MA411 1/4" Preamplifier

MA411A/B is 1/4" ICCP power supply preamplifier developed by BSWA, which is suitable for MP series 1/4" pre-polarized microphones. It is a low-noise and high-quality preamplifier that can be used in a variety of acoustic applications. MA411A is SMB connector and MA411B is 10-32 connector.

The main function of the preamplifier is impedance change, since the output impedance of the microphone is above GΩ, it cannot be directly connected to the common data acquisition equipment. The high input impedance and low output impedance of the preamplifier can reduce the output impedance of the microphone to less than 100 Ω.

MA411A/B does not provide polarization voltage, so it is only applicable to pre-polarized microphone. The power supply mode named ICCP (Integrated constant current power) can operate on a constant current power supply and give output signals in the form of voltage modulation on the coaxial cable. This kind of power supply mode can keep a very low signal attenuation even using a long cable. The MC1xx series power supply conditioner is required.

MA411A/B can choose to supply with TEDS to support read microphone information directly by data acquisition equipment, including microphone model, serial number, sensitivity, etc. BSWA TEDS microphone supports the IEEE 1451.4 standard. The version of 0.9 is used by default to be compatible with more data acquisition equipment. The version of 1.0 can also be selected according to user’s requirements.


  Suitable for 1/4" pre-polarized microphone

  ICCP power supply preamplifier

  Frequency response: 2.5 Hz ~ 100 kHz (±0.2 dB)

  Attenuation: 0.3 dB (typ.)

  Connector: SMB (MA411A) or 10-32 (MA411B)

  Optional TEDS (IEEE.1451.4)


  Common acoustic measurement

  Environmental, industrial, traffic and other acoustic measurement


Type MA411A MA411B
Diameter 1/4"
Polarization Voltage Support 0V (Prepolarized)
Frequency Response (Hz) (±0.2 dB) 2.5 ~ 100 k
Attenuation (dB) 0.3 (typ.)
Maximum Output Voltage (Vp) ±8
Self-generated Noise A-weighted <3 μV (2.5 μV typ.)
20 Hz ~ 20 kHz <10 μV (6 μV typ.)
Input Impedance (GΩ ǁ pF) 15 ǁ 0.4
Output Impedance (Ω) <30
Power Supply ICCP (2mA ~ 20mA, 4mA typ.)
DC Bias Voltage (V) 12±2
Operating Temperature Range (°C) -20 ~ 60
Operating Humidity Range (%RH) 0 ~ 95
Dimensions (mm) Ø7 × 55 Ø7 × 50
Mounting Thread for Microphone Ø5.7-60 UNS-2A
Output Connector SMB 10-32
Weight (g) 5.8 5.3
TEDS Optional, IEEE 1451.4 compliant (default v0.9, optional v1.0)

  Note: Unless specified otherwise, all values are measured at 23 °C, 101.3 kPa, 50 %RH, with 3 m coaxial cable, 4 mA / 24 V power supply and microphone capacitance of 15 pF.

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