HELIX C FOUR
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.
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 |
| Subsonic | - |
| Phase | - |
| 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 |
| 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" |
Helix C FOUR
- 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