Features

Overview: The link4 is an active 4-channel line output converter designed for adding aftermarket amplifiers to a factory radio.

Speaker Input: The two pair of speaker level inputs are compatible with most factory stereo systems. They will accommodate up 40 volts RMS per channel (equivalent to 400 watts at 4Ω). The balanced-differential input design minimizes the possibility of having noise induced into the signal.

Channel Summing: The link4 has the ability to sum two pair of input channels from the factory source unit into one pair of outputs. This is useful when the factory system has multiple, actively crossed-over signals sent from the source unit or amplifier(s). For example, in some vehicles there is an actively crossed-over tweeter and woofer in the front of the vehicle. The link4 lets you take both signals and sum them together to get a high-quality, full-range, preamp signal without the use of any additional cables or hardware.

Load Detect Compatible: The inputs are loaded to simulate the factory system seeing a speaker. The "speaker" load can be removed if needed. If a lower impedance is needed, the linkLD external parallel load can be added to the link4 inputs.

Auxiliary Input: There is a 3.5mm auxiliary input jack on the unit so you can easily add an iPod, satellite radio, or other secondary source.

Output Level: The 10 volt RMS maximum allows you to adjust output voltage to the top of your amp's input range. Each stereo RCA output has its own level adjustment. There is also an output level control for the auxiliary input, so it matches the level of the speaker level inputs.

Clip Indicator: Onboard LEDs indicate when the output signal is too high and is clipping, making it easy to maximize the output levels without distortion.

Auto Turn-on: The speaker level inputs have a DC-offset circuit, and both the speaker level inputs and aux input have a signal sensing circuit. The link4 turns on when there's an input signal and turns off when the signal disappears. There is also a +12 volt remote turn-on input and the auto turn-on circuits can be disabled.

Remote: The included multi-function wired remote is designed to be dash mounted, within reach of the driver; the housing can be mounted under the dash, or the housing can be removed and the knob and LED can be custom mounted through the dash. The functions of the rotary/push-button knob vary depending on how the two dip switches are set:

• Type 1 (factory setting): volume of channel 3/4 output
• Type 2: volume of channel 3/4 output, aux input level, input select (speaker level or aux)
• Type 3: aux input level, volume of channel 3/4 output
• Type 4: master volume (all outputs), volume of channel 3/4 output, input select (speaker level or aux)

Remote Dimensions:

• Width: 1½" (2⅜" including mounting tabs)
• Height: 1⅛"
• Depth: 1¾" (3" including knob and wire)

Ground Isolation: The internal audio signal ground is switchable, in case of ground loop noise. The factory position is chassis ground (typically the best choice), but can be changed to 200Ω or ISO (isolated).

Terminal Blocks: The power/ground/remote-in/remote-out terminal and the speaker level inputs are removable Phoenix terminals (Euroblock). The wiring is attached to the block, then the block is plugged into the link4. The terminal blocks will accommodate wire up to 16-gauge.

Connections:

• Power: removable 4-pin Phoenix terminal
  • Ground: minimum 18-gauge wire recommended
  • +12 volts: minimum 18-gauge wire recommended with a 1-amp fuse (not included)
  • Remote In: unit turns on when +12 volts applied to this terminal
  • Remote Out: +12 volt output when unit is on (used to turn on amp, 500 mA max)
• Speaker Level Inputs: two separate removable 4-pin Phoenix terminals; for channels 1/2 and 3/4
• Aux Input: 3.5mm mini-jack
• Line Outputs: RCA jacks for channels 1, 2, 3, and 4
• Remote: RJ-45 jack for included wired remote control

Controls:

• Gain: rotary dials; each pair of channels has an independent gain control, as does the aux input
• Channel 1/2 Input: 3-position switch
  • CH 1/2: takes signal directly from the CH 1/2 input
  • CH 3/4: copies the signal and gain setting from channels 3 and 4
  • CH 1+3/CH 2+4: combines (sums) the signals from the channel 1/2 and channel 3/4 inputs
• Ground Reference: three jumper positions; ground (factory setting), ISO, or 200Ω

Hidden Controls: There are several jumper pins inside the link4 chassis, to make adjustments that are not typically necessary:

• Speaker Level Input Sensitivity Range: The 2-position jumpers are set to 2-20 volts RMS (factory setting) or 4-40 volts RMS. (There is a separate jumper for each channel.)
• Load: The speaker load impedance can be removed from the speaker level inputs. The factory setting is 180Ω; if the jumper is removed, the input impedance increases to 20 kΩ. (There is a separate jumper for each channel.)
• Aux Input: The 2-position jumper is set to Balanced (factory setting) or Unbalanced.
• Auto Turn-on: The DC-offset and audio signal sensing circuits can be independently turned off. The factory setting for both is on. When either jumper is removed, that circuit is disabled.

Specifications:

• Frequency response:
  • +0/-1 dB: 10 Hz-80 kHz
  • +0/-3 dB: 5 Hz-100 kHz
• Input Impedance:
  • Speaker input: 180 Ω/20 kΩ
  • Aux input: 50 kΩ
• Speaker Input Sensitivity: 2-40 volts RMS
• Aux Input Sensitivity: 0.5-5 volts RMS
• Output Impedance: 50 Ω
• Maximum Output Voltage: 10 volts RMS
• THD+N: 0.05% (at 10 volts output)
• S/N:
  • Speaker Level Input:
    • 1 volt output: 90 dBA
    • 4 volt output: 106 dBA
    • 10 volt output: 114 dBA
  • Aux Input:
    • 1 volt output: 93 dBA
    • 4 volt output: 107 dBA
    • 10 volt output: 115 dBA
• Current Draw:
  • Operating: 300mA (without remote out)
  • Standby: 2mA
• Dimensions:
  • Width: 6¼" (6¾" including cables)
  • Height: 1¼"
  • Depth: 3½"