Rens Heijnis                                      custom-built audio equipment

Battery powered (tube) microphones

After having very good results with audio electronics on rechargeable batteries,
I made a power supply for microphones, with  rechargeable batteries.
This power supply can be used for all kinds of microphones and tube microphones such as:
AKG, B&K, Brauner, Groove tube, Neumann, Royer, Sanken, Schoeps and Sonodore.

The sonic improvements due to battery powering (no dirty main power) are: 

• more robustness in the low frequencies
• more softness in the high frequencies
• faster reaction time
• an overall a much more realistic and pleasant sound

Battery power for Sonodore RCM-402HP, +60V microphones and Neumann tube microphones

                 

Battery power for Brauner, Groove tube, Neumann and Royer microphones .
The original power supply of the microphone has to be modified with a switch (internal-external power) and a connector
for connecting with the battery powered supply. The original power supply will be used for the heater voltage and output transformer.
In order to reach 180V you need 14 batteries of 12V. Depending on the type of microphone you can use the batteries 1 to 4 days
before you need to recharge them.

48V Phantom power: battery powered. In 19" enclosure, 8 channel, with good audio capacitors.
Recording time about 28 hours with 8 microphones consuming 5mA.

Separated main power supply for microphones:
better powering and printed circuit board for all phantom microphones

Phantom-fed microphones are inherently less suitable for high-quality audio usage since they work as compressors: when, for
instance, high dynamics are required, strong demands are made on the current supply of the phantom. As a result, the current supply
drops drastically and the stereo image and frequency response collapse with it.
To avoid this, I can make a new printed-circuit board for microphones such as AKG, B&K, Neumann, Schoeps, Sanken and
Sennheiser with an external power supply.

The sonic improvements are:

• clearer placement of musical instruments within the stereo sound field
• exceptionally fast reaction time to intermittent high impulse sound waves
• extreme clarity and definition of complex low frequency sounds
• measurably less distortion across the entire sound spectrum

In the block diagrams you can clearly see the difference.

  
Phantom power (power and audio together)                     Active +60V power (power separated from the audio)

A few examples of active powered microphones

New printed-circuit board (price: 295 euro).

A few examples of different power supplies(+60V) for active microphones

      

8 channel stage box with 8 power supplies                                   12 channel stage box (price: 1670 euro).
For powering of microphones on the stage. With Socapex connector for multi-cables.
Can be supplied with battery power.

12 channel active power supply (+60V) for active powered microphones:

12 channel active power supply (price: 1850 euro).

A few examples of modifications to microphones:

B&K4041 phantom modified to active powered.
2 channel power supply with 60V and 200V capsule voltage.
With Black Gate capacitor and other components selected for there sound quality.

Modified Neumann UM57 microphone: the original sound was sluggish, dull and to little low frequencies.
After changing some capacitors, the microphone is now fuller, more responsive and a more richer sound.

Modified Groove Tube microphone: the anode voltage of the tube is now adjustable.
The sound is changed from sluggish to responsive