Helix AMPLIFY 201 X-OVER – Compact Mono Subwoofer Amplifier with Active Crossover
The AMPLIFY 201 X-OVER is a monoblock for subwoofer upgrades within the 2-Series, the entry point and technical core of the HELIX AMPLIFY platform, which is offered in DIRECT, X-OVER and DSP variants. It delivers up to 750 W RMS at 1 Ohm, which suits two 2-Ohm subwoofers wired in parallel.
As an X-OVER model it is aimed at classic upgrades with factory or aftermarket head units: the high-level stereo input accepts up to 32 V, the amplifier turns on automatically from the music signal, and ADEP.3 prevents error messages in OEM systems. An active crossover with 12 dB low-pass and subsonic filters plus phase control, and an included cable remote for bass level, complete the package.
Key Features
- High output: 250 W RMS at 4 Ohms, 450 W RMS at 2 Ohms and 750 W RMS at 1 Ohm (≤1% THD+N, 14.4 V; continuous 1-Ohm power with music signal only)
- Subwoofer-ready load handling: 1-Ohm capability matches two 2-Ohm subwoofers wired in parallel
- Factory system upgrades: integrated active crossover and high-level stereo input accepting up to 32 V RMS
- High-level input with ADEP.3: for trouble-free integration into OEM systems without error messages
- Automatic turn-on: activates via the music signal – no separate remote wire needed
- Active crossover: adjustable low-pass, subsonic filter and phase control
- Cable remote: included for subwoofer volume adjustment
- Start-stop capability: keeps operating during supply voltage drops down to 6 V (max. 5 s)
- Class D technology: high efficiency and low heat dissipation
- Removable top cover: conceals all connections and controls for a protected, tidy installation; matte, minimalist styling suited to modern interiors
- Compact chassis: for space-saving installation
Inputs & Outputs
- 1 x RCA input
- 2 x high-level speaker inputs
- 1 x remote input
- 1 x remote control input (for the cable remote)
- Input sensitivity: RCA 0.5–6 V, high-level 3–32 V
- Input impedance: RCA 8 kOhms, high-level 9–33 Ohms
- 1 x speaker output
Power & Amplifier Section
- 1 x 250 W RMS at 4 Ohms (≤1% THD+N, 14.4 V)
- 1 x 450 W RMS at 2 Ohms (≤1% THD+N, 14.4 V)
- 1 x 750 W RMS at 1 Ohm (≤1% THD+N, 14.4 V; continuous 1-Ohm power with music signal only)
- Maximum output: up to 850 W RMS at 1 Ohm
- Amplifier technology: Class D
- Frequency response: 10–250 Hz
- Signal-to-noise ratio: 114 dB (A-weighted) at full power
- THD at 100 Hz (1 W into 4 Ohms): below 0.003%; THD+N below 0.02%
- Damping factor: 200
- Fuses: 2 x 30 A LP-Mini (APS); power rating 12 V DC, 80 A max.
DSP & Sound Tuning
- Low-pass filter: 50–250 Hz, adjustable, 12 dB/oct.
- Subsonic filter: 10–50 Hz, adjustable, 12 dB/oct.
- Phase: 0–180°, adjustable
Installation & Connectivity Notes
- Operating voltage: 10.5–16 V, for max. 5 seconds down to 6 V (start-stop capable)
- Idle current: 1,100 mA
- Operating temperature range: −40 °C to +70 °C
Technical Specifications
| Power RMS ≤ 1% THD+N @ 14.4 V | |
| – @ 4 Ohms | 1 x 250 Watts |
| – @ 2 Ohms | 1 x 450 Watts |
| – @ 1 Ohm | 1 x 750 Watts* |
| – bridged @ 4 Ohms | – |
| – bridged @ 2 Ohms | – |
| Max. output power | Up to 850 Watts RMS @ 1 Ohm |
| Amplifier technology | Class D |
| Inputs | 1 x RCA / Cinch 2 x Highlevel speaker input 1 x Remote In 1 x Remote control input |
| Input sensitivity | RCA / Cinch: 0.5 – 6 Volts Highlevel: 3 – 32 Volts |
| Input impedance | RCA / Cinch: 8 kOhms Highlevel: 9 – 33 Ohms |
| Outputs | 1 x Speaker output |
| Output voltage RCA / Cinch | – |
| Signal converter for digital input | – |
| Frequency response | 10 Hz – 250 Hz |
| Bass boost | – |
| Highpass | – |
| Lowpass | 50 Hz – 250 Hz adjustable |
| Bandpass | – |
| Subsonic | 10 Hz – 50 Hz adjustable |
| Phase | 0° – 180° adjustable |
| Slope high- / lowpass | Lowpass: 12 dB/Oct. |
| Slope subsonic | 12 dB/Oct. |
| Slope subsonic / lowpass | – |
| Signal-to-noise ratio (A-weighted) | 114 dB @ full power |
| Distortion (THD @ 1 kHz, 1 W into 4 Ohms) | – |
| Distortion (THD+N @ 1 kHz, 1 W into 4 Ohms) | – |
| Distortion (THD @ 100 Hz, 1 W into 4 Ohms) | < 0.003% |
| Distortion (THD+N @ 100 Hz, 1 W into 4 Ohms) | < 0.02 % |
| Damping factor | 200 |
| Operating voltage | 10.5 – 16 Volts (max. 5 sec. down to 6 Volts) |
| Idle current | 1,100 mA |
| Fuse | 2 x 30 A LP-Mini-fuse (APS) |
| Power rating | DC 12 V ⎓ 80 A max. |
| Operating temperature range | -40 °C to +70 °C |
| Additional features | Active, adjustable crossover, Start-Stop capability, highlevel input with automatic turn-on function, ADEP.3 |
| Dimensions (H x W x D) | 41.5 x 248 x 118 mm / 1.63 x 9.76 x 4.65” |
* Continuous 1 Ohm power achieved only with music signal
Scope of Delivery
1 x Amplifier HELIX AMPLIFY 201 X-OVER
1 x Cable remote control
2 x Allen key
1 x Connection cable
2 x Fuse
1 x Mounting material
1 x Instruction manual
