AC-AUDIO AC-AUDIO HA8M User manual

User Manual
AC-AUDIOHA8M
Economic 8-ChannelHeadphones Distribution Amplifier
www.ac-audio.com

1.OVERVIEW
WelcometochooseAC-AUDIO!
Withthe HA8M,you haveacquired an economicandusefulheadphone amplifier.Theunitwas
developedforthe mostrequiredapplications:professionalrecording,radioandtelevision studios,as
well asCD/digitalsound production, and asbenchmark unitsforjudging mix-downqualityaswellas
distribution amplifiersforflexible playbackapplicationsin studioenvironments.
Balancedinputs andoutputs
The equipmentfeatureselectronicallyservo-balanced inputsandoutputs.The servofunction
automaticallyrecognizeswhen unbalanced pinsareassigned. Itinternallymodifiesthenominal
signallevel,thuspreventsanyoccurrenceofsignalleveldifferencebetween inputsand outputs(6
dBcorrections).
2.BEFOREYOUSTART
1)Utilizing theUserManual
Thisusermanualhasbeen written insuchawaytoenableyou an overviewoverthe control
elementsofthe unitand offersatthe same timedetailed information aboutpossible applications.To
facilitate quicklook-ups,controlelementshavebeendescribed ingroupsdepending on their
function. Shouldyou needdetailed information about specifictopics notcovered inthismanual,
pleasevisitourwebsiteat www.AC-AUDIO.com.Forexample,additionalinformationabout power
ampsand effectsprocessors couldbefound in ourwebsite.
The following usermanualisintendedto familiarizeyouwith the unitscontrolelements, so that you
can masterall thefunctions.Afterhaving thoroughly read theusermanual,storeitat asafeplace
forfuture reference.
lBesure toread the SafetyPrecautionsbeforeusingthe product.
lReferto the INSTALLATIONwhen installing yourproduct.
lUsing the SPECIFICATIONS, you can easilyfind the detailed parametersofthe product.
lPleaseread thismanualfullybeforeinstalling oroperatingthe unit.
ATTENTION!
Wewouldliketobringyourattention to the factthat extremelyloud sound levelsmaydamageyour
hearing aswell asyourheadphones.PleaselowerallOUTPUTLEVELknobsleftwardsbefore
powering up the unit.
2)SafetyPrecautions
All the safetyandoperation instructionsshould beread beforethe device isoperated.

RetainInstructions:
The safetyand operating instructionsshouldbe retained forfuturereference.
HeedWarnings:
All warningson the device andin the operating instructionsshouldbeadheredto.
FollowInstructions:
All operation and userinstructionsshouldbe followed.
Waterand Moisture:
The deviceshouldnot be usednearwater(e.g. nearabathtub, washbowl,kitchen sink,laundrytub,
ina wet basement,neara swimming pooletc.).
Ventilation:
The deviceshouldbe situated sothat itslocationorposition doesnot interferewith itsproper
ventilation. Forexample, the deviceshould notbe placed on a bed, sofa, rug,orsimilarsurfacethat
mayblock the ventilation openings,orused inabuilt-ininstallation,suchasabookcaseorcabinet
that mayimpede the flow ofairthrough the ventilation openings.
Heat:
The device shouldbe situated awayfrom heat sourcessuchasradiators,heat registers,stoves,or
otherdevices(including amplifiers) that produce heat.
PowerSource:
The deviceshouldonlybe connected to apowersupplyofthe typedescribed intheoperating
instructionsoronthe device.
Beforeplugging the unitinto apowersocket,pleasemakesureyou haveselectedthe correct
voltage.
ATTENTION: Thisdoesnot applyto exportmodelsthat wereforexamplemanufactured onlyforuse
with120 V!
Ifyou altertheunitsvoltage,you must changethe fusesaccordingly.
Faultyfusesmustbe replaced with fusesofappropriate ratingwithoutexception!
Powerisdelivered viathe cable enclosed with the unit.Allrequired safetyprecautionshavebeen
adheredto.
Foryourown protection,you should nevertamperwith the groundingofthecable orthe unititself.
GroundingorPolarization:
Thisdevicemust be grounded.
PowerCords:
Powercordsshouldbe routed so that theyarenot likelyto be walkedon orpinched byitemsplaced
upon oragainstthem,paying particularattention tocordsand plugs,sockets,outletsand the point
wheretheyexitfromthe device.
Cleaning:
The deviceshould be cleaned onlyasrecommendedbythe manufacturer.
Non-use Periods:

