APART Champ-2 User manual

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MANUAL
Champ - 2
MANUAL
Audiophile Stereo Power Amplier

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• Caution: hot and sharp surfaces ! This professional device needs to be installed by
qualied personnel only.
Please check the carton box for any kind of damage on reception of the goods. In case of a• damaged carton, please contact your dealer before opening the carton.
!!!! Danger !!!! Exposure to extremely high noise levels may cause a permanent hearing• loss. Individuals vary considerably to noise induced hearing loss but nearly everyone will lose
somehearingifexposedtosufcientlyintensenoiseforasufcientamountoftime.Therefore
it is recommended that all persons exposed to equipment capable of producing high sound
pressurelevels,suchasthisamplier,beprotectedbyhearingprotectionwhileinstallingor
operating this unit.
Read all documentation before operating your equipment.• Keep all documentation for future reference.• Save the carton and packing material even if the equipment has arrived in good condition.• Should you ever need to ship the unit, use only the original factory packing.• Do not spill water or other liquids into or on the unit.• Make sure power outlets conform to the power requirements listed on the back of the unit.• Do not use the unit if the electrical power cord is frayed or broken.• Always operate the unit with the AC ground wire connected to the electrical system ground.•
Havegaincontrolsonampliersturneddownduringpower-uptopreventspeakerdamageif• there are high signal levels at the inputs.
Donotconnecttheinputs/outputsofampliersorconsolestoanyothervoltagesource,such•
asabattery,mainssource,orpowersupply,regardlessofwhethertheamplierorconsoleis
turned on or off.
Power down & disconnect units from mains voltage before making connections.• Do not use the unit near stoves, heat registers, radiators, or other heat producing devices.•
Donotoperateequipmentonasurfaceorinanenvironmentwhichmaydistortthenormalow• of air around the unit. If the unit is used in an extremely dusty or smoky environment, the unit
should be periodically “blown free” of dust.
Do not remove the cover. Removing the cover will expose you to potentially dangerous volt-• ages.
Do not drive the inputs with a signal level higher than that required to drive equipment to full• output.
Donotruntheoutputofanyamplierbackintoanotherinput.• Do not ground the red output terminal, never connect a red output terminal to another red• output terminal.
Incaseofmal-functionthisdeviceshouldbeservicedbyqualiedservicepersonnelonly.•
Safety First!

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Dear customer,
Whydoeslivemusicleaveanunforgettableimpressiononyou?Theanswerissimple:dynamics.
Theabilityofasoundsystemtoproducecrystalclearlowlevelsoundsaswellasextreme
musical peaks without any distortion, the power to leave some headroom for those occasional
peaksinmusic.Purepower!Thiseaseofmusicreproductioncannotbedescribedinguresor
specications.
In the following pages we will explain how we have reached our goal. Champ-2 features an
exceptionallydynamicoutputstage,auniqueclassGamplier,allpackedinaoneunitfanless
enclosure. While our competitors are struggling with often poorly designed so called energy
efcientclassDdigitalampliers…well,wehavetakenacloselookandlistenedcarefullytosome
of these designs, and we were not impressed. We got inspired to make somethingAPart from all
the rest, and started from scratch.
Takealookatournewchampionwithhisstrikingdesignandpowerfulsetoffeaturesthatwill
exceed the demands of passionate music lovers as well as system integrators. Designed with
a continuous 4 ohm, 2 ohm dynamically stable high current output stage, Champ-2 will surprise
youwithitssonicexcellenceanddynamiccapacities.Remember,thisuniqueamplierhasbeen
developed with the impact of live music dynamics in mind. A true beauty, inside as well as outside,
but also a beast if necessary.
TakeyourtimeandlistentoournewChamp-2amplier.Pleasefastenyourseatbeltsandbeware,
you might get blown away, not by the cooling fan, simply because there isn’t any. Experience the
pure musical power of Champ-2.
Manual contents
1. Fanless design and highlights
2. Features
3. Inputs and outputs
4. Rack mounting and wiring
5. Standalone use
6. Technical specications
Introduction

