Krell Industries EVOLUTION TWO MONAURAL PREAMPLIFIER manual Ensuring Maximum Performance

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(SECTION ONE: About Krell continued)

Ensuring Maximum Performance

“My pursuit of excellence in sound reproduction and my love of great musical performance fuels the ongoing Evolution design effort at Krell.”

Dan D’Agostino

The product of breakthrough Krell technology, the Evolution Two Monaural Preamplifier works in tandem with the Evolution One Monaural Power Amplifier to provide a sound that is supremely dynamic and musical. Indeed, it is the sound of the music itself.

Core Technologies

Zero Feedback Balanced Current Mode Design

The signal path is fully complementary and fully balanced from input to output. All transistors operate in Class A mode. CAST inputs drive a newly designed current- mode balanced input stage, which uses a unique topology able to reject com- mon-mode input noise over an unusually wide bandwidth.

Single-ended and balanced inputs drive a dynamically-cascoded JFET buffer, which has tremendous open-loop linearity and very high input impedance, to elim- inate loading effects. The voltage signals are then converted into balanced current signals, the form in which they remain through the remainder of the signal path. The audio signal remains in the current domain throughout the entire preamplifier. Only at the single-ended and voltage outputs is it converted back to the voltage domain.

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 Evolution Two preamplifier, nor is it necessary. Open-loop distortion is typically less than 0.005% (50 parts per mil- lion), and the open loop bandwidth extends to two megahertz. The result is an extraordinarily wide and deep image, with an open, effortless sound.

The signal switching relays are hermetically sealed and use gold-plated bifurcated contacts for maximum signal integrity. Where needed multiple relays are connect- ed in a “T” configuration to virtually eliminate crosstalk from unselected inputs.

The volume setting can be adjusted and displayed either numerically, from 0 to 151, or in dB, from –inf to +12.0 dB.

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Contents Evolution Page Contents List of Illustrations Letter from Dan D’Agostino Letter from Dan D’Agostino About Krell Krell LegacyRevolutionary Krell Cast Technology Voltage Signal Transmission Traditional Audio SystemHow Cast and Krell Current Mode Interact Cast BasicsEvolution Cast Cast Cable ConstructionBest Musical Performance Ensuring Maximum Performance Zero Feedback Balanced Current Mode DesignCore Technologies Fully Balanced Discrete Volume Control Separate Power SupplyAdvanced Microprocessor Control Custom Software Definition of Terms ConfigurationsInputs and Outputs Operation Krell Current ModePreamplifier TechnologyLeft/Right Channel Orientation Unpacking and PlacementOpening the Evolution Two Shipping Carton To Remove the Preamplifier Channel from the Shipping CartonAC Power Guidelines PlacementRepeat Steps 1-5 for the remaining preamplifier channels Connecting the Evolution Two to Your System Quick StartOperating the Evolution Two Linked Mode Anatomy of an Evolution Two 11 12 13Evolution Two Remote Control Chassis PowerFront Panel Description Remote Functions on the Front PanelPreamplifier Functions DisplayMenu Button or Key Level ControlNavigate/Customize Enter Button or KeyRemote Control Description Battery Installation and RemovalCompact Disc Functions Amplifier FunctionsIEC Power Cord Receptacle Outputs Back Panel DescriptionInputs 35, 36 Main Bus Outputs42 RC-5 Remote Connections on the Back Panel37, 38 Record Bus Outputs 43 RS-232Phono Stage Connector Link ControlInput and Output Connections Connecting the Evolution Two to Your SystemXLR Pin Configuration Connection StepsNever connect two power supplies together Connections Using can Link To Connect Multiple Evolution Two Preamplifiers via can LinkOn/Off and Stand-by Operation Linked Mode Evolution Two OperationPlay and Record To Turn Off Your SystemOperation Using can Link Customizing the Evolution Two Navigation ConventionsBacklight Menu FunctionsAC Mains Enter the menu, thenChannel Assign BalanceUse to make a left channel respond as a right channel Clone Use to make a right channel respond as a left channelDisplay Front panel display is always on InfoFront panel display times out after 5 seconds Input Name Input Level TrimTo select input names for other inputs, repeat Steps 3 Phase of the selected input is inverted 180 degrees Input PhasePhase of the selected input is unaffected Input TriggerEvolution Two responds to 12 V input trigger commands IR Out ControlLink Control can Link Output Trigger MuteOutput of the Evolution Two is completely silenced RC-5 Control Recall Recalls the factory settingsRS-232 Control Save Software CloneBegins the software clone process Tape InputInitiates the software clone Theater Mode Volume Display +12 dB. The options are Enter the menu, thenQuestions and Answers Troubleshooting System Noise Appendix can Link and Multiple Evolution Two Preamplifiers Connection of multiple preamplifier channelsAppendix can Link and Multiple Evolution Two Preamplifiers Warranty Warranty Service@krellonline.com Return Authorization ProcedureTo contact the Krell Service Department AM to 500 PM ESTSpecifications Control outputs

EVOLUTION TWO MONAURAL PREAMPLIFIER specifications

Krell Industries has long been a name synonymous with high-fidelity audio equipment, and their EVOLUTION TWO MONAURAL PREAMPLIFIER is a testament to this legacy. This premium preamp is designed to cater to audiophiles, delivering unparalleled sound quality and meticulous attention to detail.

At the heart of the EVOLUTION TWO lies Krell's commitment to superior audio performance. The preamplifier employs a fully balanced, differential signal path that minimizes noise and distortion, ensuring that the audio output is pure and true to the source. This architecture not only enhances sound quality but also integrates seamlessly with other high-end audio components in any setup.

One of the standout features of the EVOLUTION TWO is its advanced power supply design. Krell employs a toroidal transformer coupled with high-energy storage capacitors to provide stable, clean power. This allows for improved dynamics and transient response, helping to reproduce the complex nuances of music in a way that engages the listener. The preamplifier's power supply is designed to operate with extreme efficiency, ensuring consistent performance even during the most demanding listening sessions.

Additionally, the EVOLUTION TWO comes equipped with Krell's proprietary CAST (Current Audio Signal Transmission) technology. This innovative feature allows for a direct, impedance-matched connection between components, significantly reducing signal degradation over long cable runs. Audiophiles will appreciate the clarity and fidelity produced by CAST, revealing subtle textures and details in their favorite recordings.

The preamplifier also includes a range of inputs and outputs, catering to various audio sources and systems. Users can connect multiple devices, including digital sources, with ease, thanks to the EVOLUTION TWO's advanced input switching capabilities. The unit supports balanced XLR connections as well as unbalanced RCA outputs, providing flexibility for users with different equipment configurations.

Moreover, the EVOLUTION TWO MONAURAL PREAMPLIFIER boasts a stunning aesthetic, showcasing Krell's hallmark design philosophy. With its sleek chassis and elegant finish, the preamp not only sounds good but looks great in any audio setup.

In summary, the Krell Industries EVOLUTION TWO MONAURAL PREAMPLIFIER is a high-performance audio component that encapsulates cutting-edge technology and exceptional craftsmanship. With its balanced signal path, innovative power supply design, CAST technology, and versatile connectivity options, it is a remarkable addition to any serious audiophile's system, promising a listening experience that truly transcends the ordinary.
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