Listen Technologies MLD7 Owner's manual

Brand: Listen Technologies

Model: MLD7

Category: Musical Equipment

Type: Owner's manual

MLD7

Installation Handbook

www.ampetronic.com

Handbook Contents

• Safety

• Introduction

• Quickstart

• Installation

• Overview

• Troubleshooting

• Accessories

• Technicalspecications

• Warranty

• Declarationofconformity

Box Contents

• 1xMLD7

• 2xLoopconnector

• 1xStatusconnector

• 1xDCconnector

• 1xInstallationhandbook

• 2x2mmsteel1Urackmountbrackets

• 1xPowercable(regionsspecic)

• 1xInductionLoopSign

This symbol is used to alert the user to important

operating or maintenance instructions.

The Lightning bolt triangle is used to alert the user

to the risk of electric shock.

SAFETY

1. Itisimportanttoreadtheseinstructions,andtofollowthem.

2. Keepthisinstructionmanualinanaccessibleplace.

3. Cleanonlywithadrycloth.Cleaninguidsmayeffecttheequipment.

4.

Donotblockanyventilationopenings.Installinaccordancewiththemanufacturer’s

instructions.

5. Donotinstallthisequipmentnearanyheatsourcessuchasradiators,heatingventsorother

apparatusthatproducesheat.

6.

WARNING–THISAPPARATUSMUSTBEEARTHED/GROUNDED.

7. Onlypowercordswiththecorrectpowerconnectormaybeusedtomaintainsafety.Cables

incorporatingtheUK13Afusedplug,SchukowithearthingcontactsandULapproved

“groundingtype”areacceptable.Thesemustbepluggedintopoweroutletswhichprovidea

protectiveearth.

8. Referallservicingtoqualied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anyrainor

moisture,doesnotoperatenormallyorhasbeendropped.

9.

WARNING–Toreducetheriskofreorelectricshock,donotexposethisapparatusto

rainormoisture.Theapparatusshallnotbeexposedtodrippingorsplashingandno

objectslledwithliquids,suchasvases,shallbeplacedontheapparatus.

TO PREVENT ELECTRIC SHOCK DO NOT REMOVE THE

COVER. THERE ARE NO USER SERVICEABLE PARTS

INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL

Ampetronic MLD7 Installation Handbook Page 1

Ampetronic MLD7 Installation Handbook Ampetronic MLD7 Installation HandbookPage 2 Page 3

CONNECTIONS

Inputs



  

  

 

  



























Outputs



  

  

 

  



























BLOCK DIAGRAM

1=TwistedPair,2=QuadCore

Refertotechnicalspecicationsforconnectiondetails



  

  

 

  



























INPUT 1

PHANTOM

POWER

GAIN BOOST

INPUT 1

GAIN

INPUT 2

PHANTOM

POWER

GAIN BOOST

INPUT 2

GAIN

AUTOMATIC

GAIN

CONTROL

(AGC)

METAL

LOSS

CORREC-

TION

(MLC)

MLC

LEVEL

PHASE

SHIFTER

AGC

DISPLAY

RED L.E.D.

YELLOW L.E.D.

GREEN L.E.D.

PHASE

SWITCH

0/90°

CHANNEL

CURRENT

LEVEL

CHANNEL

CURRENT

LEVEL

POWER

AMPLIFIER

POWER

AMPLIFIER

CURRENT A

CURRENT B

TEMP

RED L.E.D.

MONITOR

OUTPUT

YELLOW L.E.D.

GREEN L.E.D.

YELLOW L.E.D.

GREEN L.E.D.

CLIP A RED L.E.D.

LOOP A RED L.E.D.

CLIP B RED L.E.D.

LOOP B RED L.E.D.

OUTPUT

Introduction

TheMLD7Inductionloopdriverhasbeendesignedasahighqualitydualchannelamplierforuse

withmultiplelooporPhasedArrayloopdesigns.

AnArraySystemprovidesasolutionwhereasimplelooparoundtheroomperimeterwillnotwork.

Arraysarethestandardsolutionforbuildingswithmetalstructureorreinforcements,orforcovering

largeareas.Arrayscanalsodramaticallydecreasethe‘spill’ofthemagneticsignaloutsideofthe

room,allowinginductionloopstobeinstalledinadjacentrooms,andprovidinganimprovedlevel

ofcondentiality.Arrayscanalsobeusedtochangethewaytwoloopsinterferewitheachother,

providingwaysofsolvingeventhemostcomplexinstallationproblems.

