Krell Industries KAV-250a User's Manual
Contents
1. minimize sonic loss but also have immu nity to induced noise especially for instal lations using long cable lengths Balan ced connections have 6dB more gain than single ended connections When level matching is critical keep this speci fication in mind WARNING Use only one set of inputs to the amplifier at a time The KAV 250a amplifier is shipped with shorting pins in the XLR inputs These pins should remain in the XLR inputs if the KAV 250a amplifier is operating in the single ended mode When the shorting pin is insert ed pins 1 and 3 are shorted together The shorting pins must be removed to connect the KAV 250a amplifier for balanced operation The XLR pin configuration is described below Pin 1 Ground Pin 2 Non inverting 0 Pins Inverting 180 3 Insert the AC power cord into the recepta cle located on the back of the KAV 250a amplifier Insert the other end into the AC wall receptacle 4 The amplifier is now ready for operation See Amplifier Operation on page 7 KRELL KAV 250a Linking Multiple Amplifiers Multi Amp Throughput MAT For systems containing multiple amplifiers Multi Amp Throughput MAT simplifies installations MAT provides a daisy chain system option that reduces installation complexity and cabling requirements To use this option connect the outputs of the amplifier either balanced via XLR or single ended via RCA connectors to the inputs o2. aau The Leader in Audio Engineering Instructions for Use Owner s Reference KAV 250a Amplifier Page INTRODUCTION 3 UNPACKING _ 3 PLACEMENT 7 3 Cabinetry Considerations 4 AC Power Guidelines 4 Krell Industries Inc 45 Connair Road CONNECTING THE KAV 250a oO NN N O TO YOUR SYSTEM 4 Orange CT 06477 3650 USA Input and Output Connections 4 Linking Multiple Amplifiers 9 TEL 203 799 9954 Configuring the KAV 250a FAX 203 799 9796 for Bridged SpPeralon l AMPLIFIER OPERATION E MAIL krell krellonline com On Off and Stand by Operation System Noise Considerations WARRANTY RETURN AUTHORIZATION PROCEDURE 9 SPECIFICATIONS 12 ILLUSTRATIONS Page THE KAV 250a BACKPLATE AND CONNECTIONS FOR BRIDGED OPERATION 6 1997 by KRELL Industries Inc All rights reserved Se P N 19608 0230 0000 CE Marking This product complies with the EMC direc tive 89 336 EEC and the low voltage directive 73 23 EEC Introduction Thank you for your purchase of the Krell KAV 250a To obtain the best performance from your KAV 250a amplifier pay careful attention to its placement installation and operation A thorough understanding of these details will help insure satisfactory operation and long life for the KAV 250a_ and related system components THERE ARE NO USER SERVICEABLE PARTS INSIDE ANY KRELL PRODUCT Please contact your authorized dealer distributor o
3. Procedure IMPORTANT If you believe there is a prob lem with your unit please contact your deal er distributor or the Krell factory immedi ately Do not return any unit to KrelP for repair without first discussing the problem and obtaining a Return Authorization Number To return a product the owner is required to Mm Obtain a Return Authorization Number R A number and shipping address from the Krell Service Department WE Insure and accept all liability for loss or damage to the product during shipment to the Krell factory and prepay all ship ping charges The product may also be hand delivered if arrangements with the Service Department have been made in advance Proof of purchase may be re quired for warranty validation at the time of hand delivery Mm Use the original packaging to insure the safe transit of the product to the factory dealer or distributor The use of any packaging material other than the original packaging materials is not recommend ed 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 non standard packaging or if the original packaging was so damaged that it was unusable If Krell determines that new packaging is required the owner will be notified before the product is returned To purchase additional packaging Page 9 of 12 English please contact your authorized Kre
