If you like to rev up your front and rear speakers, the M FOUR will be exactly the right “tool” to do so. With generously 100 Watts RMS per channel into both 4 Ohms and 2 Ohms load this amp will heat up your voice coils in no time despite its super-compact dimensions. On the other hand the M FOUR stays totally cool thanks to the highly efficient Class D design topology. 3-channel or 2-channel configurations are possible as well, delivering up to 2 x 200 Watts RMS of clean and undistorted output power.

Needless to say that the M FOUR is equipped with a bunch of intelligent attributes like “start-stop capability” and our proprietary “ADEP” highlevel input so that it easily deals with all installation challenges of modern cars. Finally the extensive audio features will offer a sound quality at its best.

Class-D Highlevel-Input RCA-InputRemmote-Control-ready ADEP Active crossover Start-Stop-Capability SMD Ultra compact dimensions


  • Small footprint Class D amplifier with high output power of 100 Watts RMS @ 4 and 2 Ohms load
  • Start-Stop capability down to 6V supply voltage
  • Smart highlevel input with ADEP circuit (Advanced Diagnostics Error Protection) and Auto Turn-On function
  • Integrated, active crossover with highpass, lowpass and bandpass
  • “Input mode” switch for flexible input signal routing
  • SMD (Surface Mounted Device) manufacturing technology combines minimum space requirement with maximum reliability
  • Exclusive, extremely compact and clean design with illuminated HELIX-logo and low heat dissipation thanks to extraordinary efficiency


Special features:

Smart highlevel input
The latest generation of OE car radios incorporates sophisticated possibilities of diagnosing the connected speakers. If a common amplifier will be hooked up failure messages and loss of specific features (e.g. fader function) quite often appear – but not with the M FOUR.
The new ADEP circuit (Advanced Diagnostics Error Protection) avoids all these problems without loading the speaker outputs of the OE radio during high volumes unnecessarily.

Start-Stop capability
The switched power supply of the HELIX M FOUR assures operation even if the battery’s voltage drops down to 6 Volts during engine crank.

Output power RMS / max.
– @ 4 Ohms4 x 100 / 200 Watts
– @ 2 Ohms4 x 100 / 200 Watts
– @ 1 Ohm
– bridged @ 4 Ohms2 x 200 / 400 Watts
– bridged @ 2 Ohms
Max. output power per channel*Up to 135 Watts RMS @ 2 Ohms
Amplifier technologyClass D
Inputs4 x RCA / Cinch
4 x Highlevel speaker input
1 x Remote In
Input sensitivityRCA / Cinch 0.5 – 6 Volts
Highlevel 1.3 – 13 Volts
Input impedance RCA / Cinch20 kOhms
Input impedance highlevel13 Ohms
Outputs4 x Speaker output
Output voltage RCA / Cinch
Signal converter for digital input
Frequency response10 Hz – 30,000 Hz
Bass boost
Highpass15 Hz – 4,000 Hz adjustable
Lowpass40 Hz – 4,000 Hz adjustable
Bandpass15 Hz – 4,000 Hz adjustable
Slope high- / lowpass12 dB/Oct.
Slope subsonic / lowpass
Signal-to-noise ratio digital input
Signal-to-noise ratio analog input98 dB (A-weighted)
Distortion (THD)0.05 %
Damping factor100
Operating voltage10.5 – 16 Volts (max. 5 sec. down to 6 Volts)
Idle current1,100 mA
Fuse2 x 30 A Maxi-fuse (APX)
Additional featuresActive, adjustable crossover, input mode switch, Start-Stop capability, highlevel input with automatic turn on function and Advanced Diagnostics Error Protection (ADEP)
Dimensions (H x W x D)50 x 230 x 154 mm /
2.00 x 9.06 x 6.06”

* In typical multi-channel applications (2- / 3-way system + rear + subwoofer)

Delivery contents

1 x Amplifier HELIX M FOUR
1 x Mounting material
1 x Instruction manual