Instruction manual

B-52 US Series Professional Power Amplifiers - Instruction Manual
THE BEAUTY OF POWER
US SERIES AMPLIFIERS
US-Series amplifiers feature comprehensive protection
circuitry that protects both the loudspeakers and the
electronics from malfunctioning. The protection is non-
intrusive, sonically transparent and does not affect the
soundunlessthereareextremeconditionsthatacti-
vate the protection circuitry.
ThePROTECTLEDsonthefrontpanelilluminatewhen
the protection is active during the power-up sequence,
when thermal protection is activated, or when there is
amalfunction.WhenthePROTECTLEDsareON,the
amplifier’s outputs are muted.
INITIAL POWER-UP: The protection circuitry will
activate for about two to three seconds from the time
youturnONtheamplier.Thespeakeroutputsare
muted during this period. If the amplifier is operating
normally, the protection circuitry will deactivate and
the amplifier will switch to operation mode.
NOTE:ItisnormalforthePROTECTLEDtofade
 graduallyaftertheamplieristurnedOFF.
THERMAL PROTECTION:Excessiveheat-sinktem-
peratures will engage the thermal protection circuitry
to avoid damage to your amplifier. The speaker
outputwillmuteandthePROTECTLEDwillilluminate.
Thermal protection only engages on the channel
which has the overheating heatsink. The thermal pro-
tection will automatically restore to normal operation
mode automatically once the heatsink temperature
drops to a safe level.
NOTE: If the thermal protection constantly
activates, check the impedance of your loud-
speakers and the condition of the air filters on
front of the amplifier. The loudspeakers
impedance must not be lower than what is
specified in this manual for 2-channel and
 BRIDGEoperation.8Ohmsand4Ohmsspeaker
 loadsperchannel(8Ohmsand16Ohmsin
 BRIDGEmode)shouldnottriggerthethermal
protection circuitry if the air access is not
 blockedandtheairltersareclean.2Ohms
 speakerloadsperchannel(4OhmsinBRIDGE
mode) can cause the thermal protection circuitry
to activate occasionally. If this occurs, decrease
the signal level and consider reconnecting the
speaker connections to reduce the load on the
 amplier(forexample,donotconnecttoomany
speakers in parallel to the same channel).
NOTE:Makesurethereisadequateairaccess
to the amplifier. Do not block the air vents on
PROTECTION
13
and contact an authorized B-52 Service Center.
There are rare instances when the circuit breaker acts
on a constant heavy overload with a very low imped-
ance load connected to amplifier, protecting your
amplifier against such improper usage. In such cases
you need to check and correct your load (loudspeak-
ers)toprovidefortheproperloadimpedance,and/
or reduce output signal.
10. AC INPUT
US-5000/6000ampliersarefactoryprecongured
foreither120Vor230VACvoltage,basedonwhere
theyaresold.120Vmodelsarettedwithaxedheavy
AWG12cordtoprovidehighcurrentconsumptionwith-
out losses and deliver power peaks without sags.
NOTE:US-6000120Vamplier’scordis
 terminatedwith20ANEMAplugand
 mustbeconnectedtoproper20Arated
 ACline.Thepinsonthis20Aratedplugare
 orienteddifferentlythanonastandard15A
 ratedplug,andwillnottintostandard15A
 ratedwallACoutlet.
WARNING:Nevercutoff20AratedACplug
 toreplacewithdifferentplug;itwillrepresent
safety hazard.
NOTE: 230Vmodelsareequippedwitha
 standardIECconnectoronrearpaneland
 suppliedwithheavygaugeACpowercord
appropriate with country of sale.
NOTE: NeverdisconnecttheEARTHpinfrom
 theACconnection.Itwilldefeatsafetymeasures
used in your power amplifier and void the
warranty.
11. LED STRIPS SWITCH
TheLEDSTRIPSswitchallowsyoutoturnblueLED
stripslightsonfrontpanelON,OFFordimthemhalf-
way.Thisgivesyouexibilityforinstallationswhere
you may want to control lights.