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Audiophile grade components mounted on solid aluminum and steel construction chassis for•
thehighestpossiblesignalintegrityandreliability,evenunderdifcultcircumstances.
Highcurrent,highvoltagediscreteoutputstageinclassGconguration,capableofdriving• even the most demanding speaker systems and combinations. Either at low or high power, you
will hear the Champ-2 difference.
Customdesignedsidemountheatsinks,incombinationwithclassGampliertopologyhave•
madeitpossibletocreateadiscretehighpoweramplierwithouttheneedofanoisydustcol-
lectingcoolingfaninsidetheenclosure.Thismeanslessmaintenance,noannualfanordust
lterexchangeprocedure,nomoreampliercleanout…no unwanted noise from cooling
fans, Champ-2 relies on convectional cooling only, a unique feature in this output power class,
and all packed in a 1 unit 19 inch case!
IntegratedAPClimitercircuitryandcliplimiteradaptabletotheactualspeakerload.Thisintel-• ligent circuit will prevent harsh distortion caused by clipping, provided that the input signal itself
isnotdistortedofcourse…whatgoesin,comesout.
A stunning 38800 µF of high grade electrolytic capacitors, high power toroidal transformer for• ultimate power reserve.
Self-supportinglowresonancesteelsubframe.Torsionfreefrontandsidepanelconstruction• with integrated heatsink assembly.
Solid aluminum brushed front panel with removable 19” brackets and handles for use in a rack• or as a standalone unit in high quality audio systems.
MultipurposeinputcongurationfeaturingbalancedinputsonXLRconnectorsandunbalanced•
inputsonRCAconnectors…
1. Fanless design and highlights

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Intelligent• APC circuitry constantly analyses incoming music signals and keeps dynamics
alive.Anadditionalultrafastpeaklimiteravoidsamplierclippingincasesomeonehitsthe
inputstoohard.Pleaseremember,thisisamusicalamplier,pleaseleavesomeheadroom
and enjoy the music.
Bridgeorstereomode:morethandoubletheoutputpowerandconvertthisamplierintoa•
monoblockamplierwithonepushonabutton.Minimum load impedance is 8 ohms in
bridge mode.
Protectioncircuitry:theprotectioncircuitryisanotheruniquedesignfeatureofthisampli-•
er:togetherwiththeAPCcircuitry,outputsignalsareconstantlymonitoredbytheprotection
circuits, and speaker outputs will be cut in case of extreme overload, short circuits, DC offset,
overheating…Thiscircuitisalsocapable(withincertainlimits)ofreducingtheinputsignalto
prevent clipping, distortion and other musically destructive situations. We have done our best to
makesurethisamplierwillproducecleanpower,butit is also the user who is responsible
for the nal result: the APC circuitry can not clean up a clipped input signal, in other
words: what goes in, comes out. Don’t forget to set the impedance selector correctly for
both channels and remember to divide the speaker’s impedance by a factor 2 if you are
planning to use the amplier in bridge mode ! Example in bridge mode: speaker load = 8
ohms, set channel 1 impedance selector to 8 : 2 = 4 ohms setting (4 – 8 ohms).
Versatileinputandoutputconnectorcongurationwithbalancedandunbalancedinputsand•
additionallinelevelsignaloutputsforlinkingthesignaltootherdevicesforincreasedexibility.
Thespeakeroutputterminalsacceptspeakercablesaswellas4mmbananaplugs.
Groundliftswitchtoenableyoutondthecauseofsystemgroundloopsincaseofhumor• excessive noise.
2. Features

