2669-B 1/2-inch Microphone Preamplifier, cylindrical, LEMO 1B connector, no cable

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.1/2-inch Microphone Preamplifier Type 2669 is a Falcon Range product for making precision acoustic measurements with Brüel & Kjær’s wide range of condenser microphones. You can connect 1/2-inch microphones directly and 1-inch, 1/4-inch and 1/8-inch types using adaptors.

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 technique.

The preamplifier’s low output impedance allows the use of long extension cables without problems.

Product Data

Uses

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

Features

Full electromagnetic compatibility (EMC)
Detachable, thin cable for easy installation
Compact LEMO connector at preamplifier
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
Falcon™ Range product with a three-year guarantee

The low output impedance and high output current capability means that you can use long cables between the preamplifier and your measuring instrument without loss of signal quality. Furthermore, this Falcon™ Range microphone preamplifier comes with an extended guarantee period of three years. It is supplied in an elegant and strong plastic box made from recyclable materials.

EMC Certification

Charge-injection Calibration

Microphones and Sockets

Preamplifier Type 2669 L is delivered with a cable which fits the LEMO preamplifier input socket on new Brüel & Kjær instruments (as well as instruments from Hewlett-Packard and Nortronic). Adaptor ZG 0350 is available for converting it to traditional 7-pin Brüel & Kjær preamplifier sockets. Alternatively, Type 2669 B is available for direct use with traditional Brüel & Kjær instruments. This cable has the same diameter and flexibility, but is equipped with a traditional Brüel & Kjær plug. Both types are fitted with a LEMO 0B connector at the preamplifier.

In contrast the cylindrical Type 2669 C is fitted with a LEMO 1B connector, which means that it can be connected directly to LEMO to LEMO extension cables. Type 2669 C is supplied without a cable.

Power Supply

Detachable Cable (2669 L and B)

Accessories

Characteristics

Small Signal Frequency Response

Large Signal Frequency Response

Noise

Fig. 3 shows typical noise frequency spectra when loading the preamplifier with 6.4 pF and 15 pF microphone capacities. The low noise of the preamplifier ensures that the noise floor for a microphone/preamplifier assembly is determined mainly by the associated microphone over most of the frequency range. The preamplifier can work at temperatures up to 150°C, but reduced specifications for noise and output capability will apply.

More information on preamplifiers and other Falcon™ Range products are...

For a full Description and Specifications, see Product Data