Dependingonanumberoffactorsregardingtheinstallationoftheloopandtheset-upofthe

ampliertheMLD7canprovidecompliancewithIEC60118-4forperimeterloopareasofupto2x

700m

orphasedarraysystemsupto840m

Easeofinstallationandusehavebeenmajorfactorsinthedesign,combinedwithoptimised

performance,andthefreedomfromR.F.I.generation.

TheMLD7stwooutputchannelscanbeconguredwithorwithout90°ofphaseshiftbetween

thetwo,allowingtheuseofarraysystemsortwoseparateloopswiththesamesignaltherefore

doublingtheareacoverage.

TheMLD7hastwobalancedinputs.Thesecanbeconguredformicrophoneorlineinputswith

individuallyselectablephantomandgainboost.

Formorecomplexinstallations,youmayneedancillaryequipmentsuchasmicrophonepre-

amplier(s),adaptor(s)forusewith100Vline,orsignalprocessingunits.SeeAccessoriesor

contactAmpetronicforadvice.

QUICK START

Forthosewhohaveagoodappreciationofloopsystems,thefollowingisaveryquickguideto

settinguptheamplier:Allyouneedisanacpowersource,asignalsourceandaPhasedArray

looppair.See‘DesigningInductionLoops’handbook(supplied)orcontactAmpetronicforadvice.

Installation

a.Turnallcontrolsfullyanti-clockwise.

b.Connectloopcables.

c.Connectsignalinput(s).

d.Connectpower.Seepoints6and7inSAFETYsection.

e.Ifrackmountedremoveallrubberfeetfromunits.DONOTre-tthefeetxingscrewsasthis

maycausedamageandinvalidatethewarranty

Operation

1. SwitchON–check‘earsymbol’ashesduringselftestandilluminatescontinuouslywhen

checksarecomplete.

2. ApplyinputsignalandincreasetheinputcontroluntiltwogreenCOMPRESSIONLEDsare

illuminatedonthepeaksofthesignal.

3. Selectphaseshiftrequired0or90°.

4. AdjusttheCURRENTcontrolsuntiltheCURRENTLEDsilluminatetoachievethedesired

peakcurrents.

5. Repeatstep2foranyotherinputsused.

6. Listentothemagneticeldproducedinsidetheloopareausingareceivingdevice(e.g.

AmpetronicILR3),orexaminetheperformanceinmoredetailwithaeldstrengthmeter.

7. AdjustMLCcontroltoachieveaatfrequencyresponse.

Ampetronic MLD7 Installation Handbook Ampetronic MLD7 Installation HandbookPage 4 Page 5

INSTALLATION

Location

Theunitmaybefreestandingor19”rackmountableusingtherack‘ears’supplied.Fittingofthe

‘ears’isachievedbyremovingthethreeforwardmostscrewsonbothsides.Thesamescrews

arethenre-usedtosecurethe‘ears’inplace.(APH2screwdriverwillberequired).For19”rack

mountingthefourrubberfeetmustberemoved.

Thelocationmustprovideadequateventilationfortheunit.

Internalfansprovideforcedventilationusingairventsatthefront(intake)andrear(exhaust)ofthe

unit.Theseventsmustbeunobstructedforsatisfactorycooling.Iftheunitisinstalledinanenclosed

environment,sufcientairowintotheenclosuremustbeprovidedthroughvents,fansorother

means,suchthattheunitsexhaustairisnotrecycledtotheinlet–causingareductioninoutput

currentorOVERHEATLEDtobeilluminated.

ContactAmpetronicforadviceoncoolingrequirementsforyourinstallation.

Tools and Equipment

Smallhandtoolsincludingawirestripperandasmallatbladescrewdriverwillberequired.

AnILR3loopreceiveroramagneticeldstrengthmeterisvitaltocheckthattheloopsystemis

providingthedesiredlevelofperformance.

Apairofstereoheadphoneswitha3.5mmjackplugconnectionisalsousefultomonitortheloop

signal.

System Requirements

Theinductionloopcablesshouldbealreadyinstalledaccordingtothe‘DesigningInductionLoops’

handbook,orasperspecicdesigninstructionsprovidedbyAmpetronic.Asaresult,atarget

currentshouldbeknown,basedonachievingacceptableeldstrengthacrosstheareatobe

covered.

Itisimportantthatthetotalresistanceofloopandfeedmustbebetween0.5Ωand3.0Ω(atDC).