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What is APC ?
APC is one of the most intelligent amplier protection circuits ever designed, simply
because it does the job without interfering with the typical dynamic character of
music. APC allows you to fully exploit the potential of the amplier, maintaining high
power reserves and thus producing high, clean power.
It is a common misunderstanding that high power ampliers will overload or destroy
lower power speakers, the opposite is true. You can easily destroy a 500 Watt rated
speaker with a simple 50 watt power amplier ! Why ? In order to produce a low tone,
such as a kick drum or bass guitar, you need about 80 % or more of an amplier’s
power. Because distortion is less audible in low frequencies, you would want to
increase the level more than the amplier can supply. This causes low frequency
distortion which causes high frequency harmonics. These harmonics contain more
high frequency energy than the high frequency speaker can deal with. Result: harsh
distortion and sudden heat rise in the high frequency speaker’s voice coil. After a
short while, the high power speaker may burn out.
Conclusion: don’t punish your speakers with weak ampliers. Set the APC control
to a power level equal to your speaker’s RMS input power and avoid hitting the clip
limiter !

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1)Volumepotmeterchannel1:usethispotmetertopresetthevolume.Incasetheamplierhas
been switched to bridge mode, this potmeter sets the level for bridge operation.
2)Signalledchannel1:thisledlightsupgreenwhenasufcientlystrongsignalispresentonthe
left channel, after passing the input level control. At startup, the led will light up red during a
few seconds, this is perfectly normal. When it lights up red during use, the power transformer
orpoweramplierisoverheatedorinprotectmodeandisshutdown.Turnoffthepower.The
amplier will not turn on automatically after most error conditions. In some cases, the
user MUST turn off power and remove the overload and then power on again ! More
details can be found in the table below.
3)APCactivityledleftchannel:thisledlightsupwhentheAPCcircuitryisactive.TheAPC
circuitry reduces the gain at the inputs to guarantee the full dynamic range of the power
ampliercircuits.
4)Clipledchannel1:thisledlightsupwhenevertheamplierclips.Thisisawarningsign:you
are pushing things a little too far or you are overloading the amp. Reduce the input level by a
few dB so that this led never lights up anymore ! Don’t ignore this!
5)Templedleftchannel:thisledlightsupwhentheamplierisoverheated.Outputpower
willautomaticallybecutbytheAPCcircuitry.Thispartoftheprotectioncircuitresetsitself
automaticallywhentemperaturehasnormalized.Whenbothsignalled(2)andtempled(5)are
red,thepowertransformer’sthermalprotectionisactiveandtheamplierisshutdown.Turn
off the power and let it cool down. The amplier will not turn on automatically after the
transformer has cooled down, the user MUST turn off the power, remove the cause of
the fault condition, wait for cooling down and then power on again!
6)Bridgeled:thisledlightsuptoindicatethattheamplierisinbridgemode.
7)Powerswitchandpowerled:iptheswitchtopowerontheamplier.Theblueledwilllightup
to indicate that mains power is present.
3. Inputs and outputs
Frontpanellayout:
1234 756 8910 11 12

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8) Signalledchannel2:thisledlightsupgreenwhenasufcientlystrongsignalispresent
on the left channel, after passing the input level control. At startup, the led will light up red
during a few seconds, this is perfectly normal. When it lights up red during use, the power
transformerorpoweramplierisoverheatedorinprotectmodeandisshutdown.Turnoffthe
power. The amplier will not turn on automatically after most error conditions. In some
cases, the user MUST turn off power and remove the overload and then power on
again ! More details can be found in the table below.
9)  APCactivityledrightchannel:thisledlightsupwhentheAPCcircuitryisactive.TheAPC
circuitry reduces the gain at the inputs to guarantee the full dynamic range of the power
ampliercircuits.
10)Clipledchannel2:thisledlightsupwhenevertheamplierclips.Thisisawarningsign:you
are pushing things a little too far or you are overloading the amp. Reduce the input level by a
few dB so that this led never lights up anymore ! Don’t ignore this !
11)Templedleftchannel:thisledlightsupwhentheamplierisabouttooverheat.Outputpower
willautomaticallybelimitedbytheAPCcircuitrytoavoidfurtheroverheating.Thispartofthe
protection circuit resets itself automatically when temperature has normalized. When both
signalled(2)andtempled(5)arered,thepowertransformer’sthermalprotectionisactive
andtheamplierisshutdown.Turnoffthepowerandletitcooldown. The amplier will not
turn on automatically after it has cooled down, the user MUST turn off power, wait for
cooling down and then power on again ! More details can be found in the table below.
12)Volumepotmeterchannel2:usethispotmetertopresetthevolume.Inbridgemode,this
potmeter has no function.

