KAV-250a Leader in Audio Engineering Stereo PowerAmplifier KAV-250a/3 Three-Channel Power Amplifier Instructions for Use,v 99.
KAV-250aStereo Power Amplifier and KAV-250a/3 Three-Channel Power Amplifier Instructions for Use, v 99.2 Cover: KAV-250a/3 Three-Channel Power Amplifier Krell Industries,Inc. 45 Connair Road Orange, CT 06477-3650 USA TEL 203-799-9954 FAX 203-799-9796 E-MAILkrell @krellonline.com WEBSITEhttp://www.krellonline.com This product complieswith the EMCdirective (89/336/EEC)and the low-voltage directive (73/23/EEC).
Contents Page INTRODUCTION’ 1 DEFINITION OF TERMS 1 UNPACKING 2 PLACEMENT 3 ACPower Guidelines 3 FRONTPANEL DESCRIPTION: KAV-250a 5 BACK PANEL DESCRIPTION: KAV-250a 7 FRONTPANEL DESCRIPTION: KAV-250a/3 10 BACKPANEL DESCRIPTION: KAV-250a/3 12 CONNECTING THE KAV-250a or KAV-250aJ3 AMPLIFIER TO YOUR SYSTEM 14 Input and Output Connections 14 OPTIONAL SYSTEM CONFIGURATIONS 15 Multi AmpThroughput 15 Bridged Operation 20 Examplesof Connection Scenarios 22 AMPLIFIER OPERATION On/Off
Illustrations Page FIGURE1 The KAV-250aFront Panel 4 FIGURE 2 The KAV-250aBack Panel 6 FIGURE 3 The KAV-250a/3Front Panel 9 FIGURE 4 The KAV-250a/3 Back Panel 11 FIGURE 5 Reconfiguring the KAV-250afor MAT or Bridged Operation 16 FIGURE6 Reconfiguring the KAV-250a/3for MAT or Bridged Operation iv 19 KAV-250aand KAV-250a/3Amplifiers
Introduction Thankyou for your purchaseof the Krell KAV-250a Stereo PowerAmplifier or KAV-250a/3Three-ChannelPowerAmplifier.. The KAV-250aand KAV-250aJ3 amplifiers provide substantial two- and three-channel output powerthat delivers realistic musicproductionat an exceptional value. These amplifiers can be customizedwith a variety of optional systemconfigurations: Multi AmpThroughput (MAT), bridged operation, and high powermonooperation.
Unpacking Openthe shipping box, which contains: 1 amplifier unit (packedin foamend-caps) 2 ribbon connection cables KAV-250afuses: 2 AGC-8 (~ ’amp) 1 slow-blow (20 ampfor 100/120V or 12 ampfor 220/240V) or KAV-250a/3fuses: 3 AGC-.8 ~ amp) 1 slow-blow (20 ampfor 100/120V or 12 ampfor 220/240V) 1 12 VDCoutput (12 V trigger) cable 1 IEC connector (AC power) cord 1 T-15 Torx wrench 1 packet containing the owner’s reference manualand the warranty registration card.
Placement Before you integrate the KAV-250aor KAV-250a/3into your system, review the following guidelinesto choosethe location for the component. This will facilitate a clean, trouble-freeinstallation. The KAV-250aand KAV-250aJ3 require at least two inches (5 cm) of clearance eachside and at least two inches (5 cm) of clearance abovethe component to provide adequateventilation. Youramplifier doesnot require any type of special rack or cabinet for installation.
FIGURE 1 THE KAV-250a FRONT PANEL 1 2 1 PowerButton 2 Power LED
Front Panel Description: KAV-250a See Figure 1 on page 4 1 Power Button Usethis button to turn the KAV-250a poweron and off and also to switch the 12 VDC output (12 V trigger) on andoff. 2 Power LED Theblue powerLEDilluminates whenthe amplifier is on.