Ifthisisnotachieved,theLOOPERRORLEDwillbecomeilluminated,andtheampliersoutput

willbedisabled.SeeTroubleshootingsectionfordetailsonhowcorrectthis,andgetyoursystem

working.

The‘DesigningInductionLoops’handbookcontainsmoredetailsonloopandfeedcables.The

correctdesignandpositioningoftheactualloopisvitalforsatisfactorysystemperformance.Ifin

doubtconsultAmpetronicforadvice.

CONNECTION & SET-UP

ItisadvisedthattheloopsystemisinitiallysetupusingalocalaudiosourcesuchasaCDplayer,

whichisnotconnectedintoanyothersystem.Thisavoidsthecomplicationofgroundloopsand

feedbacketc,whilsttheunitissetup.

Thefollowingproceduredescribestheinstallationofastand-aloneMLD7,anddoesnotincorporate

connectionofotherancillaryunitssuchasmicrophonepre-amps,mixingdesks,orsignal

processingunits.

1. Turnallcontrolsfullyanti-clockwise.

2. ConnectthefeedcablesfromtheloopsintotheNL4loop

connectorssuppliedasshown:



Note: To avoid unwanted stray magnetic elds the feed cable

should be tightly twisted or star-quad connected.

3. Connectthesignalinputsappropriately:

Microphones:Suitabledynamicorcondensermicrophonewithbalancedcablefeed.Select

phantompowerasrequired.ConnecttoINPUT1andINPUT2(withselectorswitchesinthe

appropriateposition)usinga3-poleXLRplugwiredasperConnectionsdrawing.

Linelevelsignals:FromotheraudioequipmentsuchasPAsystem,mixingdeskorCDplayer.

ConnecttoINPUT1andINPUT2(withselectorswitchesintheappropriateposition)usinga

3-poleXLRplugwiredasperConnectionsdrawing.

Youmayuseeitherorbothinputs.

Donotruninputandoutputcablesclosetogether

4. ConnectACpowertotheMLD7.Seepoints6and7inSafetysection.

5. SwitchON.The‘ear’symbolwillashforafewsecondswhilstaninternalself-testisperformed

andtheloopresistanceistested.Ifbothtestsaresuccessful,the‘ear’symbolwillilluminate

continuouslyandtheunitwillbeinanoperationalmode.Ifthe‘ear’symbolcontinuestoash,or

oneorbothLOOPLEDsilluminate,consulttheTroubleshootingsection.

6. Selectoneinputandapplyasuitableaudiosignal(ideallyaCDplayerwithmusicorcontinuous

speechappliedtooneinput,withnoconnectiontotheother).Turntheassociatedinputcontrol

clockwiseuntiltwoCOMPRESSIONLEDsareilluminatedonthepeaksofthesignal.

7. TurnCHACURRENTcontrolclockwiseuntilthetargetcurrentisachieved–asindicatedby

theCHACURRENTLEDs.NotethatconsecutiveLEDsilluminateat3dBintervals.TurnCH

BCURRENTcontrolclockwiseuntilthetargetcurrentisachieved–asindicatedbytheCHB

CURRENTLEDs.HeadphonescanbeusedwiththeMONITORsockettolistendirectlytothe

loopcurrent.NOTE:channelAoutputappearsintheleftheadphoneandchannelBintheright.

Ifhighfrequencyoscillationorlowfrequencyhumisexperienced,consulttheTroubleshooting

section.

8. Theloopsystemshouldnowbeprovidingamagneticeldinsidetheareaoftheloop–usethe

ILR3oreldstrengthmetertoexamineitsperformancewithrespectto:

 a) Magneticeldstrength.Thismayvaryacrossthecoverageduetolayout,metallossand

   loopcurrent.

 b) Frequencyresponse.Metallossestendtoincreasewithfrequency,andmayrequirethe

   adjustmentoftheMLCcontrol.

  Asaresultofthisanalysis,adjusttheCURRENTandsettheMLCtoachievethebestsound

  quality.Thisshouldresultinadequatemagneticeldstrengthandalevelfrequency

  responseinordertosatisfyIEC60118-4.Note:DoNOTadjusttheMLCcontrolwhilst

  listeningtotheMONITORsocketasthiswillnotgiveatrueindicationoftheresponseofthe

  actualloop.

  OncetheCURRENTandMLCcontrolshavebeenadjustedtothecorrectleveltheyshould

  NOTneedre-adjusting.

9. Ifnotalreadydoneso,stepscannowbetakentointegratetheMLD7intoaPA/mixer

arrangementfollowingstandardaudiotechniques.Ifanyunusualeffectsareexperiencedreferto

theTroubleshootingsection.