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Fault
condition SGL led CH1 = red TEMP led CH1 = red SGL led CH2 = red TEMP led CH2 = red What to do ? Output signal condition
Ch 1 amp
overheat
Yes Reduce input
signal or check
amplierload.
Wait for cool
down.
No output
Ch 2 amp
overheat
Yes Reduce input
signal or check
amplierload.
Wait for cool
down.
No output
Ch 1 amp
error (DC,
HF, short
circuit,
overload)
Yes Switch off power
and remove
error.Leave
switched off
for at least 10
seconds. Switch
power on.
No output
Ch 2 amp
error (DC,
HF, short
circuit,
overload)
Yes Switch off power
and remove
error.Leave
switched off
for at least 10
seconds. Switch
power on.
No output
Transformer
thermal
protection
Yes Yes Yes Yes Switch off power
and wait for cool
down*.
No output
*In case the transformer is overheated, it may take a long time before the amplier has cooled
down sufciently. In such cases, you may have overloaded the amplier too much. Power off the
amplier immediately, correct the error and wait until the amplier has cooled down.
Led status messages
Under normal circumstances, this amplier will not overheat. If any of the above
mentioned overheating situations occur, please check the load impedance, the
ventilation and last but not least, input levels. The intelligent APC circuitry will
reduce input gain and level to a safe margin within certain limits. This circuitry can
not correct an input signal that is already clipped and distorted.

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1)Channel2unbalancedinputoncinchconnectors:usethetoporbottomcinchconnectorto
applyanunbalancedsignalonchannel2.Theseconnectorsarewiredinparallel,thismeans
you can use the second connector as a signal link connector.
2)Channel2balancedinputonNeutrikXLRconnector,thisconnectoriswiredinparallelto
connector‘3’.Thisallowsyoutolinkthebalancedsignaltoanotheramplier.
3)Channel2balancedinputonNeutrikXLRconnector,thisconnectoriswiredinparallelto
connector‘2’.Thisallowsyoutolinkthebalancedsignaltoanotheramplier.
4)Groundliftswitch:usethisswitchtoliftorconnectaudiogroundtosafetyground.Thiscanbe
usefull in case of hum.
5)Speakerloadimpedanceselectorchannel2:setthisselectorcorrectlyaccordingtothe
actualloadimpedance.For4to8ohmsapplications:switchisnotpushedin.For2to3
ohmapplications:pushthebuttonin.Pleasenotethattheimpedancementionedisthetotal
loadoftheamplierchannel,thismeansthatifyouconnectforexample3speakerswith8
ohmimpedance,youMUSTpushthebuttoninbecausetheloadontheamplieris8:3=
2.7 ohms. In case of bridge operation this button has no function. Use channel 1 impedance
selector in case of bridge operation.
6)Channel2speakerbindingpost:thisconnectoracceptsspeakercableaswellas4mm
banana plugs. Remove the protective cover from the middle of the red/black binding post in
caseyouwanttousebananaplugs.Forbridgemodeapplications,youMUSTusethered
bindingpostsonly:channel2redplugisbridgemodenegativespeakerconnector.
7)Mainscableconnector:plugthemainscableconnectorhere,thissocketalsocontainsamains
fuseholder.Replacethisfuseonlywitha3AT250Vtype.
8)Channel1speakerbindingpost:thisconnectoracceptsspeakercableaswellas4mm
banana plugs. Remove the protective cover from the middle of the red/black binding post in
caseyouwanttousebananaplugs.Forbridgemodeapplications,youMUSTusethered
bindingpostsonly:channel1redplugisbridgemodepositivespeakerconnector.
Rearpanellayout:
1 2 3 4 5 6 7 8910 11 12 13

