Click to open expanded view
Buy now, pay later
Product features
Helix Amplify 201 X-Over Mono Class D Subwoofer Amplifier 750W with Active Crossover and ADEP.3
A mono Class D subwoofer amplifier from the Helix Amplify 2-Series, the Amplify 201 X-Over delivers 250W RMS at 4Ω, 450W RMS at 2Ω, and 750W RMS at 1Ω (up to 850W RMS maximum), with 2 high-level ADEP.3 inputs (3-32V), 1 RCA input, adjustable active lowpass (50-250Hz, 12dB/Oct), adjustable subsonic filter (10-50Hz, 12dB/Oct), adjustable phase (0-180°), auto turn-on via music signal, 114dB SNR at full power, THD below 0.003% at 100Hz, damping factor of 200, cable remote control, clipping LED, Start-Stop capability, and a removable top cover in an ultra-compact 40 x 248 x 114mm housing.
Product Overview
The Helix Amplify 201 X-Over is the active crossover variant of the Amplify 201 subwoofer monoblock, designed for traditional sound upgrades using factory or aftermarket head units without a dedicated DSP processor. As the X-OVER variant, it includes switchable high-level and RCA inputs, an integrated active crossover with adjustable lowpass, subsonic, and phase controls, and ADEP.3 OEM integration circuitry, making it the most versatile and self-contained of the Amplify 201 variants for standalone subwoofer upgrade applications.
The amplifier delivers identical output power to the DIRECT variant: 750W RMS at 1Ω (up to 850W RMS maximum), 450W RMS at 2Ω, and 250W RMS at 4Ω at 14.4V with less than 1% THD+N. THD at 100Hz into 4Ω is below 0.003% and SNR is 114dB at full power. The damping factor of 200 provides strong speaker cone control for tight, accurate bass reproduction.
The 2 high-level inputs accept 3-32V from factory OEM head units and premium factory audio systems with up to 32V output voltage. The ADEP.3 circuit prevents error messages and feature loss in OEM systems during high-volume operation. The auto turn-on function activates the amplifier from the music signal without requiring a separate remote wire. The adjustable active lowpass filter (50-250Hz, 12dB/Oct) and adjustable subsonic filter (10-50Hz, 12dB/Oct) provide onboard crossover control, and the 0-180° phase control optimises subwoofer integration with the main speaker system. A cable remote control input allows external volume adjustment. Operating voltage is 10.5-16V with Start-Stop capability to 6V. Fused at 2 x 30A LP-Mini (APS).
Features & Benefits
750W RMS at 1Ω - Up to 850W RMS Maximum: Delivers 250W RMS at 4Ω, 450W RMS at 2Ω, and 750W RMS at 1Ω with music signal, and up to 850W RMS maximum, suited for 2 x 2Ω subwoofers in parallel, DVC subwoofers wired to 1Ω, or multiple subwoofers at a 1Ω combined load.
2 High-Level ADEP.3 Inputs with Auto Turn-On - Up to 32V RMS: The 2 high-level ADEP.3 inputs accept 3-32V, covering the full range of OEM factory head unit output levels from standard to premium high-output factory systems. The integrated ADEP.3 circuit prevents error messages and feature loss during high-volume operation. The auto turn-on function activates the amplifier from the music signal without a separate remote wire, maximising compatibility with factory head units.
Active Adjustable Lowpass Filter - 50-250Hz at 12dB/Oct: The fully adjustable lowpass filter from 50Hz to 250Hz at 12dB/Oct precisely limits the frequency range sent to the subwoofer, providing onboard crossover control without requiring an external DSP processor or crossover unit.
Active Adjustable Subsonic Filter - 10-50Hz at 12dB/Oct: The adjustable subsonic filter from 10Hz to 50Hz at 12dB/Oct removes infrasonic content below the subwoofer's usable range, protecting the driver from overexcursion without affecting audible bass frequencies.
Adjustable Phase Control - 0-180°: The 0-180° continuously adjustable phase control aligns the subwoofer output phase with the main speaker system for maximum bass integration and output at the crossover point.
114dB SNR at Full Power - THD Below 0.003% at 100Hz: Identical audio performance to the DIRECT variant: 114dB SNR (A-weighted) at full power and THD below 0.003% at 100Hz into 4Ω, delivering performance well beyond conventional subwoofer amplifier standards.
Damping Factor 200 - Precise Subwoofer Control: The damping factor of 200 provides strong resistance to subwoofer cone back-EMF for tight, accurate, and well-controlled bass with fast transient response.
Cable Remote Control Input: A cable remote control input allows external volume adjustment via the included cable remote, providing convenient level control without accessing the amplifier directly after installation.
RCA Input (0.5-6V) for Aftermarket Head Units: The mono RCA input accepts 0.5-6V from aftermarket head units and DSP processor line-level outputs, providing full system flexibility alongside the high-level inputs.
Advanced Class D - High Efficiency and Low Heat Dissipation: The advanced Class D concept delivers high efficiency and very low heat dissipation, enabling 750W RMS output from an ultra-compact 40 x 248 x 114mm housing.
