Microphone Preamplifiers

2669-L 1/2-Inch Microphone Preamplifier

2669-L 1/2-Inch Microphone Preamplifier

This ½” microphone preamplifier operates over a wide range of temperature, humidity and other environmental conditions.


  • Sound measurements with Brüel & Kjær 1/2″ (1″, 1/4″ and 1/8″ with adaptor) and compatible microphones
  • General-purpose preamplifier and high-impedance input probe for Brüel & Kjær measuring instruments


  • The preamplifier, cable and its connectors all fulfil electromagnetic compatibility (EMC) requirements
  • Compact LEMO connector at preamplifier. Connector: lemo 0B 7 pin & lemo 0B to lemo 1B
  • Patented charge-injection calibration technique for on-site calibration of the whole measuring channel including the microphone
  • Wide dynamic range
  • Very low inherent noise, high input impedance
  • Low output impedance and high output current allows use with long extension cables
  • Wide working temperature range

The preamplifier has a very high input impedance presenting virtually no load to the microphone. The high output voltage together with an extremely low inherent noise level gives a wide dynamic range. The preamplifier’s low output impedance allows the use of long extension cables without problems. You can connect ½” microphones directly and 1″, ¼” and 1/8″ types using adaptors.

You can verify the condition of the microphone, preamplifier and cable on-site using its patented charge injection calibration technique.


Diameter: 1/2
Optimised for: Acoustical
Connector at preamplifier: LEMO 0B, 7-pin
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: 3 to 200000
Attenuation: < 0.35
Noise A-weighted, typical: 1.9
Noise 22,4 Hz to 300 kHz, typical: 8.2
Input impedance: 15||0.3
TEDS UTID: 1025 from serial number 2221155