FRONT PANELINFORMATION
1.POWER SWITCH: This switchapplies AC power totheamplifier.The ampison when the top
ofthe switch isdepressed, offwhen the bottom ofthe switch is depressed. The power LED
indicator illuminates when the amplifier is on.
2.POWER LED: ThisLED illuminates when ACpowerisappliedbymeans ofthe Powerswitch.
If theLED fails to illuminate, check theACoutlet or the fuse on the rear panel.
3.PROTECT LED: This LEDilluminates whenever the internal protection relayfor the channel is
activated. Theprotectionrelayisactivated for a short period upon initialturn-on and at turn-off
to prevent transient “spikes”from being reproduced through your speakers.Afaultcondition is
also indicated in the event ofanover temperature status,or ifDC voltages arepresentat the
output. Duringthermal protection, bothchannels areshut down until thetemperature returns to
asafeoperating level. In theevent of DC voltage on the output,only the affected channelwill
bedisconnected. The circuitryassociated withthe LED indicator providesvaluableprotection
for boththeamplifier andyour speakers.
4.SIGNAL LED: This LEDilluminateswhensignal is detectedatthe amplifier’s output terminals.
Thelevelofthe signalmustbeatleast 1%oftheamplifier’s fullrated output to maketheLED
illuminate.
5.PEAK LED: The PR-150 designedan internal automatic limitcircuitto prevent theamplifier
from clipping. The Peak LEDilluminates(indicates the limiterisactive) whenevertheinput
signalattemptsto overdrivetheamplifier.(Notonlydoesclippingproduce harshsounding
distortion,it is alsocapable ofdamaging speaker components –particularly highfrequency
driver.) Periodic flashing ofthe Peak LEDindicates operationator near full output.This is
normal.Steadyillumination of theLED indicates constant operation ofthe Limiter, with the
possibilitythat the input signal should bereduced bymeansofthe Level control. TheLimiter
withinthePR-150isfullyautomatic,withno defeatswitch,insuring you complete protection
against clippingatall times.
6.SENSITIVITYCONTROL: These rotarypotentiometers control the level or gain ofeach
channel, with the fullyclockwise position ofeachprovidingasensitivityof+2dBv.Normal
calibrationofthe PR-150 to a mixer wouldcause the PeakLED toflash at thesame time that
themixer’s VU meters indicatefull output.
7.FRONT PANELEXHAUST VENT: Avariable speed internalcooling fanisused to drawair
throughtheunit tokeep it runningeven under extremeoperating conditions. Air is drawn in
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