Helix AMPLIFY 204 X-OVER - 4-channel amplifier with crossovers

HELIX AMPLIFY 204 X-OVER

HELIX AMPLIFY – Powerful. Clear. Consistent.
With AMPLIFY, HELIX redefines the standard for modern amplifier design: through a contemporary interpretation of classic concepts. Instead of "one-size-fits-all" solutions, AMPLIFY focuses on specialized models that are precisely tailored to different application areas. This stringent philosophy guarantees that each model delivers maximum performance for its intended purpose – while concentrating on the essentials.

The 2 Series marks the entry into the AMPLIFY platform – and simultaneously forms its technical and sonic core. These compact Class D amplifiers combine power, a fully bridgeable multi-channel architecture, and outstanding efficiency with practical integration capabilities. Brilliant and precise highs, controlled mids, and tight, powerful bass – the 2 Series brings all facets of natural and powerful sound to every vehicle with sound quality and performance values far exceeding expectations in its class. Whether as a DIRECT, X-OVER, or DSP version (from summer 2025): everything is offered, from flexible 6-channel configurations for full-range applications to a powerful 1-channel subwoofer powerhouse.

AMPLIFY 204 – The versatile solution for full-range applications

The AMPLIFY 204 amplifiers combine four fully bridgeable outputs with excellent sound and impressive performance – ideal for powerful front or multi-channel setups. Whether classic 4-channel operation, a 3-channel configuration with a subwoofer, or bridged 2-channel solutions: the 204 series flexibly adapts to the requirements of a wide variety of vehicles and system designs. With an output of 4 x 100 watts RMS at 4 Ω, 4 x 190 watts RMS at 2 Ω, or 2 x 380 watts RMS bridged at 4 Ω, it offers more than enough power for ambitious setups. Available in the X-OVER version with an active crossover or as a DIRECT model for purist operation with external DSPs, the focus is always on high-quality sound performance.

Sound and Performance – Above the Standard

The AMPLIFY 2 Series not only stands for perfectly tailored solutions for diverse applications, but also for the clear goal of far exceeding the expectations of its class in terms of sound and performance in each of these applications. All amplifiers in the series offer brilliant sound quality, low distortion, and outstanding signal-to-noise ratios – coupled with bridgeable multi-channel outputs throughout for maximum performance and installation flexibility. The result: A series that doesn't define itself by its class, but sets new standards within it – making it the first choice for anyone seeking application-oriented performance without compromise.

AMPLIFY X-OVER – Maximum Flexibility for Classic Upgrades

The AMPLIFY X-OVER models are the ideal choice for conventional sound upgrades with factory radios or aftermarket head units. The centerpiece is the integrated, active crossover with high-quality, adjustable high- and low-pass filters and input mode switches – it enables precise signal tuning and facilitates the implementation of a wide variety of system configurations. Whether for an active front system with separate control of tweeters and woofers, the operation of passive front and rear systems, or the combined use of a front system with a subwoofer via bridged channels: the X-OVER models offer maximum flexibility in system design. Switchable high-level and RCA inputs with up to 16 V input sensitivity enable integration into virtually any factory or aftermarket environment. The integrated ADEP.3 circuit ensures flawless communication with OEM radios, while an automatic power-on function minimizes installation effort. As an additional feature, the DirectDSP function allows the input signal to bypass the crossover untouched and pass directly to the power amplifier – ideal for anyone who wants to upgrade their system with an external DSP at a later date.

Form follows function
The design of the HELIX AMPLIFY 2 series combines modern functionality with a clean, technical look. The compact dimensions allow for flexible installations, even in tight spaces. A removable cover conceals connections and controls, providing additional protection and creating a tidy, high-quality overall impression. Matte surfaces, precise lines, and a minimalist design language create a stylish, exclusive look that blends seamlessly into any modern vehicle interior.

Features

• Highly efficient amplifier with high output power of up to 240 watts RMS @ 2 ohms per channel for impressive dynamics and powerful sound
• Bridgeable output channels for flexible system configurations and maximum power output
• Very compact design for easy integration even in limited space
• Start-stop capability down to 6V supply voltage for uninterrupted performance
• Integrated, active crossover with high- and low-pass filters, as well as input mode switches for optimal system configuration
• DirectDSP function – input signal bypasses the integrated, active crossover and is fed unfiltered to the power amplifier given
• Intelligent high-level input with ADEP.3 for interference-free integration into OEM sound systems
• Advanced Class D concept for high efficiency with minimal heat generation

Technical specifications

• Power RMS ≤ 1% THD+N @ 14.4 V
• @ 4 Ohm 4 x 100 Watts
• @ 2 Ohm 4 x 190 Watts
• @ 1 Ohm -
• Bridged at 4 Ohm 2 x 380 Watts
• Bridged at 2 Ohm 
• Max. Power per channel* Up to 240 watts RMS @ 2 ohms
• Amplifier technology: Class D
• Inputs: 4 x RCA
• or
• 4 x Line-level speaker inputs
• 1 x Remote In
• Input sensitivity: RCA: 1 - 8 volts
• Line-level: 2 - 16 volts
• Input impedance
• RCA: 8 kOhms
• Line-level: 9 - 33 ohms
• Outputs: 4 x Speaker outputs
• Output voltage: RCA
• Signal converter for the digital input
• Frequency range: 10 Hz - 20,000 Hz
• Bass Boost 
• High-pass 45 Hz - 400 Hz adjustable (can be switched off)
• Low-pass 45 Hz - 400 Hz adjustable (can be switched off)
• High-pass / Low-pass Slope: 12 dB/oct.
• Low-pass: 12 dB/oct.
• Subsonic Slope 
• Subsonic / Low-pass Slope 
• Signal-to-noise ratio (A-weighted) 99 dB @ maximum power
• Total harmonic distortion (THD @ 1 kHz, 1 W at 4 ohms) < 0.012%
• Tonal harmonic distortion (THD+N @ 1 kHz, 1 W into 4 ohms) < 0.02%
• Total Harmonic Distortion (THD @ 100 Hz, 1 W at 4 Ohms)
• Total Harmonic Distortion (THD+N @ 100 Hz, 1 W at 4 Ohms)
• Attenuation Factor 70
• Operating Voltage 10.5 - 16 Volts (max. 5 seconds down to 6 Volts)
• No-Load Current Consumption 1,100 mA
• Fuse 2 x 30 A LP mini plug-in fuses
• Power Consumption DC 12 V ⎓ 70 A max.
• Operating Temperature Range -40 °C to +70 °C
• Additional Features Active, adjustable crossover, Input mode switch, start-stop capability, high-level input with automatic switch-on, ADEP.3, DirectDSP function
• Dimensions (H x W x D) 40 x 248 x 114 mm
• * One channel driven (≤ 10% THD+N @ 14.4 V)

Scope of delivery

• 1 x HELIX AMPLIFY 204 X-OVER amplifier
• 2 x Allen keys
• 3 x Connection cables
• 2 x Fuse
• 1 x Mounting hardware
• 1 x User manual