4. is in the BRIDGED position Connect the interconnect cable to the BRIDGED input either balanced via the XLR connector or single ended via the RCA connector Do not use both inputs simultaneously Connect the speaker cables to the speaker terminals labeled BRIDGED and BRIDGED The amp lifier is now ready for bridged operation THE KAV 250a BACKPLATE AND CONNECTIONS FOR BRIDGED OPERATION NOTE The KAV 250a may be configured for bridged operation using either a single ended input 1 or a balanced input 2 1 Single ended input for connection to a preamplifer 12 volt trigger input 12 volt trigger output O N OO BP W DN Fem i LEFT OUTPUT ZT NE OUTPUT l e O HT T O i ere eo LEFT T OK oo zd O O t LINE IN FA BRIDGED BRIDGED I X Page 6 of 12 English Balanced input for connection to a preamplifier 5 way binding post speaker terminals Red switch in bridged position with the numeral 2 displayed Single ended output for connection to another amplifier Balanced output for connection to another amplifier KAV 250a KRELL Industries Inc Power Amplifier 45 Connair Road Orange CT 06477 3650 USA No user serviceable parts inside VOLTAGE FUSE 100 120 MDA 20_ 200 240 _ MDA 12 A 50 60Hz 12VDC REMOTE NON j 30ma max MADE IN USA 7 KRELL KAV 250a Amplifier Operation It is easy to understand the operation of the KAV 250a amp
5. continued be placed as close to the speakers as pos sible Run long balanced interconnect cables to the amplifier and keep the speak er cable length to a minimum Speaker cable adds impedance to the load the amplifier must drive regardless of the cable s gauge All Krell amplifiers will drive the lowest impedances with ease but when impedance is added due to long cable lengths amplifier power is wasted in the cable Long speaker cables reduce the maximum power that can be delivered to the speakers Cabinetry Considerations The KAV 250a amplifier can become quite warm under normal operation Install the KAV 250a in a location that provides unob structed ventilation If you place the amplifi er in a closed cabinet extra ventilation such as modified shelf spacing may be neces sary In extreme instances small fans help to removing excess heat from enclosed spaces In general when the front and rear of a cabinet is open the amplifier has ade quate ventilation with two inches of clear ance on each side and eight inches of clearance above and below AC Power Guidelines For best performance Krell recommends using a dedicated AC power line rated at a minimum of fifteen amps with the KAV 250a amplifier For maximum power output the KAV 250a should be operated from a dedi cated twenty amp AC power line The KAV 250a amplifier should only be operated with the power cord supplied Please consult your dealer dis
6. days of purchase KRELL KAV 250a Krell Industries Inc 45 Connair Road Orange CT 06477 3650 USA TEL 203 799 9954 FAX 203 799 9796 E MAIL krell krellonline com Specifications FREQUENCY RESPONSE 20Hz 20KHz 0 0 0 1dB AHz 170KHz 0 0 3 0dB SIGNAL TO NOISE RATIO 118dB A weighted DISTORTION 1KHz 0 06 THD 20KHz 0 25 THD GAIN 26 4dB INPUT SENSITIVITY 2 15 Vrms INPUT IMPENDENCE 100K ohms OUTPUT VOLTAGE Peak to peak 138 V RMS 49 V KAV 250a OUTPUT POWER each channel driven 8 ohms 1 000W bridged 8 ohms 250W 4 ohms 500 W POWER CONSUMPTION Idle 210 W Max 1850 W DIMENSIONS 19w x 6 3h x 15 3d in 48 3w x 16h x 38 9d cm WEIGHT Shipped 57 Ibs 25 9 kg Unit only 43 Ibs 19 5 kg All operational features functions specifications and policies are subject to change without notification
7. f another amplifier The output of the first amplifier sends the preamplifier signal to the next amplifier in the chain 12 VDC REMOTE POWER IN This input accepts 12 volt power on off sig nals from other Krell components as well as from other devices that incorporate a 12 volt power on off trigger output This allows for remote turn on off of the KAV 250a with the power activation of another Krell com ponent as well as with with other compo nents used in a custom installation 12 VDC REMOTE POWER OUT This output sends 12 volt power on off sig _ nals to other Krell components as well as other devices that incorporate a 12 volt power on off trigger input This allows for remote turn on off of the KAV 250a with the power activation of another Krell compo nent as well as with other components used in a custom installation NOTE Consult the owner s manual of any device used in a custom installation to take full advantage of the remote capability of the KAV 250a English Page 5 of 12 Configuring the KAV 250a for Bridged Operation The KAV 250a may be configured to operate in a bridged mode When bridged the amplifi er will deliver 1000 watts to an 8 ohm load To implement this configuration 1 Turn the KAV 250a off 2 Locate the red switch on the back of the amplifier and slide it from the NORMAL position to the BRIDGED position The numeral 2 will appear on the switch when the switch
