging to ensure the safe transit of the product to the factory, dealer,
or distributor. Krell may, at its discretion, return a product in new packaging and bill the
owner for such packaging if the product received by Krell was boxed in nonstandard pack-
aging or if the original packaging was so damaged that it was unusable. If Krell deter-
mines that new packaging is required, the owner will be notified before the product is
returned.
To purchase additional packaging, please contact your authorized Krell dealer,
distributor, or the Krell Service Department for assistance.
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Specifications
Frequency response
Inputs
20 Hz to 20 kHz 0.05 dB
0.6 Hz to 220 kHz +0, –3 dB
1 balanced via XLR connector
1 CAST via 4-pin bayonet connector
Signal-to-noise ratio
118 dB, “A”-weighted
Outputs
1 pair Krell binding posts
Gain
25.8 dB
Dimensions
Amplifier chassis:
15.8 in. W x 6.2 in. H x 21.5 in. D
40 cm W x 15.8 cm H x 54.7 cm D
Total harmonic distortion
<0.01% at 1 kHz, at 450 W, 8 Ohms
<0.1% at 20 kHz, at 450 W, 8 Ohms
Power supply chassis:
15.8 in. W x 6.4 in. H x 20.5 in. D
40 cm W x 16.1 cm H x 52.2 cm D
Input impedance
Balanced: 100 kHz
CAST: 50 Hz
Amplifier channel:
15.8 in. W x 12.5 in. H x 21.5 in. D
40 cm W x 31.6 cm H x 54.7 cm D
Input sensitivity
Balanced: 3.08 V RMS
CAST: 3.08 mA RMS
Weight
Amplifier chassis:
Shipped: 70 lbs., 31.7 kg
Unit Only: 55 lbs., 24.9 kg
Output power
450 W RMS at 8 Ohms
900 W RMS at 4 Ohms
1800 W RMS at 2 Ohms
Power supply chassis:
Shipped: 110 lbs., 49.8 kg
Unit Only: 95 lbs., 43 kg
Output voltage
170 V peak-to-peak
60 V RMS
Output current
57 A peak
Slew rate
100 V/us
Power consumption
Standby: 225 W
Idle: 300 W
Maximum: 3600 W
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