Lab.gruppen LAB 4000 Specifications

Also see for LAB 4000: Brochure User manual

Contents

Features

Lab.gruppen LAB 4000 Specifications Manual pdf 1 page image

POWER AMPLIFIER 4000FEATURESu 2x1300 W into 8 Ω2x2100 W into 4 Ω2x2400 W into 2 Ωat clip level with twochannels drivenu Compact design, 2 U high(88 mm)u Low weightu MLS™ switches for each channeloffers power matching intodifferent loads without increasedpower lossesu Electronically balancedinputsu LED indicators showoutput voltage andheadroomu Output cooled by Intercooler®u Two proportional speed fansu Independent protection circuitryu Short circuit protectionmanages long-term short-circuitoperationsu DC protectionu Clip limiteru VHF protectionu AFS™-limiterThe LAB 4000 is a compact (2 unithigh) light-weight (10 kg) poweramplifier designed for high qualitytouring sound systems and fixedinstallations.The chassis is made of 2 mm blackanodised aluminium, with a 4 mmthick front panel. The switch-modepower supply is placed just behind thefront panel to ensure noise freeoperation. Both the power supply andthe two output channels are cooled bytwo proportional speed fans withairflow from front to back.The switch-mode power supply isthe modern solution of the weight andsize problem. With switch technologyoperating at a high frequency, it ispossible to use ferrite transformersinstead of heavy iron transformers andlarge electrolytic capacitors.Switch-mode technology has beenapplied in power supplies in TV-setsduring the latest 30 years. But in theLAB 4000 the power capacitivity is 20times larger.We have designed the LAB 4000 toobtain the same characteristics as aconventional power supply. Thanks tothe switch-mode power supply it iseasy to get the DC-rail voltagestabilised. This is made by controllingthe magnetic energy in the ferritetransformer with a pulse widthprocessor and magnetic “Flux Sense”windings.The LAB 4000 has an upgradedversion of the well known switch modeoutput stage from the LAB 2000. Thepower transistors are cooled by a solidcopper cooler, called Intercooler(r),originally designed for our LAB 1300power amplifier. Lab.gruppen’s speciallydesigned thermal feedback circuitprotects against thermal breakdown.Short circuit protection;The LAB 4000 is completely short-circuit protected -even in reactive loads.The LAB 4000 is equipped withLab.gruppen’s specially designed short-circuit protection, which permits veryhigh peak-currents,, but still holds thetransistors within the so-called “SafeOperation Area” at the presentoperating voltage. This makes it possibleto run loudspeakers with impedancevariations, which are considerably lowerthan the lowest permitted impedance ofthe power amplifier.Six more protection circuits, whichare separate for each channel, protectthe LAB 4000 and the loudspeakers:DC protection; There are two types ofD.C. protection; Fuses on the supplybranches of each channel (this is anIEC 65 requirement) and a Crowbarbar protection that shorts the output.Thermal protection; Protects theamplifier from over heating andcausing damage to the output stages.The indicators come on before thesignal is muted.Clip limiter; Prevents severely clippedwaveforms from reaching the loudspeakers, but maintains full peak power.As a by product, when the amplifiercomes out of a protect condition, theoutput level has a slow rise time. Theeffect is like turning the gain up slowly.VHF(Very high frequency)protection; Protects the loudspeakeragainst non-musical signals outside theaudible area.AC protection; shuts down the outputsif the line voltage is outside theoperating voltage of the LAB 4000.AFStm-limiter; Adaptive Fuse Saver,limits the mains current to a safe levelaccording to the time lag of an 16ampere slow blow fuse.All electronics are mounted on fourmodules. The modules are easilyaccessible for replacement or repair, etc.

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