Millennia M-2B Transformerless Vacuum Tube Stereo Microphone Preamplifier - Manual (Page 8)

M-2b

A WORD ABOUT DPA (Brüel & Kjær) MICROPHONES
At present, Danish Pro Audio (formerly Brüel & Kjær Pro Audio Division) manufactures two families
of 4000-series professional recording microphones. One family is +48 VDC phantom powered, the
other is +130 VDC direct powered. A primary difference between families (4003/4 vs. 4006/7) is that
the high voltage microphones are transformer-less whereas the phantom powered varieties are trans-
former coupled. Millennia Media has used both varieties extensively with symphony orchestra, choir,
jazz ensemble, pop recording, and so forth. We have found the transformerless high voltage omni ver-
sion to perform substantially better than its transformer-coupled omni counterpart. The transformerless
version (4003) sounds generally "clearer" and more true to the source; especially during frequency and
amplitude extensions. And this is saying a lot considering that DPA's transformer-coupled microphones
sound extremely pure.
The following is a brief summary of DPA high-voltage microphone products and specifications. Most of
this material is taken directly from DPA's documentation and is thought to be accurate, however, Millennia
Media assumes no responsibility for errors or subsequent changes in the following specifications. Those
desiring up-to-date information concerning DPA microphones should contact DPA directly.
Model 4003 4004 4012
Pattern OMNI OMNI CARDIOID
Self-Noise 15 dB (a) 24 dB (a) 19 dB (a)
SPL (max) 154 dB SPL 168 dB SPL 168 dB SPL
Freq Response 8 Hz - 30 kHz 8 Hz - 45 kHz 35 Hz - 25 kHz
Impedance < 30 ohms < 30 ohms < 30 ohms
Sensitivity 50mV / Pa 10 mV / Pa 9 mV / Pa
A number of options are available for the 4003 microphone. One grid, the 0777, provides superior omni-
directional response throughout the high frequencies. Another grid, the 0297, provides a high frequency
presence boost. The standard grid provides the most accurate response on-axis. A development called
the APE (acoustic pressure equalizer) tailors the 4003 to respond like vintage M-50 or newer TLM-50
microphones. The various APE attachments boost mid to high frequencies arriving on axis without ex-
hibiting proximity effect at lower frequencies. When used with various grids, numerous polar patterns
and response curves can be achieved.
DPA offers a service of factory-matching new pairs of high voltage (+130 VDC) microphones for tight
stereo tracking of sensitivity and frequency response curves. Millennia Media highly recommends this
service and can assist customers in obtaining these microphones. A high voltage microphone preamplifier
upgrade is available for your M-2b at any time. Please call the factory for details.