Note: Ideally, each input signal level should be set up to achieve 6dB (one LED) of

COMPRESSION with the quietest level of input likely to be used. This will maximize the dynamic

range of the system and ensure satisfactory performance.

10.Repeattheaboveprocedureforeachinputused.Whenadjustingeachinput,makesurethe

signalsareremovedfromtheotherinputs.Thisensuresthatallsignalsaresettoequivalent

loudnessanddrivethecompressorproperly.



  

  

 

  



























INPUT 1 INPUT 2 MLC

AGC (dB)

9.0

6.4

4.5

3.2

2.3

1.6

CURRENT (A pk)

CLIP

LOOP

CLIP

LOOP

CH BCH A TEMP

MLD7

01 01 01 01

INDUCTION LOOP DRIVER

Gain boos

Phantom

Gain boost

Phantom

MIC LINE

INPUT 2

INPUT 1

OUTPUT

PHASE

Induction Loop Driver

~ 230V

45 - 65Hz

Power: 85W

Fuse: T 630mA L

Designed and Engineered in the UK

Serial No

MLD7

LOOP O/P CONNECTIONS

www.ampetronic.com

CHANNEL B

LOOP OUTPUT

CHANNEL A

LOOP OUTPUT

STATUS

0.1A

+12V

DC OUTPUT

Ampetronic MLD7 Installation Handbook Ampetronic MLD7 Installation HandbookPage 6 Page 7

OVERVIEW

I/O:PowerSwitch.

INPUT 1 & 2:Screwdriveradjustablecontrolswhichsettheleveloftheinputsignals.

AUTOMTIC GAIN CONTROL (AGC) COMPRESSION:Showstheamountofgain

reductionindecibels(dB)thatisappliedtotheinputsignal(s).

METAL LOSS CORRECTOR (MLC):Screwdriveradjustablecontrolwhichcompensates

forthefrequencydependanteffectsofmetalintheloopedenvironment.

OUTPUT CHANNEL WARNING LEDs:‘CLIP’LEDsigniesoutputvoltageisclipping,

‘LOOP’LEDsigniesacablespecicationerrorordamage.Seetroubleshootingfordetails.

OUTPUT CHANNEL CURRENT ADJUSTMENT:Screwdriveradjustablecontrolwhichsets

thelevelofoutputcurrentdeliveredtotheloop.

OUTPUT CHANNEL CURRENT LEDs:Indicatesthepeakcurrentdeliveredtotheloop.

TEMPERATURE WARNING LED: Indicatesthattheinternalheatsinkistoohot.Loop

currentisnotdeliveredtoeitherchannel.Seetoubleshootingfordetails.

MONITOR: 3.5mmjacksocketforusewithstereoheadphonestolistentothesignalbeing

deliveredtotheloop.

POWER INDICATOR LIGHT:Flashescontinuouslywhenamplierhasfailedselftestand

isinsafemode.Seetroubleshootingfordetails.

FRONT VENT:Fanassistedventilationinletwithlter.DONOTcover.

10 1198

765

321

REAR VENT:Fanassistedventilationoutlet.DONOTcover.

LOOP OUTPUT(S):Neutrik‘Speakon’highcurrentconnectionstoloopcable(s).

STATUS:Connectiontorelaycontactsprovidingremotefaultindication.

DC OUTPUT:2-pinconnectionforancillaryunits.

PHASE SHIFT SELECTOR:Selectable90°phaseshiftbetweenoutputs.

XLR INPUTS: SocketforbalancedMICorLINEsignals.

INPUT GAIN BOOST SELECTOR SWITCH: Gainselector(ON=+15dB)

INPUT SELECTOR SWITCH:ModeselectbetweenMICandLINEinputsignals.

INPUT PHANTOM POWER SELECTOR SWITCH

AC POWER: Standard3-poleIEC320connectorcontainingprimaryfusefortheunit.

