Helix P ONE MK2

Helix P ONE MK2 – high-res mono amplifier with optical digital input

The P ONE MK2 is a single-channel Class D amplifier from the HELIX range, stable down to 1 Ohm and fitted with a digital signal input. Its primary job is powering subwoofers – it can drive, for example, two 2 Ohm subwoofers wired in parallel – and its high damping factor gives the amplifier firm control over the woofer. Thanks to a frequency range reaching 40 kHz, a high signal-to-noise ratio and very low distortion, the manufacturer also positions it for full-range use.

Its key differentiator is the newly integrated optical digital input: signals of up to 96 kHz arrive via fiber optic, free of interference and ground-isolated, and are converted by a native 32-bit BurrBrown D/A converter (instead of the common 24 bit) for better precision at low signal levels. An SPDIF Direct In switch sends the digital signal straight to the power stage, bypassing the input stage. Audiotec Fischer states that the Class D design gives the P ONE MK2 the highest power density in the HELIX amplifier range with low heat dissipation. Made in Germany.

Key Features

• Class D mono power: 1,500 W RMS at 1 Ohm, and up to 1,800 W RMS at 1 Ohm in typical subwoofer applications.
• 1 Ohm stability: rated into 4, 2 and 1 Ohm loads, e.g. two 2 Ohm subwoofers in parallel.
• High-res capability: frequency response from 21 Hz up to 40 kHz.
• Optical S/PDIF input: lossless, ground-isolated digital transmission at 28–96 kHz.
• 32-bit BurrBrown D/A converter: native 32-bit conversion of the digital input signal.
• SPDIF Direct In switch: routes the digital signal directly to the power stage, avoiding any influence of the input stage.
• Switchable subsonic filter: 21 Hz, Butterworth characteristic, 48 dB/octave.
• High damping factor: greater than 450 for tight control of the woofer.
• Regulated, start-stop capable power supply: keeps output stable during voltage drops; operation continues when battery voltage falls to 6 V during cranking.
• Input Mode switch: matches the amplifier to the incoming signal.
• Efficient SMD construction: compact, reliable surface-mount design with low heat dissipation and small dimensions.

Inputs & Outputs

• 2 x RCA inputs, sensitivity 0.5–8 V, input impedance 20 kOhm
• 1 x optical digital input (S/PDIF, 28–96 kHz)
• 1 x remote input
• 1 x speaker output
• Signal-to-noise ratio 110 dB (A-weighted) for both analog and digital input

Power & Amplifier Section

• 1 x 500 W RMS at 4 Ohm, 1 x 880 W RMS at 2 Ohm, 1 x 1,500 W RMS at 1 Ohm (at ≤1% THD+N)
• Maximum output up to 1,800 W RMS at 1 Ohm in typical subwoofer applications
• Class D amplifier technology; THD below 0.01%; damping factor above 450
• Fusing: 4 x 30 A LP-Mini (APS); maximum current draw 160 A at 12 V DC; idle current 1,500 mA

DSP & Sound Tuning

• No DSP; the analog processing is limited to a switchable subsonic filter at 21 Hz (Butterworth, 48 dB/oct)
• Digital input path: 32-bit BurrBrown D/A converter with SPDIF Direct In bypass

Installation & Connectivity Notes

• Operating voltage 10.5–17 V, with up to 5 seconds down to 6 V (start-stop capable)
• Pairs with the HELIX P SIX DSP ULTIMATE, whose optical digital output can feed the P ONE MK2 digitally
• Operating temperature range −40 °C to +70 °C

Technical Specifications

* In typical applications as subwoofer amplifier

Scope of Delivery

1 x Amplifier HELIX P ONE MK2
1 x Instruction manual