Krell Evolution Two Brochure

an evolution in sound technology
from the leader in audio engineering

www.krellonline.com

The Evolution Two
Monaural Preampli er

•

Two megahertz open loop bandwidth in

a zero feedback, balanced, Krell Current

Mode and CAST circuitry design.

•

To eliminate loading effects, single-ended

and balanced voltage inputs drive a

dynamically cascoded JFET buffer, which has

tremendous open-loop linearity and very high

input impedance.

•

All signal gain is realized in the current

domain using proprietary multiple-output

current mirrors with nearly 500 times the

open loop linearity of other designs.

•

Negative feedback is not used anywhere in

the preamp because it is not necessary.

Openloop distortion is typically less than

0.005% (50 parts per million).

•

The volume control is realized with a 16-bit

balanced resistor ladder — bandwidth and

transient response of the preamp circuitry

are virtually unaffected by the volume

setting.

•

Housed in a separate chassis, the power

supply makes use of extensive electrical

and magnetic shielding to keep radiated

interference out of critical preampli er

circuits.

•

Each monaural preampli er has a power

supply capability equivalent to many stereo

power ampli ers.

•

A 170 VA toroidal transformer drives

four 8-amp bridge recti ers and 39,600

microfarads of  lter capacitance.

•

A new Krell-designed digital control circuit

monitors and optimizes the preampli er’s

operating parameters.

•

Any number of preampli ers may be linked

and controlled from a single master, making

high quality, multi-channel audio systems a

reality for the  rst time.

•

Offered in diamond-cut silver or luxurious

black  nish.

The Evolution One
Monaural Power Ampli er

•

Newly redesigned Evolution Plateau Bias

System features 12 individual bias levels for

optimum performance and ef ciency.

•

A proprietary bias monitor continuously

measures and adjusts the output stage

bias, insuring a lifetime of accuracy.

•

Housed in a separate chassis, the power

supply makes use of extensive electrical

and magnetic shielding to keep radiated

interference out of critical ampli er circuits.

•

Internal high current line conditioning

circuitry  lters RF noise on the AC mains, as

well as compensating for asymmetric power

waveforms and DC on the mains.

•

Advanced microprocessor control monitors

critical operational parameters.

•

Bias, load impedance, regulator output

voltages and operating temperature are all

continuously monitored.

•

All signal gain is realized in the current

domain using proprietary multiple-output

current mirrors with extraordinary open loop

linearity.

•

The signal path is fully complementary and

fully balanced from input to output, featuring

Krell Current Mode and CAST circuitry.

•

The ampli er employs no global negative

feedback, and the  nal gain stages use only

8 dB of local, nested, negative feedback.

This is one  ve-hundredth the amount used

in most solid-state power ampli ers. The

result is an extraordinarily open, liquid,

effortless sound.

•

The rails powering the ampli er ís low level

and gain stages are regulated twice for total

immunity from  uctuations in the AC mains

and virtually noise-free output.

•

All the regulators are located in the ampli er

chassis to provide ultra low impedance

supply rails for the audio circuitry.

•

Offered in diamond-cut silver or luxurious

black  nish.

The Evolution Series culminates more than two decades of cutting edge

audio design. When envisioning Evolution, Krell had one solitary goal – to

hand craft a preampli er and power ampli er that, simply put, were the

best sounding products ever built. The result is a synthesis of almost

impossible contradictions; a unique blend of beauty, grace, and the

effortless power synonymous with the Krell name.

Evolution One Ampli er

The Evolution One is a Class A, 450-watt monaural ampli er that utilizes proprietary current gain topologies from input

to output allowing the audio signal to remain in the current domain throughout the entire ampli er thereby avoiding

unnecessary current to voltage conversions that add distortion, require heavy feedback and severely limit bandwidth.

The Evolution One circuitry is virtually devoid of feedback and sports a bandwidth an order of magnitude greater

than any conventional design. Coupled to this circuitry is a power section that is virtually limitless in its capability to

drive any speaker to its full potential. With all of this unrestricted power on tap, the Evolution One employs advanced

microprocessors that constantly monitor operating conditions and can automatically adjust the operating parameters

or shut the ampli er down to prevent damage to the input stages or loudspeakers. $50,000.

Evolution Two Preampli er

The Evolution Two monaural preampli er is a Class A design that was built to absolute perfection inside and out. The

audio signal path operates in full balanced mode from input to output and the proprietary Krell CAST inputs further

ensure absolute integrity of the audio signal. Nothing was overlooked when designing the Evolution Two; not even the

volume control that features a 16-bit balanced resistor ladder which uses low-resistance, high-linearity solid-state

switches and discrete precision resistors for the purest line stage possible. Although the Evolution Two embraces the

simplistic pleasures of a high-end two channel preamp, it also features sophisticated RS-232, IR and 12-volt controls

for better integration into a state-of-the-art home environment. $40,000.

Ferrari and Cartier say you enjoy luxury and know quality.

Krell says you never compromise.