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9)Bridgemodeswitch:usethisswitchtoconverttheamplierintoamonobridgeamplier.In
thiscaseyoucanapplyaninputsignaltothechannel1inputonly!Leavethechannel2
connectors open ! Bridge mode input level is controlled by the channel 1 volume controller
only.The‘BR’ledonthefrontpanelwillindicatethattheamplierisinbridgemode.Minimum
bridgemodespeakerloadis8ohms.Neverusethespeakeroutput–(minus)connectorsin
bridge mode !
10)Speakerloadimpedanceselectorchannel1:setthisselectorcorrectlyaccordingtothe
actualloadimpedance.For4to8ohmsapplications:switchisnotpushedin.For2to3
ohmapplications:pushthebuttonin.Pleasenotethattheimpedancementionedisthetotal
loadoftheamplierchannel,thismeansthatifyouconnectforexample3speakerswith8
ohmimpedance,youMUSTpushthebuttoninbecausetheloadontheamplieris8:3=
2.7 ohms. Use channel 1 impedance selector in case of bridge operation. In case of bridge
operationthisswitchmustbeputto4-8ohmoperationbecausetheminimumloadimpedance
inbridgemodeis8ohm.Lessthan8ohmsinbridgemodeisnotallowed!
11)Channel1balancedinputonNeutrikXLRconnector,thisconnectoriswiredinparallelto
connector‘12’.Thisallowsyoutolinkthebalancedsignaltoanotheramplier.
12)Channel1balancedinputonNeutrikXLRconnector,thisconnectoriswiredinparallelto
connector‘11’.Thisallowsyoutolinkthebalancedsignaltoanotheramplier.
13)Channel1unbalancedinputoncinchconnectors:usethetoporbottomcinchconnectorto
applyanunbalancedsignalonchannel1.Theseconnectorsarewiredinparallel,thismeans
you can use the second connector as a signal link connector.
What is bridge mode ?
In bridge mode, you can unite the power of 2 small ampliers into 1 giant amp.
The resulting power usually is more than double the power of both ampliers used
individually with the same load. There is a simple reason for this power boost:
because the speaker load is wired to the channel’s positive (hot) connectors, the
ampliers ‘feel’ half of the actual speaker’s impedance. This means that, despite
the fact that you connect for example an 8 ohm speaker, the amp thinks there is a 4
ohm load, resulting in higher power output per amplier, and since both ampliers
work in bridge mode, this increased power is doubled. As a result, the minimum load
impedance in bridge mode is limited to 8 ohms, because every amplier only ‘feels’
half of this impedance. Set the speaker impedance selector of channel 1 to the 4-8
ohms position for 8 ohms(or higher) loads in bridge mode.

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Champ-2canbemountedina19”rack,takinguponly1rackspace.Alwaysallowagoodairow
aroundtheamplier’sfront,rear,side,topandbottom.Wheninstallinginarackwithmultipleaudio
devices, it is compulsory to leave one rack space between units. Fill the empty rack spaces with
meshedblindpanelsforimprovedventilation.Nevermounttheamplierinasealedcabinet,unless
adequateforcedventilationisprovided.Theampliermaynotbeabletomeetthespecications
when installed in a poorly ventilated environment. Support the unit at the rear when installing in a
rack !
Always remember: excessive heat is one of your amplier’s biggest enemies !
4. Rack mounting and wiring
When wiring an audio rack, it is a good installation practice to route all AC wiring
along one side of the rack and all audio wiring along the other side to avoid coupling
mains cable interference into the audio path. Please use only high quality signal
and speaker cables and connectors. Pay special attention to avoiding ground loops
when installing audio devices in metal racks, use special insulating rack mounting
hardware, such as the so called ‘humfrees’. This mounting hardware will make sure
that several devices mounted in a rack will be electrically isolated from the rack, and
thus are a great help in avoiding ground loops. Any damage caused by user induced
ground loops are not covered by warranty ! Ground loops can cause hum or other
strange side effects that will affect stable and safe operation of audio hardware and
peripheral devices. Ground loops are often created by connecting tuners to cable
distribution sockets. Use a RF isolating transformer whenever there is a cable signal
tuner or digital TV tuner in the audio path !

