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Evolution 302, 402, 403, 400, 600 and 900 Power Amplifiers 
Owner’s Reference, v08.0

Krell Industries, Inc.
45 Connair Road
Orange, CT 06477-3650 USA

This product complies with the EMC directive (89/336/EEC) and the low-voltage directive
(73/23/EEC).

IMPORTANT SAFETY INSTRUCTIONS

1.

Read Instructions.

2.

Keep these Instructions.

3.

Heed all Warnings.

4.

Follow all Instructions. 

5.

Do not use this apparatus near water.

6.

Clean only with a dry cloth.

7.

Do not install near any heat sources such as radiators, heat registers, stoves, or other appa-
ratus (including amplifiers) that produce heat.

8.

Unplug this apparatus during lightning storms or when unused for long periods of time.

9.

Refer all servicing to qualified service personnel. Servicing is required when the apparatus
has been damaged in any way, such as a power-supply cord or plug is damaged, liquid has
been spilled or objects have fallen into the apparatus, the apparatus has been exposed to
rain or moisture, does not operate normally, or has been dropped.

10. An Evolution amplifier must be placed on a firm, level surface where it is not exposed to drip-

ping or splashing.

11. The ventilation grids on the top of every Evolution amplifier, the ventilation grids on the back of

the Evolution 302 and 400 amplifiers, and the space underneath every Evolution amplifier must
be unobstructed at all times during operation. Do not place flammable material above or
beneath an Evolution amplifier.

12. Before making connections to an Evolution amplifier, ensure that the power is off and other com-

ponents are in mute or stand-by mode. Make sure all cable terminations are of the highest quali-
ty, free from frayed ends, short circuits, or cold solder joints.

13. THERE ARE NO USER SERVICEABLE PARTS INSIDE AN EVOLUTION AMPLIFIER.

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

This product is manufactured in the United States of America. Krell

®

is a registered trademark of Krell Industries, Inc., and is restricted for use by

Krell Industries, Inc., its subsidiaries, and authorized agents. CAST

™, Evolution 

CAST

™, 

and Krell Current Mode

are trademarks of Krell

Industries, Inc. All other trademarks are registered to their respective companies.

TEL 203-298-4000
FAX 203-891-2028
E-MAIL [email protected]
WEBSITE http://www.krellonline.com 

P/N 309888

© 2007 by Krell Industries, Inc. All rights reserved .

Summary of Contents for Evolution 302

Page 1: ...O W N E R S R E F E R E N C E EVOLUTION E V O L U T I O N A M P L I F I E R S 3 0 2 A N D 4 0 2 S T E R E O 4 0 3 T H R E E C H A N N E L 4 0 0 6 0 0 A N D 9 0 0 M O N A U R A L ...

Page 2: ...t is not exposed to drip ping or splashing 11 The ventilation grids on the top of every Evolution amplifier the ventilation grids on the back of the Evolution 302 and 400 amplifiers and the space underneath every Evolution amplifier must be unobstructed at all times during operation Do not place flammable material above or beneath an Evolution amplifier 12 Before making connections to an Evolution...

Page 3: ...nt Panel Description and Back Panel Description SECTION FOUR Connecting an Evolution Amplifier to Your System page 22 CAST Connections Balanced Connections Single ended Connections Evolution DC Protection Circuitry Using Tube Preamplifiers Connection Steps SECTION FIVE Evolution Amplifier Operation page 24 On Off and Stand by Operation SECTION SIX Troubleshooting System Noise page 25 How to Evalua...

Page 4: ... page 15 Evolution 302 Stereo Back Panel Figure 3 page 16 Evolution 402 Stereo Amplifier Back Panel Figure 4 page 17 Evolution 403 Three channel Amplifier Back Panel Figure 5 page 18 Evolution 400 Monaural Amplifier Back Panel Figure 5 page 19 Evolution Monaural Amplifier Back Panel ...

Page 5: ...to sound its best without regard to impedance or efficiency I believe that linearity an amplifier s ability to output an exact duplicate of the input signal is the ultimate measure of that amplifier s work At Krell I drive amplifier designs toward the com mon goal of linearity through the rigorous application of Krell design principles that focus our efforts on four major performance factors disto...

Page 6: ...fiers Features Evolution Series amplifiers are designed with a signal path that incorporates Krell Current Mode and CAST circuitry All amplifiers feature massive power supplies The power supply makes use of extensive electrical and magnetic shielding to keep radiated interference out of critical amplifier circuits The Evolution 302 design utilizes a 3000 VA power supply The Evolution 402 and Evolu...

Page 7: ...nter connects into an electrically linked whole The original signal remains unaltered from source to speaker CAST Basics Here is 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 u...

Page 8: ...s 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 revolutionary current mirror circuitry the Evolution amplifier compo nents raises CAST technology to another level This advanced use of the technol ogy increases the linearity transient speed and ...

