User manual HELIX DARK BLUE FOUR

[. . . ] The attractive typical HELIX DARK BLUE design makes this amplifier an outstanding and top of the class product. General installation instructions for HELIX amplifiers To find out how HELIX amplifiers work best for you, read this manual carefully and follow the instructions for installation. We guarantee that this product has been checked for proper functioning before shipping. [. . . ] In order to ensure safe installation, use only high-quality connections and materials. 5 1 Connecting the ground cable 2 Connecting the remote lead 3 Connecting the battery cable 5 1 Connecting the ground cable 2 Connecting the remote lead 3 Connecting the battery cable 1 Connecting the ground cable The ground cable should be connected to a central ground reference point (this is located where the negative terminal of the battery is grounded at the metal body of the vehicle), or to a bright bare-metal location on the vehicle chassis, i. 2 Connecting the remote lead The remote lead is connected to the automatic antenna (aerial positive) output of the head unit (radio). 4 Fuses The input fuses are connected in parallel and provide protection against an internal equipment fault, i. The system must be additionally protected by a further line fuse located in the vicinity of the battery (max. The impedance per channel should not be lower than 2 ohm as overheating could cause a shut down of the amplifier. 6 Signal inputs The DARK BLUE amplifiers have RCA connectors for RCA cables that can be connected with the pre-amplifier output of the lineoutputs of the headunit or with a pre-amplifier. This connectors are gold-plated to ensure a better signal transmission. 7 High- and low level signal switch To change the input signals from low level (head unit or preamplifier) to high level (speaker outputs of head unit). 8 Level controls for input sensitivity These controls can be used to match the input sensitivity of the individual channels to the output voltage of the connected head unit. These controls are not volume controls and are solely intended for the purpose of sensitivity trimming. 9 Bassboost control To raise the bass signal from 0 to 18 dB at 45 Hz. If this switch is set on HPF Highpass the crossover frequency for the highpass can be adjusted with control 10. With switch 10 adjust the highpass and with control 12 adjust the lowpass. Thus every desired bandpass between 15 Hz and 4000 Hz can be adjusted. To avoid a lost of sound pressure make sure that the crossover frequencies of high- and lowpass are separated of 2 octaves when building a bandpass. That means: If the lowpass signal is adjusted to 320 Hz the highpass should be adjusted 2 octaves lower on approx. (1 octave = double frequency or half frequency) If a subwoofer is connected we recommend to use highpass control 10 as variable subsonic filter or turn it counter-clockwise to 15 Hz to get a subsonic filter. [. . . ] D) Products which have been repaired incorrectly or modified or where the product has been opened by other persons than us. F) Reimbursement when repairing damages by third parties without our previous permission. The DARK BLUE amplifiers have several electronic protection circuits that shut off the amplifier at overheating, overloading, shortcircuit on loudspeaker, low-ohmic mode or defective power supply. [. . . ]