C FOUR | Helix C Series 4 Channel Amplifier

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  • Regular price $2,850.00
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Helix C Series 4-Channel Amplifier

| *Special Order* | Owners Manual |


Audiophile sound quality combined with impressive output power

The C FOUR is a high-end 4-channel amplifier that has been designed down to the last detail for ultimate sound quality. Audiotec Fischer’s proprietary ultra low-noise and ultra low-distortion Class A driver stage feeds a total of 32 hand-selected MOSFET power transistors, resulting in an incredible damping factor of 1,000 for relentless control of every loudspeaker. The intelligent regulation of the power supply assures stable conditions for the output stages and therefore phenomenal output power independent of the cars battery voltage.
In combination with the optionally available digital input module HDM 2, the C FOUR demonstrates the perfect transition to the digital era. The HDM 2 accepts digital audio signals up to 96 kHz sampling rate via its two optical inputs followed by cutting-edge BurrBrown D/A converters with 32 Bit resolution that transform the signals back to the analog domain. Therefore the C FOUR is absolutely future-proof and perfectly prepared for the combination with our digital signal processors.


  • Extremely broadband Class AB amplifier with eight selected MOSFET transistors per channel for exceptional sound quality - ideal for High-Resolution audio
  • Ultra low-noise and distortion-free power amp drivers in Class A technology
  • Enormous damping factor of 1,000 @ 4 Ohms for perfect speaker control
  • Optionally available HELIX Digital Input Module (HDM) to extend the amplifier with two optical digital inputs in SPDIF format
  • Integrated, active crossover with highpass, lowpass and bandpass
  • Regulated DC / DC switching power supply with Start-Stop capability down to 6V supply voltage
  • Microprocessor-based monitoring of amplifier status including temperature-dependent fan control
  • Input Mode switch for flexible routing of the input signals
  • Cutting-edge BurrBrown D/A converters with 32 Bit resolution in combination with the optional HDM 2 module
  • Massive 24-carat gold-plated power and speaker terminals
  • Quad-layer PCB with extra-solid 70μ copper traces for lowest possible losses and SMD (Surface Mounted Device) manufacturing technology


Special features:

Start-Stop capability

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

High-Resolution audio

The extremely broadband audio bandwidth of the amplifier ensures a lossless audio reproduction of High-Resolution audio content to provide the best possible sound in studio quality.

Technical data

Output power RMS  ≤ 1% THD+N  
- @ 4 Ohms 4 x 150 Watts
- @ 2 Ohms 4 x 220 Watts
- @ 1 Ohm
- bridged @ 4 Ohms 2 x 440 Watts
- bridged @ 2 Ohms
Max. output power per channel* Up to 250 Watts RMS @ 2 Ohms
Amplifier technology Class AB
Inputs 4 x RCA / Cinch
1 x Remote In
Optional via HDM 2 module:
2 x Optical SPDIF (28 - 96 kHz)
Input sensitivity RCA / Cinch 1 - 8 Volts
Input impedance RCA / Cinch 7.5 kOhms
Input impedance highlevel
Outputs 4 x Speaker output
Output voltage RCA / Cinch
Signal converter for digital input
Frequency response 10 Hz - 80,000 Hz
Bass boost -  
Highpass 15 Hz - 4,000 Hz adjustable
Lowpass 15 Hz - 4,000 Hz adjustable
Bandpass 15 Hz - 4,000 Hz adjustable
Slope high- / lowpass 12 dB/Oct.
Slope subsonic / lowpass
Signal-to-noise ratio digital input
Signal-to-noise ratio analog input 112 dB (A-weighted)
Distortion (THD) < 0.007 %
Damping factor > 1000
Operating voltage 9 - 16 Volts  (max. 5 sec. down to 6 Volts)
Idle current 2400 mA
Operating temperature range -40° C to +70° C
Fuse 3 x 30 A LP-Mini-fuse (APS)
Additional features Active, adjustable crossover, HDM slot, input mode switch, High-Resolution audio, Start-Stop capability
Dimensions (H x W x D) 37.1 x 430 x 240 mm /
1.46 x 16.93 x 9.45"

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

Scope of delivery

1 x High-end amplifier HELIX C FOUR
2 x Allen key
1 x Mounting material
1 x Instruction manual

Press & awards



Amplifier Class

Class AB Feature


RCA Input Feature Helix Digital Input Module Feature


Hardware Technologies

Regulated Power Supply Feature Surface Mounted Device Active Crossover Feature


Additional Features

High Res Audio Feature Start Stop Capability Feature Made in Germany Feature