FU-A4K professional Class D power amplifier – Overview

The FEUR FU-A4K amplifier represents the perfect entry into our K Series of professional Class D amplification. With 4,000 watts RMS per channel into 4Ω (6,000W into 2Ω), this two-channel amplifier combines energy efficiency exceeding 90% with exceptional sound quality for mid-sized professional audio systems.

Specifically designed for stage monitors, corporate PA systems, and small venues, the FU-A4K utilizes state-of-the-art PWM modulation technology with switching frequency exceeding 100kHz. Its switch-mode power supply architecture with active PFC guarantees stable operation on any global electrical network, while multiple protection systems (short circuit, DC offset, thermal) ensure maximum reliability.

FU-A4K | 4,000W RMS per channel at 4Ω | High-efficiency 2-channel amp for monitors, PA and subs

The FU-A4K professional power amplifier brings 4,000 watts per channel at 4Ω into a compact, high-efficiency Class D design tailored for mid-sized professional systems. Its 2-channel architecture with 6,000W available at 2Ω and up to 4,000W in bridge mode gives you flexible power delivery for stage monitors, corporate PA, small theaters and church installations. With more than 90% energy efficiency, it delivers serious output while keeping heat and power consumption under control.

Advanced PWM modulation with switching frequency above 100 kHz and a switch-mode power supply with active PFC ensure stable performance on global power grids, from touring racks to permanent installs. Multiple protection layers—short circuit, DC, thermal—protect your investment and keep shows running even under demanding conditions. Whether driving 2×15″ wedges, compact arrays of 8″ modules or dual 15″/single 18″ subwoofers, the FU-A4K maintains clarity and punch at any level.

For rental companies, integrators and venues, the FU-A4K is a smart entry point into the K Series ecosystem. It offers enough headroom for audiences of 150–250 people in corporate events and community spaces, while remaining light and efficient enough for everyday use. If you need a reliable, professional-class amplifier that bridges touring-grade performance and installation practicality, the FU-A4K is designed to be your go-to workhorse.

External Resources and Technical Information:

• Professional Audio Line Array Design Principles
• Speaker Rigging Safety Standards
• Acoustical Society of America – Sound Reinforcement Resources

Professional Applications

• Stage Monitors: Powering up to 2×15″ wedges with clean headroom for vocal and instrument mixes.
• Corporate PA Systems: Ideal for events of 150–250 people in hotels, conference rooms and auditoriums.
• Houses of Worship & Community Centers: Reliable main or monitor amplification for church and community spaces.
• Small Theater Reinforcement: Driving main arrays or fills in intimate performance venues.
• Subwoofer Duty: Suitable for dual 15″ or single 18″ subs and compact 8″ arrays (4–6 modules).

FEUR builds the FU-A4K as a professional Class D platform that balances power, efficiency and reliability for real-world touring and installation needs. High-efficiency architecture keeps operating costs and rack temperatures low, while robust protection ensures consistent performance event after event. For contractors and rental houses, this means fewer failures, easier logistics and a dependable base for mid-sized systems.

Why Choose FEUR for your FU-A4K?

FU-A4K professional Class D power amplifier for mid-sized systems

Within FEUR’s ecosystem, the FU-A4K pairs naturally with stage monitors, compact arrays and subwoofers, simplifying design and deployment. Integrators gain a flexible amp that can serve as main, monitor or subwoofer power without changing hardware families, streamlining inventory and service. Choosing FEUR for your FU-A4K means partnering with a brand focused on practical, field-proven amplification solutions.

Within FEUR’s ecosystem, the FU-A4K pairs naturally with stage monitors, compact arrays and subwoofers, simplifying design and deployment. Integrators gain a flexible amp that can serve as main, monitor or subwoofer power without changing hardware families, streamlining inventory and service. Choosing FEUR for your FU-A4K means partnering with a brand focused on practical, field-proven amplification solutions.