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Full Power Balanced 

X Series Power Amplifiers

700cx, 400cx, 300cx Stereo

750Mcx, 450Mcx, 350Mcx Monaural

with Krell CAST II Technology

THE LEADER IN AUDIO ENGINEERING

Instructions for Use

Owner’s Reference

Summary of Contents for 300cx

Page 1: ...Full Power Balanced X Series Power Amplifiers 700cx 400cx 300cx Stereo 750Mcx 450Mcx 350Mcx Monaural with Krell CAST II Technology THE LEADER IN AUDIO ENGINEERING Instructions for Use Owner s Reference ...

Page 2: ...speaker terminals to ground or attempt to bridge the left and right speaker binding posts of Full Power Balanced stereo amplifiers Do not connect a Full Power Balanced amplifier to a speaker selector device that employs a common ground scheme as it may short circuit the amplifier output THERE ARE NO USER SERVICEABLE PARTS INSIDE ANY KRELL PRODUCT Please contact your authorized Krell dealer distrib...

Page 3: ... 10 CONNECTING THE FULL POWER BALANCED AMPLIFIER TO YOUR SYSTEM 13 Input and Output Connections 13 Krell Trigger Connections 14 DC Protection Circuitry 14 Using a Tube Preamplifier 15 AMPLIFIER OPERATION 16 On Off and Stand by Operation 16 Krell Trigger Operation 17 REMOTE CONTROL OPERATION 18 How to Turn Off the Amplifier LEDs 18 How to Turn On the Amplifier LEDs 18 How to Switch between Krell CA...

Page 4: ...er 8 Front Panel FIGURE 2 The Full Power Balanced Monaural Amplifier 8 Front Panel FIGURE 3 The Full Power Balanced Stereo Amplifier 10 Back Panel FIGURE 4 The Full Power Balanced Monaural Amplifier 10 Back Panel iv Krell Full Power Balanced X Series Power Amplifiers ...

Page 5: ...series are identical however a pair of Full Power Balanced Monaural amplifiers are required for stereo operation Full Power Balanced amplifiers can be configured to accommodate any sophisticated music or home theater system and can be oper ated by an optional remote control or through the remote control of other Krell components This owner s reference manual contains important information on place...

Page 6: ...tions have 6 dB more gain than single ended con nections and allow the use of long interconnect cables Balanced connections are completely immune to induced noise from the sys tem or the environment Krell Current Audio Signal Transmission CAST A proprietary Krell circuit technology for connecting analog compo nents in which the audio waveform is transmitted between compo nents in the current rathe...

Page 7: ...etary 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 Krell Sustained Plateau Bias III A patented microprocessor control system that maintains Class A bias operation regardless of musical demand Class A bias is the most accurate method use...

Page 8: ...voltage domain between each component CAST transmission unifies the individual components and their intercon nects into an electrically linked whole The sonic presentation of the entire system remains intact CAST Basics Here s how a CAST audio system works Internally each CAST source transfers or amplifies current using Krell Current Mode cir cuitry This current signal is then output using CAST ci...

Page 9: ...d 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 The Best Musical Performance When you operate a CAST system you will hear significant improvements in every performance area speed precision dynam ic range depth and width of the sound stage transient impact...

Page 10: ...th 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 simultaneously lift the amplifier straight up out of the carton 3 Place the amplifier in a safe location and remove the protective plastic wrapping If any of the items mentioned above are not included in the ship ping box please contact ...

Page 11: ...fans to increase ventilation For the dimen sions of your Full Power Balanced amplifier see Specifications on pages 25 26 Place the amplifier as close to the loudspeakers as possible Krell CAST technology permits you to use interconnect cables of any length see Revolutionary CAST II Technology on page 4 how ever try to keep the cable length to a minimum All Full Power Balanced amplifiers drive the ...

Page 12: ...8 Krell Full Power Balanced X Series Power Amplifiers Figure 1 The Full Power Balanced Stereo Amplifier Front Panel Figure 2 The Full Power Balanced Monaural Amplifier Front Panel ...

Page 13: ...ft of triangle illuminates after the front panel power button is pressed indicating that the Sustained Plateau Bias III is engaged 3 Power Button The silver power button powers on the amplifier from stand by mode 4 Infrared Sensor The infrared sensor receives the signal from a remote control 5 Krell CAST LED The red Krell CAST LED center of triangle illuminates when a Krell CAST input on the back ...

Page 14: ...10 Krell Full Power Balanced X Series Power Amplifiers Figure 3 The Full Power Balanced Stereo Amplifier Back Panel Figure 4 The Full Power Balanced Monaural Amplifier Back Panel ...

Page 15: ... posts use both upper and lower pairs of loudspeaker binding posts See the loudspeaker s instruction manual for biwiring connections Loudpeaker binding posts for stereo and monaural amplifiers accept spade lugs only Bare wire banana lugs or pins will not work Use the red terminal for the positive connection and the blue terminal for the negative connection 14 Krell CAST Inputs The Krell CAST input...