FIGURE 2 THE KAV-250a BA(;K PANEL 5 11 12 10 BalancedInputs 3 Right Input 4 Left Input (Bridged) Fuses 9 AGC~ Fuses 10 Line Fuse Single-endedInputs 5 Right Input 6 Left Input (Bridged) RemoteControls 11 12 VDCRemote Power Out 12 12 VDCRemotePower In Amplifier ChannelOutputs 7 Right Output(Bridged-) Power 13 IEC Power Connector 8 Left Output(Bridged+) 13
Back Panel Description: KAV-250a See Figure 2 on page 6 The KAV-250a back panel provides connectionsfor all inputs and outputs, remote control input and output links, and ACpowersupply. Inputs andoutputs labeled left and right are on the left andright side of the amplifier, respectively, whenviewingthe amplifier fromthe front panel. Balanced Inputs 3, 4 Inputs Theseare the right (3) and the left (4) KAV-250a channelinputs for output devices balanced XLRconnectors.
BackPanelDescription,continued RemoteControls 11 12 VDC Remote Power Out 12 12 VDCRemotePower In The KAV-250ais equippedwith an output that sends 12 VDCpoweron/off (12 trigger) signals to other Krell components andother devicesthat incorporate 12 V trigger. This allows you to turn the KAV-250a on and off using a Krell or other component in a custominstallation. Notes 12 VDCOut/in (12 V trigger) remotepoweris limited to 30 ma.
FIGURE 3 THE KAV-250a/3 FRONTPANEL 14 15 14 PowerButton 15 Power LED
Front Panel Description: KAV-250a/3 See Figure 3 on page 9 14 Power Button Usethis button to turn the KAV-250a/3 poweron and off and also to switch the 12 VDC output (12 V trigger) on andoff. 15 Power LED Theblue powerLEDilluminates whenthe amplifier is poweredon.
FIGURE 4 16 19 25 22 THE KAV-250a/3 17 BACK PANEL 2o 18 25 23 BalancedInputs 16 Right Input 17 Center Input 18 Left Input Single-endedInputs 19 Right Input 20 Center Input 21 Left Input Amplifier ChannelOutputs 22 Right Output 23 Center Output 24 Left Output 21 25 24 27 28 26 Fuses 25 AGCe~Euses ~-----’~ 26 Line Fuse RemoteControls 27 12 VDCRemote Power Out 28 12 VDCRemotePower tn Power 29 IEC Power Connector ZOO0.
Back Panel Description: KAV-250a/3 See Figure 4 on page 11 The KAV-250a/3back panel provides connectionsfor all inputs and outputs, remote control input and output links, andACpowersupply. Inputs and outputs labeled left and right are on the left andright side of the amplifier, respectively, whenviewingthe amplifier from the front panel. Balanced Inputs 16, 17, 18 Inputs Theseare the right (16), center (17), and left (18) KAV-250a/3 channe~inputs output devices with balancedXLRconnectors.
BackPanelDescription,continued Note Fusesmust be replaced with the fuse value specified on the KAV-250a/3back panel Use a 20 ampslow-blow line fuse for 100/120V systemsor a 12 ampslow-blow line fuse for 220/240V systems. RemoteControls 27 12 VDC Remote Power Out 28 12 VDCRemotePower In The KAV-250a/3is equippedwith an output that sends 12 VDCpoweron/off (12 trigger) signals to other Krell components andother devicesthat incorporate 12 V trigger.
Connecting the KAV-250aor KAV-250a/3 Amplifier to Your System INPUT AND OUTPUT CONNECTIONS The following steps describe howto connect cables to the KAV-250aor KAV-250a/3 amplifier. 1. Neatly arrangeandorganizethe wiring to and from the amplifier andall components.SeparateACwires from audio cables to prevent humor other unwantednoise from being introduced into the system.
Optional SystemConfigurations The KAV-250aand KAV-250a/3can be reconfigured for either Multi AmpThroughput (MAT)or bridged operation. IMPORTANT Removing the cover to reconfigure for MAT or for bridged operation is the ONLY instance you are authorized to removethe cover of ANYKre// componentwithout voiding your Warranty.For moreinformation on product/imitations and restrictions, see Warranty, on page 28.
