Linea Research 44C20 Power Amplifier

• 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
• Tamperproof front panel
• Ethernet network for system operation and monitoring
• Analogue, AES3 and optional Dante™ / AES67 digital network audio
• Powerful grouping & multi‐layer EQ
• Accepts 48kHz and 96kHz FIR files via System Engineer (certain models)
• Fully designed and engineered in house by Linea Research
• Manufactured in the UK

General

• Number of output channels:  Four
• Total power output, all channels driven:  20,000, 10,000 and 6,000 Watts RMS
• Audio inputs:  4x Analogue, 2x AES3 and 4x Dante™ / AES67 (factory fitted option)
• Digital Signal Processing:  High performance 96kHz DSP on all inputs and outputs
• Control, monitoring and system status alarms:  
  • Ethernet network, RS232 & RS485
  • Volt-free relay and contact closure ports. Heartbeat system health output
• Power-save modes:
  • Standby after user defined time with fast wake up on audio
  • Deep ECO sleep after user defined time with wake up on command
• System standby and wakeup:  Network command, audio detection & contact closure

Power Output

• Model:  44 series C20
• Power specification:  RMS output power per channel, all channels driven with continuous program material and a nominal ambient temperature of 40ºC / 105ºF
• Crest Factor of 4 (12dB), 2-Ohm nominal load:  5,000W
• Crest Factor of 2.8 (9dB), 4-Ohm nominal load:  3,000W
• Crest Factor of 2 (6dB), 8-Ohm nominal load:  1,500W
• Bridged, per channel pair, 4 Ohm load:  10,000W
• 25V line (CV) operation, Crest Factor 4 (12dB):  1250W
• 70V line (CV) operation, Crest Factor 4 (12dB):  3500W
• 100V line (CV) operation, Crest Factor 4 (12dB):  5,000W

Audio Performance

• Amplifier topology:  Linea Research high performance Class D
• Amplifier modulation scheme: 
• Low feedback, multiple loop, with feed-forward error correction
• Dynamic range (Measured relative to the amplifier output):  
  • Analogue input, better than 113dBA typical
  • AES / Dante™ input, better than 114dBA typical
• Gain (with all the 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 combination:  better than -85dBr at 1kHz and -75dBr at 10kHz
• Slew rate:  >60V per microsecond typical
• Damping factor (Ref 8 Ohms):  >800 at amplifier output (see Linea’s “Damping factor debunked” white paper)
• Maximum analogue input level:  +20dBu
• Analogue input sensitivity range for full output:  0dBu to +20dBu, continuously adjustable
• Analogue input (four channels):  Input 20k Ohm, electronically balanced, link directly connected to input
• Analogue ground scheme:  AES48 standard compliant
• AES3 input (two audio channels):  Transformer isolated with unique active cable equalisation for extended range
• AES3 link (two audio channels):  Active 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 rates:  24kHz to 192kHz (auto locking)

Digital Signal Processing

• Resolution:  40 bit, Linea Research proprietary algorithms
• Sample rate:  96kHz throughout
• Physical inputs to DSP drive modules:  4x analogue, 2x AES & 4x Dante™ inputs can be routed to four DSP drive modules
• Drive module input processing:  
  • Input signal routing, delay, gain, HPF, Phase, Mute
  • EQ: 2x low shelf, 6x PEQ / band pass and FIR shelving filters
• Drive module output processing:  
  • Source, delay, gain, Phase, Mute, crossover filters, VX limiters
  • EQ: low shelf, 8x PEQ / band pass and shelving filters
• Preset management:
  • 10 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

• Overlays:  
  • Twelve additional independent overlays of EQ, Delay and Gain
  • Flexible grouping for effective control of many amplifier channels in large systems
• Class leading VX limiters:  See the ‘speaker protection systems’ section
• Hardman crossover filters:  Better out of band rejection than Linkwitz-Riley
• LIR crossover filters:  Unique Linear Phase alignments 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 range:  85V to 240V, Power supply automatically detects voltage and configures accordingly
• Mains input frequency range:  47Hz to 63Hz
• Mains inrush current (max for <10ms):  6A at 115V, 12A at 230V

Physical

• Cooling:  Dual vari-speed fans, front to back airflow. Washable, tool-less change filter media.
• Analogue IN and LINK:  Phoenix™ pluggable terminal block (mating plugsupplied)
• AES3 IN and LINK:  Phoenix™ pluggable terminal block (mating plug supplied)
• Amplifier output:  Neutrik Speakon™ NL4 connectors
• Mains input connector:  Neutrik 32A Powercon™
• Dante Primary and Secondary:  2x Shielded RJ45
• Ethernet network:  Shielded RJ45
• RS232 and RS485:  Phoenix™ pluggable terminal block (mating plug supplied)
• Relay, ‘heatbeat’ outputs:  Phoenix™ pluggable terminal block (mating plug supplied)
• Contact closure inputs:  Phoenix™ pluggable terminal block (mating plug supplied)
• Front panel LED indicators:  Per channel - Input level, output level & status
• Enclosure, all models:  Standard 19” 2U (88mm), 357mm (14”) deep with handles and optional rear support
• Net Weight:  12.5kg (27.5 pounds).