13 14 15 16 18

17 19 20

INPUT 1 INPUT 2 MLC

AGC (dB)

9.0

6.4

4.5

3.2

2.3

1.6

CURRENT (A pk)

CLIP

LOOP

CLIP

LOOP

CH BCH A TEMP

MLD7

01 01 01 01

INDUCTION LOOP DRIVER

Gain boos

Phantom

Gain boost

Phantom

MIC LINE

INPUT 2

INPUT 1

OUTPUT

PHASE

Induction Loop Driver

~ 230V

45 - 65Hz

Power: 85W

Fuse: T 630mA L

Designed and Engineered in the UK

Serial No

MLD7

LOOP O/P CONNECTIONS

www.ampetronic.com

CHANNEL B

LOOP OUTPUT

CHANNEL A

LOOP OUTPUT

STATUS

0.1A

+12V

DC OUTPUT

Ampetronic MLD7 Installation Handbook Ampetronic MLD7 Installation HandbookPage 8 Page 9

TROUBLESHOOTING

Ear symbol not illuminated

•CheckthatthepowerswitchistoggledtotheON(I)position.

•Checkfusecontinuity.A20mmfuseisincorporatedintotheACPOWERinlet.Itisnecessary

toremovethepowercordbeforeextractingthefuseholder.Testthecontinuityofthefuse

usingamultimeter.Asparefuseisprovidedinthefuseholder.



AnyreplacementfuseMUSTbeofthesameratingandtypeasprintedontherearof

theunit.

Ear symbol flashing continuously

Amplierhasfailedselftestandisinsafemode.Signalwillnotbefedintooneorbothloops.

Switchtheunitoff,removeallconnectionsexcepttheloopandpowerconnections,turnallfront

panelcontrolstominimumandswitchbackon.Iftheproblempersists,contactAmpetronicfor

advice.

COMPRESSION LEDs not illuminating

Checkinputconnections.

Ensurethattheappropriatefrontpanelcontrol(INPUT1orINPUT2)isturnedup.Checkthereis

sufcientsignallevelfortherequiredinput.

CURRENT LEDs not illuminating

Therearemanypossiblecausesforthis:

•ChecktheCOMPRESSIONLEDsareilluminating.

•CheckthattheCURRENTcontrolsareturnedupsufciently.

•ChecktheLOOP,orTEMPLEDsarenotilluminated.

•EnsuretheEarsymbolisilluminatedandnotashing.

•Checkthattheloopcablesareconnected,terminatedcorrectlyandinsertedintotheLOOP

OUTPUTsockets.

•Checktheloopsarenotopencircuit,shortcircuit,orconnectedtoearth(seeinstabilityorhigh

frequencynoisesectionofTroubleshooting)

•Switchtheunitoffandturnbackon.

Note: You can listen to the actual loop signal by using a pair of headphones plugged into the

monitor socket. Channel A = left, channel B = right.

CLIP LED(s) illuminated

Indicatesthattheoutputvoltageisclipping.Occasionallightingofthisindicatorisnormalonpeaks

ofsignal.

•TurndowntheCURRENTcontrolonthechannel(s)inquestiontoavoidcausingtheoutput

voltagetoclip.

•Checktheloopisnotopencircuit,shortcircuit,orconnectedtoearth(seeinstabilityorhigh

frequencynoisesectionofTroubleshooting)

•Checktheloopiswithinspeciedlimits.

TEMP LED illuminated

Indicatesthattheinternalheatsinkistoohot.Loopcurrentisnotdeliveredtoeitherchannel.

•Ensurethattheunitisinstalledinalocationwithsufcientventilation

•Checkthatnothingisblockingthefreeowofairthroughtheventsatthefrontandbackofthe

unit.

•Checktheloopsarenotopencircuit,shortcircuit,orconnectedtoearth(seeinstabilityorhigh

frequencynoisesectionofTroubleshooting)

LOOP LED(s) illuminated

Indicatestheloopcablesconnectedtotheunitareoutsidespecication.Itisimportantthatthe

totalresistanceofloopandfeedmustbebetween0.5Ωand3Ω(atDC).Ifthisisnotachieved,the

LOOPLED(s)mayilluminateandtheamplieroutput(s)willbedisabled.

Important: Once the cause of any loop error has been established the unit will need to be restarted.

Turn the power OFF - wait 5 seconds, and switch ON.

•Checkthattheloopcablesareconnected,terminatedcorrectlyandinsertedintotheLOOP

OUTPUTsockets.Restarttheamplierasabove.

•EnsuretheDCresistanceisacceptable-between0.5Ωand3Ω.Inallcasestheamplierwill

needtoberestartedoncetheproblemissolved.

Note: Meter leads can easily measure 0.2Ω, and should be factored out.

•Ifeitherloopisopencircuit-itmayhavebeencutsomewhereandwillrequireinvestigation

andpotentiallyre-laying.

•Ifeitherloopishighresistance>3Ω-checkallconnectionsandre-tighten,theremaybe

somethingloose.