Page 9: ...te Evolution CAST yield accurate realistic music reproduction enabling connected compo nents to perform as if they are all part of a single circuit CAST and Evolution CAST are balanced connections and reject induced noise Single ended A two wire input or output circuit Single ended connections are not recommend ed for connections requiring long cable runs Use care when using single ended connectio...

Page 10: ...educing the load on individual devices and improving circuit wide linearity Krell Current Mode A proprietary Krell circuit topology in which the audio gain stages of a component operate in the current domain rather than the voltage domain This unique technol ogy provides the component with exceptional speed and a wide bandwidth SECTION ONE Definition of Terms continued ...

Page 11: ...VDC 12 V trigger cable 1 Packet containing the Quick Setup Guide and the warranty registration card 2 Orient the shipping box so that one person stands at the front of the amplifier and one person stands at the back of the amplifier Both people need to grab a pair of the cardboard handle cutouts one pair located at the front of the amplifier and one pair located at the back of the amplifier and si...

Page 12: ...r in a closed cabinet you may need to modify shelf spac ing or use small fans to increase ventilation When the front and back of a cabinet are open the air space between the chassis and shelf must be unobstructed Place the amplifier s as close to the loudspeakers as possible While Evolution CAST technology permits long interconnect cable lengths keep loudspeaker cable lengths to a minimum AC Power...

Page 13: ...N THREE Anatomy of an Evolution Amplifier This section describes Evolution amplifier functions Figure 1 Evolution Amplifier Front Panel Evolution 402 shown 1 Power Button 2 Power Status Indicator Power continued ...

Page 14: ...r is in stand by mode The indicator illuminates in blue when the amplifier is in operational mode If there is no illumination please check the following items The power cord is connected to the amplifier The power cord is plugged into a live AC power supply The back panel power breaker switch 10 is set to the on position The back panel backlight switch 8 is set to the on ext position There is no 1...

Page 15: ...lifier Back Panel 3 Loudspeaker Binding Posts 4 CAST Inputs 5 Single ended Inputs 6 Balanced Inputs 7 12 VDC Out In 12 V Trigger 8 Backlight Control 9 IEC Power Cord Receptacle 10 Power Breaker Switch Inputs Outputs Remote Power continued ...

Page 16: ...o Amplifier Back Panel 3 Loudspeaker Binding Posts 4 CAST Inputs 5 Single ended Inputs 6 Balanced Inputs 7 12 VDC Out In 12 V Trigger 8 Backlight Control 9 IEC Power Cord Receptacle 10 Power Breaker Switch Inputs Outputs Remote Power ...

Page 17: ...eaker Binding Posts 4 CAST Inputs 5 Single ended Inputs 6 Balanced Inputs 7 12 VDC Out In 12 V Trigger 8 Backlight Control 9 IEC Power Cord Receptacle 10 Power Breaker Switch Inputs Outputs Remote Power SECTION THREE Anatomy of an Evolution Amplifier continued continued ...

Page 18: ...onaural Amplifier Back Panel 3 Loudspeaker Binding Posts 4 CAST Input 5 Single ended Input 6 Balanced Input 7 12 VDC Out In 12 V Trigger 8 Backlight Control 9 IEC Power Cord Receptacle 10 Power Breaker Switch Outputs Remote Power ...

Page 19: ...r Back Panel Evolution 600 shown 3 Loudspeaker Binding Posts 4 CAST Input 5 Single ended Input 6 Balanced Input 7 12 VDC Out In 12 V Trigger 8 Backlight Control 9 IEC Power Cord Receptacle 10 Power Breaker Switch Inputs Outputs Remote Power ...

Page 20: ...one pair per channel Each channel has one positive and one negative binding post They accept spade lugs only Inputs 4 CAST Inputs one per channel These are CAST inputs with 4 pin bayonet connectors for use with Krell CAST equipped preamplifiers and components 5 Single ended Inputs one per channel These are single ended analog inputs with RCA connectors 6 Balanced Inputs one per channel These are b...

Page 21: ...of the components used in a custom installation to take full advantage of the remote capabilities of an Evolution amplifier 8 Backlight Control Ext In Connect a 12 V trigger to the Ext In input connector to turn off the power status indicator 2 using a remote control The switch must be set to On Ext in order for this to function see below On Ext This activates the power status indicator This is th...

Page 22: ...performance for connections between the Evolution amplifier and other CAST equipped components Krell CAST uses flexible interconnecting cables that can be drawn through tight spaces and concealed Balanced Connections The Evolution amplifier also offers balanced operation The circuitry and connec tions associated with balanced operation not only can minimize sonic loss but also are immune to induce...