FIGURE5 RECONFIGURING THE KAV-250a FOR MATOR BRIDGEDOPERATI( tN Left Right Left Right PCboards showing MATjumper configuration PCboards showing bridged jumper configuration Powersupply PCboards Right 16 KAV-250a andKAV-250-a/3 Amplifiers
Reconfiguring the KAV-250afor MAT See Figure 5 on page 16 Tools needed: T-15 Torx wrenchand one ribbon connection cable 1. Turn the KAV-250a off by pressing the powerbutton (1) on the front panel. Theblue powerLED(2) extinguishes. Unplug the ACpowercord from the IEC power connector(13) on the back panel. 2. Using the T:15 Torx wrench,removethe 12 screwsthat secure the amplifier cover. Carefully removethe cover. 3.
5. Connectone end of the secondribbon connectioncable to jumper pin J4 on the center amplifier channel. Connectthe other end of this ribbon connectioncable to jumperpin J5 on the right amplifier channel. 6. Replacethe cover (slide the front panel endin first). Usingthe T-15Torx wrench, secure the 12 screws. The KAV-250a/3amplifier is nowreconfigured for MAToperation. Connecting the KAV-250a/3 Reconfigured for MAT See Figure 4 on page 11 1.
FIGURE 6 RECONFIGURING THE KAV-250a/3 FOR MAT OR BRIDGEDOPERATION Left Center Right PCboards showing MATjumper configuration PCboards showing bridged jumper configuration (See Option 1, on page21) PCboards showing bridged jumper configuration (See Option 2, on page21) Powersupply PC boards ht KAV-250a andKAV-250-a/3 Amplifiers 19
BRIDGED OPERATION The KAV-250a andthe KAV-250a/3 can be reconfigured for bridged operation. When the KAV-250a amplifier’s channelsare bridged,the amplifier’s outputpoweris quadrupled:the amplifier delivers 1,000Wattsto an 8 Ohm load. TheKAV-250a/3 can be reconfiguredto bridgeanytwo of its three amplifier channels to operateas one combined amplifier channel.When using the bridgedamplifier channelonly, the KAV-250a/3 delivers 1,000 Wattsto an 8 Ohmload.
IMPORTANT Whenoperating the amplifier in bridged modeand using an output device with single-ended RCAcables, be sure to removethe shorting pin from the/eft balanced XLRinput (4). Reconfiguringthe KAV-250a/3for Bridged Operation See Figure 6 on page 19 Tools needed: T-15 Torx wrenchand two ribbon connection cables 1. Turn the KAV-250a/3 off by pressing the powerbutton (14) on the front panel. The blue powerLED(15) extinguishes. Unplugthe ACpowercord from the IEC power connector(29) on the back panel. 2.
2. When the center and right amplifier channelsare bridged (Option 2), connectthe output cable from the output device to the right balancedXLR(16) or single-ended RCA(19)input. Connectthe positive loudspeakerlead (red) to the positive binding post on the (right) amplifier channel(22). Connectthe negative loudspeakerlead (black) positive binding post of the center amplifier channel(23). The remaining channel maybe connectedfor normal operation.
Examples of Connection Scenarios, continued Power Biamplification (Stereo, 2-channel) Powerbiamplification uses the MATfeature of the KAV-250ato send the samemusic signal to all amplifier channelsusing onebalancedor single-endedinput connection. Whenthe KAV-250ais reconfigured for MAT,one channel of the amplifier powersthe Ioudspeaker’shigh frequency end, and the other channel powersthe Ioudspeaker’slow frequencyend.
Examplesof Connection Scenarios, continued Multi Power Mode Multi powermodeuses the KAV-250a/3’s MATfeature to independentlypowermultiple pairs of stereo loudspeakers to extendthe listening environment throughoutyour home. Whenthe KAV-250a/3 is reconfiguredfor MAT,eachchannelpowersan individual loudspeaker,with oneKAV-250a/3 dedicatedto driving outputsto the left loudspeakers andoneKAV-250a/3 driving outputsto the right loudspeakers.
