Diagnosis: Bias is wrong, or output transistors are desoldered.
Schematic Solution:
Disclaimer: Always respect copyright laws. Schematics are often provided for repair purposes only.
If you can share a photo of the actual RX 4000 board or note whether it’s car audio or PA mains powered, I can give more precise component IDs and test points.
The NX Audio RX 4000 is a professional 2-channel Class AB power amplifier known for its durability in adverse power conditions. While a full manufacturer-issued circuit diagram is typically proprietary, technical documentation describes its architecture as featuring bipolar junction transistors and power MOSFETs designed for high stability at 2-ohm loads. Circuit & Design Features nx audio rx 4000 circuit diagram
Architecture: Proven Class AB circuit design, which offers "zero noise" operation.
Thermal Management: Utilizes 4 individual cooling fans to maintain thermal stability during high-output use.
Specialized Protection Circuitry: Includes comprehensive systems for: Super Short Circuit and Overload protection. DC Fault and Soft Start. Thermal Overload and Back-EMF protection.
Integrated Crossover: Built-in 160Hz Hi-Pass and Low-Pass filters, allowing the unit to function as a subwoofer or mid-highs amplifier without external hardware. Diagnosis: Bias is wrong, or output transistors are
Signal Monitoring: Front-panel indicators for Peak, Level, and Signal status. Technical Specifications Specification Output Power (2Ω) 1550W + 1550W RMS Output Power (4Ω) 1150W + 1150W RMS Bridge Mono (8Ω) 2000W - 2400W Damping Factor S/N Ratio Frequency Response 20Hz – 20kHz Operating Modes Stereo, Bridge, Parallel
The amplifier is specifically marketed for its ability to handle low voltage and uneven frequencies, making it a "workhorse" for live sound in environments with unstable power grids. NX Audio RX 4000 Circuit Diagram | PDF - Scribd
Since specific proprietary schematics for brands like NX Audio are rarely released to the public in high resolution, this text serves as a technical reference guide. It explains the architecture, signal flow, and typical component layout you will find inside the RX 4000 amplifier, which will assist you in reading the physical board or troubleshooting issues.
The NX Audio RX 4000 is a high-power professional PA amplifier. Its circuit design follows the standard Class-AB topology common to robust audio amplifiers of this class, designed to handle low-impedance loads (4Ω–8Ω) and 100V/70V constant voltage systems. Disclaimer: Always respect copyright laws
Diagnosis: Dead short in the switching power supply.
Schematic Solution:
| Test point | Expected (AC mains version) | Car version (SMPS) | |--------------------------------|-----------------------------|--------------------| | Main rails (after rectifier) | ±45V to ±70V | ±35V to ±55V | | Op-amp supply pins (e.g., NE5532 pin 4 & 8) | -15V / +15V | -15V / +15V | | Output transistor bias (Vbe) | 0.5–0.6V | same | | Speaker terminal DC offset | < ±50mV | < ±50mV |