Lab Gruppen C5-4X
4-Channel C-Series Power Amplifier


The Lab.Gruppen C 5:4X is a versatile four-channel amplifier, delivering 4 × 125 W at 4 ohms, 8 ohms, 16 ohms or 70 Vrms; 250 W at 100 Vrms is available in bridge mode.

The C 5:4X is uniquely suited for a range of installed applications with its relatively lower power output requirements, compact & lightweight 2U chassis, and a channel density and installation flexibility that are greater than those found in Lab.Gruppen's C Series amps.  Because the unique benefits of Class TD® are more applicable at higher power levels, the C5:4X employs a cost-efficient proprietary Class D output design.  Other features include a universal power supply, selectable 35 Hz high-pass filter, and built-in GPIO control facilities.

This amplifier is capable of adapting to a wide variety of demanding load conditions.  Each channel has an individually configurable Voltage Peak Limiter (VPL™), which allows the output to be optimized for any loudspeaker load – whether a single large subwoofer or a series of small 70 V loudspeakers (100 V in bridge mode).  VPL works in combination with adjustable input gain (adjustable in 2-channel blocks) to achieve maximum headroom regardless of input levels or output impedances.  Additionally a 35 Hz high pass filter may be inserted in each 2-channel section.

Every C Series amplifier is ready for the NomadLink® network right out of the box. With NomadLink, key amplifier parameters are displayed via DeviceControl software, and remote control of channel mutes and power on/off is under network control.

GPIO facilities – provided exclusively on the C5:4X allows access to key amplifier functions such as power on/off and fault reporting.

Lab.Gruppen C5-4x Amplifier Features:

  • Four channels in 2U: High channel density reduces space requirements and installation time
  • High continuous output power of 125 W per channel at 70 V, 4 ohms, 8 ohms,and 16 ohms*
    * Maximum continuous output power, all 8 channels driven, VPLset at 100 V and Gain set at 32 dB.
  • All channels individually selectable for lo-Z or hi-Z: Loudspeakers (2 ohm– 16 ohm) and distributed systems can be connected to the same unit
  • Bridged operation: Channel pairs bridgeable for increased output or fordriving 100 V systems
  • Patented output stage based on Class D topology
  • High efficiency for lower thermal stress
  • General Purpose Input/Output (GPIO): Compatible with third-party control systems
  • NomadLink® network ready
  • Universal Power Factor Corrected PSU with IEC inlet
  • Efficient cooling: Dual variable speed, intelligent fans and parallel airflow over output devices provide uniform cooling
  • Comprehensive circuit protection and fault indication
  • Phoenix-style input connectors and barrier strip output connectors

Lab.Gruppen C5-4x Amplifier Specifications:

  • Number of channels: 4
  • Peak total output all channels driven: 500 W
  • Peak output voltage per channel: 100 V / 70 Vrms
  • Max. output current per channel: 5.6 Arms
  • Performance with Gain: 32 dB and VPL: 100 V
  • THD 20 Hz - 20 kHz for 1 W:<0.1%
  • THD at 1 kHz and 1 dB below clipping: <0.05%
  • Signal To NoiseRatio: >112 dBA
  • Channel separation (Crosstalk) at 1 kHz: >70dB
  • Frequency response (1 W into 8 ohms) +0/-3 dB: 2.3 Hz - 56 kHz
  • Inputimpedance: 20 kOhm
  • Input Common Mode Rejection, CMR: 50 dB
  • Output impedance @ 100 Hz: 48 mOhm
  • Voltage Peak Limiter (VPL), max. peak output
  • VPL, selectable per ch.*:100, 63, 45, 32 V
  • VPL, selectable when bridged*^: 200, 126, 90, 64V
  • Voltage Peak Limiter mode (per ch.): Hard / Soft
    *For sine waves, peakvoltage output values translate to Vrms with the formula V/1.41=
    ^Automatic -6 dB gain compensation when bridging channels. Ch.s A+Band/or C+D, can be bridged individually
  • Gain and Level
  • Amplifier gain selectable (all channels)^ – rear-panel switches: 29, 32, 35, 38 dB
    ^Automatic -6 dB gain compensation when bridging channels. Ch.s A+B and/or C+D, can be bridged individually
  • Defaultgain: 32 dB
  • Level adjustment (per ch.): Front-panel potentiometer, 21position detented from -inf to 0 dB, hidden behind security panel/dust filter grille
  • Input connectors (per ch.): 3-pin Phoenix, electronically balanced
  • Output connectors (per ch.): Barrier strip 2-pole screw terminals
  • Output bridge mode: A+B and/or C+D, inputs A and C are signal source
  • High pass filter: Fixed at 35 Hz, switchable per channel
  • NomadLink® network: On board, 2 x RJ45 connectors, IN and OUT
  • Intelligent fans (on/off): Yes, depending on presence of output signal
  • Power on/off and Remote enable on/off: Individual switches on front-panel
  • Cooling: Two fans, front-to-rear airflow, temperature controlled speed
  • General Purpose Outputs (GPO): Contact Closure types, 2-pole Phoenix
  • General Purpose Inputs (GPI): Contact Closure types, 2-pole Phoenix
  • Front-panel indicators:
  • Common: NomadLink® Network; Power AverageLimiter (PAL) 2); Power on
  • Per channel:
    • Signal present / High-impedance;Voltage Peak Limiter (VPL); Current Peak Limiter (CPL):
    • Very High Frequency(VHF); High temperature; Fault; Mute
  • Operating voltage, 230 V / 115 V nominal: 100-240 V
  • Minimum power-up voltage, 230 V / 115 V: 80 V
  • Power Average Limiter (PAL)**: Yes
    PAL can reduce the maximum outputpower to keep the power supply operating safely, and/or to prevent excessivecurrent draw tripping the mains breaker. Refer to Operation Manual.
  • Soft start / Inrush current draw: Yes / max. 5 A
  • Mains connector: IEC Inlet / NEMA 5-15P
  • Dimensions: 19" W x 2 RU H x 13.5" D (483 x 88 x 343 mm)
  • Weight: 18.75 lbs. (8.5 kg)
  • Finish: Black painted steel chassis with gray painted steel front
  • Approvals: CE, ANSI/UL 60065 (ETL), CSA C22.2 NO. 60065, FCC
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