•Checkforshortcircuitsintheloopconnectors.

•Ifeitherloopisjustverylowresistance,foldadenedlength(seebelow)of0.5mm²cable

inhalfandtwistittogetherneatly–usingahanddrillcanbehelpful.Coilthislooselyon

theforearmandbinditsothatitdoesnotcomeun-coiled.Thenconnectthetwoends

inserieswiththelowresistancelooptoensurethattheunitwillalwaysturnon,butthe

systemperformanceisun-affected.5mof0.5mm²wirewilladdapproximately0.15Ωtoloop

resistance.Useanappropriatelengthtoensuretheloopresistanceexceeds0.5Ω

Note: High or low resistance loops can be encountered in a venue with a pre-installed loop, which

was designed for use with an old loop driver which might be being replaced. Before using this loop

ensure that the existing loop will allow the system to perform to an acceptable level by checking it’s

layout details in the ‘Designing Induction loops’ handbook.

Low magnetic field strength

DuetoinsufcientCURRENTorexcessivemetalloss.

Mayrequireaspecialloopdesigntoachieveacceptableperformance,contactAmpetronicfor

advice.

Instabilityorhighfrequencynoise

1. Itispossiblefortheloopcablestobegroundedunderfaultconditions,resultingininstability

whichmaysoundlikehighfrequencynoise,buzzorwhistling.Theresultsofthistypeoffault

areunpredictableandmayappearasanycombinationofthefrontpanelindicationerrors

2. Thisfaultiseasytodetermine.Simplyunplugtheloopcablesfromtheamplierandtest

witharesistancemeterbetweeneitheroftheloopwiresandagoodearthpointsuchasa

metalradiator.Thereshouldbeaninnitelyhighreadingi.e.noconnectionatall.Anyreading

indicatesafailureoftheloopcableinsulationandyouwillneedtoeitherrepairorreplacethe

loopcable.

3. Instabilitycanbecausedbyusingpoorqualitysignalcables,longunbalanced(2-wire)signal

Ampetronic MLD7 Installation Handbook Ampetronic MLD7 Installation HandbookPage 10 Page 11

Technical Specifications

runstotheinputs,orbyrunninginputcablesincloseproximitywiththeloopwireover

anappreciabledistance.Loopampliersarecapableofdeliveringhighcurrentsataudio

frequencies.Iftheloopcablesarerunclosetosensitivesignalcablesitmaybepossibleto

induceasignalbackintotheinputoftheampliercausingfeedback.Cablerunsandloop

wiresshouldbekeptwellapartfromeachother.Toavoidinterferencemaintainaseparation

ofatleast300mm.

4. InstabilitycancausetheampliertorunhotandmayresultintheTEMPLEDilluminating.

Interference

1. Backgroundmagneticeldsignalsorinterferencemaybepresentinanylocationandmaynot

beanythingtodowiththeloopsystem.Monitorthiswithaloopreceiver(suchasanILR3).If

theinterferenceisstillpresentwiththeloopsystemswitchedoff,thenyouneedtolocateand

eliminatethesourceoftheinterferencebeforeswitchingtheloopsystembackon

2. Magneticeldscaninducecurrentsintoanylowimpedanceelectricalpathorloop.Audioor

videosystemswithmultipleearthsmayexperiencepickupoftheloopsignal.Checkentire

soundsystemforevidenceofloopsignal,andtracesourceofpickup.

3. Undercertaincircumstances,theloopsignalmayappearasjaggedlinesorhumbarsona

CCTVpicture.ThiscouldbeduetorunningCCTV(lowimpedanceunbalanced2-wirecircuit)

cablesincloseproximitytotheloopcable.Separatetheloopcablestoreducetheeffect.

4. Remote(andapparentlyunconnected)PAsystemscansometimespickuploopsignals.This

isusuallybecausetheloopcablebecomesdamaged(seepoint1ofInstability)orinduces

signalsintotheremotesystemthroughlongunbalancedcables.Alwaysrunlongaudiosignal

cablesas3-wirebalancedcircuitsandkeepawayfromloopcables.

5. Seealsopoint1ofInstability

Failed AC power fuse in rear of unit

UnplugtheloopandACpowersupplyfromamplier,andreplacethefailedfusewiththesparefuse

inACpowerinputfusetray.

ReconnecttheACpowersupplyandswitchon.Ifthefusefailsagain,returntheunittoAmpetronic

forevaluation-itmaywellbecoveredunderwarranty,whichwillbeinvalidatedbyremovingthe

cover.Ifthefusedoesnotfaila'looperror'maybeindicated,butshowsthattheunitisworking

correctly.Re-connecttheloopandswitchthepoweroffthenonagaintoresetlooperror.

