Resolution Series 411-MKII Precision Power AmplifierrMusic reproduction to dream ofrrProprietary discrete circuitry using specialcurve-tracer analysed and hand selectedsemiconductorsOutputs drive any speaker load perfectlyeven very low impedance or highcapacitance transducersrUnique dynamic damping of speakersrProprietary enhanced Class A circuitryproviding unmatched musicalityrPrecision low noise level controls avoidchange in tonal characteristics whenadjusting the levelrLowest-loss FORCEPLUG 200 outputconnectors.rPeak output current is not limitedrMechanical resonance eliminationrInternal transformer employs highefficiency shielding. Special techniquesprevent stray fieldsrLowest impedance power supplyrHand-selected and perfectly matchedcomponents of DIN, IEC & MIL standardrHandcrafted in Switzerland to highestperformance standardsrSuperb balanced discrete Class A inputstage.Unbalanced and pseudo-balanced signalsare automatically balanced right at inputrTremendous headroom and reservesrSuperb rejection of noise, hum or interferencethanks to perfectly balanced inputs(interference rejection is 100-1000 timesbetter than other so-called "balanced"equipment)rMulti-protection systems for amplifier andspeakers trigger the output and resetautomatically when the error disappears.rNo signal compression, limiting nor anyother negative influence on the audio signal is possible. The protection circuits aretotally separate from all audio stages.r5000V mains transient suppression
It is with great joy that FM ACOUSTICS announces the "MK-II" version of the FM 411.The original winner of the coveted "Component Of The Year" award, the FM 411 was somewhatexpected to find admirers but who would have thought that it would stay such a success over its 12years of continuous production.Perfected so carefully that it never required a single modification or correction in all these years, itprovides an unmatched price/performance ratio.Recently, new parts have become available that - together with advanced insights from continuousresearch - allow the first amelioration since 1995. With such a background, the refinements can ofcourse not be "tremendous". They result in some smaller modifications but also some more substantialimprovements - as described on the following pages.The new HR modules are used on the inputs. They help toachieve an astoundingly high rejection of Common Modesignals (such as interference, hum, noise etc.- which mustbe cancelled out before the amplification stages). Theyrend the FM 411-MKII immune against interferences. ThisCMRR rejection is achieved not with cheap op amps butwith individually fine-tuned discrete Class A circuits guaranteeing the ultimate resolution FM ACOUSTICS productsare esteemed for.Hand selected long-life level controls useconductive plastic tracks rather than theusual carbon or cermet track. In additionto longer lifetime this provides betterresolution and guarantees no noise.Every little detail matters.Superb hand-craftsmanship is evident, evenwhere it is not visible: here the underside ofthe internal chassis.Each connector is hand-pressed and individually inspected before assembly.Outstanding standard of hand-soldering.The massive power supply is helped bylinearized double rectifiers which feature highspeed at the same time as very high currentcapability.2
Light bulb changes are a thing of the past.FM ACOUSTICS' new frontpanel displayprovides a more even light distribution anduses high reliability LED's instead ofincandescent light bulbs.These LED's have a theoretical lifetime inexcess of 100'000 hours (we could notreally test them for that long so let's hopethe manufacturer's specifications arerealistic.).Another small detail: top left the new ultra-bright multiLED bulb now used for the mains power switch display.The cost is 2000% of the good old "long life" light bulb onthe right (which - depending on quality of mains power needed replacement after a while).This new lamp uses dozens of LED's in its housing andcan also be installed in the MKI version upon request.To avoid negative influence from spuriousresonance and guarantee positive coupling the711-MKII employs FM ACOUSTICS uniqueresonance-eliminator supports. These isolate theunit and make the FM 711-MKII immune toparasitic resonances.A number of ameliorations are not visible but help the performance, amongst them: The new FM 411-MKII employs some circuit technology that is pioneered in the FM 1811 and in the FM 115(the winner of the prestigious "Grand Prix"). Total absence of any form of distortion - be it dynamic orstatic - and this even at the lowest signal levels betters other designs by magnitudes. New higher capacity power supply allowing more linearity and even higher output into low impedances An even better suppression of interchannel crosstalk Multiple layout refinements achieve some slight plus some noticeable improvements over the MKI version Superb Common Mode Rejection on input stage guarantees unmatched interference rejection andsignal symmetry New high reliability components Several power supply refinements and more.3
