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The FEUR FU-A4K is a audio product with frequency response 20Hz - 20kHz, input impedance 20k Ohms, power consumption 500W / 25A Peak. It is built for working audio professionals.
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.
At a Glance
| Description | Tour Grade 2 Channel |
| Frequency Response | 20Hz - 20kHz |
| Signal to Noise | 93dB |
| Input Sensitivity | 0.7V |
| THD at 1 kHz | < 0.5% |
| Input Impedance | 20k Ohms |
| Input Connectors | 3 pin XLR |
| Output Connectors | 2 Pin Speakon |
Where Is the FU-A4K Used?
FEUR lists these as the professional applications for this model:
- 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).
What Comes in the Box?
- 1× K Series power amplifier (model per order)
- IEC power cable
- Rack-mount hardware
- User manual
Specifications
| Description | Tour Grade 2 Channel |
| Frequency Response | 20Hz - 20kHz |
| Signal to Noise | 93dB |
| Input Sensitivity | 0.7V |
| THD at 1 kHz | < 0.5% |
| Input Impedance | 20k Ohms |
| Input Connectors | 3 pin XLR |
| Output Connectors | 2 Pin Speakon |
| Power Consumption | 500W / 25A Peak |
| Rating: 4 Ω Stereo | 2000W / 63V |
| Rating: 8 Ω Stereo | 1700W / 75V |
| Rating: 4 Ω Bridge | 4000W / 100V |
| Rating: 8 Ω Bridge | 2500W / 123V |
Certifications and Industry Recognition
| NAMM Member | Member of the National Association of Music Merchants, the global trade association for the music products industry. |
| USA Verified | Manufactured and quality checked under FEUR's USA verification standards. |
| CE Marking | Compliant with European Union safety, health and environmental protection directives. |
| RoHS Compliant | Free from restricted hazardous substances under the RoHS directive. |
Why FEUR?
FEUR was founded in Germany by a team of engineers and sound specialists who set out to make professional audio equipment that performs at a high level and stays within reach of the people who actually use it every week. Where most of the industry aims either at high-end studio work or at the bottom of the market, FEUR builds for the working middle: independent artists, houses of worship, schools, mobile operators and installed systems that need gear to show up and work every week.
Frequently Asked Questions
Is this a genuine FEUR product?
Yes. Victory is a veteran owned dealer in Miami and units ship new in original packaging.
Does the FU-A4K come with a warranty?
Yes. It carries the FEUR manufacturer warranty against defects in materials and workmanship. Keep your invoice and call us at 844-687-4208 if you ever need service.
How does the K Series differ from the TRA Series?
The K Series uses a switching power supply optimized for tour-grade portability and high instantaneous peak power delivery. The TRA Series uses a toroidal transformer, offering superior stability in permanent installations and regions with fluctuating mains voltage.
Is the FU-A10K suitable for multi-zone or bi-amp applications?
Yes. As a 4-channel amplifier, the FU-A10K is well-suited for distributed audio systems, bi-amping active speaker arrays, or driving multiple speaker zones from a single rack unit.
What speaker systems benefit most from the FU-A14K?
The FU-A14K is ideal for driving large passive subwoofer stacks and high-power main PA arrays at major concerts and festival productions.
Why Victory Musical Instruments?
Victory Musical Instruments is a veteran owned pro audio and musical instrument dealer based in Miami, Florida. We are working musicians and certified audio engineers, not a fulfillment warehouse, so when you call us about a speaker or an amplifier you are talking to someone who has actually run one at a gig. Every unit ships new in original manufacturer packaging. Call us at 844-687-4208 and we will help you spec the right thing the first time.