The powercordofthedeviceshouldbeunplugged fromtheoutletwhen leftunusedforalong period
oftime.
Damage Requiring Service:
The deviceshould be serviced byqualified servicepersonnelwhen:
The powercordorthe plug hasbeendamaged;orDebrisorliquidhasenteredthe device;orthe
devicehasbeen exposedto rain; orthe devicedoesnotappearto operatenormallyorexhibitsa
markedchange in performance; orthe device hasbeen dropped, orthe enclosuredamaged.
Servicing:
The usershouldnotattemptto servicethe devicebeyond that whichisdescribedinthe operating
instructions.All otherservicing should be referred to qualified service personnel.
The equipmentwascarefullypacked atthe assemblyplant to assuresecuretransport.Shouldthe
condition ofthecardboardboxsuggestthatdamagemayhavetakenplace,pleaseinspecttheunit
immediatelyand lookforphysicalindicationsofdamage.
DamagedunitsshouldNEVERbe sentdirectlytous.Pleaseinformthe dealerfromwhomyou
acquired theunit immediatelyaswell asthe transportation companyfromwhichyoutookdeliveryof
theunit.Otherwise, all claimsforreplacement/repairmaybe renderedinvalid.
3.INSTALLATION
Thischaptercontainsdescriptionsofvariouscontrolsofyourequipment. Allcontrolsand
connectionsarediscussedindetail.Additionally,usefuladviceabouttheirpossibleapplicationsis
also given.
1)Frontpanel
The DIRECTIN socket isusedto feed inadditionalstereosignals. In the case ofthe equipment, the
signalbrought in via the DIRECTIN input hasthe same priorityasthe MAINsignal.
The MASTERLEVELcontrolgovernsthe levelofthe input signalthat isfed throughthe MAIN
INPUTconnectors on the backorthrough the DIRECTINconnector.
The equipment featurestwolevelcontrols(MAININ 1/MAININ 2)sothat twoseparatelycontrollable
inputsignalscan beconnected. You selectwhichofthetwosignalsismonitored byusing the IN1/IN
2switchesinthe respectivechannelsections.
The PHONESOUTconnectorisconnected inparalleltothe outputconnectorslocated onthe rear,
presenting an easilyaccessibleadditionalmonitoroption forindividualchannels.Thisfunctionis
particularlyhelpfulwhen the unit ispermanentlyinstalled in a rack.
The ST./2-CH. switchisused toalternatewhetherinput signalsareaudibleinstereo(not depressed:
ST.)orinmono (depressed:2-CH.).
The POWERswitchpowersthe POWERPLAYPROon.You shouldalwaysmakesurethatthe

POWERswitchisin the“Off”position when initiallyconnecting the unitto the mains.
Pleasetakenote: Merelyswitching theunitoffdoesnot meanthat itisfullydisconnected fromthe
mains.Whennot usingthe unitforprolongedperiodsoftime, pleaseunplugthe unitspowercord
fromthepoweroutlet.
2)Rearpanel
Powerissupplied via an IECconnector.Thematching cable isprovided withthe unit.
FUSECOMPARTMENT/VOLTAGESELECTION.Beforeconnecting theunittoapoweroutlet,
pleasemakesurethatthe selected voltage matchesyourlocalvoltage.When replacingfuses,
pleasemakesurethatyoualwaysusefusesofthe sametype.Someunitsallowforswitching
between 230Vund 120 V.Pleasenote:whenconnecting aunitintended forthe European marketto
a120 Vpoweroutlet,you mustalso replacethe factoryfuse witha higher-valuefuse.
The DIRECTIN connectsvariousinputsignalsforeach amp section, located on the rear. If a signal
isfed into thisconnector,both MAININ signalswill be muted.
Thesearethe MAIN OUTconnectorsofthe equipment.The respectivejacksand XLRconnectors
arewired inparallel.Viatheseconnectors,you can linkasmanyheadphoneampsasdesiredto
allow forconnection ofadditionalheadphones.
The MAIN INconnectorsofthe equipment comeasbalanced1/4"TRSand XLR connectors.
The equipment featuresonly1/4"TRSconnectorsforMAIN INPUT1 andMAIN INPUT2.
4.GETTING STARTED
1)Using theMAIN INconnectors
Connectaprogramsourcewiththe MAININ connectors locatedonthe rear,and connectyour
headphonestoanampsection ofyourchoice. Inthe caseoftheequipment, MAININ controls1and
2regulate the input leveloftwo separate input signals.
2)Connecting multipleheadphones
You can connectmultipleheadphonesto an ampsimultaneously,provided thatthe minimaloutput
load impedanceofthe ampdoesnot fall below8Ohms.In thecaseofthe equipment, the minimal
outputload impedanceis100 Ohmsperamp.
Whenconnectingtwoheadphones,individualheadphonesshouldnot haveimpedancelowerthan
16 Ohms;when connecting three headphones,the impedanceofindividualheadphonesshould not
fall below200 Ohms.

Eventhoughgoing underthe abovementioned minimalimpedancesdoesnot causedefective
operation,youmayexperience a qualitylossaudibleaslowered performanceand distortion.
3)Audio connections
Pleaseassurethatthe unitisinstalled and operated onlybypeoplewithanunderstanding ofthe
unitsfunctions.Duringandafterthe installation alwaysmakesurethatthosehandling the unitare
themselvesproperlygrounded.Failuretodo somaycauseundesirableorfaultyoperation through
electrostaticdischarge.
5.SERVICE
Ifyou want to requireserviceofthe equipment,youmusttakeitorpostittoanauthorized dealer
withadescription ofthe fault.When claiming serviceunderwarranty,proofofpurchasedate must
be included with the equipment forrepair.Pleaseretainthe originalpacking forpossiblefutureuse,
and ensurethat the unitisprotectedsuitablyduring transit.Themanufacturercannotaccept
responsibilityfordamage caused during transportation.
The equipment issupported byalimited warrantyforaperiod ofoneyearfromthedate ofpurchase.
During thisperiod, anyfaultsdue to defectivematerialsorworkmanshipwill be repairedfree of
charge.Thewarrantyexcludesdamage causedbydeliberate oraccidentalmisuse, tampering,
operation onthe incorrectmainsvoltage, orwithout the correcttype and value offusefitted.It isthe
user sresponsibilityto ensurefitness forpurposein anyparticularapplication.
The warrantyislimited tothe originalpurchasepriceofthe equipment, and excludesany
consequentialdamage orloss.
Pleaserecord the following details,andretain proofofpurchase:
SerialNumber................................................................................
Region/ Country............................................................................
Date purchased..............................................................................
Dealer.............................................................................................
Username......................................................................................
Tel...................................................................................................
Address...........................................................................................