Amplifier Operation ON/OFF AND OPERATION Whenpowering up your system, turn amplifiers on last. Whenpowering downyour system,turn amplifiers off first. Theprocedures for amplifier operationfollow. 1. Press the KAV-250apowerbutton (1) or KAV-250a/3powerbutton (14) on amplifier’s front panel. Wait until the blue powerLED(2) on the KAV-250a or (15) on the KAV-250a/3 illuminates and you hear a click. Theamplifier is nowready for operation. 2.
Amplifier Troubleshooting HOW TO TROUBLESHOOT SYSTEM NOISE Whenyou mix and matchaudio components,each with its ownground potential, a low frequency hummayoccur in one or both loudspeakers. This often occurs when introducing a newcomponentinto a system. If a low frequency humemanatesfrom the loudspeakers whenyou place the KAV250astereo or KAV-250a/3 three-channel amplifier into your system, follow these simple troubleshooting steps.
Question and Answer Q. Should I leave the KAV-250a or KAV-250a/3amplifier on at all times? A. No. Theseamplifiers do not havea stand-by mode.Leavingthemon at all times wouldresult in considerableheat output andpowerconsumption.For best results, turn the amplifier off whennot in use, andallow a five minutewarm-up after it is turnedon. See Amplifier Operation, on page25. QoWhenI turn the amplifier on there is a loud humthrough the loudspeakers.What should I do? A.
Warranty The KAV-250aand KAV-250a/3 amplifiers have. a limited andtransferable warrantyof five yearsfor parts andlabor on cimuitry. Shouldthis productfail to performat anytime during the warranty,Krell will repair it at no cost to the owner,exceptas set forth in this warranty. This warranty does not apply to damage causedby acts of Godor nature.
ReturnAuthorization Procedure To return this productto Krell, please follow this procedure so that we may serve youbetter: 1. Obtain a Return Authorization Number (R/A number) and shipping address from the Krell Service Department. If you believe there is a problemwith your component, please contact your dealer, distributor, or the Krell factory to discussthe problembefore you return the component for 2. Insureandacceptall liability for loss of repair.
Specifications KAV-250aStereo Amplifier FREQUENCY RESPONSE 20 Hz to 20 kHz +0 dB, -0.1 dB 0.4 Hz to 170 kHz +0 dB, -3 dB SIGNAL TO NOISE RATIO "A" WEIGHTED 118dB TOTAL HARMONICDISTORTION (THD) 1 kHz < 0.06% 20 kHz < 0.25% GAIN 26.4 dB INPUT IMPEDANCE 100 kOhms INPUT SENSITIVITY 2.15 Vrms OUTPUT VOLTAGE Peak to Peak RMS 138 V 49 V OUTPUT POWER, EACH CHANNEL 8 Ohms 250 W DRIVEN 4 Ohms 500 W BRIDGED 8 Ohms 1,000 W POWER CONSUMPTION Idle 210W Max.
KAV-250a/3 Three-Channel Amplifier FREQUENCY RESPONSE 20 Hz to 20 kHz +0 dB, -0.2 dB 0.4 Hz to 112 kHz +0 dB, -3 dB SIGNAL TO NOISE RATIO "A" WEIGHTED 118dB TOTAL HARMONICDISTORTION (THD) 1 kHz < 0.06% 20 kHz < 0.25% GAIN 26.4 dB INPUT IMPEDANCE 100 kOhms INPUT SENSITIVITY 2.15 Vrms OUTPUT VOLTAGE Peak to Peak RMS 138 V 49 V OUTPUT POWER, EACH CHANNEL 8 Ohms 250 W DRIVEN 4 Ohms 500 W BRIDGED 8 Ohms 1,000 W POWER CONSUMPTION Idle Max.
Krell Industries,Inc. 45 Connair Road Orange, CT 06477-3650USA TEL 203-799-9954 FAX203-799-9796 E-MAIL krell@krellonline.com WEBSITE http://www.krellonline.