Ifthefusefailswhentheloopisre-connectedtotheunit,thentheloopcouldbeshortedto

electricalmains(andbuilding)earth.Thiscanhappenevenifnoaudiosignalispresent,asthe

shorttoearthislikelytocauseaninstability/oscillation/feedbackconditiontodevelop.Aloop

cableshorttoearthmostcommonlyoccurswhereatcoppertapeisinstalledonametal-clad

raisedaccessooringsystem.Iftheinsulationontheatcoppertapeisabraded(forexamplebya

pieceofmetalswarftrappedbelowthecoppertape),theconductorcouldshorttotheearthedtiles.

Wheninstallingonraisedaccessoors,itisadvisabletoinsulatebeneaththeatcoppertape

installationusingAmpetronicPWTorsimilartape.

Theloopshorttoearthmayonlybecompletedwhenapersonstepsonthetapeintheaffected

location,whichcancreatesignicantdifcultieswhendiagnosingthecauseoffusefailure.Contact

Ampetronicforfurtheradviceifaunitissufferingrecurringbutuntraceablefailureoftherearpanel

fuse.

ACCESSORIES

DetailsofallproductsandservicesprovidedbyAmpetroniccanbefoundatwww.ampetronic.com

INPUTS AND PROCESSING MIC Line UNITS

Inputguresquotedatmaximumfrontpanelgaincontrolsetting. Low gain High gain Low gain High gain

INPUTS;XLRconnector.Balanced,Suitableforupto600Ωmicrophonesorlinelevel.

Inputimpedance

Sensitivity

Overload

Phantom(via680Ωsource)

8700

-62

-24

8700

-77

-39

8700

-37

8700

-52

-14

-

Ω

dBu

Vdc

AGC;CompressionofsignalindBshownonsixfrontpanelLEDs

Inputrange

Outputrange

Min.inputlevelforAGC

Attacktime

Decaytime

>36

±1

Dependsoninputmodeused(seesensitivity)

METAL LOSS CORRECTION; Speciallydesignedadjustableltertocompensatefor

theeffectsofmetalloss.Gain@1kHzremainsconstant

Min.slope

Max.slope

dB/oct.

PHASE SHIFT; Theloopoutputscanbeconguredforphasedarraysystemsby

selectingtheappropriaterearpanelswitchoption.Phaseshiftbetweenoutputs:

Phaseshiftoff

Phaseshifton

SLAVE IN; 6.35mmjack.Inputforlinkingmorethanoneamplier.Insertingplug

disablesotherinputs.

Inputimpedance/channel

Inputlevel/channel

MLD7 MLD7

MLD9

UNITS

N/A

Ω

Vpk

100k

1.5

OUTPUTS MLD5 MLD7 MLD9 UNITS

SLAVE OUT; Processedaudiosignaloutput.PostAGC,MLCandPhaseshift.For

linkingtoanotheramplier.

Sourceimpedance/channel

Outputlevel/channel

N/A

220

1.5

Ω

Vpk

LOOP OUTPUT;(perchannel);NL4speakon.1perchannel.

Voltagepeak/RMS

Currentpeak/RMSintosingleturnloop.

Absolutemaximumshorttermpeakcurrent.

THD+N(@1kHzfulloutput)

Outputimpedance

Frequencyresponse(±1.5dBnoAGC)

OutputcurrentindicatedviasixfrontpanelLEDs(perchannel)at3dBintervals.

BipolarPPMstylecircuit

Attack

decay

14.5/10

7/5

>10

<0.2

100to5000

4.7

24/17

9/6.4

>13

<0.2

100to5000

4.7

45/32

13/9.2

>19

<0.2

100to5000

4.7

Ω

STATUS SOCKET;2pin5mmpitch90°header.Thestatussocketconsistsofapair

ofisolatedcontacts.

Amplierorloadfault

AmplierandloadOK

Contactrating

Dielectricstrength(coil–contact)

Open

Closed

DC2A,28V,60W

AC0.5A,125V,60VA

1000Vac50/60Hz

DC POWER SOCKET; 2pin5mmpitch90°header.TheDCPOWERsocketisused

topoweravarietyofAmpetronicaccessories.

Outputvoltage

Outputcurrent(max.)

