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AtlasIED FM250-4

Amplifier card module (4 and 8 ohm output only)

Item # 978FM2504

Fits into one of the six amplifier card slots of an F6-MF mainframe chassis to provide up to 250 watts of power.

Fits into one of the six amplifier card slots of an F6-MF mainframe chassis to provide up to 250 watts of power.

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About the AtlasIED FM250-4

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Amplifier for the F6-MF system

Atlas Sound F6-FM250-4

The Atlas Sound FM250-4 amplifier module can provide up to 250 watts of power for your commercial speaker installation, playing music and speech clearly and loudly enough for all to hear. Each FM250-4 fits into one of the six amplifier card slots of an F6-MF mainframe chassis, connecting internally to the master unit's power supply and inputs.

Onboard adjustments and indicators

A Dip switch lets you set the amp's input sensitivity to maximize the signal over background noise, and engage a high-pass filter to clear any low rumble out of the mix. Rear-panel status LEDs, like the ones on the F6-MF's front panel, let you know how the amp's behaving.

See what our satisfied customers have to say.

Product highlights:

  • amplifier card module for Atlas Sound F6-MF mainframe system
  • designed for 4- or 8-ohm speakers
  • 250 watts (continuous) x 1 at 4 ohms
  • 125 watts (continuous) x 1 at 8 ohms
  • selectable high-pass filter (100 Hz at 12 dB/octave)
  • selectable input sensitivity (1 or 2 volt)
  • fixed subsonic filter (30 Hz)
  • dimensions: 1-1/2"W x 3-7/16"H x 10-7/16"D
  • weight: 12.8 oz.
  • warranty: 3 years
  • Our 60-day money-back guarantee
  • MFR # FM250-4

What's in the box:

  • 4/8 Ohm amplifier module

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Crutchfield response

<< >>

More details on the AtlasIED FM250-4

Russ B.

Product Research


Overview: The Atlas FM250-4 is an amplifier module is designed to work specifically with the Atlas F6-MF power rack, which can hold up to 6 modules. The FM250-4 module can output 250 watts, features a defeatable Limiter and a High-Pass Filter, and can power both 4 and 8 ohm speakers. It's Class-D amp technology is designed to be 90% efficient, allowing the amp to run cooler and consume less energy than conventional amplifiers.

Installation: The FM250-4 module includes a multi-terminal strip on the rear of the PC board that lines up with a contact slot on the F6-MF power rack. The card is then secured in place with 2 front panel screws. Signal input to the card is through the rack, which has six 3-pin Euroblock connectors on the back of it, along with Level dials for each channel. The front of the module includes a 2-pin Euroblock connector for connecting a 4 Ω or 8 Ω speaker load. If powering speakers in a 70.7 volt system, the FM250-70 module can be used. This installs into the F6-MF power rack in the same manner and provides the same power output for running 70 volt speakers.

Settings: The FM250-4 module includes a 3-setting DIP switch on the rear of the module which includes:

  • DIP Switch 1: This switch changes the Input Sensitivity
    • On: Sensitivity is 1 volt
    • Off: Sensitivity is 2 volts
  • DIP Switches 2&3: Activates the High-Pass Filter
    • On: When both switches are On, a 100 Hz / 12 dB per octave High-Pass Filter is engaged.
    • Off: Both switches Off allows a full-bandwidth signal to pass

Status Indicators: The front of the module includes 4 Status LEDs for the following:

  • Ready: Will light green when the FM250-4 power module is installed and the F6-MF is powered on.
  • Signal: Will light green when the FM250-4 amp module's output signal produces a minimum 1 watt signal.
  • Limit: If the FM250-4 amp module's function switch is set to Limit, the the LED will light yellow acting as a maximum level indicator. If the amp module's Limit function is off, the LED acts as a Clip indicator. Also, under low impedance loads, the LED serves as a current Limit indicator.
  • Protect: Will light red to indicate a speaker short, too high internal temperature, or too low of a speaker impedance.


  • Output Power, Burst power @ 1 kHz, ultra fast recovery power supply:
    • 8Ω:
      • 1 Channel: 150 Watts
      • 2 Channels: 140 Watts each
      • 6 Channels: 125 Watts each
    • 4Ω:
      • 1 Channel: 300 Watts
      • 2 Channels: 280 Watts each
      • 6 Channels: 250 Watts each
  • Continuous Power @ 1 kHz
    • 8Ω:
      • 1 Channel: 135 Watts
      • 2 Channels: 125 Watts each
      • 6 Channels: 95 Watts each
    • 4Ω:
      • 1 Channel: 270 Watts
      • 2 Channels: 250 Watts each
      • 6 Channels: 170 Watts each
  • Frequency Response: 30 Hz - 20 kHz
  • Signal to Noise Ratio: -90 dB below rated output
  • Dimensions: Width - 1.5", Height - 3.4", Depth - 10.4"
  • Weight: 0.8 lbs.

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