Resolution Series 411 MK II Precision Power AmplifierSPECIFICATIONSThe measurements and specifications below apply to a normal living room environment with amains supply of 10A at 230V or 20A at 115V AC(similar to that available in typical living rooms).These conditions are more realistic than thosewhich are present in a laboratory, where highperformance power supplies can be utilized. Thisalso means that the specifications taken this wayare realistically achievable results in a home environment. In a laboratory environment the resultsmay be even better. This must be kept in mindwhen comparing the specifications below with thoseof other products which are taken in laboratoryenvironments.Specifications are often misused, misunderstood,or utilized only to sell a product instead of indicating its actual performance capabilities. “Typical”specifications will not tell much about the truevalue of a certain component. Only guaranteedminimum data as specified for all FM ACOUSTICSproducts, together with carefully controlled listening tests, will provide accurate information.Please observe these distinctions if you makecomparisons with data sheets of other products.All specifications are guaranteed minimum figuresfor every single FM 411 MK-II that leaves thefactory.Minimum Power Output:per channel, both channels operatingwith music or continuous toneburst:320 Wpeakinto 8 Ohm600 Wpeakinto 4 Ohm1000 W peakinto 2 OhmHum and Noise:Below full power typically:-110 dB(20Hz-20kHz).Minimal unweighted: better than -100 dB160 WRMS300 WRMS500 WRMSInput: Proprietary electronically balanced discreteenhanced class A circuitry, floating ground,non-inverting or inverting mode.Optimal performance with either balancedor unbalanced (single-ended) sources.Unbalanced sources are automaticallybalanced right at the input of the FM 411MK-II.into 8 Ohminto 4 Ohminto 2 Ohm100 hours operation using continuoussinewave in the audio-band at lowestdistortion (per channel):RMS135 W210 WRMS280 WRMSMax. Output Voltage:Input Sensitivity:1,6 V RMS for full outputinto 8 Ohminto 4 Ohminto 2 OhmInput Impedance:At all level settings from balanced andunbalanced sources:40 kOhm110 V pp.Input Stage Common Mode Rejection:100 dB typically, better than 90 dB at 50Hz, even better at other frequencies.Max. Output Current:Unlimited repetitive peak output current.More than 20 A continuous per channel.No output or DC fuses, absolutely no formof current-, voltage- or any other kind oflimiting.Distortion:Maximum Input Level: 20 dBm (7,75 VRMS)Load Impedance:No minimum impedance. Designed for 1Ohm to 10’000 Ohm systems. Can driveany speaker impedance (even below 1Ohm) with dynamic (music) signals withoutany limiting, compression or other negativeeffects on the audio signal.Despite this, the amplifier is fully protectedagainst short circuits, open circuits andother adverse conditions via uniqueonboard circuitry that continuously surveysall important parameters.0,005% THDBandwidth including Input Filter:Less than 3 Hz to 60 kHz;if required, internally settable to anyfrequency between 1 kHz and 60 kHz(Low-Pass) and 1 Hz to 1 kHz (High-Pass).Gain:30.5dB4
Protection:Unique protection systems proprietary toFM ACOUSTICS safeguard against adverse conditions such as short-circuit, HFoscillation, RF interference, DC and - DCoffset, high temperature, damage to theprotection system itself, etc.Open circuit stability protection assuresthat the amplifier remains absolutely stableeven when no load or source is connected.Back Panel:Output connectors:FORCEPLUG 200, proprietary ultra low lossprecision high performance connectors.Continuous current handling 200A, 1200ApkBurn-in Time at Factory:Minimum 100 hours (500 thermal cycles)Vibration Test:Minimum 60 minutes (50’000 vibrationcycles)Chassis Resonance Damping:Special chassis design effectively isolatesall sensitive electronic components frompossible negative influences such asinduced resonance. In addition, mechanicalresonance of panels are damped and thewhole chassis, including cover, plates,transformer mounting, side panels, etc.are all supported in FM ACOUSTICS’ antiresonance technology.Spare Parts Availability:Guaranteed available for a minimum of 10years. Guaranteed ex stock availability:99.8% of all individual parts .Average Life Expectancy:36 years at 25 oC ambient, medium power,10 hours per day, 365 days per yearAC Voltage:100 WRMS600 WRMS1600 WRMS430 mm wide170 mm high450 mm deepDIN 384-4DIN 40040DIN 40046DIN 40050 P 54DIN 41332 TYPE IIADIN 44061DIN 44112DIN 44356DIN 45910 PART 1201DIN 45921-107MIL-R-STD 202 method 101, 103, 106, 204,213, 82MIL-R-22684MIL-R-45204 TYPE 2MIL-R-23285MIL-C-19978 BMIL-VG-95-295MIL-S-23190 R.I.N.A. Nr. 5/206 /85Mains Supply Requirement:No mains voltage drop when supplying:5 A continuous, 25A peak at 230 V10A continuous, 50A peak at 115 V0o C to 40o CAmbient and Operating Humidity:Short-term: 0 to 95%Long-term: 0 to 85%Amplifier works perfectly in high humidityareas but continuous high humidity mayshorten lifetime of certain componentssomewhat."You've never heard it so good!"Back Panel:Input Connectors:Female XLR 3-pin balanced:Non-inverting:Pin 1: groundPin 2: return (cold)Pin 3: signal (hot)Dimensions:IEC 68 55/155/56IEC 68 55/085/21IEC 144/IP 65IEC 40/100/56IEC 115-1IEC 384-9IEC 384-8 IBIEC 68: 2-6IEC 68: 55/085/056IEC 68: 55/200/56Maximum Mains Overvoltage:Short-term, not on switch-on: 180% VnominalLong-term,incl. switch-on: 120% VnominalOperating Temperature:22 kg net / 25 kg packedIEC, DIN and MIL (Military)Standards of components used:115 V or 230 V, 50 - 60 HzPower Consumption:At idle:At 30% power:At full power:Weight:FM ACOUSTICS LTD.Inverting:Pin 1: groundPin 2: signal (hot)Pin 3: return (cold)Gewerbestrasse 16CH-8132 Egg b. ZürichSwitzerlandTelephone: .41/44/725 77 77Facsimile: .41/44/725 77 90S.E.& O. exceptedCopyright: FM ACOUSTICS LTD., February 2012.Due to continuous research, FM ACOUSTICS LTD. reserves the right to change specifications without further notice.\data\dat41125
Resolution Series 411 MK II Precision Power Amplifier SPECIFICATIONS The measurements and specifications below ap-ply to a normal living room environment with a mains supply of 10A at 230V or 20A at 115V AC (similar to that available in typical living rooms). These conditions are more realistic than those which are present in a laboratory .