Page 16: ...control to operate a linked amplifier configuration See Krell Trigger Connections on page 14 for more information An optional remote control is available for Full Power Balanced ampli fiers 18 AC Mains Power Cord All Full Power Balanced amplifiers are equipped with a perma nently attached AC power cord 19 Handles The handles help to move the amplifier easily and safely Stereo These amplifiers are ...

Page 17: ...d components off before connecting inputs and outputs 2 Neatly arrange and organize wiring 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 3 Connect the Krell CAST cables from your CAST enabled pre amplifier source component to the left and right Krell CAST 4 pin bayonet inputs 14 on the a...

Page 18: ...oper remote control oper ation 3 Connect one end of the MIDI cable to the Krell Trigger out con nector 17 on the back panel of the component 4 Connect the other end of the MIDI cable to the Krell Trigger in connector on the next component To link another component connect a second MIDI cable to the Krell Trigger out connector on the back panel of the second com ponent Connect the remaining end of ...

Page 19: ... engaged when using a tube preamplifier An authorized Krell deal er distributor or Krell must activate these capacitors Coupling capacitors must be inserted into the signal path by your authorized Krell dealer distributor or Krell before you can use your Full Power Balanced amplifier with a tube preamplifier Please read Warranty on page 23 to understand the warranty limi tations of Full Power Bala...

Page 20: ...iers first 1 Move the back panel power breaker switch 15 to the up position to engage the input circuitry and place the amplifier into the stand by mode The front panel blue power stand by LED 1 illu minates 2 Press the silver power button 3 on the amplifier front panel The blue regulator LED 6 illuminates Once the regulator provides power to the output stage the blue bias LED 2 illuminates The Su...

Page 21: ...e up position This ensures that all compo nents will be synchronized when signals from the control com ponent are sent to the linked components in the system 2 When the components are in stand by switch the control com ponent to the operational mode from the control component s front panel or by using the component s remote control The linked components switch to the operational mode simulta neous...

Page 22: ...amplifier in the stand by mode turn the rear panel power breaker switch to the off position Then turn the rear panel power breaker switch back to the on position The next time the amplifier is powered up from the front panel or the remote control the blue LEDs illuminate during the turn on sequence Press the meter key on a Krell remote to switch between CAST inputs and the balanced XLR inputs Full...

Page 23: ...cables checked before pro ceeding 2 If the interconnect 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 sugges tions on how to solve this problem Full Power Balanced amplifiers are protected by a series of nonin trusive circuits that constantly evaluate the amplifier s operation This ci...

Page 24: ...ort in loudspeaker cables or inside loudspeaker Insufficient AC current from the wall outlet Excessive heat DC present at the output stage Internal amplifier problem COURSE OF ACTION Have source unit and preamplifier checked for high DC output If preamplifier is a tube model see Using a Tube Preamplifier on page 15 Check all loudspeaker cables for any cuts or frayed edges that might form a connect...

Page 25: ...My system includes multiple pairs of loudspeakers Can I connect them to my Full Power Balanced amplifiers through a loudspeak er selector box A No Most loudspeaker selector boxes use a common ground scheme The differential circuitry in Full Power Balanced ampli fiers prohibits the use of these devices Do not connect a Full Power Balanced amplifier to a loudspeaker selector device that employs a co...

Page 26: ...ns they can be driven into clipping in which DC current goes to the loudspeakers due to loss of amplifier power Clipping can damage loudspeakers Avoid damage to your speakers by reviewing your loudspeaker specifications and exercise caution in heavy demand situations Questions and Answers continued ...

Page 27: ...ght 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 ...

Page 28: ...f 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 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 ...

Page 29: ...eak 170 V Peak to Peak 240 V RMS 49 V RMS 60 V RMS 84 V POWER CONSUMPTION Stand by 60 W Stand by 75 W Stand by 85 W Idle 175 W Idle 350 W Idle 430 W Max 1 700 W Max 3 000 W Max 6 000 W INPUTS 1 pair balanced via 1 pair balanced via 1 pair balanced via XLR connectors XLR connectors XLR connectors 1 pair CAST via 4 pin 1 pair CAST via 4 pin 1 pair CAST via 4 pin bayonet connectors bayonet connectors...

Page 30: ...W OUTPUT VOLTAGE Peak to Peak138 V Peak to Peak 170 V Peak to Peak 240 V RMS 49 V RMS 60 V RMS 84 V POWER CONSUMPTION Stand by 30 W Stand by 37 5 W Stand by 42 5 W Idle 150 W Idle 175 W Idle 220 W Max 1 700 W Max 3 000 W Max 6 000 W INPUTS 1 balanced via 1 balanced via 1 balanced via XLR connectors XLR connectors XLR connectors 1 Krell CAST via 4 pin 1 Krell CAST via 4 pin 1 Krell CAST via 4 pin b...

Page 31: ...CT 06477 3650 USA TEL 203 799 9954 FAX 203 891 2028 E MAIL krell krellonline com WEB SITE www krellonline com Full Power Balanced X Series Power Amplifiers 700cx 400cx 300cx Stereo 750Mcx 450Mcx 350Mcx Monaural with Krell CAST II Technology v03 0 ...

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