Removable Top Cover - Clean Appearance and Control Protection: The removable top cover conceals all connections and controls when installed, providing a clean streamlined appearance and protection for wiring and crossover adjustment controls.
Start-Stop Capable - 10.5-16V Operating Range: Start-Stop capable power supply maintains stable operation during voltage drops to 6V for up to 5 seconds.
What's in the Box
- Helix Amplify 201 X-Over Amplifier
- 1 x Cable Remote Control
- 2 x Allen Key
- 1 x Connection Cable
- 2 x Fuse
- Mounting Material
- Instruction Manual
Technical Specs
| Specification | Detail |
|---|---|
| SKU | AMPLIFY 201 X-OVER |
| Brand | Helix |
| Range | Amplify 2-Series |
| Variant | X-Over (Active Crossover) |
| Channels | 1 (Mono) |
| Amplifier Class | Class D |
| Built-in DSP | No |
| Power RMS at 4Ω (14.4V) | 1 x 250W |
| Power RMS at 2Ω (14.4V) | 1 x 450W |
| Power RMS at 1Ω (14.4V) | 1 x 750W (with music signal) |
| Max Output at 1Ω | Up to 850W RMS |
| THD at 100Hz, 1W into 4Ω | Less than 0.003% |
| THD+N at 100Hz, 1W into 4Ω | Less than 0.02% |
| SNR at Full Power | 114dB (A-weighted) |
| Damping Factor | 200 |
| RCA Input | 1 x RCA Mono (0.5-6V, 8kΩ) |
| High-Level Inputs | 2 x High-Level ADEP.3 (3-32V, 9-33Ω) |
| Remote Control Input | Yes (Cable Remote) |
| Outputs | 1 x Speaker |
| RCA Preout | None |
| Frequency Response | 10Hz-250Hz |
| Lowpass Filter | 50-250Hz Adjustable, 12dB/Oct |
| Subsonic Filter | 10-50Hz Adjustable, 12dB/Oct |
| Phase Control | 0-180° Adjustable |
| ADEP.3 | Yes |
| Auto Turn-On | Yes (via Music Signal) |
| Clipping LED | Yes |
| Operating Voltage | 10.5-16V (Stable to 6V for 5 Seconds) |
| Power Rating | DC 12V, 80A Max |
| Idle Current | 1100mA |
| Fuse | 2 x 30A LP-Mini (APS) |
| Operating Temperature | -40°C to +70°C |
| Start-Stop Capable | Yes |
| Top Cover | Removable |
| Dimensions | 40mm x 248mm x 114mm |
Compatible With
The Amplify 201 X-Over is compatible with 10.5-16V vehicle electrical systems. High-level ADEP.3 inputs accept 3-32V from factory OEM and premium factory head units with auto turn-on. RCA input accepts 0.5-6V from aftermarket head units and DSP line-level outputs. The Amplify 201 X-Over has no RCA preout. Confirm subwoofer impedance matches the 1Ω, 2Ω, or 4Ω rated output configurations before purchase. The active crossover controls (lowpass, subsonic, phase) replace external DSP crossover function for standalone installations.
Frequently Asked Questions
What is the difference between the Amplify 201 X-Over and the Amplify 201 Direct?
The Amplify 201 X-Over is designed for standalone subwoofer upgrades with factory or aftermarket head units. It includes 2 high-level ADEP.3 inputs (3-32V), 1 RCA input, an integrated active crossover with adjustable lowpass (50-250Hz), subsonic (10-50Hz), and phase (0-180°) controls, auto turn-on from music signal, and a cable remote control. The Amplify 201 Direct is designed as a clean amplification stage downstream of a DSP processor, with DirectDSP inputs and no onboard filtering. Choose the X-Over for standalone installations; choose the Direct for DSP-based systems.
Does the Amplify 201 X-Over require a separate remote wire for turn-on?
No. The auto turn-on function activates the amplifier automatically from the music signal via the high-level inputs, eliminating the need for a separate remote wire. This maximises compatibility with factory head units and OEM audio systems.
What subwoofer configurations is the Amplify 201 X-Over suited to?
The Amplify 201 X-Over is rated at 750W RMS at 1Ω, ideal for 2 x 2Ω subwoofers in parallel, DVC subwoofers wired to 1Ω, or multiple subwoofers configured to a 1Ω combined load. It is also rated at 450W RMS at 2Ω and 250W RMS at 4Ω for single voice coil configurations.
Does the Amplify 201 X-Over work with high-output premium factory audio systems?
Yes. The high-level ADEP.3 inputs accept up to 32V RMS, covering premium factory audio systems including Harman, Bose, Burmester, and other high-output OEM audio configurations that produce speaker-level output voltages well above standard levels.
What does the cable remote control do on the Amplify 201 X-Over?
The included cable remote control connects to the remote control input on the amplifier and allows external subwoofer volume adjustment from a convenient location in the vehicle cabin, without requiring physical access to the amplifier after installation.
Recommended for You
- Choosing a selection results in a full page refresh.
!