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ItispossibletointegrateChamp-2inahighqualityaudiochain.Inordertoadaptthefrontpanel
dimensions to the dimensions of other equipment, it is possible to remove the 19” brackets and
handlesforanevenmoresleekandrenedlook.
Remove the two screws marked in red circles and slide off the handles.
5. Standalone use

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Dynamic program power, both channels driven
Bridge-monooperation8ohm 750 W
2 channel mode 8 ohm 200 W / ch
2 channel mode 4 ohm 350 W / ch
2 channel mode 2.7 ohm 450 W / ch
Dynamic capacity at 2 ohm, both channels
driven 600 W / ch
6. Technical specifications
Rated output power, both channels driven:
Bridge-mono operation 8 ohm 350 W
2 channel mode 8 ohm 120 W / ch
2 channel mode 4 ohm 180 W / ch
2 channel mode 2.7 ohm 200 W / ch
Sine wave power, both channels driven (not recommended, for reference only)
This amplier is designed for an audiophile music experience, not for lab testing!
*a 2.7 ohm load can be seen as 3 pieces of 8 ohm speakers in parallel (or even 6 pcs of 16 ohm speakers).
A 2 ohm load is technically possible but not recommended for long term use at high power.

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Input impedance / sensitivity unbalanced
(RCA)/4ohm
10 Kohm / 1 V 0dBV
Inputimpedance/sensitivitybalanced(XLR)
/ 4 ohm 20 Kohm / 1 V 0 dBV
Frequencyresponse(0,-0.5dB) 10 Hz – 50 kHz
THD < 0.05 %
IMD < 0.06 %
Noise >100 DBA
Gain 30dB(36dBbridged)
Damping factor > 200
Dynamics and level control APC,switchablefor2-3or4-8ohms
Power amp circuit design High current, high voltage class G
Efciency(dynamicprogramof10dB,1V
input)
70 %
Protection circuits DC,HF,clip,overcurrent,short-circuit
Temperatureprotection 95°C/ch + transformer 105°C
Cooling convectional, no fan
Power consumption 15VA idle, 600VA full program, 1KVA peak
Mains power requirements 230VAC, 50Hz
General technical specications
Physical specications
Netdimensions(cm)(WxHxD) 48.3X4.4X36
Grossdimensions(cm)(WxHxD) 56 x 10 x 55
Net weight 7.5 kg
Gross weight 9.0 kg
APart-Audio general warranty conditions:
APart-Audio warrants this product to be free of defects in material and workmanship for a period of one* year for parts and for a
period of one* year for labor from the date of original end-user purchase. This warranty is valid only for the original end-user and
cannot be transferred.
During the warranty period APart-Audio orone of its authorized service partners shall either repair or replace any product, free of
charge, that proves to be defective on inspection by APart-Audio or its authorized service representative.

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ANY SUGGESTION?
They are well appreciated and eventually rewarded!
Send your ideas or suggestions to
[email protected]
CHAMP-2 is developed by
Audioprof nv
Lanteernhofstraat 90
BE-2100 Deurne
BELGIUM
Company names, product names, and names of formats etc. are the trademarks or registered trademarks of
their respective owners.
© 2008 APart-Audio specifications subject to change without notice.