Helix H 400X (H – Series)

HELIX H 400X

Refined Power – Audiophile Sound in a Compact Design

The HELIX H 400X brings together the best of both amplifier technologies—ultra-fast MOSFET Class A driver circuits for precision and robust bipolar output transistors for power and warmth. This uniquely engineered 4-channel amplifier is compact in size but colossal in capability, designed for unmatched stability, refined sonic performance, and total reliability. Its intelligent processor-controlled architecture ensures stable and consistent operation even under extreme loads or environmental conditions.

Unparalleled Sound Quality with Bipolar Output Technology

Unlike typical amplifiers, the H 400X employs bipolar output transistor technology to deliver a natural, warm, and harmonically rich sound that audiophiles crave. Combined with high-speed Class A MOSFET drivers, the amplifier achieves exceptionally low THD (Total Harmonic Distortion) and high-resolution clarity, offering a dynamic and immersive listening experience.

Compact Yet Powerful Form Factor

Housed in a remarkably shallow heatsink, the HELIX H 400X is ideal for space-constrained installations without compromising on performance. The amplifier’s transparent top cover not only reveals its meticulously designed circuitry but also showcases its premium craftsmanship, proudly Made in Germany.

Advanced Protection and Control

The built-in processor-controlled safety system protects the amplifier from a wide range of conditions including overheating, over-/undervoltage, speaker short-circuiting, low impedance, and incorrect wiring. This ensures long-term reliability and safe operation in any environment, even under high-performance demands.

Fully Active Crossover and Signal Flexibility

With a fully active crossover section featuring highpass, lowpass, and bandpass filters, the H 400X is ready for seamless system integration and precise frequency tuning. The Input Mode switch allows for flexible routing of signal inputs, while RMI (Realmixed Input) technology intelligently generates an optimized mono-summed signal from stereo inputs, perfect for subwoofer or center channel applications.

Premium Build and German Engineering

Every HELIX H 400X is manufactured in Germany using only hand-selected premium-grade components, ensuring exceptional quality control and audio performance. The amplifier features 24-carat gold-plated solid connection terminals compatible with 25 mm² / gauge 4 wiring, providing a secure and efficient power and speaker connection.

Special Features

Hybrid Amplifier Architecture

Combining MOSFET Class A drivers with bipolar output stages, the H 400X achieves the best balance of speed, fidelity, and warmth—a rare feat in automotive amplifier design.

Processor-Controlled Reliability

Smart protection systems ensure operational safety across a variety of failure conditions, maintaining performance without thermal or voltage-induced shutdowns.

RMI (Real Mixed Input)

Automatically sums left and right channel signals into a clean, optimized mono signal, ideal for system setups requiring dedicated mono output.

High-Fidelity Audio in Compact Form

The shallow chassis design makes it easy to install in vehicles with tight space constraints while still delivering the full-bodied, high-performance sound expected from HELIX.

Features Summary

• 4-channel hybrid amplifier with Class A driver stage and bipolar output transistors
• Fastest MOSFET drivers for ultra-low THD
• Natural and warm sound signature with rich harmonics
• Processor-controlled protection for thermal, voltage, impedance, and wiring safety
• Fully active crossover with highpass, lowpass, and bandpass filters
• Input Mode switch for flexible signal routing
• Realmixed Input (RMI) for mono-summed signal from stereo input
• 24-carat gold-plated terminals, suitable for 25 mm² / gauge 4 cables
• Made in Germany with selected premium components
• Transparent enclosure cover showcasing build quality and design