8. lifier However great care needs to be exercised when operating a sys tem that includes the KAV 250a because of the amplifiers enormous power output Switching between active sources without muting the preamplifier output or bump ing miscuing a cartridge can generate large transients at low frequencies The KAV 250a amplifier may generate enough power with these transients to damage most loudspeak ers All switching of sources should be done with the preamplifier level either muted or fully attenuated Do not change inputs to the ampli fier while the amplifier is On NOTE Care must be taken when setting high playback levels Because of their tremendous reserve of clean power Krell amplifiers can safely drive speakers to high er sound pressure levels than other ampli _ fiers Always turn the level down at the first sign of speaker distress On Off and Standby Operation When powering up any system amplifiers should always be turned on last and turned off first 1 Press the power button on the front panel of the amplifier You will hear a click The amplifier is ready for operation 2 With the preamplifier in the Mute position or the volume control fully attenuated select a source Turn the volume control up to the desired listening level 3 When turning the system off lower the volume of the preamplifier completely or place it into the Mute or Stand by posi tion Switch the amplifier to Stand by by pres
9. lity of such damages KRELL KAV 250a The warranty for this Krell product is valid only in the country to which the product was originally shipped through the authorized Krell distributor for that country and at the factory There may be restrictions on or changes to Kreil s warranty because of reg ulations within a specific country Please check with your distributor for a complete understanding of the warranty in your coun try 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 responsibili ty Krell will pay return freight to the U S A based freight forwarder of your choice Freight and other charges to ship the prod uct from the freight forwarder to you are also your responsibility The operating voltage of this product is determined at the factory and can only be changed by an authorized Krell distributor or at the factory The voltage for this product in the U S A cannot be changed for six months from the original purchase date _Any unauthorized voltage conversion dis assembly component replacement perfo ration of chassis updates or modifica _ tions performed to the product will void the warranty English Page 8 of 12 Return Authorization
10. ll dealer distributor or the Krell Service Department for assistance Krell is not responsible for any damage incurred in transit Krell will file claims for damages as necessary for products dam aged in transit to the factory The owner is responsible for filing claims for shipping dam ages that occur during the return shipment Replacement parts and or products will be furnished 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 In the event that Krell receives a product for warranty service which has been modi fied in any way without Krell authorization all warranties on that product will be void The product will be returned to original fac tory layout specifications at the owners expense before it is repaired All repairs required after the product has been returned to original factory specification will be charged to the customer at current parts and labor rates To contact the Krell Service Department TEL 203 799 9954 Monday Friday 9 00 AM to 5 00 PM EST FAX 203 799 9796 E MAIL krell krelloniine com KAV 250a PRODUCT SERIAL NUMBER To register your product for warranty benefits complete and return the Warranty Registration Card enclosed in the shipping box within 15
11. r Krell if you have any questions not addressed in this refer ence manual KRELL KAV 250a Unpacking 1 Open the box and remove the top layer of foam You will see these items 1 KAV 250a 1 AC power cord 1 packet containing the Owner s Reference and the Warranty Registration Card 2 x Y er sep HA NOTE If any of these items are nit included CP please contact your authorized Krell dealer or distributor immediately for assistance 2 Carefully remove the unit and acces sories from the box Remove the protec tive plastic wrap from the unit NOTE Save all packing materials If you must ship your KAV 250a in the future repack the unit in its original packaging to prevent transit damage Placement WARNINGS The amplifier must not be located where it could be exposed to dripping or splashing fluids Before you install the KAV 250a into your system review the following guidelines to choose the location for the KAV 250a This will facilitate a clean trouble free installation The KAV 250a does not require any type of special rack or cabinet for installation For the dimensions of the KAV 250a see Specifications on page 12 Place the KAV 250a amplifier on a firm level surface away from dirt or moisture When using custom racks or cabinetry keep in mind the weight and ventilation requirements for this amplifier Ideally the amplifier should English Page 3 of 12 Php Placement
