Rens Heijnis                                      custom-built audio equipment

B&K  DPANeumannSchoeps  AKG



Improve the sound of your B&K /DPA microphone by retrofitting and separated power supply.

When you are not satisfied with the sound of your microphone: too sharp, strident, thin, lacking vibrancy
or anything else, it is possible to retrofit your microphone with better electronics to improve the sound.
Retrofitting is possible for nearly all B&K/DPA condenser microphones
such as 4003 4004 4006 4006A
4011 4011A 4041.
After retrofitting your microphone has a smoother sound, less sharp and strident, more vibrancy.
At the former
microphones page you can read the theory about retrofitting:

DPA also use the inferior sounding SMD printed circuit boards in his modern microphones.

A retrofitted microphone has a new printed circuit board with trough-hole components.
All the components are selected for there proven sound quality.


Mains power supply for active powered B&K /DPA microphones

No phantom power is used so an external power supply is necessary.

Technical Specifications PS-402
Number of channels: 2
Input: 4-pin XLR female connector
Output: 3-pin XLR male connector
Power requirements: 105-120V and 210-240V, 50 to 60 Hz
Power consumption max: 3W
Weight: 1 kg
Dimensions: 108mm Χ 165mm Χ 52mm (4.3” x 6.5” x 2.1”)


The microphone Cable for active powered microphones

A special microphone cable is necessary between the microphone and power supply.
The standard microphone cable is a Mogami starquad cable:
Mogami 2534
For the +60V norm it is supplied with 4 pin XLR connectors.
Every cable length is available.
The output of the power supply is a normal 3 pin XLR.

For microphone cables with an other sound than the Mogami see: Microphone Cables


Retrofitted DPA4041 with active power

DPA4041 phantom, modified to active powered.
2 channel power supply with 60V and 200V capsule voltage (with 5pin XLR).
With Black Gate capacitor and other components selected for there sound quality.

Retrofitted DPA4041SP with battery powered power supply


DPA4041SP phantom, retrofitted to active power with battery power.
With Black Gate capacitor and other components selected for there sound quality.

Technical Specifications power supply
Number of channels: 3 
Input: 6-pin XLR female connector. (not the modified DPA 7 pin XLR)

Output: 3-pin XLR male connector
Maximum operating time fully charged Li-ION batteries: 70 Hours
Power requirements: 90-264V, 50/60Hz
Dimensions: 255mm Χ 135mm Χ 70mm (10” x 5.3” x 2.7”)


Retrofitted B&K4006 with active power

B&K4006 (20years old) phantom modified to active powered.
Reference from the customer:
They are now flatter throughout the upper register, less strident, without the annoying dip
in the 10-12k range they had before. The bottom octave is slightly extended and improved.
Off axis response is noticeably better, and they seem faster - more 'bounce' in the meters.
Imaging is also more accurate now


Pre-amplifier and power supply for B&K /DPA 120V microphones, replacement for B&K 2812


Pre-amplifier for B&K/DPA 120V microphones

Technical Specifications
Number of channels: 2
Gain: 0, 6, 12, 18 or 24dB
Input: 4-pin modified XLR female connector.
Maximum recommended cables length microphone-power supply: 10m unbalanced.
Output: 3-pin XLR male connector
Power supply pin 3: 120V
Power requirements: 210-240V, 50Hz
Weight: 1,5 kg
Dimensions: 170mm Χ 60mm Χ 170mm (6.7” x 2.4” x 6.7”)
Price: 900 euro

Power Supply for B&K /DPA 120V microphones

For connecting B&K/DPA 130V microphones on an external pre-amplifier.

Technical Specifications
Number of channels: 2
Input: 4-pin modified XLR female connector.
Maximum recommended cables length microphone-power supply: 10m unbalanced.
Output: 3-pin XLR male connector
Maximum recommended cables length power supply-preamplifier: 30m balanced.
Power supply: 120V
Power requirements: 105-120V and 210-240V, 50 to 60 Hz
Power consumption max: 3W
Weight: 1 kg
Dimensions: 108mm Χ 165mm Χ 52mm (4.3” x 6.5” x 2.1”)


Battery powered pre-amplifier for active powered B&K /DPA microphones

Sonodore MPB-502


Pre-amplifier for standard B&K /DPA Microdot and active powered B&K /DPA microphones

Special light weight (2,9kg) 3 channel pre-amplifier with Lithium ion batteries and the latest developments in improved
sound quality.
With DPA MircoDot (4060serie) and active (6pin) microphone input. With battery power for the microphones.
Recording time 34 hours with active microphones, 43 hours with only DPA MicroDot.
Back view


Pre-amplifier for standard (not retrofitted) B&K /DPA 4041tube and 120V models

2 Channel pre-amplifier for DPA, B&K4041Tube and all 120V models. For replacement of the HMA4000/5000.
With a special battery stabilized power supply. With the latest developments
in improved sound quality.


Reference on the retrofitted B&K4006 microphone with an active 60V PCB. 

Joseph Scott California:

The first thing I noticed is that the phase is completely different, and that I might need to spend some time learning how
to place my microphones all over again. I record a lot of solo acoustic guitar, from a distance of almost one meter away
from the chair in a fairly live room.
With the original microphone PCB I have come to settle on a rather unconventional closely spaced pair, with the bodies
parallel to each other, at a distance of about 5.75 inches (14.6cm) from each other as a compromise of tonal balance
and stereo image. I have a feeling that the differences I am hearing in the tonal and phase accuracy of the new PCBs
that I will be able separate the microphones a bit more and settle for much less compromises!

Tonally, the microphones are quite different. I hear a lot more detail in the low frequencies, and clarity in the high
frequencies with the new PCB. The mid range frequencies are where the biggest tonal benefit that I've noticed is;
before the mid-range sound seemed to always be a bit exaggerated and fatiguing in comparison to everything
else - and now it's much clearer and feels right.

I've also noticed that the image is robust. Let me explain. With the original PCB, the image with few notes played on the
guitar would usually be pretty stable. When playing a complicated guitar part (solo fingerstyle acoustic) the image would
become much less clear, to the point one would have to sometimes struggle to hear where all the notes are coming from.
Now I hear the image to be very stable and easy to "see" no matter how many notes or sounds are coming from the guitar.

Also, the transient response feels much better timed to the note which it supports. A pluck or hit of a sting results in a much
better connected sound as picked up by the microphone. I suppose many people would say the microphone is "faster".
To me, it sounds like the microphone is simply reproducing all frequencies within a very similar time delta (and perhaps
before, the phase of the higher frequencies was slightly different than that of the other frequencies - causing a smearing
disconnect). The result is a much clearer recording, much more open and natural.

To be fair, the PCBs are not the only thing that has changed in my system. With the new active power scheme I was able
to remove the dc blocking transformer. In the past I had experimented with DC blocking transformers and different
capacitors and settled on a custom transformer as the best compromise. With the new PCB I am using a single
1.5uf Vcap TFTF .

I also notice quite a bit more output (maybe 4 to 6dB) from the new PCBs.

Steven Wielink Netherlands:
We are very satisfied with the modified version of the B&K4006.
It gives a fantastic open and very lifelike imagery.
The bass is
very clean and goes very deep without being predominate.

Steven Cahen
I have used the L&R mics of the „new“ 4006 as an AB, and they sound absolutely stunning.
I can't believe the low end sharpness and response, totally awesome!