Linea Research 44M20 4 x 5000w 4 Channel Power Amplifier

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Linea Research 44M20 4 x 5000w 4 Channel Power Amplifier


44M Series Features

  • Four channels of sonically pure Class D amplification
  • Unique, precise, 96kHz digital signal processing
  • Over‐designed switch mode power supply
  • 85V to 240V Auto-sensing PSU
  • 6,000 to 20,000 watts RMS total output
  • Full front panel user interface
  • Ethernet network for system operation and monitoring
  • Analogue, AES3 and optional DanteTM digital network audio
  • Powerful grouping & multi‐layer EQ
  • Fully designed and engineered in house by Linea Research
  • Manufactured in the UK

RMS per channel, all 4 channels driven
Model2 Ohms4 Ohms8 Ohms70/100V

Linea’s 44M Series of four channel amplifiers are optimised for live sound applications. Offering a unique combination of massive power and peerless audio performance integrated with unique DSP, the 44M Series represents an unmatched advancement in amplifier technology.

Sharing the same feature set and form factor as Linea's 48M Series of eight channel amplifiers the 44M Series is available in models that develop between 1,500Watts and 5,000 Watts per channel (up to 10,000 Watts for a bridged pair). Unusually these are not, ‘transient’, ‘burst’ or ‘peak’ power figures, they are the power levels that are delivered by all channels simultaneously even when driven with the same dense program material.

With Linea amplifiers there is no need to ration power between channels, you can use all the power you have paid for all the time. This has been independently verified.

Linea can do this because state of the art components and a finely optimised design results in an amplifier that is between 7% and 10% more efficient than any competitive product. This efficiency gain directly translates in to the generation of about half the wasted energy (heat) which is clearly significant. In addition to reducing energy costs high efficiency results in generous power reserves ensuring that pristine sound quality is maintained even under the most extreme conditions.

Uniquely, each channel can be configured to deliver its maximum power into 2, 4 or 8 Ohms (2 or 4 Ohms for the M20 model), nominal loads as well as 25V, 70V & 100V constant Voltage (CV) lines. This offers designers and integrators unparalleled flexibility and cost effectiveness.

Ethernet is used for remote control and monitoring while a front panel, optimised for use in challenging live environments, allows full local control of all features. Control via Linea’s intuitive Podware PC application provides many convenient and time saving features such as very flexible management of presets, and Overlay grouping of Mutes, Gains, Delays and EQ across an entire system.

The advanced 96kHz DSP is fully integrated into the product and provides an array of unique and genuinely useful features. Because all aspects of the DSP algorithms are designed and hand crafted in house by Linea, they are not available on products from any other manufacturer. For example, LIR linear phase crossover filters which are as easy to use as more conventional filter shapes, and have less latency than FIR filters. Also the powerful VX Limiter suite which sports Peak, RMS and Excursion limiting, as well as multiband limiting for passive 2-way enclosures.

Number of channelsFour
Total power output, all channels driven20,000, 10,000 and 6,000 Watts RMS
Audio inputs4x Analogue, 2x AES3 and 4x DanteTM (factory fitted option)
Digital Signal ProcessingHigh performance DSP processing on all inputs and outputs
Control, monitoring and system status alarmsEthernet network
Volt-free relay and contact closure port
Power-save modesStandby after user defined time, instant wake up on audio
Deep ECO sleep after user defined time, wake up on command
System sleep and wakeupFront panel switch, network command and audio detection

Power Output

Model44 Series M2044 Series M1044 Series M06
Power specificationRMS output power per channel, all channels driven with continuous program material and a nominal ambient temperature of 40degC / 105degF
Crest Factor of 4 (12dB), 2-Ohm nominal load5,000W2,500W1,500W
Crest Factor of 2.8 (9dB), 4-Ohm nominal load3,000W2,500W1,500W
Crest Factor of 2 (6dB), 8-Ohm nominal load1,500W1,500W1,500W
Bridged, per channel pair, 4-Ohm nominal load10,000W5,000W3,000W
100V line (CV) operation, Crest Factor 4 (12dB)5,000W3,000W1,500W
70V line operation, Crest Factor 4 (12dB)3,500W2,500W1,500W
25V line operation, Crest Factor 4 (12dB)1,250W885W685W

