Microphone Preamplifiers

2670 1/4-Inch Microphone Preamplifier

2670 1/4-Inch Microphone Preamplifier

The preamplifier Type 2670 is very compact and operates over a wide range of temperature, humidity and other environmental conditions.


  • Sound measurements with 1/4- and 1/8-inch Brüel & Kjær and other compatible microphones
  • Sound intensity probes


  • Full electromagnetic compatibility (EMC)
  • LEMO connector for instrument input socket
  • Wide dynamic range
  • Very low inherent noise, high input impedance
  • Low output impedance and high output current allow use with long extension cables
  • Wide working temperature range
  • Excellent phase linearity

The high distortion limit together with an extremely low inherent noise level gives a wide dynamic range. You can connect ¼” microphones directly and 1/8-inch types using an adaptor. The preamplifier, cable and its connectors all fulfil EMC requirements. You can verify the condition of the microphone, preamplifier and cable on-site using its patented charge injection calibration (CIC) technique.

The low output impedance and high output current capability mean that you can use long cables between the preamplifier and your measuring instrument without loss of signal quality.


Diameter: 1/4
Optimised for: Phase
Connector at preamplifier: Fixed (2 m)
Connector at instrument/cable: LEMO 1B, 7-pin
Calibration facility: Charge Injection Calibration
Polarization voltage support: Yes
Supply voltage: ± 14 to ± 60
Max output voltage (peak): 55
Max output current (peak): 20
Frequency range: 15 to 200000
Attenuation: <0.4
Noise A-weighted, typical: 4
Noise 22,4 Hz to 300 kHz, typical: 14
Input impedance: 15||0.25
TEDS UTID: 1025 from serial number 2248944