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AtlasIED CP400

Power amplifier — 200W x 2 at 70V

Item # 978CP400

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About the AtlasIED CP400

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Atlas Sound designed the CP400 professional-grade power amplifier specifically for demanding contractor applications. The CP400 features toroidal power supply and output transformers which offer exceptional reliability as well as extended frequency response. These high-quality transformers also offer the extra safety of true transformer output isolation, a feature not often found in this price range.

The CP400's two independent channels ensure maximum channel separation and ultra-low distortion while providing years of service. Whether your application is a large distributed constant voltage system or a high SPL sound reinforcement system, the CP400 is the perfect answer for your amplification needs.

For more information, check the owner's manual in the Details tab. See what our satisfied customers have to say.

General features:

  • 25V, 70.7V, 100V, and direct coupled (2, 4, and 8 ohm) outputs
  • balanced inputs on barrier strip and XLR connectors
  • loop-through feature on male XLRs, one per channel input
  • short-circuit, temperature, and DC offset protection
  • variable-speed fan
  • soft clip limiter protection
  • stereo, bridge, or parallel operating modes selectable via rear mounted switch
  • toroidal output transformers provide full electrical isolation and meet worldwide safety agency approval
  • connector type: terminal block and XLR
  • 70.7 volts stereo: 200 watts x 2
  • 25V stereo: 175 watts x 2
  • 140 volts/200 volts bridged mono: 400 watts
  • direct power output:
    • 8 ohm stereo: 160 watts x 2
    • 4 ohm stereo: 240 watts x 2
  • dimensions: 18-15/16"W x 5-3/16"H x 16-7/8"D
  • warranty: 3 years
  • Our 60-day money-back guarantee
  • MFR # CP400

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More details on the AtlasIED CP400

Russ B.

Product Research


Overview: The Atlas Sound CP400 is a high-performance 2-channel power amplifier. This rack-mountable amp features balanced inputs (XLR and barrier strip terminals) and outputs for 25V, 70V and 100V transformer speaker systems, or direct-connect 8Ω, 4Ω, 2Ω, 8Ω bridged, and 4Ω bridged speaker loads. The amplifier has a built-in two-speed fan to keep the internal circuitry cool during operation for years of reliable service.

Uses: The CP400 amplifier is ideal for distributed paging/background music systems, foreground music systems, and distributed sound masking applications. You can also use them in night clubs, theaters, and portable sound systems.

Toroidal Transformers: The professional-grade CP400 amplifier is built with esoteric-grade toroidal power supply and output transformers. These transformers are extremely reliable, and provide extended frequency response. Each channel is driven with a separate power supply to ensure maximum channel separation and ultra-low distortion levels.

Front Panel: The front panel of the amplifier features a rocker-style power switch, and separate LED indicators for each channel. Each channel has the following LED indicators on the front panel:

  • Protect: LED glows yellow when the amplifier (or particular channel) has gone into Protect mode to safeguard the amplifier. (See below for the different types of protection).
  • Limit: LED lights red when the internal limiter circuitry is activated. An occasional flash of the LED is acceptable for peak level indication. If the LED glows solid, the limiter circuitry is being engaged constantly, indicating the input level should be turned down.
  • Signal Status: LED glows green to indicate the presence of an input signal at -26dBV or higher.

Rear Panel: The CP400's rear panel features the following connections and controls:

  • Amplifier Inputs: Female XLR balanced inputs (one per channel) are provided for systems where quick connect and disconnect is needed. For permanent installations, barrier strip terminals are provided (+ and - for each channel plus a Ground terminal for both channels).
  • Loop Through: Male XLR connectors are provided for each channel for looping the input signals to other devices. They are wired in parallel with the female XLR inputs.
  • Gain Controls: Independent gain controls for each channel are provided. These rotary controls are stepped, and increase/decrease the sensitivity by 2dB per step (30 total steps). Maximum voltage gain is 32dB.
  • Mode Switch: A 3-position switch lets you change the operating mode of the amplifier to one of the following:
    • Stereo: The amp operates as two independent amplifiers--for stereo program material or for two discreet paging or sound masking zones.
    • Parallel: The amp powers two channels from a single mono input signal. You can connect the source to either channel 1 or channel 2 input. A 6 dB loss of output power occurs in this mode, unless jumper wires are applied between the two positive and two negative terminals.
    • Bridge: The input is connected to channel 1 only, and the speaker load is connected across the two positive terminals. The amplifier will deliver approximately twice the voltage across the load. Amplifier is bridgeable to 8Ω or 4Ω loads.
  • Direct Speaker Terminals: Low impedance barrier strip speaker terminals are provided for each channel. The amplifier will drive 2Ω, 4Ω, and 8Ω loads. Use of appropriately-sized spade lugs is recommended.
  • Constant Voltage Speaker Terminals: The amplifier is designed to drive constant voltage speaker loads for use in commercial business music and paging systems and sound masking systems. Terminals for 0 (common), 70V, and 100V are provided. (Wiring diagrams for 25V, 70.7V and 100V systems are provided in the Owner's Manual.) Use of appropriately-sized spade lugs is recommended.

Protection Circuitry: The CP400 features three types of protection circuitry to safeguard the amplifier during power-up and fault conditions. If the front panel Protect LED illuminates, the amplifier has gone into protection mode, and the output relays disconnect the speaker loads. The types of protection modes include:

  • Loudspeaker (Power Up Muting): When power is first applied, the speaker protection relay is open to prevent transients ("thumps") from reaching the loudspeakers. After the internal circuits have stabilized, the relay closes, connecting the amplifier output to the load.
  • Thermal: The amplifier constantly monitors itself for excessive internal operating temperatures. If, because of fan failure or high ambient temperatures, the circuitry detects abnormal thermal conditions, the speaker relay will disconnect the speaker load from the amplifier. Once the internal temperature drops to a safe level, the relay will close and reconnect the amp's output to the speaker load.
  • Short Circuit: If the amplifier's protection circuitry should detect a short circuit on the attached speaker load, or if the load impedance is too low, the speaker relay will disconnect the speaker load from the amplifier. Once the short circuit fault is remedied, the relay will close and reconnect the amp's output to the speaker load.


  • Direct Output Power:
    • 160 Watts x 2 at 8Ω (1 kHz, 0.1% THD)
    • 240 Watts x 2 at 4Ω (1 kHz, 0.1% THD)
    • 270 Watts x 2 at 2Ω (1 kHz, 0.1% THD)
    • 500 Watts x 1 Bridged Mono at 8Ω (1 kHz, 1% THD)
    • 600 Watts x 1 Bridged Mono at 4Ω (1 kHz, 1% THD)
  • Transformer Outputs:
    • 175 Watts at 25V
    • 200 Watts at 70.7V
    • 200 Watts at 100V
    • 400 Watts at 140V Bridged
    • 400 Watts at 200V Bridged
  • Frequency Response:
    • Direct Outputs: 30Hz - 50kHz (±3dB)
    • Transformer Outputs: 30Hz - 16kHz (±3dB)
  • THD+N: <0.05% (8Ω, 1 kHz, 240 Watts per channel)
  • Signal-to-Noise Ratio: >100dB (8Ω at 240 Watts per channel)
  • Power Consumption:
    • Idle: 38 watts
    • Average Power (audio signal, 1/3 power): 291 watts
    • Max Power (audio signal, peak): 876 watts
  • Dimensions: Width: 18.9" Height: 5.19" Depth: 16.85"
  • Weight: 44.5 pounds

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