Phoenix A404 4 Channel EEG Amplifier/Encoder


Acclaimed for its accuracy and reliabilty in 4-channel neurofeedback work, this amp continues to grow in popularity.

EEGer users who want to do 4-channel training will need a 4-channel keyfile enable. A $50.00 value, it is included with the purchase of this amplifier.

  • Highest-quality EEG amplifier/encoder for neurofeedback applications.
  • Five-year manufacturer's warranty.
  • Includes built-in impedance-checking circuitry, usable within EEGer.
  • Renowned customer service and technical support.


  1. Channels: 4 EEG channels + 3 Auxiliary channels (0 to +2.0 volts dc)
  2. Input Impedance: > 5 Meg Ohms differential at the electrode jacks
    > 100 Gig Ohms at the amplifier inputs
  3. CMR: > 100 dB
  4. Noise: < 1.0 uV p-p referred to input
  5. Preamp Gain: Software Selectable: 50, 100, 500 microvolts p-p full scale
  6. Anti-Alias Filter: 4th Order Butterworth at 55Hz
  7. Bandpass: 0.5 Hz to 55 Hz
  8. Notch Filter: > 50dB rejection at 60Hz / 50Hz or Notch OFF
  9. Impedance Test: An electrode test command is sent under software control to produce a simultaneous test of all electrodes.
  10. Calibration: An internal calibration system is based on a crystal controlled DDS (direct digital synthesizer) with amplitude adjustment. Under software control, the calibrator can generate any frequency from 000.01 Hz up to 999.99 Hz with an accuracy of +/- .002 Hz. Amplitudes from 0 up to 100 microvolts may be selected.
  11. A2D Resolution: 16 bits
  12. Sample Rate: 256 samples/sec.
  13. Aux Inputs: The Alpha400 amplifier provides three AUX input channels. Inputs to these channels must be isolated from the patient. Input voltage is: 0.0VDC to 2.50VDC.
  14. Computer Interface: Isolated USB
  15. Power: All Alpha400 power is derived directly from the USB cable.
  16. Isolation: Medical grade digital isolation per UL 1577 Component Recognition Program.

Each isolator is fully tested with 3000V rms for 1 second, and 2500V rms for 1 minute. Internal isolated dc-dc converter rated at 6000 VAC isolation.

EEG Product: