Lab Gruppen C 28:4 - 700W 4-Channel at 4-Ohm 70V/100V Power Amplifier with Terminal Outputs and NomadLink Network Monitoring in Black Finish

The Lab Gruppen C 28:4 is a high-performance, 4-channel power amplifier designed to meet the demanding needs of professional sound systems, whether installed or on tour. Its superior sound quality, built on Lab Gruppen's renowned Class TD technology, offers a tight and transparent sound signature that has earned the praise of engineers and sound rental companies worldwide. At the core of the C 28:4's performance is its use of Class TD, a patented technology that provides the efficiency of Class D amplifiers while maintaining the sonic quality of Class A/B stages. This ensures both exceptional power output and high-fidelity sound reproduction.

The amplifier features a Regulated Switch Mode Power Supply (R.SMPS) that guarantees stable operation even with wide voltage fluctuations, contributing to the overall efficiency and power density of the unit. With up to 2800 watts of total output, it delivers 700 watts per channel at 4 ohms, making it suitable for a wide range of applications, from powerful subwoofers to smaller 100V loudspeakers. Each channel is equipped with an individually configurable Voltage Peak Limiter (VPL) to optimize performance for different loudspeakers and ensure maximum headroom. The C 28:4 is engineered for reliability, with a comprehensive set of protection features that monitor voltage, current, temperature, and more, ensuring consistent performance and minimizing downtime.

Designed with space efficiency in mind, the C 28:4 features a compact 2U rackmount chassis, making it ideal for installations where rack space is limited. The amplifier's Intercooler copper cooling system dissipates heat efficiently, enabling sustained high-power output without compromising on thermal management. The C 28:4 is also fully equipped with NomadLink network monitoring, allowing for remote control of key amplifier functions such as channel mutes and power on/off through the DeviceControl software. This network functionality ensures seamless integration into complex audio setups, with real-time monitoring and control capabilities for all channels.

Designed for easy integration and operation, the C 28:4 offers balanced analog audio inputs and secure barrier strip 2-pole screw terminal outputs, providing flexibility for different system configurations. The amplifier is equipped with an intelligent fan system that adjusts its speed based on temperature, ensuring quiet operation while maintaining optimal cooling. Additionally, its front-panel indicators provide clear feedback on the status of each channel, including signal presence, limiter status, and fault conditions, making it easy to monitor and troubleshoot during live events or installations.

Features

• 4-channel amplifier with up to 700W output per channel
• Class TD technology for efficient power with high-fidelity sound
• Regulated Switch Mode Power Supply (R.SMPS) for stable operation
• Individually configurable Voltage Peak Limiters (VPL) for optimized performance
• NomadLink network support for remote control and monitoring via DeviceControl software
• Comprehensive protection features including voltage, current, temperature, and fault warnings
• Intercooler copper cooling system for efficient heat dissipation
• Compact 2U rackmount chassis for space-efficient installation
• Balanced analog audio inputs with barrier strip 2-pole screw terminal outputs
• Intelligent fan system for temperature-controlled cooling
• Front-panel indicators for clear operational status feedback
• CE, ANSI/UL 60065, CSA C22.2 NO. 60065, and FCC approvals

Specifications

General

• Number of channels: 4
• Peak total output all channels driven: 2800 W
• Peak output voltage per channel: 141 V
• Max. output current per channel: 12 Arms

Maximum Output Power

• Per channel (all channels driven): 600W @ 16 Ohm, 700W @ 8 Ohm, 700W @ 4 Ohm, 300W @ 2 Ohm, 700W (70Vrms/100V peak) @ Hi-Z
• Bridged per channel: 1400W @ 16 Ohm, 1200W @ 8 Ohm, 600W @ 4 Ohm, 1400W (140Vrms/200V peak) @ Hi-Z

Performance with Gain (35 dB and VPL: 100V)

• THD 20 Hz - 20 kHz for 1 W: <0.1%
• THD at 1 kHz and 1 dB below clipping: <0.05%
• Signal To Noise Ratio: >112 dBA
• Channel separation (Crosstalk) at 1 kHz: >70 dB
• Frequency response (1 W into 8 ohms) +0/-3 dB: 6.8 Hz - 34.2 kHz
• Input impedance: 20 kOhm
• Input Common Mode Rejection, CMR: 50 dB
• Output impedance @ 100 Hz: 30 mOhm

Voltage Peak Limiter (VPL), Maximum Peak Output

• VPL, selectable per channel: 141, 118, 100, 85, 71, 59, 50, 42V
• VPL, when bridged: 282, 236, 200, 170, 142, 118, 100, 84V
• Voltage Peak Limiter mode (per channel): Hard/Soft

Gain and Level

• Amplifier gain selectable (all channels): 23, 26, 29, 32, 35, 38, 41, 44 dB
• Default gain: 35 dB
• Level adjustment (per channel): Front-panel potentiometer, 21 position detented from -inf to 0 dB, hidden behind security panel/dust filter grille

Connectors and Switches

• Input connectors (per channel): 3-pin Phoenix, electronically balanced
• Output connectors (per channel): Barrier strip 2-pole screw terminals
• Output bridge mode: A+B and/or C+D, inputs A and C are input source
• NomadLink network: On board, 2 x RJ45 connectors
• 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

Front-Panel Indicators

• Common: NomadLink Network; Power Average Limiter (PAL) 2); Power on
• Per channel: Signal present / High-impedance; -10 dB and -4 dB output signal; Voltage Peak Limiter (VPL); Current Peak Limiter (CPL); Very High Frequency (VHF); High Temperature; Fault; Mute

Power

• Operating voltage, 230V / 115V nominal: 130-265V / 65-135V
• Minimum power-up voltage, 230V/115V: 171V / 85V
• Power Average Limiter (PAL): Yes
• Soft start / Inrush Current Draw: Yes/max. 5 A
• Mains connector: 230V CE: 16 A, CEE7; 115V ETL: 20A/NEMA 5-20P

Physical

• Dimensions (WHD): 19 x 3.46 x 13.5 inches
• Weight: 26.4 lbs
• Finish: Black painted steel chassis with gray painted steel front
• Approvals: CE, ANSI/UL 60065 (ETL), CSA C22.2 NO. 60065, FCC