Page 23: ...e AC wires from audio cables to prevent hum or other unwanted noise from being introduced into the system 3 Connect the outputs of your preamplifier to the appropriate CAST 4 balanced 6 or single ended inputs 5 on the Evolution amplifier Note Connect the u shaped jumpers between pins 1 and 3 of the XLR connectors when using single ended inputs 4 Connect the loudspeaker cables to the loudspeaker bi...

Page 24: ...r status indicator 2 illuminates in blue The initial power up phase lasts approximately 30 seconds from the moment the back panel power breaker switch is placed in the up position If the power button is pressed during this period the power status indicator flashes blue for the remainder of the initial power up phase When the initial power up phase is complete the power indicator illuminates in blu...

Page 25: ...m disappears turn the amplifier into stand by mode again and reinsert one of the interconnect cables Turn the amplifier back on Repeat this process for each cable 3 If the hum reappears with one or both interconnect cables reinserted the cable needs to be checked 4 If the interconnect cables are sound you may be experiencing a ground loop Please contact your authorized Krell dealer distributor or ...

Page 26: ...short circuits If you are driving more than one loudspeaker per channel check that the combined load does not drop below 2 Ohms The power breaker switch must be shut off to reset the fault condi tion 4 flashes Excessive temperature Allow the amplifier to cool and increase venti lation If the problem persists please call the factory 5 flashes Excessive DC at input Check the preamplifier output and ...

Page 27: ...stem Noise on page 25 If the interconnects and cables are sound you may be experiencing a ground loop This can often be easily eliminated Please con tact your authorized Krell dealer distributor or Krell for suggestions on how to solve this problem Q My loudspeakers are rated for 150 Watts Are the Evolution models too power ful for them A No A loudspeaker seldom is damaged from overdriving More of...

Page 28: ...oduct even if Krell has been advised of the possibility of such damages IMPORTANT The single ended inputs on the Evolution amplifiers are cap coupled Use these inputs whenever you are connecting a tube preamplifier Proof of purchase in the form of a bill of sale or receipted invoice substantiating that the product is within the warranty period must be presented to obtain warranty service The warra...

Page 29: ...o Krell for exchange become the property of Krell No expressed or implied warranty is made for any Krell product damaged by acci dent 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 product will void the warranty The operating voltage of the ...

Page 30: ...o 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...

Page 31: ...160 V peak to peak 57 V rms OUTPUT CURRENT 35 A peak 37 A peak SLEW RATE 120 V µs 100 V µs OUTPUT IMPEDANCE 0 040 Ohms at 20 Hz 0 053 Ohms 20 Hz to 20 kHz 0 055 Ohms at 20 Hz 0 064 Ohms 20 Hz to 20 kHz DAMPING FACTOR Referred to 8 Ohms 200 at 20 Hz 150 20 Hz to 20 kHz 145 at 20 Hz 125 20 Hz to 20 kHz POWER CONSUMPTION Stand by Idle Maximum 150 W 320 W 3400 W 370 W 570 W 3800 W HEAT OUTPUT Stand by...

Page 32: ...t 4 Ohms 1600 W rms at 2 Ohms OUTPUT VOLTAGE 160 V peak to peak 57 V rms OUTPUT CURRENT 37 A peak SLEW RATE 100 V µs OUTPUT IMPEDANCE 0 055 Ohms at 20 Hz 0 064 Ohms 20 Hz to 20 kHz DAMPING FACTOR Referred to 8 Ohms 145 at 20 Hz 125 20 Hz to 20 kHz POWER CONSUMPTION Stand by Idle Maximum 370 W 570 W 5000 W HEAT OUTPUT Stand by Idle Maximum 1270 BTU hr 1950 BTU hr 7700 BTU hr INPUTS 3 single ended v...

Page 33: ...VOLTAGE 196 V peak to peak 69 V rms 240 V peak to peak 85 V rms OUTPUT CURRENT 49 A peak 60 A peak SLEW RATE 100 V µs 90 V µs OUTPUT IMPEDANCE 0 030 Ohms 20 Hz to 20 kHz 0 023 Ohms 20 Hz to 20 kHz DAMPING FACTOR Referred to 8 Ohms 270 20 Hz to 20 kHz 350 20 Hz to 20 kHz POWER CONSUMPTION Stand by Idle Maximum 260 W 410 W 3800 W 440 W 650 W 5000 W HEAT OUTPUT Stand by Idle Maximum 890 BTU hr 1400 B...

Page 34: ... E C T 0 6 4 7 7 3 6 5 0 U S A T E L L 2 0 3 2 9 8 4 0 0 0 FA X 2 0 3 8 9 1 2 0 2 8 E M A I L s a l e s k r e l l o n l i n e c o m h t t p w w w k r e l l o n l i n e c o m E V O L U T I O N A M P L I F I E R S 3 0 2 A N D 4 0 2 S T E R E O 4 0 3 T H R E E C H A N N E L 4 0 0 6 0 0 A N D 9 0 0 M O N A U R A L ...

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