
1.Power Switch.Afterconfirmingandconnectingthecorrectmains
voltage,pushswitchuptoengagepower.
2.Threshold.Continuouslyvariablecontrolofthresholdlevel,above
whichgainreductionbeginstooccur.Exactthresholdleveldepends
onthesettingsoftheothercontrols.
3.Sidechain Hi-Pass Filter.Pushbuttonswitchremoveslow-frequency
informationfromthecontrolsignal.Thiscanpreventunwanted
“pumping”onbassnotes,suchaskickdrum.Filterisfactoryconfigured
for150Hzcornerfrequency.Pressbuttonintoengagefilter.
4.Ratio.4-positionrotaryswitchselectsoneoffourcompressionratios:
1.5:1;2:1;4:1;or10:1.Changingtheratiowillautomaticallyadjust
thethresholdsothatthetotalamountofgainreductionwillremain
approximatelythesame,allowingformoremeaningfulcomparisonof
theaudibleeffectsofdifferentratiosettings.
5.Attack Time.10-positionrotaryswitchselectsoneoftenattacktime
settings.Thiscontrolshowquicklygainreductionbeginstooccur.A
slowerattacktimewillallowmoretransientstobepassedwithoutgain
reduction;afasterattackwilltendtoreducetransientlevels.Awide
rangeoftonalvariationispossibleasaresult.Attacktimesare
approximateandaremeasuredinmilliseconds.
6.Release Time.10-positionrotaryswitchselectsoneoftenrelease
timesettings.Thiscontrolshowquicklyfullsignallevelisrestored
aftergainreductionoccurs.Afastreleasetimewillincreasethe
audibilityofthesustain,decay,andreverberantportionsofthesound.
Aslowerreleasewilltendtobelessnoticeableonfullprogrammaterial.
Releasetimesareapproximateandaremeasuredinseconds.
7.Dual Release Time.PushbuttonswitchactivatesProgramDependent
ReleaseTimemode.Thismodefeaturesadualreleasecharacteristic
whichoffersaslowerrecoveryfromlongpassagesofabove-threshold
signalaswellasafasterrecoveryfromshorttransients.TheRelease
Timecontrolswitchcontinuestofunctioninthismode,affectingthe
“short”portionofthereleasecharacteristic.However,therelease
timesprintedonthefaceplatearenotaccurateinDualmode.
8.Makeup Gain.Continuously-variablecontrolofoutputgainappliedto
allsignal,indepentlyofanygainreductionoccurring.Rangeofthegain
controlis-14dBto+20dB.Sincethisgainisappliedafterthecom-
pressioncircuitry,itispossibletocauseoutputclippingbyexcessive
clockwiserotationoftheGaincontrol.
9.Bypass.Pushbuttonswitchbypassesallcircuitry.Thisisatruehard-
wirebypass,sothereisnoactivecircuitryinthesignalpathwhenthe
bypassswitchisengaged.Itisequivalenttounpluggingtheinputand
outputXLRcablesfromtheunitandconnectingthemtooneanother.
10.Gain Reduction Meter.Displaysinstantaneousdegreeofgain
reductioninDecibels.MeterisnotaffectedbyappliedMakeupGain.
1. Mains power connector and fuse holder. Mainspowerisappliedvia
astandardIEC3-prongpowercord(included).Mainsvoltageisselected
internallyatthefactoryfor117VACor230VACnominalmains,andcan
bereconfiguredinternallybyaqualifiedservicetechnician.Connectthe
powercordonlytoaproperlygroundedoutletofcorrectmainsvoltage.
2. Balanced XLR audio input connectors. StereoAudioinputisona
pairofelectronicallybalancedXLR-Fconnectorswithdifferentialsignal
betweenpins2and3(pin1connectstochassisground).Unbalanced
sourcesshouldbeconnectedbetweenpins2and1.
3. Balanced XLR audio output connectors. StereoAudiooutputisona
pairofelectronicallybalancedXLR-Mconnectorswithdifferentialsignals
betweenpins2and3.Unbalancedloadsshouldbeconnectedbetween
pins2and1,withpin3leftunconnected.Donotgroundtheunusedpin.
RMS755SUPERSTEREOCOMPRESSORFRONTPANELCONTROLFEATURES
REARPANELCONNECTIONDIAGRAM