Bruel & kjaer b&k 2669 microphone preamplifier

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Bruel & kjaer b&k 2669 microphone preamplifier - tested

This is a Br el & Kj r 2669 Microphone Preamplifier.This B&K's standard Type 1 microphone pre-amplifier and can be used with any of their " measurement microphones which require requires 200V polarisation like the 4190 and 4191 as well as older microphones such as 4165. It can also be used wirth 1", " and " microphones with the appropriate adapter.
This is a current B&K model and the datasheet can be found at (B&K requires you to register now to download but it's free):
http:// /doc/bp1422.pdf
An extract of the key features is given below:
1/2" Microphone Preamplifier Type 2669 is a Falcon Range product for making precision acoustic measurements with Br el & Kj r s wide range of condenser microphones. You can connect 1/2" microphones directly and 1", 1/4" and 1/8" types using adaptors. The preamplifier, cable and its connectors all fulfil EMC requirements. You can verify the condition of the microphone, preamplifier and cable onsite using its patented charge-injection calibration technique. The preamplifier s low output impedance allows the use of long extension cables without problems.
* Sound measurements with Br el& Kj r 1/2" (1", 1/4" and 1/8" with adaptor) and compatible microphones
* General-purpose preamplifier and high-impedance input probe for Br el & Kj r measuring instruments
* 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
* Very low inherent noise, high input impedance
* Low output impedance and high output current allows use with long extension cables
* Wide working temperature range
* FREQUENCY RESPONSE (re 1 kHz): 3Hz to 200kHz, 0.5 dB.
* ATTENUATION: 0.35 dB (max.)
* PHASE MATCHING: 0.3 at 50Hz
* INPUT IMPEDANCE: 15GW || 0.45 pF
* OUTPUT IMPEDANCE: 25 W (max.)
* CONNECTOR TYPE: LEMO type FGJ.OB.307 at preamp. (2669 L & B), LEMO type FGG.1B.307 (2669 L), or Br el &
* Kj r JP0715 (2669 B) to measuring device, LEMO type FWG.1B.307 at preamp. (2669 C)
* MAX. OUTPUT VOLTAGE: Maximum output voltage Vp-p is equal to total supply voltage minus 10 V
* DISTORTION (THD): Less than 80 dB at 25 V out, 1 kHz
8.2 mV Lin. 20Hz 300 kHz, 10.0 mV Lin. 20Hz 300 kHz (max.), 1.9 mV A weighted, 2.2 mV A weighted (max.)
* POWER SUPPLY, DUAL: 14 V to 60 V
* POWER SUPPLY, SINGLE: 28 V to 120 V
1 V for a dual supply, or 1/2 the voltage of a single supply
This preamplifier is used but in excellent condition. The threads and the 7-pin connector are in perfect condition in fact there's nothing more than surface scuffing on the entire unit and it looks almost new.
I did a calibration measurement with my 94dB calibrator and one of my calibrated microphones (a 4191). As you can see the calibration came out almost exactly at 94dB and the small difference is more likely to be from my aged 4130 than from the preamp.