12. rs for all mechanical components from the original date of purchase Should this product fail to perform at any time during the warranty Krell will repair it at no cost to the owner except as set forth in this warranty Transfer of warranty to a second owner occurs automatically Please contact Krell to have the name on the warranty changed Transfer of warranty does not extend the duration of the original warranty period NOTE This warranty does not apply to damage caused by acts of God or nature The warranty period begins on the date of retail purchase as noted on the retail sales slip provided by an authorized Krell dealer or distributor or on the warranty registration card sent to Krell In the event that an ade quate proof of purchase date is unavailable the warranty period will begin on the date the product was originally shipped from the factory The warranty described in this para graph shall be in lieu of any other warranty express 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 pur chase use or inability to use this product even if Krell has been advised of the pos sibi
13. sing the power button It is now safe to turn off the rest of the system English Page 7 of 12 System Noise Considerations AC grounding becomes critical when con necting high performance audio components When mixing and matching audio compo nents each with their own ground potential a low frequency hum may occur in one or both speakers This often occurs when introducing anew component into a system If there is a low frequency hum emanating from the speakers when the KAV 250a amplifier is placed into the system follow these simple trouble shooting steps before contacting your authorized Krell dealer dis tributor or Krell 1 Check all input and output connections making sure they are of sound construc tion With the amplifier Off remove the interconnect wiring and turn the amplifier On If the hum disappears turn the ampli fier Off and reinsert one of the intercon nect cables Then turn the amplifier back On If the hum reappears with one or both interconnects reinserted there may be a defective cable Have the interconnect cabling checked before proceeding 2 If the interconnects prove to be sound you may be experiencing a ground loop This can often be easily eliminated Con tact your authorized Krell dealer distribu tor or Krell KRELL KAV 250a Warranty Krell warrants this product to be free from defects in material or workmanship for a period of five years for circuitry and three yea
14. tributor or Krell before using any devices designed to alter or stabilize the AC power for the KAV 250a Page 4 of 12 English Connecting the KAV 250a to Your System WARNING When making connections to this compo nent or any other make sure the power amplifier is Off and the preamplifier is in the Mute or Stand by mode Make sure all cable terminations are of the highest quality free from frayed ends shorts or cold solder joints Input and Output Connections To prevent the introduction of hum or other noise into the system organize all wiring between the KAV 250p and other system components neatly Separate AC wires from audio cables 1 Connect the cables from your speakers to the output terminals of the amplifier The KAV 250a amplifier utilizes five way binding post speaker terminals for the left and right channels The speaker terminals accept spade lugs bare wire banana plugs or pins The red terminals are used for positive connections and the black terminals are used for the neg ative connections 2 Connect the interconnect cables from your preamplifier to the input terminals of the amplifier The KAV 250a amplifier is equipped with balanced and single ended inputs The balanced inputs use three pin XLR con nectors and the single ended inputs use RCA connectors Krell recommends the use of balanced interconnects Balanced interconnects not only have the ability to KRELL KAV 250a
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