0.1

PROTECTION FEATURES MLD5 MLD7 MLD9 UNITS

CLIPPING;ClippingofeitheroutputisshownonthefrontpanelCLIPLEDs.Ifclipping

persistsamplierwillshutdownandrestart.

Clipthreshold(%ofpeakoutputvoltage)

93 93 93 %

OUTPUT DC OFFSET;IfDCoffsetisdetectedamplierwillshutdownandrestart

Threshold

±0.7 ±0.7 ±0.7 Vdc

TEMPERATURE; Internalheatsinksaremonitored.Iftemperaturereachessetlimits

theoutputcurrentisreducedandeventuallymuted.MLD7&9haveseparateinde-

pendentsystemsforeachchannel,MLD7hasasinglecontrolforbothchannels.

Outputcurrentreduction(3dBmax)

Outputmute(illuminatesTEMPLED)

Any of the above faults also cause the status relay contacts to open.

Commences88,max@92

92(outputreturnsatapprox.60)

°C

LOOP RESISTANCE TESTING;Checkstheresistanceoftheloadonstartup(The

POWERLEDashesduringthisperiod)andonlyallowsoperationifwithinlimits.The

LOOPLEDsareilluminatedifloadsareoutsidelimits

Startuptime

Lowerlimit

Upperlimit

Upperlimit(linkremoved)

8approx.

0.3

Nolimit

8approx.

0.3

Nolimit

8approx.

0.5

Nolimit

Ω

OUTPUTS

SLAVE IN; 6.35mmjack.Inputforlinkingmorethanoneamplier.Insertingplug

disablesotherinputs.

Inputimpedance/channel

Inputlevel/channel

MLD5 MLD7 MLD9 UNITS

N/A

100

1.5

kΩ

Vpk

PROTECTION FEATURES CONTINUED MLD5 MLD7 MLD9 UNITS

CURRENT LIMIT; 15 22 22 Apk

COOLING;internalvariablespeedfan(s).Intakeonfront,exhaustonrearpanel

No.offans

Fannoise(@1mnoload)

Fannoise(@1mEN600625testsignalmax

ratedcurrent)

<47

dBA

POWER REQUIREMENTS & PHYSICAL MLD5 MLD7 MLD9 UNITS

Standard IEC inlet

Mainssupplyvoltage

Frequency

230(115)

45-65

230(115)

45-65

230(115)

45-65

Vac

Power (EN60065testsignalmaxratedcurrent) 80 160 220 W

Fuse

T630mAL

(T1.25AL)

T1.6mAL

(T3.15AL)

T2.5mAL

(T5AL)

Inrush Current 16 27 40 Apk

Weight 3.75 4.77 6.35 Kg

Dimensions;

Width

Height

Depth

430

220

430

250

430

330

ENVIRONMENTAL;

IngressProtection

Operatingtemperaturerange

Relativehumidity

IP20

0-35

20-90

IP20

0-35

20-90

IP20

0-35

20-90

°C

WARRANTY

ThisproductcarriesaveyearpartsandlabourwarrantyfromdateofshipmentfromAmpetronic.To

qualifyfortheveyearwarranty,theproductmustberegisteredatwww.ampetronic.com(products/

warranty),withoutwhichthewarrantywillbevalidfortwoyearsonly.

Thewarrantycouldbeinvalidatediftheinstructionsinthishandbookarenotfollowedcorrectly,orif

theunitismisusedinanyway.

DECLARATION OF CONFORMITY

Manufacturer: AmpetronicLtd.

   Unit2,TrentsideBusinessVillage,FarndonRoad,Newark,Nottinghamshire,

   NG244XB,UnitedKingdom.

Declaresthattheproduct:

Description: InductionLoopDriver

Typename: MLD7

ConformstothefollowingDirective(s)andNorm(s):

 Directive 2004/108/EC

 EMC:  EN55103-1:2009Emission

   EN55103-2:2009Immunity

 Directive 2006/95/EC

 Safety: EN60065:2002+A12:2011

 Directive 2011/65/EU RoHS

Date:  May2013

J.R.Pieters

ManagingDirector,

AmpetronicLtd.

Ampetronic MLD7 Installation Handbook

Page 12

INSTALLATION NOTES:

.......................................................................................................................................................

Ampetronic MLD7 Installation Handbook Page 13

UP17701-2

Listen Technologies MLD7 Owner's manual

Brand: Listen Technologies

Model: MLD7

Category: Musical Equipment

Type: Owner's manual

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Listen Technologies MLD7 Owner's manual

Listen Technologies MLD7 Owner's manual

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