Audio Performance

Amplifier topologyLinea Research high performance Class D
Amplifier modulation schemeLow feedback, multiple loop, with feed-forward error correction
Dynamic range
Measured relative to the amplifier output
Analogue input, better than 113dBA typical
AES / DanteTM input, better than 114dBA typical
Gain (with all DSP level controls set to 0dB)32dB
Frequency response, 4 Ohm load<7Hz to >30kHz, 4 Ohms, -2.5dB points
Total harmonic distortion, THD<0.05% typical, 1kHz signal, AES17 filter, 4 Ohm load
Inter-channel crosstalk, worst case combinationbetter than -85dBr at 1kHz and -75dBr at 10kHz
Maximum analogue input level+20dBu
Analogue input sensitivity range for full output0dBu to +20dBu, continuously adjustable
Analogue input and linkInput 20k Ohm, electronically balanced, link directly connected to input
Analogue ground schemeAES48 standard compliant
AES3 inputTransformer isolated with unique active cable equalisation for extended range
AES3 linkActive AES3 signal regeneration. Automatic direct bypass to the AES3 input ensuring the audio signal will still flow even when the amplifier is powered down
AES3 supported sampling rates24kHz to 192kHz (auto locking)

Digital Signal Processing

Resolution40 bit, Linea Research proprietary algorithms
Sample rate96kHz throughout
Physical inputs to DSP drive modules4x analogue, 2x AES & 4x DanteTM inputs can be routed to four DSP drive modules
Drive module input processingInput signal routing, delay, gain, HPF, Phase, Mute
EQ: 2x low shelf, 6x PEQ / band pass and FIR shelving filters
Drive module output processingSource, delay, gain, Phase, Mute, crossover filters, VX limiters
EQ: low shelf, 8x PEQ / band pass and shelving filters
Preset management10 snapshots for device wide setup, 50 presets for loudspeaker settings
Presets can be recalled to sets of outputs or individual outputs as required
Unique high performance processing 
OverlaysTwelve additional independent overlays of EQ, Delay and Gain
Flexible grouping for effective control of many amplifier channels in large systems
Class leading VX limitersSee the ‘speaker protection systems’ section
Hardman crossover filtersBetter out of band rejection than Linkwitz-Riley
LIR crossover filtersLinear Phase without the compromises of FIR filters

Power Supply

Topology (main power supply)Linea Research high performance Series Resonant
Topology (auxiliary and standby supplies)Low quiescent Eco-Flyback
Internally stored energy>600 Joules
Nominal mains input voltage range85V to 240V Power supply automatically detects voltage and configures accordingly
Mains input frequency range47Hz to 63Hz
Mains inrush current (max for <10ms)6A at 115V and 12A at 230V

Protections Systems

Under all circumstances the control and protection systems will endeavour to deliver the maximum power possible for a given set of conditions, applying limiters only in extreme circumstances. Muting will only occur when a dangerous situation is detected, normal operation automatically resuming when the condition clears.
System protectionSpeaker protection
Excessive power supply current or amplifier output currentSustained clipping prevention
Excessive temperature per sub system: PSU, amplifier and DSPDC offset protection
Mains voltage within acceptable limitsExcessive HF energy (VHF) limiter
Internal power rails producing correct output 
Fans operating at correct speedVX audio output limiters
 Vx provides a linear phase virtual crossover and two limiter paths on each output. This unique system delivers effective protection for systems that incorporate passive crossovers.
Power distribution protection systemsVx Limit      Multiband peak limiter, two per output
Mains inrush current limiting for soft start and anti-surgeVx Max       Multiband overshoot limiter, two per output
Mains average current limiting for mains breaker managementX-Max         Driver excursion limiter
Randomised initialisation when remotely powered upT-Max         Driver thermal limiter (long term power limiter)
Monitoring, measurements recorded against timeMonitoring, device statistics and counters
Supply currentNumber of power cycles counted
Supply voltageNumber of mains brownout events counted
Thermal CapacityFan speeds continuously monitored
Each driver currentFan under-speed events counted
Each driver impedanceVarious protection mute events counted
Protection limiting for each outputDriver Impedance continuously monitored
An inbuilt notification system is provided to indicate problems to remote devices either via the network or the Volt-free changeover relay contacts accessible on the rear panel.


CoolingDual vari-speed fans, front to back airflow. Washable, tool less change filter media.
Analogue IN and LINK4x female and 4x male NeutrikTM XLR
AES3 dual channel IN and LINK1x female and 1x male NeutrikTM XLR
Amplifiers output4x Neutrik SpeakonTM NL4 connectors
Mains input connectorNeutrik 32A PowerconTM
Dante Primary and Secondary2x Shielded RJ45
Relay output & contact closure inputsPhoenixTM pluggable terminal block (supplied)
Front panel display (backlit)Graphical, high contrast, daylight visible
Front panel encodersTwo, indented, velocity sensitive
Front panel push buttonsLarge, tactile, illuminated
LED indicatorsBright, easily differentiated
EnclosureStandard 19” 2U (88mm), 357mm (14”) deep  with handles and optional rear support
Net Weight12.5kg (27.5 pounds).